title: Breadfruit content: human migration throughout the Pacific, scientists have used molecular dating of breadfruit hybrids and cultivars in concert with anthropological data. Results support the west-to-east migration hypothesis, in which the Lapita people are thought to have traveled from Melanesia to numerous Polynesian islands. The world's largest collection of breadfruit varieties was established by botanist Diane Ragone, from over 20 years' travel to 50 Pacific islands, on a plot outside of Hana, on the isolated east coast of Maui (Hawaii). Breadfruit Breadfruit ("Artocarpus altilis") is a species of flowering tree in the mulberry and jackfruit family (Moraceae) originating in the South Pacific


title: Stingray content: Stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwater stingray), Urolophidae (stingarees), Urotrygonidae (round rays), Dasyatidae (whiptail stingrays), Potamotrygonidae (river stingrays), Gymnuridae (butterfly rays), and Myliobatidae (eagle rays). Stingrays are common in coastal tropical and subtropical marine waters throughout the world. Some species, such as "Dasyatis thetidis", are found in warmer temperate oceans, and others, such as "Plesiobatis daviesi", are found in the deep ocean. The river stingrays, and a number of whiptail


title: Stingray content: stingrays (such as the Niger stingray), are restricted to fresh water. Most myliobatoids are demersal (inhabiting the next-to-lowest zone in the water column), but some, such as the pelagic stingray and the eagle rays, are pelagic. There are about 220 known stingray species organized into 10 families and 29 genera. Stingray species are progressively becoming threatened or vulnerable to extinction, particularly as the consequence of unregulated fishing. As of 2013, 45 species have been listed as vulnerable or endangered by the IUCN. The status of some other species is poorly known, leading to their being listed as data deficient. The


title: Stingray content: mouth of the stingray is located on the ventral side of the vertebrate. Stringrays exhibit euhyostyly jaw suspension, which means that the mandibular arch is only suspended by an articulation with the hyomandibula. This type of suspensions allows for the upper jaw to have high mobility and protrude outward. The teeth are modified placoid scales that are regularly shedded and replaced. In general, the teeth have a root implanted within the connective tissue and a visible portion of the tooth, is large and flat, allowing them to crush the bodies of hard shelled prey. Male stingrays display sexual dimorphism by


title: Stingray content: developing cusp, or pointed ends, to some of their teeth. During mating season, some stingray species fully change their tooth morphology which then returns to baseline during non-mating seasons. Stingrays can breathe through their spiracles, which are openings just behind their eyes. The respiratory system of stingrays is complicated by having two separate ways to take in water to utilize the oxygen. Most of the time stingrays take in water using their mouth and then send the water through the gills for gas exchange. This is efficient, but the mouth cannot be used when hunting because the stingrays bury themselves


title: Stingray content: in the ocean sediment and wait for prey to swim by. So the stingray switches to using its spiracles. With the spiracles, they can draw water free from sediment directly into their gills for gas exchange. These alternate ventilation organs are less efficient than the mouth, since spiracles are unable to pull the same volume of water. However, it is enough when the stingray is quietly waiting to ambush its prey. The flattened bodies of stingrays allow them to effectively conceal themselves in their environments. Stingrays do this by agitating the sand and hiding beneath it. Because their eyes are


title: Stingray content: on top of their bodies and their mouths on the undersides, stingrays cannot see their prey after capture; instead, they use smell and electroreceptors (ampullae of Lorenzini) similar to those of sharks. Stingrays settle on the bottom while feeding, often leaving only their eyes and tails visible. Coral reefs are favorite feeding grounds and are usually shared with sharks during high tide. During the breeding season, males of various stingray species such as "Urolophus halleri", may rely on their ampullae of Lorenzini to sense certain electrical signals given off by mature females before potential copulation. When a male is courting


title: Stingray content: a female, he follows her closely, biting at her pectoral disc. He then places one of his two claspers into her valve. Reproductive ray behaviors are associated with their behavioral endocrinology, for example, in species such as "Dasyatis sabina", social groups are formed first, then the sexes display complex courtship behaviors that end in pair copulation which is similar to the species "Urolophus halleri." Furthermore, their mating period is one of the longest recorded in elasmobranch fish. Individuals are known to mate for 7 months before the females ovulate in March. During this time, the male stingrays experience increased levels


title: Stingray content: of androgen hormones which has been linked to its prolonged mating periods. The behavior expressed among males and females during specific parts of this period involves aggressive social interactions. Frequently, the males trail females with their snout near the female vent then proceed to bite the female on her fins and her body. Although this mating behavior is similar to the species "Urolophus halleri", differences can be seen in the particular actions of "Dasyatis sabina". Seasonal elevated levels of serum androgens coincide with the expressed aggressive behavior, which led to the proposal that androgen steroids start, indorse, and maintain aggressive


title: Stingray content: sexual behaviors in the male rays for this species which drives the prolonged mating season. Similarly, concise elevations of serum androgens in females has been connected to increased aggression and improvement in mate choice. When their androgen steroid levels are elevated, they are able to improve their mate choice by quickly fleeing from tenacious males when undergoing ovulation succeeding impregnation. This ability affects the paternity of their offspring by refusing less qualified mates. Stingrays are ovoviviparous, bearing live young in "litters" of five to 13. During this period, the female’s behavior transitions to support of her future offspring. Females hold


title: Stingray content: the embryos in the womb without a placenta. Instead, the embryos absorb nutrients from a yolk sac, and after the sac is depleted, the mother provides uterine "milk". After birth, the mothers typically protect their young until they physically mature, which can take about 3 years. This process ensures the survival of their young until they learn how to camouflage themselves in the sand through burial to where only the eyes and spiracles can be seen. At the Sea Life London Aquarium, two female stingrays have delivered seven baby stingrays, although the mothers have not been near a male for


title: Stingray content: two years. This suggests some species of rays can store sperm then give birth when they deem conditions to be suitable. The stingray uses its paired pectoral fins for moving about. This is in contrast to sharks and most other fishes, which get most of their swimming power from a single caudal (tail) fin. Stingray pectoral fin locomotion can be divided into two categories: undulatory and oscillatory. Stingrays who use undulatory locomotion have shorter thicker fins for slower motile movements in benthic areas. Longer thinner pectoral fins make for faster speeds in oscillation mobility in pelagic zones. Visually distinguishable oscillation


title: Stingray content: has less than one wave going, opposed to undulation having more than one wave at all times. Stingrays employ a wide range of feeding strategies. Some have specialized jaws that allow them to crush hard mollusk shells, whereas others use external mouth structures called cephalic lobes to guide plankton into their oral cavity. Benthic stingrays (those that reside on the sea floor) are ambush hunters. They wait until prey comes near, then use a strategy called "tenting". With pectoral fins pressed against the substrate, the ray will raise its head, generating a suction force that pulls the prey underneath the


title: Stingray content: body. This form of whole-body suction is analogous to the buccal suction feeding performed by ray-finned fish. Stingrays exhibit a wide range of colors and patterns on their dorsal surface that to help them camouflage with the sandy bottom. Some stingrays can even change color over the course of several days to adjust to new habitats. Since their mouths are on the side of their bodies, they catch their prey, then crush and eat with their powerful jaws.Like its shark relatives, the stingray is outfitted with electrical sensors called ampullae of Lorenzini. Located around the stingray's mouth, these organs sense


title: Stingray content: the natural electrical charges of potential prey. Many rays have jaw teeth to enable them to crush mollusks such as clams, oysters, and mussels. Most stingrays feed primarily on mollusks, crustaceans, and occasionally on small fish. Freshwater stingrays in the amazon feed on insects and break down their tough exoskeletons with mammal-like chewing motions. Large pelagic rays like the Manta use ram feeding to consume vast quantities of plankton and have been seen swimming in acrobatic patterns through plankton patches. Stingrays are not usually aggressive and attack humans only when provoked, such as if a ray is accidentally stepped on.


title: Stingray content: Contact with the stinger causes local trauma (from the cut itself), pain, swelling, muscle cramps from the venom, and later may result in infection from bacteria or fungi. The injury is very painful, but seldom life-threatening unless the stinger pierces a vital area. The barb usually breaks off in the wound, and surgery may be required to remove the fragments. Fatal stings are very rare. The death of Steve Irwin in 2006 was only the second recorded in Australian waters since 1945. The stinger penetrated his thoracic wall, causing massive trauma. The venom of the stingray has been relatively unstudied


title: Stingray content: due to the mixture of venomous tissue secretions cells and mucous membrane cell products that occurs upon secretion from the spinal blade. Stingrays can have anywhere between 1-3 blades. The spine is covered with the epidermal skin layer. During secretion, the venom punctures through the epidermis and mixes with the mucus to release the venom on its victim. Typically, other venomous organisms create and store their venom in a gland. The stingray is notable in that it stores its venom within tissue cells. The toxins that have been confirmed to be within the venom are cystatins, peroxiredoxin, and galectin. Galectin


title: Stingray content: induces cell death in its victims and cystatins inhibit defense enzymes. In humans, these toxins lead to increased blood flow in the superficial capillaries and cell death. Despite the number of cells and toxins that are within the stingray, there is little relative energy required to produce and store the venom. The venom is produced and stored in the secretory cells of the vertebral column at the mid-distal region. These secretory cells are housed within the ventrolateral grooves of the spine. The cells of both marine and freshwater stingrays are round and contain a great amount of granule-filled cytoplasm. The


title: Stingray content: cells of marine stingrays are located only within these lateral grooves of the stinger. The cells of freshwater stingray branch out beyond the lateral grooves to cover a larger surface area along the entire blade. Due to this large area and an increased number of proteins within the cells, the venom of freshwater stingrays has a greater toxicity than that of marine stingrays. Rays are edible, and may be caught as food using fishing lines or spears. Stingray recipes abound throughout the world, with dried forms of the wings being most common. For example, in Malaysia and Singapore, stingray is


title: Stingray content: commonly grilled over charcoal, then served with spicy "sambal" sauce, or soy sauce. Generally, the most prized parts of the stingray are the wings, the "cheek" (the area surrounding the eyes), and the liver. The rest of the ray is considered too rubbery to have any culinary uses. While not independently valuable as a food source, the stingray's capacity to damage shell fishing grounds can lead to bounties being placed on their removal. Stingrays are usually very docile and curious, their usual reaction being to flee any disturbance, but they sometimes brush their fins past any new object they encounter.


title: Stingray content: Nevertheless, certain larger species may be more aggressive and should be approached with caution, as the stingray's defensive reflex (use of its poisoned stinger) may result in serious injury or death. The skin of the ray is used as an under layer for the cord or leather wrap (known as "ito" in Japanese) on Japanese swords due to its hard, rough, skin texture that keeps the braided wrap from sliding on the handle during use. They are also used to make exotic shoes, boots, belts, wallets, jackets, and cellphone cases. Several ethnological sections in museums, such as the British Museum,


title: Stingray content: display arrowheads and spearheads made of stingray stingers, used in Micronesia and elsewhere. Henry de Monfreid stated in his books that before World War II, in the Horn of Africa, whips were made from the tail of big stingrays, and these devices inflicted cruel cuts, so in Aden, the British forbade their use on women and slaves. In former Spanish colonies, a stingray is called "raya látigo" ("whip ray"). Monfreid also wrote in several places about men of his crew suffering stingray wounds while standing and wading into Red Sea shallows to load or unload smuggled wares: he wrote that


title: Stingray content: to "save the man's life", searing the wound with a red-hot iron was necessary. Batoids (rays) belong to the ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling that of today's chondrichthyans date at least as far back as the Ordovician, with the oldest unambiguous fossils of cartilaginous fish dating from the middle Devonian. A clade within this diverse family, the Neoselachii, emerged by the Triassic, with the best-understood neoselachian fossils dating from the Jurassic. The clade is represented today by sharks, sawfish, rays and skates. Although stingray teeth are rare on sea bottoms compared to


title: Stingray content: the similar shark teeth, scuba divers searching for the latter do encounter the teeth of stingrays. Permineralized stingray teeth have been found in sedimentary deposits around the world, including fossiliferous outcrops in Morocco. Stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwater stingray), Urolophidae (stingarees), Urotrygonidae (round rays), Dasyatidae (whiptail stingrays), Potamotrygonidae (river stingrays), Gymnuridae (butterfly rays), and Myliobatidae (eagle rays). Stingrays are common in coastal tropical and subtropical marine waters throughout the


title: "Grand Prix motorcycle racing" content: awarded to the most successful rider over a season, as determined by a points system based on Grand Prix results. Giacomo Agostini is the most successful champion in Grand Prix history, with 15 titles to his name (8 in the 500 cc class and 7 in the 350 cc class). The most dominant rider of all time was Mike Hailwood, winning 10 out of 12 (83%) races, in the 250 cc class, in the 1966 season. Mick Doohan, who won 12 out of 15 (80%) of the 500 cc races in the 1997 Grand Prix motorcycle racing season also deserves


title: "Louis XV of France" content: King, one law, one Parlement; the law of the kingdom is a sacred pact of your alliance with the French nation; it is a kind of contract which destines the King to reign and the people to obey. In truth, no one except God can compel you to obey this sacred pact...but we can ask you, with respect, with submission...to keep your promises." This was too much for the King. He responded on 31 January 1761 that the Parlement's complaint "contained principles so false and so contrary to my authority and with expressions so indecent, particularly in connection with my


title: "Hello Kitty" content: means "beckoning cat" in English, no definitive statement supports that speculation. Hello Kitty sold well immediately after the 1974 launch, and Sanrio's sales increased seven times up until they slumped temporarily in 1978. New series with Hello Kitty in different themed designs are released regularly, following current trends. Yuko Yamaguchi, the main designer for most of Hello Kitty's history, has said that she is inspired by fashion, movies and TV in creating new designs. Hello Kitty was originally marketed only towards a child and preteen audience. In the 1990s, the target market for Hello Kitty was broadened to include teens


title: "Samuel L. Jackson" content: lie. But now we have a representative... the American Dream is a reality. Anyone can grow up to be a president." Jackson also said: "I voted for Barack because he was black. That's why other folks vote for other people because they look like them". He compared his "Django Unchained" character, a villainous house slave, to black conservative Justice Clarence Thomas, saying that "I have the same moral compass as Clarence Thomas does". In June 2013, Jackson launched a joint campaign with the charity Prizeo in an effort to raise money to fight Alzheimer's disease. As part of the campaign,


title: Miami content: the location of Miami's City Hall in Dinner Key, the Coconut Grove Playhouse, CocoWalk, many nightclubs, bars, restaurants and bohemian shops, and as such, is very popular with local college students. It is a historic neighborhood with narrow, winding roads, and a heavy tree canopy. Coconut Grove has many parks and gardens such as Villa Vizcaya, The Kampong, The Barnacle Historic State Park, and is the home of the Coconut Grove Convention Center and numerous historic homes and estates. The western side of Miami includes Little Havana, West Flagler, and Flagami, and is home to many of the city's traditionally


title: "Jim Thorpe" content: In 1982, Wheeler and Ridlon established the Jim Thorpe Foundation and gained support from the U.S. Congress. Armed with this support and evidence from 1912 proving that Thorpe's disqualification had occurred after the 30-day time period allowed by Olympics rules, they succeeded in making the case to the IOC. In October 1982, the IOC Executive Committee approved Thorpe's reinstatement. In an unusual ruling, they declared that Thorpe was co-champion with Ferdinand Bie and Wieslander, although both of these athletes had always said they considered Thorpe to be the only champion. In a ceremony on January 18, 1983, the IOC presented


title: Fallacy content: Rican" faculty) via reference to aggregate data about a larger and different group (e.g. "Hispanic" faculty). Sometimes a speaker or writer uses a fallacy intentionally. In any context, including academic debate, a conversation among friends, political discourse, advertising, or for comedic purposes, the arguer may use fallacious reasoning to try to persuade the listener or reader, by means other than offering relevant evidence, that the conclusion is true. Examples of this include the speaker or writer: In humor, errors of reasoning are used for comical purposes. Groucho Marx used fallacies of amphiboly, for instance, to make ironic statements; Gary Larson


title: Opal content: to produce a "solid" may be combined with other materials to form attractive gems. An opal doublet consists of a relatively thin layer of precious opal, backed by a layer of dark-colored material, most commonly ironstone, dark or black common opal (potch), onyx, or obsidian. The darker backing emphasizes the play of color, and results in a more attractive display than a lighter potch. An opal triplet is similar to a doublet, but has a third layer, a domed cap of clear quartz or plastic on the top. The cap takes a high polish and acts as a protective layer


title: "Lyndon B. Johnson" content: hospital insurance for the aged under Social Security. The key player in initiating this program, named Medicare, was Wilbur Mills, Chairman of the House Ways and Means Committee. In order to reduce Republican opposition, Mills suggested that Medicare be fashioned as a three layer cake: hospital insurance under Social Security; a voluntary insurance program for doctor visits; and an expanded medical welfare program for the poor, known as Medicaid. The bill passed the house by a margin of 110 votes on April 8. The effort in the Senate was considerably more complicated; however, the Medicare bill passed Congress on July


title: "Root beer" content: Root beer Root beer is a sweet North American soft drink traditionally made using the sassafras tree "Sassafras albidum" (sassafras) or the vine "Smilax ornata" (sarsaparilla) as the primary flavor. Root beer may be alcoholic or non-alcoholic (but it is usually non-alcoholic), come naturally free of caffeine or have caffeine added, and be carbonated or non-carbonated. It usually has a thick, foamy head when poured. Modern, commercially produced root beer is generally sweet, foamy, carbonated, nonalcoholic, and flavored using artificial sassafras flavoring. Sassafras root is still used to flavor traditional root beer, but since sassafras was banned by the U.S.


title: "Root beer" content: Food and Drug Administration due to the carcinogenicity of its constituent safrole, most commercial recipes do not contain sassafras. Some commercial root beers do use a safrole-free sassafras extract. Major producers include Dr Pepper Snapple Group, Coca-Cola, Sprecher Brewing, Dad’s Root Beer, Berghoff Beer, Whole Foods Market, and Stewart’s Restaurants. Sassafras root beverages were made by indigenous peoples of the Americas for culinary and medicinal reasons before the arrival of Europeans in North America, and European culinary techniques have been applied to making traditional sassafras-based beverages similar to root beer since the 16th century. Root beer was sold in confectionery


title: "Root beer" content: stores since the 1840s, and written recipes for root beer have been documented since the 1860s. It possibly was combined with soda as early as the 1850s, and root beer sold in stores was most often sold as a syrup rather than a ready-made beverage. The tradition of brewing root beer is thought to have evolved out of other small beer traditions that produced fermented drinks with very low alcohol content that were thought to be healthier to drink than possibly tainted local sources of drinking water, and enhanced by the medicinal and nutritional qualities of the ingredients used. Beyond


title: "Root beer" content: its aromatic qualities, the medicinal benefits of sassafras were well known to both Native Americans and Europeans, and druggists began marketing root beer for its medicinal qualities. Pharmacist Charles Elmer Hires was the first to successfully market a commercial brand of root beer. Hires developed his root tea made from sassafras in 1875, debuted a commercial version of root beer at the Philadelphia Centennial Exposition in 1876, and began selling his extract. Hires was a teetotaler who wanted to call the beverage "root tea". However, his desire to market the product to Pennsylvania coal miners caused him to call his


title: "Root beer" content: product "root beer", instead. In 1886, Hires began to bottle a beverage made from his famous extract. By 1893, root beer was distributed widely across the United States. Non-alcoholic versions of root beer became commercially successful, especially during Prohibition. Not all traditional or commercial root beers were sassafras-based. One of Hires's early competitors was Barq's, which began selling its sarsaparilla-based root beer in 1898 and was labeled simply as "Barq's". In 1919, Roy Allen opened his root-beer stand in Lodi, California, which led to the development of A&W Root Beer. One of Allen's innovations was that he served his homemade


title: "Root beer" content: root beer in cold, frosty mugs. IBC Root Beer is another brand of commercially produced root beer that emerged during this period and is still well-known today. Safrole, the aromatic oil found in sassafras roots and bark that gave traditional root beer its distinctive flavour, was banned for commercially mass-produced foods and drugs by the FDA in 1960. Laboratory animals that were given oral doses of sassafras tea or sassafras oil that contained large doses of safrole developed permanent liver damage or various types of cancer. While sassafras is no longer used in commercially produced root beer and is sometimes


title: "Root beer" content: substituted with artificial flavors, natural extracts with the safrole distilled and removed are available. One traditional recipe for making root beer involves cooking a syrup from molasses and water, letting the syrup cool for three hours, and combining it with the root ingredients (including sassafras root, sassafras bark, and wintergreen). Yeast was added, and the beverage was left to ferment for 12 hours, after which it was strained and rebottled for secondary fermentation. This recipe usually resulted in a beverage of 2% alcohol or less, although the recipe could be modified to produce a more alcoholic beverage. Commercial root beer


title: "Root beer" content: is now produced in every U.S. state and in Canada. Although this beverage's popularity is greatest in North America, brands are produced in other countries, including Australia, the United Kingdom, Malaysia, Argentina, Germany, the Philippines, Singapore, Taiwan, South Korea, Indonesia, Sweden, Vietnam, and Thailand. The flavor of these beverages may vary from typical North American versions. While no standard recipe exists, the primary ingredients in modern rootbeer are filtered water, sugar, and artificial sassafras flavoring, which complements other flavors. Common flavorings are vanilla, wintergreen, cherry tree bark, licorice root, sarsaparilla root, nutmeg, acacia, anise, molasses, cinnamon, sweet birch, and honey.


title: "Root beer" content: Soybean protein is sometimes used to create a foamy quality, and caramel coloring is used to make the beverage brown. Ingredients in early and traditional root beers include allspice, birch bark, coriander, juniper, ginger, wintergreen, hops, burdock root, dandelion root, spikenard, pipsissewa, guaiacum chips, sarsaparilla, spicewood, wild cherry bark, yellow dock, prickly ash bark, sassafras root, vanilla beans, dog grass, molasses, and licorice. Many of these ingredients are still used in traditional and commercially produced root beer today, which is often thickened, foamed, or carbonated. Although most mainstream brands are caffeine-free, Barq's does contain caffeine. Root beer can be made


title: "Root beer" content: at home with processed extract obtained from a factory, or it can also be made from herbs and roots that have not yet been processed. Alcoholic and non-alcoholic traditional root beers make a thick and foamy head when poured, often enhanced by the addition of yucca extract, soybean protein, or other thickeners. Root beer Root beer is a sweet North American soft drink traditionally made using the sassafras tree "Sassafras albidum" (sassafras) or the vine "Smilax ornata" (sarsaparilla) as the primary flavor. Root beer may be alcoholic or non-alcoholic (but it is usually non-alcoholic), come naturally free of caffeine or


title: Cicada content: Cicada The cicadas ( or ) are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, Tettigarctidae, with two species in Australia, and Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed. Cicadas have prominent eyes set wide apart, short antennae, and membranous front wings. They have an exceptionally loud song, produced in most species by the rapid buckling and unbuckling of drumlike tymbals. The earliest known fossil


title: Cicada content: Cicadomorpha appeared in the Upper Permian period; extant species occur all around the world in temperate to tropical climates. They typically live in trees, feeding on watery sap from xylem tissue and laying their eggs in a slit in the bark. Most cicadas are cryptic, singing at night to avoid predators. The periodic cicadas spend most of their lives as underground nymphs, emerging only after 13 or 17 years, which may reduce losses by starving their predators and eventually emerging in huge numbers that overwhelm and satiate any remaining predators. The annual cicadas are species that emerge every year. Though


title: Cicada content: these cicada have life cycles that can vary from one to nine or more years as underground larvae, their emergence above ground as adults is not synchronized so some appear every year. Cicadas have been featured in literature since the time of Homer's "Iliad", and as motifs in art from the Chinese Shang dynasty. They have been used in myths and folklore to represent carefree living and immortality. Cicadas are eaten in various countries, including China, where the nymphs are served deep-fried in Shandong cuisine. The name is directly from the onomatopoeic Latin "cicada". Cicadas are arranged into two families:


title: Cicada content: the Tettigarctidae and Cicadidae. The two extant species of Tettigarctidae include one in southern Australia and the other in Tasmania. The family Cicadidae is subdivided into the subfamilies Cicadinae, Tibicininae (or Tettigadinae), Tettigomyiinae, and Cicadettinae; they are found on all continents except Antarctica. Some previous works also included a family-level taxon called the Tibiceninae. The largest species is the Malaysian emperor cicada "Megapomponia imperatoria"; its wingspan is up to about . Cicadas are also notable for the great length of time some species take to mature. At least 3000 cicada species are distributed worldwide with the majority being in the


title: Cicada content: tropics. Most genera are restricted to a single biogeographical region and many species have a very limited range. This high degree of endemism has been used to study the biogeography of complex island groups such as in Indonesia and the Orient. There are several hundred described species in Australia and New Zealand, around 150 in South Africa, over 170 in America north of Mexico, at least 800 in Latin America, and over 200 in Southeast Asia and the Western Pacific. About 100 species occur in the Palaearctic. A few species are found in southern Europe, and a single species was


title: Cicada content: known from England, the New Forest cicada, "Cicadetta montana", which also occurs in continental Europe. Many species await formal description and many well-known species are yet to be studied carefully using modern acoustic analysis tools that allow their songs to be characterized. Many of the North American species are the annual or jarfly or dog-day cicadas, members of the Neotibicen, Megatibicen, or Hadoa genus, so named because they emerge in late July and August. The best-known North American genus, however, may be "Magicicada". These periodical cicadas have an extremely long life cycle of 13 or 17 years, with adults suddenly


title: Cicada content: and briefly emerging in large numbers. Australian cicadas are found on tropical islands and cold coastal beaches around Tasmania, in tropical wetlands, high and low deserts, alpine areas of New South Wales and Victoria, large cities including Sydney, Melbourne, and Brisbane, and Tasmanian highlands and snowfields. Many of them go by common names such as cherry nose, brown baker, red eye, greengrocer, yellow Monday, whisky drinker, double drummer, and black prince. The Australian greengrocer, "Cyclochila australasiae", is among the loudest insects in the world. Forty-two species from five genera populate New Zealand, ranging from sea level to mountain tops, and


title: Cicada content: all are endemic to New Zealand and the surrounding islands (Norfolk Island, New Caledonia). Fossil Cicadomorpha first appeared in the Upper Permian. The superfamily Palaeontinoidea contains three families. The Upper Permian Dunstaniidae are found in Australia and South Africa, and also in younger rocks from China. The Upper Triassic Mesogereonidae are found in Australia and South Africa. The Palaeontinidae or "giant cicadas" come from the Jurassic and Upper Cretaceous of Eurasia and South America. The first of these was a forewing discovered in the Taynton Limestone Formation of Oxfordshire, England; it was initially described as a butterfly in 1873, before


title: Cicada content: being recognised as a cicada and renamed "Palaeontina oolitica". Most fossil Cicadidae are known from the Cenozoic, and the oldest unambiguously identified specimen is "Davispia bearcreekensis" (subfamily Tibicininae) from 59-56 Ma. One fossil genus and species ("Burmacicada protera") based on a first-instar nymph has recently been reported from 98-99 Ma in the Late Cretaceous, although questions remain about its assignment to the Cicadidae. Cicadas are large insects made conspicuous by the courtship calls of the males. They are characterised by having three joints in their tarsi, and having small antennae with conical bases and three to six segments, including a


title: Cicada content: seta at the tip. The Auchenorrhyncha differ from other hemipterans by having a rostrum that arises from the posteroventral part of the head, complex sound-producing membranes, and a mechanism for linking the wings that involves a down-rolled edging on the rear of the forewing and an upwardly protruding flap on the hindwing. Cicadas are feeble jumpers and nymphs lack the ability to jump altogether. Another defining characteristic is the adaptations of the forelimbs of nymphs for underground life. The relict family Tettigarctidae differ from the Cicadidae in having the prothorax extending as far as the scutellum, and by lacking the


title: Cicada content: tympanal apparatus. The adult insect, known as an imago, is in total length in most species, although the largest, the empress cicada ("Megapomponia imperatoria"), has a head-body length of about , and its wingspan is . Cicadas have prominent compound eyes set wide apart on the sides of the head. The short antennae protrude between the eyes or in front of them. They also have three small ocelli located on the top of the head in a triangle between the two large eyes; this distinguishes cicadas from other members of the Hemiptera. The mouthparts form a long sharp rostrum that


title: Cicada content: they insert into the plant to feed. The post-clypeus is a large, nose-like structure that lies between the eyes and makes up most of the front of the head: it contains the pumping musculature. The thorax has three segments and houses the powerful wing muscles. They have two pairs of membranous wings that may be hyaline, cloudy or pigmented. The wing venation varies between species and may help in identification. The middle thoracic segment has an operculum on the underside, which may extend posteriorly and obscure parts of the abdomen. The abdomen is segmented, with the hindermost segments housing the


title: Cicada content: reproductive organs, and terminates in females with a large, saw-edged ovipositor. In males, the abdomen is largely hollow and used as a resonating chamber. The surface of the forewing is super-hydrophobic; it is covered with minute waxy cones, blunt spikes that create a water-repellent film. Rain rolls across the surface, removing dirt in the process. In the absence of rain, dew condenses on the wings. When the droplets coalesce, they leap several millimetres into the air, which also serves to clean the wings. It has been found that bacteria landing on the wing surface are not repelled, rather their membranes


title: Cicada content: are torn apart by the nanoscale-sized spikes, making the wing surface the first-known biomaterial that can kill bacteria. Desert cicadas such as "Diceroprocta apache" are unusual among insects in controlling their temperature by evaporative cooling, analogous to sweating in mammals. When their temperature rises above about 39 °C, they suck excess sap from the food plants and extrude the excess water through pores in the tergum at a modest cost in energy. Such a rapid loss of water can be sustained only by feeding on water-rich xylem sap. At lower temperatures, feeding cicadas would normally need to excrete the excess


title: Cicada content: water. By evaporative cooling, desert cicadas can reduce their bodily temperature by some 5 °C. Some non-desert cicada species such as "Magicicada tredecem" also cool themselves evaporatively, but less dramatically. Conversely, many other cicadas can voluntarily raise their body temperatures as much as above ambient temperature. The "singing" of male cicadas is produced principally and in the majority of species using a special structure called a tymbal, a pair of which lie below each side of the anterior abdominal region. The structure is buckled by muscular action and being made of resilin unbuckled rapidly on muscle relaxation and the rapid


title: Cicada content: action of muscles produces their characteristic sounds. Some cicadas however have mechanisms for stridulation, sometimes in addition to the tymbals. Here the wings are rubbed over a series of mid-thoracic ridges. The sounds may further be modulated by membranous coverings and by resonant cavities. The male abdomen in some species is largely hollow, and acts as a sound box. By rapidly vibrating these membranes, a cicada combines the clicks into apparently continuous notes, and enlarged chambers derived from the tracheae serve as resonance chambers with which it amplifies the sound. The cicada also modulates the song by positioning its abdomen


title: Cicada content: toward or away from the substrate. Partly by the pattern in which it combines the clicks, each species produces its own distinctive mating songs and acoustic signals, ensuring that the song attracts only appropriate mates. Average temperature of the natural habitat for the South American species "Fidicina rana" is approximately . During sound production, the temperature of the tymbal muscles was found to be significantly higher. Many cicadas sing most actively during the hottest hours of a summer day; roughly a 24-hour cycle. Most cicadas are diurnal in their calling and depend on external heat to warm them up while


title: Cicada content: a few are capable of raising their temperature using muscle action and some species are known to call at dusk. "Kanakia gigas" and "Froggattoides typicus" are among the few that are known to be truly nocturnal and there may be other nocturnal species living in tropical forests. Although only males produce the cicadas' distinctive sounds, both sexes have membranous structures called tympana by which they detect sounds; the equivalent of having ears. Males disable their own tympana while calling, thereby preventing damage to their hearing; a necessity partly because some cicadas produce sounds up to 120 dB (SPL) which is


title: Cicada content: among the loudest of all insect-produced sounds. The song is loud enough to cause permanent hearing loss in humans should the cicada be at "close range." In contrast, some small species have songs so high in pitch that they are inaudible to humans. For the human ear, it is often difficult to tell precisely where a cicada song originates. The pitch is nearly constant, the sound is continuous to the human ear, and cicadas sing in scattered groups. In addition to the mating song, many species have a distinct distress call, usually a broken and erratic sound emitted by the


title: Cicada content: insect when seized or panicked. Some species also have courtship songs, generally quieter, and produced after a female has been drawn to the calling song. Males also produce "encounter calls", whether in courtship or to maintain personal space within choruses. The song of cicadas is considered by entomologists to be unique to a given species, and a number of resources exist to collect and analyse cicada sounds. In some species of cicada, the males remain in one location and call to attract females. Sometimes several males aggregate and call in chorus. In other species, the males move from place to


title: Cicada content: place, usually with quieter calls while searching for females. The Tettigarctidae differ from other cicadas in producing vibrations in the substrate rather than audible sounds. After mating, the female cuts slits into the bark of a twig where she deposits her eggs. When the eggs hatch, the newly hatched nymphs drop to the ground and burrow. Cicadas live underground as nymphs for most of their lives at depths down to about . Nymphs have strong front legs for digging and excavating chambers in close proximity to roots where they feed on xylem sap. In the process, their bodies and interior


title: Cicada content: of the burrow become coated in anal fluids. In wet habitats, larger species construct mud towers above ground in order to aerate their burrows. In the final nymphal instar, they construct an exit tunnel to the surface and emerge. They then moult (shed their skins) on a nearby plant for the last time, and emerge as adults. The exuviae or abandoned exoskeletons remain, still clinging to the bark of the tree. Most cicadas go through a life cycle that lasts from two to five years. Some species have much longer life cycles, such as the North American genus, "Magicicada", which


title: Cicada content: has a number of distinct "broods" that go through either a 17-year or, in some parts of the region, a 13-year life cycle. The long life cycles may have developed as a response to predators, such as the cicada killer wasp and praying mantis. A specialist predator with a shorter life cycle of at least two years could not reliably prey upon the cicadas. Cicada nymphs drink sap from the xylem of various species of trees, including oak, cypress, willow, ash, and maple. While it is common folklore that adults do not eat, they actually do drink plant sap utilizing


title: Cicada content: their sucking mouthparts. Cicadas, unlike other Auchenorrhyncha, are not adapted for jumping (saltation). They have the usual insect modes of locomotion, walking and flight. However, they do not walk or run well, and take to the wing to travel distances greater than a few centimetres. Cicadas are commonly eaten by birds and sometimes by squirrels, as well as bats, wasps, mantises, spiders and robber flies. In times of mass emergence of cicadas, various amphibians, fish, reptiles, mammals and birds change their foraging habits so as to benefit from the glut. Newly hatched nymphs may be eaten by ants, and nymphs


title: Cicada content: living underground are preyed on by burrowing mammals like moles. In Australia, cicadas are preyed on by the Australian cicada killer wasp ("Exeirus lateritius"), which stings and stuns cicadas high in the trees, making them drop to the ground where the cicada-hunter mounts and carries them, pushing with its hindlegs, sometimes over a distance of a hundred metres, until they can be shoved down into its burrow, where the numb cicada is placed onto one of many shelves in a "catacomb", to form the food-stock for the wasp grub that grows out of the egg deposited there. A katydid predator


title: Cicada content: from Australia is capable of attracting singing male cicadas of a variety of species by imitating the timed click replies of sexually receptive female cicadas, who respond in pair-formation by flicking their wings. Several fungal diseases infect and kill adult cicadas while another entomopathogenic fungus, "Cordyceps" spp., attacks nymphs. "Massospora cicadina" specifically attacks the adults of periodical cicadas, the spores remaining dormant in the soil between outbreaks. This fungus is also capable of dosing cicadas with psilocibin, the psychedelic drug found in magic mushrooms, as well as cathinone, an alkaloid similar to various amphetamines. Cicadas use a variety of strategies


title: Cicada content: to evade predators. Large cicadas can fly rapidly to escape if disturbed. Many are extremely well camouflaged to evade predators such as birds that hunt by sight. As well as being coloured like tree bark, they are disruptively patterned to break up their outlines; their partly transparent wings are held over the body and pressed close to the substrate. Some cicada species play dead when threatened. The periodical cicadas ("Magicicada") make use of predator satiation: they emerge, all at once, at long intervals of 13 or 17 years; their juveniles are probably the longest-lived of all insect development stages. Since


title: Cicada content: the number of cicadas in any given area exceeds the amount predators can eat, all available predators are satiated, and the remaining cicadas can breed in peace. Some cicadas such as "Hemisciera maculipennis" display bright deimatic flash coloration on their hindwings when threatened; the sudden contrast helps to startle predators, giving the cicadas time to escape. The majority of cicadas are diurnal and rely on camouflage when at rest, but some species are aposematic; the Malaysian "Huechys sanguinea" has conspicuous red and black warning coloration, is diurnal, and boldly flies about in full view of possible predators. Predators such as


title: Cicada content: the sarcophagid fly "Emblemasoma" hunt cicadas by sound, being attracted to their song. Singing males soften their song so that the attention of the listener gets distracted to neighbouring louder singers, or cease singing altogether as a predator approaches. It has been asserted that loud cicada song, especially in chorus, repels predators, but observations of predator responses refute the claim. Cicadas have been featured in literature since the time of Homer's "Iliad", and as motifs in decorative art from the Chinese Shang dynasty (1766–1122 BC.). They are described by Aristotle in his "History of Animals" and by Pliny the Elder


title: Cicada content: in his "Natural History"; their mechanism of sound production is mentioned by Hesiod in his poem "Works and Days" "when the Skolymus flowers, and the tuneful "Tettix" sitting on his tree in the weary summer season pours forth from under his wings his shrill song". In the classic 14th-century Chinese novel "Romance of the Three Kingdoms", Diaochan took her name from the sable ("diāo") tails and jade decorations in the shape of cicadas ("chán"), which adorned the hats of high-level officials. In the Japanese novel "The Tale of Genji", the title character poetically likens one of his many love interests


title: Cicada content: to a cicada for the way she delicately sheds her robe the way a cicada sheds its shell when molting. A cicada exuviae plays a role in the manga "Winter Cicada". Cicadas are a frequent subject of haiku, where, depending on type, they can indicate spring, summer or autumn. Cicadas are featured in the well-known protest song ""Como La Cigarra"" ("Like the Cicada") written by the Argentinian poet and composer, María Elena Walsh. In the song, the cicada is a symbol of survival and defiance against death. ""Como La Cigarra"" was famously recorded by Mercedes Sosa, among other Latin American


title: Cicada content: musicians. Another well-known song, """" ("The Cicada"), written by , is a song in the mariachi tradition that romanticises the insect as a creature that sings until it dies. Cicadas have been used as money, in folk medicine, to forecast the weather, to provide song (in China), and in folklore and myths around the world. In France, the cicada represents the folklore of Provence and the Mediterranean cities. The cicada has represented since classical antiquity. Jean de La Fontaine began his collection of fables "Les fables de La Fontaine" with the story "La Cigale et la Fourmi" ("The Cicada and


title: Cicada content: the Ant") based on one of Aesop's fables: in it the cicada spends the summer singing while the ant stores away food, and finds herself without food when the weather turns bitter. The cicada symbolises rebirth and immortality in Chinese tradition. In the Chinese essay "Thirty-Six Stratagems", the phrase "to shed the golden cicada skin" () is the poetic name for using a decoy (leaving the exuviae) to fool enemies. In the Chinese classic novel "Journey to the West" (16th century), the protagonist Priest of Tang was named the Golden Cicada. In Japan, the cicada is associated with the summer


title: Cicada content: season.For many Japanese people, summer hasn't officially begun until the first songs of the cicada are heard. According to Lafcadio Hearn, the song of "Meimuna opalifera", called "tsuku-tsuku boshi", is said to indicate the end of summer, and it is called so because of its particular call. In the "Homeric Hymn to Aphrodite", the goddess Aphrodite retells the legend of how Eos, the goddess of the dawn, requested Zeus to let her lover Tithonus live forever as an immortal. Zeus granted her request, but, because Eos forgot to ask him to also make Tithonus ageless, Tithonus never died, but he


title: Cicada content: did grow old. Eventually, he became so tiny and shriveled that he turned into the first cicada. The Greeks also used a cicada sitting on a harp as an emblem of music. Cicadas were eaten in Ancient Greece, and are consumed today in China, both as adults and (more often) as nymphs, in Malaysia, Burma, Latin America, North America, and central Africa. Female cicadas are prized for being meatier. Shells of cicadas are employed in traditional Chinese medicines. The 17-year "Onondaga Brood" "Magicicada" is culturally important and a particular delicacy to the Onondaga people. Cicadas feed on sap; they do


title: Cicada content: not bite or sting in a true sense, but may occasionally mistake a person's arm for a plant limb and attempt to feed. Male cicadas produce very loud calls that can damage human hearing. Cicadas are not major agricultural pests but in some outbreak years, trees may be overwhelmed by the sheer numbers of females laying their eggs in the shoots. Small trees may wilt and larger trees may lose small branches. Although in general, the feeding activities of the nymphs do little damage, during the year before an outbreak of periodic cicadas, the large nymphs feed heavily and plant


title: Cicada content: growth may suffer. Some species have turned from wild grasses to sugar cane, which affects the crop adversely, and in a few isolated cases, females have oviposited on food crops such as date palms, grape vines, citrus trees, asparagus and cotton. Cicadas sometimes cause damage to amenity shrubs and trees, mainly in the form of scarring left on tree branches where the females have laid their eggs. Branches of young trees may die as a result. Cicada The cicadas ( or ) are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder


title: Triceratops content: Triceratops Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago (mya) in what is now North America. It is one of the last known non-avian dinosaur genera, and became extinct in the Cretaceous–Paleogene extinction event 66 million years ago. The name "Triceratops", which literally means "three-horned face", is derived from the Ancient Greek words τρί- ("tri-") meaning "three", κέρας ("kéras") meaning "horn", and ὤψ ("ōps") meaning "face". It has been documented by numerous remains collected since the genus was first described in 1889,


title: Triceratops content: including at least one complete individual skeleton. Paleontologist John Scannella observed: "It is hard to walk out into the Hell Creek Formation and not stumble upon a "Triceratops" weathering out of a hillside." Forty-seven complete or partial skulls were discovered in just that area from 2000 to 2010. Specimens representing life stages from hatchling to adult have been found. As the archetypal ceratopsid, "Triceratops" is one of the most popular dinosaurs, and has been featured in film, postal stamps, and many other types of media. Bearing a large bony frill and three horns on its large four-legged body, and possessing


title: Triceratops content: similarities with the modern rhinoceros, "Triceratops" is one of the most recognizable of all dinosaurs and the best known ceratopsid. It shared the landscape with and was probably preyed upon by "Tyrannosaurus", though it is less certain that the two did battle in the manner often depicted in traditional museum displays and popular images. The functions of the frills and three distinctive facial horns on its head have long inspired debate. Traditionally, these have been viewed as defensive weapons against predators. More recent theories, noting the presence of blood vessels in the skull bones of ceratopsids, find it more probable


title: Triceratops content: that these features were primarily used in identification, courtship and dominance displays, much like the antlers and horns of modern reindeer, mountain goats, or rhinoceros beetles. The theory would find additional support if "Torosaurus" were found to be the mature form of "Triceratops", as this would mean the frill also developed holes (fenestrae) as individuals reached maturity, rendering the structure more useful for display than defense. The exact placement of the genus "Triceratops" within the ceratopsid group has been debated by paleontologists. Two species, "T. horridus" and "T. prorsus", are considered valid, although many other species have been named. Research


title: Triceratops content: published in 2010 suggested that the contemporaneous "Torosaurus", a ceratopsid long regarded as a separate genus, represents "Triceratops" in its mature form. The view was immediately disputed and examination of more fossil evidence is expected to settle the debate. Individual "Triceratops" are estimated to have reached about 7.9 to 9.0 m (25.9–29.5 ft) in length, in height, and 6.1–12.0 tonnes (13,000–26,000 lb) in weight. The most distinctive feature is their large skull, among the largest of all land animals. The largest known skull (specimen MWC 7584, formerly BYU 12183) is estimated to have been in length when complete, and could


title: Triceratops content: reach almost a third of the length of the entire animal. A specimen of "T. horridus" named Kelsey measured long with a skull, stood about tall, and was estimated by the Black Hills institute to weight nearly . A "Triceratops" long has been estimated by Gregory S. Paul to have massed . It bore a single horn on the snout, above the nostrils, and a pair of horns approximately long, with one above each eye. In 2010, paleontologists revealed a fossil (named "Yoshi's Trike," MOR 3027) with horn cores, housed and displayed at the Museum of the Rockies in Montana.


title: Triceratops content: To the rear of the skull was a relatively short, bony frill, adorned with epoccipitals in some specimens. Most other ceratopsids had large fenestrae in their frills, while those of "Triceratops" were noticeably solid. "T. horridus" can be distinguished from "T. prorsus" by having a shallower snout. "Triceratops" species possessed a sturdy build, with strong limbs, short hands with three hooves each, and short feet with four hooves each. Although certainly quadrupedal, the posture of these dinosaurs has long been the subject of some debate. Originally, it was believed that the front legs of the animal had to be sprawling


title: Triceratops content: at angles from the thorax in order to better bear the weight of the head. This stance can be seen in paintings by Charles Knight and Rudolph Zallinger. Ichnological evidence in the form of trackways from horned dinosaurs and recent reconstructions of skeletons (both physical and digital) seem to show that "Triceratops" and other ceratopsids maintained an upright stance during normal locomotion, with the elbows flexed and slightly bowed out, in an intermediate state between fully upright and fully sprawling (as in the modern rhinoceros). The hands and forearms of "Triceratops" retained a fairly primitive structure compared to other quadrupedal


title: Triceratops content: dinosaurs such as thyreophorans and many sauropods. In those two groups, the forelimbs of quadrupedal species were usually rotated so that the hands faced forward with palms backward ("pronated") as the animals walked. "Triceratops", like other ceratopsians and the related quadrupedal ornithopods, walked with most of their fingers pointing out and away from the body, the primitive condition for dinosaurs also retained by bipedal forms like the theropods. In "Triceratops", the weight of the body was carried by only the first three fingers of the hand, while digits 4 and 5 were vestigial and lacked claws or hooves. The phalangeal


title: Triceratops content: formula is 2-3-4-3-1, meaning that the innermost finger of the forelimb has two bones, the next has three, etc. The first named specimen now attributed to "Triceratops" is a pair of brow horns attached to a skull roof, found near Denver, Colorado in the spring of 1887. This specimen was sent to American paleontologist Othniel Charles Marsh, who believed that the formation from which it came dated from the Pliocene, and that the bones belonged to a particularly large and unusual bison, which he named "Bison alticornis". He realized that there were horned dinosaurs by the next year, which saw


title: Triceratops content: his publication of the genus "Ceratops" from fragmentary remains, but he still believed "B. alticornis" to be a Pliocene mammal. It took a third and much more complete skull to change his mind. The specimen, collected in 1888 by John Bell Hatcher from the Lance Formation of Wyoming, was initially described as another species of "Ceratops". After reflection, Marsh changed his mind and gave it the generic name "Triceratops", accepting his "Bison alticornis" as another species of "Ceratops" (it would later be added to "Triceratops"). The sturdy nature of the animal's skull has ensured that many examples have been preserved


title: Triceratops content: as fossils, allowing variations between species and individuals to be studied. "Triceratops" remains have subsequently been found in the American states of Montana and South Dakota (in addition to Colorado and Wyoming), and in the provinces of Saskatchewan and Alberta, Canada. An earlier specimen, also recovered from the Lance Formation, was named "Agathaumas sylvestris" by Edward Drinker Cope in 1872. Originally identified as a hadrosaur, this specimen consists only of post-cranial remains and is only provisionally considered an example of "Triceratops". Within the first decades after "Triceratops" was described, various skulls were collected, which varied to a lesser or greater


title: Triceratops content: degree from the original "Triceratops", named "T. horridus" by Marsh (from the Latin "horridus"; "rough, rugose", suggesting the roughened texture of those bones belonging to the type specimen, later identified as an aged individual). This variation is unsurprising, given that "Triceratops" skulls are large three-dimensional objects, coming from individuals of different ages and both sexes, and which were subjected to different amounts and directions of pressure during fossilization. Discoverers would name these as separate species (listed below), and came up with several phylogenetic schemes for how they were related to each other. In the first attempt to understand the many


title: Triceratops content: species, Lull found two groups, although he did not say how he distinguished them: one composed of "T. horridus", "T. prorsus", and "T. brevicornus"; the other of "T. elatus" and "T. calicornis". Two species ("T. serratus" and "T. flabellatus") stood apart from these groups. By 1933, and his revision of the landmark 1907 Hatcher-Marsh-Lull monograph of all known ceratopsians, he retained his two groups and two unaffiliated species, with a third lineage of "T. obtusus" and "T. hatcheri" that was characterized by a very small nasal horn. "T. horridus"-"T. prorsus"-"T. brevicornus" was now thought to be the most conservative lineage,


title: Triceratops content: with an increase in skull size and a decrease in nasal horn size, and "T. elatus"-"T. calicornis" was defined by large brow horns and small nasal horn. C. M. Sternberg made one modification, adding "T. eurycephalus" and suggesting that it linked the second and third lineages closer together than they were to the "T. horridus" lineage. This pattern was followed until the major studies of the 1980s and 1990s. With time, the idea that the differing skulls might be representative of individual variation within one (or two) species gained popularity. In 1986, Ostrom and Wellnhofer published a paper in which


title: Triceratops content: they proposed that there was only one species, "Triceratops horridus". Part of their rationale was that generally there are only one or two species of any large animal in a region (modern examples being the elephant and the giraffe in modern Africa). To their findings, Lehman added the old Lull-Sternberg lineages combined with maturity and sexual dimorphism, suggesting that the "T. horridus"-"T. prorsus"-"T. brevicornus" lineage was composed of females, the "T.calicornis"-"T.elatus" lineage was made up of males, and the "T. obtusus"-"T. hatcheri" lineage was of pathologic old males. His reasoning was that males had taller, more erect horns and larger


title: Triceratops content: skulls, and females had smaller skulls with shorter, forward-facing horns. These findings were contested a few years later by Catherine Forster, who reanalyzed "Triceratops" material more comprehensively and concluded that the remains fell into two species, "T. horridus" and "T. prorsus", although the distinctive skull of "T." (""Nedoceratops"") "hatcheri" differed enough to warrant a separate genus. She found that "T. horridus" and several other species belonged together, and "T. prorsus" and "T. brevicornus" stood alone, and since there were many more specimens in the first group, she suggested that this meant the two groups were two species. It is still


title: Triceratops content: possible to interpret the differences as representing a single species with sexual dimorphism. In 2009, John Scannella and Denver Fowler supported the separation of "T. prorsus" and "T. horridus", and noted that the two species are also separated stratigraphically within the Hell Creek Formation, indicating that they did not live together at the same time. Some of the following species are synonyms, as indicated in parentheses ("="T. horridus"" or "="T. prorsus""). All the others are considered "nomina dubia" ("dubious names") because they are based on remains too poor or incomplete to be distinguished from pre-existing "Triceratops" species. "Triceratops" is the


title: Triceratops content: best known genus of the Ceratopsidae, a family of large, mostly North American horned dinosaurs. The exact location of "Triceratops" among the ceratopsians has been debated over the years. Confusion stemmed mainly from the combination of short, solid frills (similar to that of Centrosaurinae), and the long brow horns (more akin to Chasmosaurinae). In the first overview of horned dinosaurs, R. S. Lull hypothesized two lineages, one of "Monoclonius" and "Centrosaurus" leading to "Triceratops", the other with "Ceratops" and "Torosaurus", making "Triceratops" a centrosaurine as the group is understood today. Later revisions supported this view, formally describing the first, short-frilled


title: Triceratops content: group as Centrosaurinae (including "Triceratops"), and the second, long-frilled group as Chasmosaurinae. In 1949, Charles M. Sternberg was the first to question this and proposed instead that "Triceratops" was more closely related to "Arrhinoceratops" and "Chasmosaurus" based on skull and horn features, making "Triceratops" a ceratopsine (chasmosaurine of his usage) genus. He was largely ignored, with John Ostrom, and later David Norman both placing "Triceratops" within Centrosaurinae. Subsequent discoveries and analyses upheld Sternberg's view on the position of "Triceratops", with Lehman defining both subfamilies in 1990 and diagnosing "Triceratops" as ceratopsine (chasmosaurine of his usage) on the basis of several


title: Triceratops content: morphological features. In fact, it fits well into the ceratopsine subfamily, apart from its one feature of a shortened frill. Further research by Peter Dodson, including a 1990 cladistic analysis and a 1993 study using RFTRA (resistant-fit theta-rho analysis), a morphometric technique which systematically measures similarities in skull shape, reinforces "Triceratops" placement in the ceratopsine subfamily. The cladogram below follows Longrich (2014), who named a new species of "Pentaceratops", and included nearly all species of chasmosaurine. For many years after its discovery, the evolutionary origins of "Triceratops" remained largely obscure. In 1922, the newly discovered "Protoceratops" was seen as its


title: Triceratops content: ancestor by Henry Fairfield Osborn, but many decades passed before additional findings came to light. Recent years have been fruitful for the discovery of several antecedents of "Triceratops". "Zuniceratops", the earliest known ceratopsian with brow horns, was described in the late 1990s, and "Yinlong", the first known Jurassic ceratopsian, in 2005. These new finds have been vital in illustrating the origins of horned dinosaurs in general, suggesting an Asian origin in the Jurassic, and the appearance of truly horned ceratopsians by the beginning of the late Cretaceous in North America. As "Triceratops" is increasingly shown to be a member of


title: Triceratops content: the long-frilled subfamily Ceratopsinae, a likely ancestor may have resembled "Chasmosaurus", which thrived some 5 million years earlier. In phylogenetic taxonomy, the genus "Triceratops" has been used as a reference point in the definition of Dinosauria; dinosaurs have been designated as all descendants of the most recent common ancestor of "Triceratops" and Neornithes (i.e. modern birds). Furthermore, the bird-hipped dinosaurs, Ornithischia, have all been designated dinosaurs with a more recent common ancestor to "Triceratops" than modern birds. Although "Triceratops" are commonly portrayed as herding animals, there is currently little evidence that they lived in herds. While several other genera of


title: Triceratops content: horned dinosaurs are known from bonebeds preserving bones from two to hundreds or thousands of individuals, to date there is only one documented bonebed dominated by "Triceratops" bones: a site in southeastern Montana with the remains of three juveniles. It may be significant that only juveniles were present. In 2012, a group of three "Triceratops" in relatively complete condition, each of varying sizes from a full-grown adult to a small juvenile, were found in Wyoming, near Newcastle. The remains are currently under excavation by paleontologist Peter Larson and a team from the Black Hills Institute. It is believed that the


title: Triceratops content: animals were traveling as a family unit, but it remains unknown if the group consists of a mated pair and their offspring, or two females and a juvenile they were caring for. The remains also show signs of predation or scavenging from "Tyrannosaurus", particularly on the largest specimen, with the bones of the front limbs showing breakage and puncture wounds from "Tyrannosaurus" teeth. For many years, "Triceratops" finds were known only from solitary individuals. These remains are very common; for example, Bruce Erickson, a paleontologist of the Science Museum of Minnesota, has reported having seen 200 specimens of "T. prorsus"


title: Triceratops content: in the Hell Creek Formation of Montana. Similarly, Barnum Brown claimed to have seen over 500 skulls in the field. Because "Triceratops" teeth, horn fragments, frill fragments, and other skull fragments are such abundant fossils in the Lancian faunal stage of the late Maastrichtian (late Cretaceous, 66 mya) Period of western North America, it is regarded as among the dominant herbivores of the time, if not the most dominant herbivore. In 1986, Robert Bakker estimated it as making up 5/6ths of the large dinosaur fauna at the end of the Cretaceous. Unlike most animals, skull fossils are far more common


title: Triceratops content: than postcranial bones for "Triceratops", suggesting that the skull had an unusually high preservation potential. "Triceratops" were herbivorous, and because of their low head, their primary food was probably low growth, although they may have been able to knock down taller plants with their horns, beak, and bulk. The jaws were tipped with a deep, narrow beak, believed to have been better at grasping and plucking than biting. "Triceratops" teeth were arranged in groups called batteries, of 36 to 40 tooth columns in each side of each jaw, with 3 to 5 stacked teeth per column, depending on the size


title: Triceratops content: of the animal. This gives a range of 432 to 800 teeth, of which only a fraction were in use at any given time (tooth replacement was continuous throughout the life of the animal). They functioned by shearing in a vertical to near-vertical orientation. The great size and numerous teeth of "Triceratops" suggests that they ate large volumes of fibrous plant material, with some researchers suggesting palms and cycads, and others suggesting ferns, which then grew in prairies. There has been much speculation over the functions of "Triceratops" head adornments. The two main theories have revolved around use in combat


title: Triceratops content: and in courtship display, with the latter now thought to be the most likely primary function. Early on, Lull postulated that the frills may have served as anchor points for the jaw muscles to aid chewing by allowing increased size and thus power for the muscles. This has been put forward by other authors over the years, but later studies do not find evidence of large muscle attachments on the frill bones. "Triceratops" were long thought to have used their horns and frills in combat with predators such as "Tyrannosaurus", the idea being discussed first by Charles H. Sternberg in


title: Triceratops content: 1917 and 70 years later by Robert Bakker. There is evidence that "Tyrannosaurus" did have aggressive head-on encounters with "Triceratops", based on partially healed tyrannosaur tooth marks on a "Triceratops" brow horn and squamosal; the bitten horn is also broken, with new bone growth after the break. Which animal was the aggressor is not known. Since the "Triceratops" wounds healed, it is most likely that the "Triceratops" survived the encounter. "Tyrannosaurus" is also known to have fed on "Triceratops", as shown by a heavily tooth-scored "Triceratops" ilium and sacrum. In addition to combat with predators using horns, "Triceratops" are popularly


title: Triceratops content: shown engaging each other in combat with horns locked. While studies show that such activity would be feasible, if unlike that of present-day horned animals, there is disagreement about whether they did so. Although pitting, holes, lesions, and other damage on "Triceratops" skulls (and the skulls of other ceratopsids) are often attributed to horn damage in combat, a 2006 study finds no evidence for horn thrust injuries causing these forms of damage (for example, there is no evidence of infection or healing). Instead, non-pathological bone resorption, or unknown bone diseases, are suggested as causes. A newer study compared incidence rates


title: Triceratops content: of skull lesions and periosteal reaction in "Triceratops" and "Centrosaurus" and showed that these were consistent with "Triceratops" using its horns in combat and the frill being adapted as a protective structure, while lower pathology rates in "Centrosaurus" may indicate visual rather than physical use of cranial ornamentation, or a form of combat focused on the body rather than the head. The frequency of injury was found to be 14% in "Triceratops". The researchers also concluded that the damage found on the specimens in the study was often too localized to be caused by bone disease. Histological examination reveals that


title: Triceratops content: the frill of "Triceratops" is composed of fibrolamellar bone which contains fibroblasts that play a critical role in wound healing, and are capable of rapidly depositing bone during remodeling. One skull was found with a hole in the jugal bone, apparently a puncture wound sustained while the animal was alive, as indicated by signs of healing. The hole has a diameter close to that of the distal end of a "Triceratops" horn. This, and other apparent healed wounds in the skulls of ceratopsians, has been cited as evidence of non-fatal intraspecific competition in these dinosaurs. The large frill also may


title: Triceratops content: have helped to increase body area to regulate body temperature. A similar theory has been proposed regarding the plates of "Stegosaurus", although this use alone would not account for the bizarre and extravagant variation seen in different members of the Ceratopsidae, which would rather support the sexual display theory. The theory that frills functioned as a sexual display was first proposed by Davitashvili in 1961 and has gained increasing acceptance since. Evidence that visual display was important, either in courtship or other social behavior, can be seen in the horned dinosaurs differing markedly in their adornments, making each species highly


title: Triceratops content: distinctive. Also, modern living creatures with such displays of horns and adornments use them similarly. A 2006 study of the smallest "Triceratops" skull, ascertained to be a juvenile, shows the frill and horns developed at a very early age, predating sexual development and thus probably important for visual communication and species recognition in general. The use of the exaggerated structures to enable dinosaurs to recognize their own species has been questioned, as no such function exists for such structures in modern species. In 2006, the first extensive ontogenetic study of "Triceratops" was published in the journal Proceedings of the Royal


title: Triceratops content: Society. The study, by John R. Horner and Mark Goodwin, found that individuals of "Triceratops" could be divided into four general ontogenetic groups, babies, juveniles, subadults, and adults. With a total number of 28 skulls studied, the youngest was only long. 10 of the 28 skulls could be placed in order in a growth series with one representing each age. Each of the four growth stages were found to have identifying features. Multiple ontogenetic trends were discovered, including the size reduction of the epoccipitals, development and reorientation of postorbital horns, and hollowing out of the horns. "Torosaurus" is a ceratopsid


title: Triceratops content: genus first identified from a pair of skulls in 1891, two years after the identification of "Triceratops". The genus "Torosaurus" resembles "Triceratops" in geological age, distribution, anatomy and size and it has been recognised as a close relative. Its distinguishing features are an elongated skull and the presence of two fenestrae, or holes, in the frill. Paleontologists investigating dinosaur ontogeny (growth and development of individuals over the life span) in the Hell Creek Formation, Montana, US, have recently presented evidence that the two represent a single genus. John Scannella, in a paper presented in Bristol, UK at the conference of


title: Triceratops content: the Society of Vertebrate Paleontology (25 September 2009) reclassified "Torosaurus" as especially mature "Triceratops" individuals, perhaps representing a single sex. Jack Horner, Scannella's mentor at Bozeman Campus, Montana State University, noted that ceratopsian skulls consist of metaplastic bone. A characteristic of metaplastic bone is that it lengthens and shortens over time, extending and resorbing to form new shapes. Significant variety is seen even in those skulls already identified as "Triceratops", Horner said, "where the horn orientation is backwards in juveniles and forward in adults". Approximately 50% of all subadult "Triceratops" skulls have two thin areas in the frill that correspond


title: Triceratops content: with the placement of "holes" in "Torosaurus" skulls, suggesting that holes developed to offset the weight that would otherwise have been added as maturing "Triceratops" individuals grew longer frills. A paper describing these findings in detail was published in July 2010 by Scannella and Horner. It formally argues that "Torosaurus" and the similar contemporary "Nedoceratops" are synonymous with "Triceratops". The assertion ignited debate. Andrew Farke had in 2006 stressed that, apart from the frill, no systematic differences could be found between "Torosaurus" and "Triceratops". He nevertheless disputed Scannella's conclusion by arguing in 2011 that the proposed morphological changes required to


title: Triceratops content: "age" a "Triceratops" into a "Torosaurus" would be without precedent among ceratopsids. Such changes would include the growth of additional epoccipitals, reversion of bone texture from an adult to immature type and back to adult again, and growth of frill holes at a later stage than usual. A study by Nicholas Longrich and Daniel Field analyzed 35 specimens of both "Triceratops" and "Torosaurus". The authors concluded that "Triceratops" individuals too old to be considered immature forms are represented in the fossil record, as are "Torosaurus" individuals too young to be considered fully mature adults. The synonymy of "Triceratops" and "Torosaurus"


title: Triceratops content: cannot be supported, they said, without more convincing intermediate forms than Scannella and Horner initially produced. Scannella's "Triceratops" specimen with a hole on its frill, they argued, could represent a diseased or malformed individual rather than a transitional stage between an immature "Triceratops" and mature "Torosaurus" form. Given the abundance of fossils, particularly of "Triceratops", additional field discoveries are expected to settle the debate in time. Opinion has varied on the validity of a separate genus for "Nedoceratops". John Scannella and Jack Horner regarded it as an intermediate growth stage between "Triceratops" and "Torosaurus". Andrew Farke, in his 2011 redescription


title: Triceratops content: of the only known skull, concluded that it was an aged individual of its own valid taxon, "Nedoceratops hatcheri". Nicholas Longrich and Daniel Fields also did not consider it a transition between "Torosaurus" and "Triceratops", suggesting that the frill holes were pathological. As described above, John Scannella had argued in 2010 that "Nedoceratops" should be considered a synonym of "Triceratops". Andrew Farke (2011) maintained that it represents a valid distinct genus. Nick Longrich agreed with Scannella about "Nedoceratops" and made a further suggestion: that the recently described "Ojoceratops" was likewise a synonym. The fossils, he argued, are indistinguishable from the


title: Triceratops content: "T. horridus" specimens that were previously attributed to the defunct species "T. serratus". Longrich observed that another newly described genus, "Tatankaceratops", displayed a strange mix of characteristics already found in adult and juvenile "Triceratops". Rather than representing a distinct genus, "Tatankaceratops" could as easily represent a dwarf "Triceratops" or a "Triceratops" individual with a developmental disorder that caused it to stop growing prematurely. "Triceratops" lived during the Late Cretaceous of North America, its fossils coming from the Evanston Formation, Scollard Formation, Laramie Formation, Lance Formation, Denver Formation, and Hell Creek Formation. These fossil formations date back to the time of


title: Triceratops content: the Cretaceous-Paleogene Extinction Event, and have been dated to 66 ± 0.07 million years ago. Many animals and plants have been found in these formations, but mostly from the Lance Formation and Hell Creek Formation. "Triceratops" was one of the last ceratopsian genera to appear before the end of the Mesozoic. The related "Torosaurus", and the more distantly related diminutive "Leptoceratops", were also present, though their remains have been rarely encountered. Theropods from these formations include genera of tyrannosaurids, ornithomimids, troodontids, avialans, caenagnathids, and dromaeosaurids. "Acheroraptor" and "Dakotaraptor" are dromaeosaurids from the Hell Creek Formation. Indeterminate dromaeosaurs are known from


title: Triceratops content: other fossil formations. Common teeth previously referred to "Dromaeosaurus" and "Saurornitholestes" later were considered to be "Acheroraptor". The tyrannosaurids from the formation are "Nanotyrannus" and "Tyrannosaurus", although the former might be a junior synonym of the latter. Among ornithomimids are the genera "Struthiomimus" as well as "Ornithomimus", although an undescribed animal named "Orcomimus" could be from the formation. Troodontids are only represented by "Pectinodon" and "Paronychodon" in the Hell Creek Formation; with a possible species of "Troodon" from the Lance Formation. One species of coelurosaur is known from Hell Creek and similar formations by a single species, "Richardoestesia". Only three


title: Triceratops content: oviraptorosaurs are from the Hell Creek Formation, "Anzu", "Leptorhynchos" and a giant species of caenagnathid, very similar to "Gigantoraptor", from South Dakota. However, only fossilized foot prints were discovered. The avialans known from the formation are "Avisaurus", multiple species of "Brodavis", and several other species of hesperornithoforms, as well as several species of true birds including "Cimolopteryx". Ornithischians are abundant in the Scollard Lance, Laramie, Lance, Denver, and Hell Creek Formation. The main groups of ornithischians are ankylosaurians, ornithopods, ceratopsians, and pachycephalosaurians. Three ankylosaurians are known, "Ankylosaurus", "Denversaurus", and possibly a species of "Edmontonia" or an undescribed genus. Multiple genera


title: Triceratops content: of ceratopsians are known from the formation other than "Triceratops", the leptoceratopsid "Leptoceratops", and the chasmosaurine ceratopsids "Torosaurus","Nedoceratops" and "Tatankaceratops". Ornithopods are common in the Hell Creek Formation, and are known from several species of the ornithopod "Thescelosaurus", and the hadrosaurids "Edmontosaurus", and a possible species of "Parasaurolophus". Several pachycephalosaurians have been found in the Hell Creek Formation and in similar formations. Among them are the derived pachycephalosaurids ""Stygimoloch"", ""Dracorex"", "Pachycephalosaurus", "Sphaerotholus", and an undescribed specimen from North Dakota. The first two might be junior synonyms of "Pachycephalosaurus". Mammals are plentiful in the Hell Creek Formation. Groups represented include multituberculates,


title: Triceratops content: metatherians, and eutherians. The multituberculates represented include "Paracimexomys", the cimolomyids "Paressonodon", "Meniscoessus", "Essonodon", "Cimolomys", "Cimolodon", and "Cimexomys"; and the neoplagiaulacids "Mesodma", and "Neoplagiaulax". The alphadontids "Alphadon", "Protalphodon", and "Turgidodon", pediomyids "Pediomys", "Protolambda", and "Leptalestes", the stagodontid "Didelphodon", the deltatheridiid "Nanocuris", the herpetotheriid "Nortedelphys", and the glasbiid "Glasbius" all represent metatherians of the Hell Creek Formation. A few eutherians are known, being represented by "Alostera", "Protungulatum", the cimolestids "Cimolestes" and "Batodon", the gypsonictopsid "Gypsonictops", and the possible nyctitheriid "Paranyctoides". "Triceratops" is the official state fossil of South Dakota, and the official state dinosaur of Wyoming. The distinctive appearance of "Triceratops" has


title: Triceratops content: led to it being frequently depicted in films, computer games and documentaries, such as the 1993 film "Jurassic Park" and the 1999 BBC television documentary "Walking with Dinosaurs". A recurring theme, especially in children's dinosaur books, is a climactic showdown or battle between "Triceratops" and "Tyrannosaurus". In 1942, Charles R. Knight painted a mural incorporating a confrontation between the two dinosaurs in the Field Museum of Natural History for the National Geographic Society, establishing them as enemies in the popular imagination. Paleontologist Bob Bakker said of the imagined rivalry between "Tyrannosaurus" and "Triceratops", "No matchup between predator and prey has


title: Triceratops content: ever been more dramatic. It's somehow fitting that those two massive antagonists lived out their co-evolutionary belligerence through the very last days of the very last epoch of the Age of Dinosaurs." Triceratops Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago (mya) in what is now North America. It is one of the last known non-avian dinosaur genera, and became extinct in the Cretaceous–Paleogene extinction event 66 million years ago. The name "Triceratops", which literally means "three-horned face", is derived from the


title: Trolleybus content: Trolleybus A trolleybus (also known as trolley bus, trolley coach, trackless trolley, trackless tram [in early years] or trolley) is an electric bus that draws power from overhead wires (generally suspended from roadside posts) using spring-loaded trolley poles. Two wires and poles are required to complete the electrical circuit. This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole (or pantograph). They are also distinct from other kinds of electric buses, which usually rely on batteries. Power is most commonly supplied as 600-volt direct current, but there


title: Trolleybus content: are exceptions. Currently, around 300 trolleybus systems are in operation, in cities and towns in 43 countries. Altogether, more than 800 trolleybus systems have existed, but not more than about 400 concurrently. The trolleybus dates back to 29 April 1882, when Dr. Ernst Werner Siemens demonstrated his "Elektromote" in a Berlin suburb. This experiment continued until 13 June 1882, after which there were few developments in Europe, although separate experiments were conducted in the U.S. In 1899, another vehicle which could run either on or off rails was demonstrated in Berlin. The next development was when Lombard Gerin operated an


title: Trolleybus content: experimental line at the Paris Exhibition of 1900 after four years of trials, with a circular route around Lake Daumesnil that carried passengers. Routes followed in 6 places including Eberswalde and Fontainebleau. on 10 July 1901 opened the world's fourth passenger-carrying trolleybus system, which operated at Bielatal (Biela Valley, near Dresden), in Germany. Schiemann built and operated the Bielatal system, and is credited with developing the under-running trolley current collection system, with two horizontally parallel overhead wires and rigid trolleypoles spring-loaded to hold them up to the wires. Although this system operated only until 1904, Schiemann had developed what is


title: Trolleybus content: now the standard trolleybus current collection system. In the early days there were many other methods of current collection. The Cédès-Stoll (Mercédès-Électrique-Stoll) system was first operated near Dresden between 1902 and 1904, and 18 systems followed. The Lloyd-Köhler or Bremen system was tried out in Bremen with 5 further installations, and the Cantono Frigerio system was used in Italy. Throughout the period, trackless freight systems and electric canal boats were also built. Leeds and Bradford became the first cities to put trolleybuses into service in Great Britain on 20 June 1911. Apparently, though it was opened on 20 June, the


title: Trolleybus content: public was not admitted to the Bradford route until the 24th. Bradford was also the last to operate trolleybuses in the UK, the system closing on 26 March 1972. The last rear-entrance trolleybus in Britain was also in Bradford and is now owned by the Bradford Trolleybus Association. Birmingham was the first to replace a tram route with trolleybuses, while Wolverhampton, under the direction of Charles Owen Silvers, became world-famous for its trolleybus designs. There were 50 trolleybus systems in the UK, London's being the largest. By the time trolleybuses arrived in Britain in 1911, the Schiemann system was well


title: Trolleybus content: established and was the most common, although the Cédès-Stoll (Mercédès-Électrique-Stoll) system was tried in West Ham (in 1912) and in Keighley (in 1913). Smaller trackless trolley systems were built in the US early as well. The first non-experimental system was a seasonal municipal line installed near Nantasket Beach in 1904; the first year-round commercial line was built to open a hilly property to development just outside Los Angeles in 1910. The trackless trolley was often seen as an interim step, leading to streetcars. In the U.S.A., some systems subscribed to the all-four concept of using buses, trolleybuses, streetcars ("trams", "trolleys")


title: Trolleybus content: and rapid transit subway and/or elevated lines (metros), as appropriate, for routes ranging from the lightly used to the heaviest trunk line. Buses and trolleybuses in particular were seen as entry systems that could later be upgraded to rail as appropriate. In a similar fashion, many cities in Britain originally viewed trolleybus routes as extensions to tram (streetcar) routes where the cost of constructing or restoring track could not be justified at the time, though this attitude changed markedly (to viewing them as outright replacements for tram routes) in the years after 1918. Trackless trolleys were the dominant form of


title: Trolleybus content: new post-war electric traction, with extensive systems in among others, Los Angeles, Chicago, Rhode Island, and Atlanta; Boston, San Francisco (California), and Philadelphia (Pennsylvania) still maintain an "all-four" fleet. Some trolleybus lines in the United States (and in Britain, as noted above) came into existence when a trolley or tram route did not have sufficient ridership to warrant track maintenance or reconstruction. In a similar manner, a proposed tram scheme in Leeds, United Kingdom, was changed to a trolleybus scheme to cut costs. Trolleybuses are uncommon today in North America, but they remain common in many European countries as well


title: Trolleybus content: as Russia and China, generally occupying a position in usage between street railways (trams) and diesel buses. Worldwide, around 300 cities or metropolitan areas are served by trolleybuses today. (Further detail under Use and preservation, below.) Trolleybuses are used extensively in large European cities, such as Athens, Belgrade, Bratislava, Bucharest, Budapest, Chisinau, Kiev, Lyon, Milan, Minsk, Moscow, Riga, Saint Petersburg, Sofia, Tallinn, Varna, Vilnius and Zurich, as well as smaller ones such as Arnhem, Bergen, Coimbra, Gdynia, Kaunas, Lausanne, Limoges, Luzern, Modena, Piatra Neamț, Plzeň, Prešov, Salzburg, Solingen, Szeged, Târgu Jiu and Yalta. "See also Trolleybus usage by country." Transit


title: Trolleybus content: authorities in some cities have reduced or discontinued their use of trolleybuses in recent years, while others, wanting to add or expand use of zero-emission vehicles in an urban environment, have opened new systems or are planning new systems. For example, new systems opened in Lecce, Italy, in 2012 and in Malatya, Turkey, in 2015. "Note: As there are numerous variations of tram and light-rail technology, the disadvantages listed may be applicable only with a specific technology or design." With the re-introduction of hybrid designs, trolleybuses are no longer tied to overhead wires. The Public Service Company of New Jersey,


title: Trolleybus content: with Yellow Coach, developed "All Service Vehicles;" trackless trolleys capable of operating as gas-electric buses when off wire, and used them successfully between 1935 and 1948. Since the 1980s, systems such as Muni in San Francisco, TransLink in Vancouver, and Beijing, among others, have bought trolleybuses equipped with batteries to allow them to operate fairly long distances away from the wires. Supercapacitors can be also used to move buses short distances. Trolleybuses can optionally be equipped either with limited off-wire capability—a small diesel engine or battery pack—for auxiliary or emergency use only, or full dual-mode capability. A simple auxiliary power


title: Trolleybus content: unit can allow a trolleybus to get around a route blockage or can reduce the amount (or complexity) of overhead wiring needed at operating garages (depots). This capability has become increasingly common in newer trolleybuses, particularly in North America and Europe, where the vast majority of new trolleybuses delivered since the 1990s are fitted with at least limited off-wire capability. These have gradually replaced older trolleybuses which lacked such capability. In Philadelphia, new trackless trolleys equipped with small hybrid diesel-electric power units for operating short distances off-wire were placed in service by SEPTA in 2008 are, instead of using a


title: Trolleybus content: conventional diesel drive train or battery-only system for their off-wire movement. King County Metro in Seattle, Washington and the MBTA in Boston use or have used dual-mode buses that run on electric power from overhead wires on a fixed right-of-way and on diesel power on city streets. Metro used special-order articulated Breda buses with the center axle driven electrically and the rear (third) axle driven by a conventional power pack, with electricity used for clean operation in the downtown transit tunnel. They were introduced in 1990 and retired in 2005, replaced by cleaner hybrid buses, although 59 of 236 had


title: Trolleybus content: their diesel propulsion equipment removed and continue (as of 2010) in trolley bus service on non-tunnel routes. The MBTA uses dual-mode buses on its new (2004-opened) Silver Line (Waterfront). With increasing diesel fuel costs and problems caused by particulate matter and NO emissions in cities, trolleybuses can be an attractive alternative, either as the primary transit mode or as a supplement to rapid transit and commuter rail networks. Trolleybuses are quieter than internal combustion engine vehicles. Mainly a benefit, it also provides much less warning of a trolleybus's approach. A speaker attached to the front of the vehicle can raise


title: Trolleybus content: the noise to a desired "safe" level. This noise can be directed to pedestrians in front of the vehicle, as opposed to motor noise which typically comes from the rear of a bus and is more noticeable to bystanders than to pedestrians. Trolleybuses can share overhead wires and other electrical infrastructure (such as substations) with tramways. This can result in cost savings when trolleybuses are added to a transport system that already has trams, though this refers only to potential savings over the cost of installing and operating trolleybuses alone. Trolleybus wire switches (called frogs in the UK) are used


title: Trolleybus content: where a trolleybus line branches into two or where two lines join. A switch may be either in a "straight through" or "turnout" position; it normally remains in the "straight through" position unless it has been triggered, and reverts to it after a few seconds or after the pole shoe passes through and strikes a release lever. (In Boston, the resting or "default" position is the "leftmost" position.) Triggering is typically accomplished by a pair of contacts, one on each wire close to and before the switch assembly, which power a pair of electromagnets, one in each frog with diverging


title: Trolleybus content: wires. ("Frog" generally refers to one fitting that guides one trolley wheel/shoe onto a desired wire or across one wire. Occasionally, "frog" has been used to refer to the entire switch assembly.) Multiple branches may be handled by installing more than one switch assembly. For example, to provide straight-through, left-turn or right-turn branches at an intersection, one switch is installed some distance from the intersection to choose the wires over the left-turn lane, and another switch is mounted closer to or in the intersection to choose between straight through and a right turn. (This would be the arrangement in countries


title: Trolleybus content: such as the US, where traffic directionality is right-handed; in left-handed traffic countries such as the United Kingdom and New Zealand, the first switch (before the intersection) would be used to access the right-turn lanes, and the second switch (usually in the intersection) would be for the left-turn.) Three common types of switches exist: power-on/power-off (the picture of a switch above is of this type), Selectric, and Fahslabend. A power-on/power-off switch is triggered if the trolleybus is drawing considerable power from the overhead wires, usually by accelerating, at the moment the poles pass over the contacts. (The contacts are lined