parent_taxon anthracotheriidae
The Eocene Epoch , lasting from , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era . The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch . The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope C in the atmosphere was exceptionally low in comparison with the more common isotope C . The end is set at a major extinction event called the " Grande Coupure " ( the " Great Break " in continuity ) or the Eocene  Oligocene extinction event , which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay . As with other geologic periods , the strata that define the start and end of the epoch are well identified , though their exact dates are slightly uncertain . The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33 . 9 million to 23 million years before the present ( to ). As with other older geologic periods , the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain . The name Oligocene comes from the Ancient Greek (" oligos ", few ) and (" kainos ", new ), and refers to the sparsity of extant forms of molluscs . The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch . The Oligocene is the third and final epoch of the Paleogene Period . The Oligocene is often considered an important time of transition , a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene . Major changes during the Oligocene included a global expansion of grasslands , and a regression of tropical broad leaf forests to the equatorial belt . Elephants are large mammals of the family ___MASK48___ and the order ___MASK45___ . Two species are traditionally recognised , the African elephant (" Loxodonta africana ") and the ___MASK6___ (" Elephas maximus "), although some evidence suggests that African bush elephants and African forest elephants are separate species (" L . africana " and " L . cyclotis " respectively ). Elephants are scattered throughout sub - Saharan Africa , South Asia , and Southeast Asia . ___MASK48___ is the only surviving family of the order ___MASK45___ ; other , now extinct , members of the order include deinotheres , gomphotheres , mammoths , and mastodons . Male African elephants are the largest extant terrestrial animals and can reach a height of and weigh . All elephants have several distinctive features , the most notable of which is a long trunk or proboscis , used for many purposes , particularly breathing , lifting water , and grasping objects . Their incisors grow into tusks , which can serve as weapons and as tools for moving objects and digging . Elephants ' large ear flaps help to control their body temperature . Their pillar - like legs can carry their great weight . African elephants have larger ears and concave backs while Asian elephants have smaller ears and convex or level backs . Whales are a widely distributed and diverse group of fully aquatic placental marine mammals . They are an informal grouping within the infraorder ___MASK52___ , usually excluding dolphins and porpoises . Whales , dolphins and porpoises belong to the order Cetartiodactyla with even - toed ungulates and their closest living relatives are the hippopotamuses , having diverged about 40 million years ago . The two parvorders of whales , baleen whales ( Mysticeti ) and toothed whales ( Odontoceti ), are thought to have split apart around 34 million years ago . The whales comprise eight extant families : Balaenopteridae ( the rorquals ), Balaenidae ( right whales ), Cetotheriidae ( the pygmy ___MASK86___ ), Eschrichtiidae ( the gray whale ), Monodontidae ( belugas and narwhals ), Physeteridae ( the sperm whale ), Kogiidae ( the dwarf and pygmy sperm whale ), and Ziphiidae ( the beaked whales ). Mammals are any vertebrates within the class Mammalia ( from Latin " mamma " " breast "), a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex ( a region of the brain ), hair , three middle ear bones and mammary glands . The sister group of mammals may be the extinct " Haldanodon ." The mammals represent the only living Synapsida , which together with the ___MASK30___ form the Amniota clade . The mammals consist of the Yinotheria including monotrema and the Theriiformes including the theria . Toulouse is the capital city of the southwestern French department of Haute - Garonne , as well as of the Occitanie region . The city lies on the banks of the River Garonne , from the Mediterranean Sea , from the Atlantic Ocean , and from ___MASK100___ . It is the fourth - largest city in France with 466 , 297 inhabitants in January 2014 . The Toulouse Metro area is , with 1 312 304 inhabitants as of 2014 , France ' s 4th metropolitan area after ___MASK100___ , Lyon and Marseille and ahead of Lille and Bordeaux . North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere . It can also be considered a northern subcontinent of the Americas . It is bordered to the north by the Arctic Ocean , to the east by the Atlantic Ocean , to the west and south by the Pacific Ocean , and to the southeast by South America and the Caribbean Sea . Anthracotherium (" Coal Beast ") was a genus of extinct artiodactyl ___MASK53___ mammals , characterized by having 44 teeth , with five semi - crescentic cusps on the crowns of the upper molars . The genus ranged from the early Eocene period until the late Oligocene , having a distribution throughout Eurasia . The last species died out near the end of the Oligocene . ___MASK52___ are a widely distributed and diverse clade of aquatic mammals that today consists of the whales , dolphins , and porpoises . Cetaceans are carnivorous and finned . Most species live in the sea , some in rivers . The name is derived from the Latin " cetus " " whale " and Greek " ketos " " huge fish ". A ___MASK65___ ( meaning " nose horn "), often abbreviated to rhino , is one of any five extant species of odd - toed ungulates in the family Rhinocerotidae , as well as any of the numerous extinct species . Two of these extant species are native to Africa and three to Southern Asia . Nice (; Niçard , classical norm , or "", nonstandard , ) is the fifth most populous city in France and the capital of the Alpes - Maritimes " département ". The urban ___MASK91___ of Nice extends beyond the administrative city limits , with a population of about 1 million on an ___MASK91___ of . Located in the French Riviera , on the south east coast of France on the Mediterranean Sea , at the foot of the Alps , Nice is the second - largest French city on the Mediterranean coast and the second - largest city in the Provence - Alpes - Côte d ' Azur region after Marseille . Nice is about 13 kilometres ( 8 miles ) from the principality of Monaco , and its airport is a gateway to the principality as well . Tertiary is the former term for the geologic period from 66 million to 2 . 58 million years ago , a time span that lies between the superseded Secondary period and the Quaternary . The Tertiary is no longer recognized as a formal unit by the International Commission on Stratigraphy , but the word is still widely used . The traditional span of the Tertiary has been divided between the Paleogene and ___MASK26___ Periods and extends to the first stage of the Pleistocene Epoch , the Gelasian age . The period began with the demise of the non - avian dinosaurs in the Cretaceous  Paleogene extinction event , at the start of the Cenozoic Era , and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch . The Atlantic Ocean is the second largest of the world ' s oceans with a total ___MASK91___ of about . It covers approximately 20 percent of the Earth ' s surface and about 29 percent of its water surface ___MASK91___ . It separates the " Old World " from the " New World ". The ___MASK26___ is a geologic period and system that spans 20 . 45 million years from the end of the Paleogene Period million years ago ( ___MASK18___ ) to the beginning of the present Quaternary Period ___MASK18___ . The ___MASK26___ is sub - divided into two epochs , the earlier Miocene and the later Pliocene . Some geologists assert that the ___MASK26___ cannot be clearly delineated from the modern geological period , the Quaternary . The North Sea is a marginal sea of the Atlantic Ocean located between Great Britain , Scandinavia , Germany , the Netherlands , Belgium , and France . An epeiric ( or " shelf ") sea on the European continental shelf , it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north . It is more than long and wide , with an ___MASK91___ of around . Invertebrates are animals that neither possess nor develop a vertebral column ( commonly known as a " backbone " or " spine "), derived from the notochord . This includes all animals apart from the subphylum ___MASK98___ . Familiar examples of invertebrates include ___MASK56___ ; crabs , lobsters and their kin ; snails , clams , octopuses and their kin ; starfish , sea - urchins and their kin ; and worms . The Phanerozoic Eon ( British English Phanærozoic ) is the current geologic eon in the geologic time scale , and the one during which abundant ___MASK83___ and ___MASK58___ life has existed . It covers million years to the present , and began with the Cambrian Period when diverse hard - shelled animals first appeared . Its name was derived from the Ancient Greek words ( phanerós ) and ( z ), meaning " visible life ", since it was once believed that life began in the Cambrian , the first period of this eon . The time before the Phanerozoic , called the " Precambrian " supereon , is now divided into the Hadean , Archaean and Proterozoic eons . The Miocene is the first geological epoch of the ___MASK26___ Period and extends from about ( Ma ). The Miocene was named by Sir Charles Lyell . Its name comes from the Greek words (',  less ) and (',  new ) and means " less recent " because it has 18 % fewer modern sea invertebrates than the Pliocene . The Miocene follows the Oligocene Epoch and is followed by the Pliocene Epoch . ___MASK49___ ( singular and plural ) are the ruminant mammals forming the family Cervidae . The two main groups are the Cervinae , including the muntjac , the fallow ___MASK49___ and the chital , and the Capreolinae , including the elk , reindeer ( caribou ), the Western roe ___MASK49___ , and the Eurasian elk ( moose ). Female reindeer , and male ___MASK49___ of all species ( except the Chinese water ___MASK49___ ), grow and shed new antlers each year . In this they differ from permanently horned antelope , which are in the same order , ___MASK55___ . Ungulates ( pronounced ) are any members of a diverse group of primarily large mammals that includes odd - toed ungulates such as horses and rhinoceroses , and even - toed ungulates such as cattle , pigs , giraffes , camels , ___MASK49___ , and hippopotami . Most terrestrial ungulates use the tips of their toes , usually hoofed , to sustain their whole body weight while moving . The term means , roughly , " being hoofed " or " hoofed animal ". As a descriptive term , " ___MASK53___ " normally excludes cetaceans ( whales , dolphins , porpoises ), as they do not possess most of the typical morphological characteristics of ungulates , but recent discoveries indicate that they are descended from early artiodactyls . Ungulates are typically herbivorous ( though some species are omnivorous , such as pigs ), and many employ specialized gut bacteria to allow them to digest cellulose , as in the case of ruminants . They inhabit a wide range of habitats , from jungles , plains and rivers . French Guiana ( pronounced or ), officially called Guiana , is an overseas department and region of France , located on the north Atlantic coast of South America in the Guyanas . It borders Brazil to the east and south , and Suriname to the west . Its ___MASK91___ has a very low population density of only 3 inhabitants per km , with half of its 244 , 118 inhabitants in 2013 living in the metropolitan ___MASK91___ of Cayenne , its capital . By land ___MASK91___ , it is the second largest region of France and the largest outermost region within the European Union . Lyon or ( more archaically ) Lyons ( or ) is a city in east - central France , in the Auvergne - Rhône - Alpes region , about from ___MASK100___ and from Marseille . Inhabitants of the city are called " Lyonnais ". Coal is a combustible black or brownish - black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams . The harder forms , such as anthracite coal , can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure . Coal is composed primarily of carbon , along with variable quantities of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . A fossil fuel , coal forms when dead ___MASK58___ matter is converted into peat , which in turn is converted into lignite , then sub - bituminous coal , after that bituminous coal , and lastly anthracite . This involves biological and geological processes that take place over time . Binomial nomenclature ( also called binominal nomenclature or binary nomenclature ) is a formal system of naming species of living things by giving each a name composed of two parts , both of which use Latin grammatical forms , although they can be based on words from other languages . Such a name is called a binomial name ( which may be shortened to just " binomial "), a binomen or a scientific name ; more informally it is also called a Latin name . The first part of the name identifies the genus to which the species belongs ; the second part identifies the species within the genus . For example , humans belong to the genus " ___MASK42___ " and within this genus to the species " ___MASK42___ sapiens ". The " formal " introduction of this system of naming species is credited to Carl Linnaeus , effectively beginning with his work " Species Plantarum " in 1753 . But Gaspard Bauhin , in as early as 1623 , had introduced in his book " Pinax theatri botanici " ( English , " Illustrated exposition of plants ") many names of genera that were later adopted by Linnaeus . Tusks are elongated , continuously growing front teeth , usually but not always in pairs , that protrude well beyond the mouth of certain ___MASK78___ species . They are most commonly canines , as with warthogs , pig , and walruses , or , in the case of elephants , elongated incisors . In most tusked species both the males and the females have tusks although the males ' are larger . Tusks are generally curved , though the narwhal ' s sole tusk is straight and has a helical structure . In the elephant , the tusks were originally second incisors . Continuous growth is enabled by formative tissues in the apical openings of the roots of the teeth . Sir Charles Lyell , 1st Baronet , ( 14 November 1797  22 February 1875 ) was a British lawyer and the foremost geologist of his day . He is best known as the author of " Principles of Geology ", which popularized James Hutton ' s concepts of uniformitarianism  the ___MASK54___ that the Earth was shaped by the same processes still in operation today . " Principles of Geology " also challenged theories popularized by Georges Cuvier , which were the most accepted and circulated ideas about geology in England at the time . ___MASK38___ is a genus of Hippopotamidae that is sometimes applied to the pygmy ___MASK59___ . Pygmy hippos may be classified as either " ___MASK81___ liberiensis " or " ___MASK38___ liberiensis ". The name " ___MASK38___ " means " six front teeth " as some of the fossil forms have three pairs of incisors . The genus ___MASK38___ also includes a number of rarely studied extinct species from Asia , sometimes labeled " Asian Hippopotami ." Merycopotamus is an extinct genus of Asian anthracothere that appeared during the Middle Miocene , and died out in the Late Pliocene . At the height of the genus ' influence , species ranged throughout southern Asia . With the extinction of the last species , " M . dissimilis ", the lineage of anthracotheres came to an end . " Merycopotamus " was closely related to the anthracothere genus " Libycosaurus ", which , unlike the former , never left Africa . In fact , some African fossils originally placed in " Merycopotamus ", but are now referred to " Libycosaurus ". In biology , an organism is any contiguous living system , such as an ___MASK83___ , ___MASK58___ , fungus , archaeon , or bacterium . All known types of organisms are capable of some degree of response to stimuli , reproduction , growth and development and homeostasis . An organism consists of one or more cells ; when it has one cell it is known as a unicellular organism ; and when it has more than one it is known as a multicellular organism . Most unicellular organisms are of microscopic scale and are thus loosely described as microorganisms . Humans are multicellular organisms composed of many trillions of cells grouped into specialized tissues and organs . The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago ( ___MASK18___ ) to the beginning of the Paleogene Period ___MASK18___ . It is the last period of the Mesozoic Era . The Cretaceous Period is usually abbreviated K , for its German translation " Kreide " ( chalk ). Libycosaurus (" ___MASK28___ of Libya ") was one of the last anthracothere genera . It lived from the Middle to the Late Miocene , and ranged throughout Central and Northern Africa , and in Uganda , in what was then a lush , marshy environment . A continent is one of several very large landmasses on Earth . Generally identified by convention rather than any strict criteria , up to seven regions are commonly regarded as continents . Ordered from largest in size to smallest , they are : Asia , Africa , North America , South America , Antarctica , Europe , and Australia . In geology , ___MASK46___ of continental crust include regions covered with water . Asia is Earth ' s largest and most populous continent , located primarily in the eastern and northern hemispheres and sharing the continental landmass of Eurasia with the continent of Europe . Asia covers an ___MASK91___ of , about 30 % of Earth ' s total land ___MASK91___ and 8 . 7 % of the Earth ' s total surface ___MASK91___ . The continent , which has long been home to the majority of the human population , was the site of many of the first civilizations . Asia is notable for not only its overall large size and population , but also dense and large settlements as well as vast barely populated regions within the continent of 4 . 4 billion people . A ___MASK84___ is any of the animals in the genus Sus , within the ___MASK96___ family of even - toed ungulates . Pigs include the domestic ___MASK84___ and its ancestor , the common Eurasian ___MASK77___ (" Sus scrofa "), along with other species ; related creatures outside the genus include the ___MASK87___ , the babirusa , and the warthog . Pigs , like all suids , are native to the Eurasian and African continents . Juvenile pigs are known as piglets . Pigs are highly social and intelligent animals . The Pliocene ( also Pleiocene ) Epoch is the epoch in the geologic timescale that extends from 5 . 333 million to 2 . 58 million years BP . It is the second and youngest epoch of the ___MASK26___ Period in the Cenozoic Era . The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch . Prior to the 2009 revision of the geologic time scale , which placed the four most recent major glaciations entirely within the Pleistocene , the Pliocene also included the Gelasian stage , which lasted from 2 . 588 to 1 . 806 million years ago , and is now included in the Pleistocene . A genus ( genera ) is a taxonomic rank used in the biological classification of living and fossil organisms in biology . In the hierarchy of biological classification , genus comes above species and below family . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus . The common ___MASK59___ (" ___MASK59___ amphibius "), or hippo , is a large , mostly herbivorous ___MASK78___ in sub - Saharan Africa , and one of only two extant species in the family Hippopotamidae , the other being the pygmy ___MASK59___ (" Choeropsis liberiensis " or " Hexaprotodon liberiensis "). The name comes from the ancient Greek for " river horse ". After the elephant and rhinoceros , the common ___MASK59___ is the third - largest type of land ___MASK78___ and the heaviest extant artiodactyl . Despite their physical resemblance to pigs and other terrestrial even - toed ungulates , the closest living relatives of the Hippopotamidae are cetaceans ( whales , porpoises , etc .) from which they diverged about . The common ancestor of whales and hippos split from other even - toed ungulates around . The earliest known ___MASK59___ fossils , belonging to the genus " Kenyapotamus " in Africa , date to around . France , officially the French Republic , is a country with territory in western Europe and several overseas regions and territories . The European , or metropolitan , ___MASK91___ of France extends from the Mediterranean Sea to the English Channel and the North Sea , and from the Rhine to the Atlantic Ocean . Overseas France include French Guiana on the South American continent and several island territories in the Atlantic , Pacific and Indian oceans . France spans and had a total population of almost 67 million people as of January 2017 . It is a unitary semi - presidential republic with the capital in ___MASK100___ , the country ' s largest city and main cultural and commercial centre . Other major urban centres include Marseille , Lyon , Lille , Nice , Toulouse and Bordeaux . Elomeryx is an extinct genus of artiodactyl ___MASK53___ , and is among the earliest known anthracotheres . The genus was extremely widespread , first being found in Asia in the middle Eocene , in Europe during the latest Eocene , and having spread to North America by the early Oligocene . " Elomeryx " was about in body length , and had a long , vaguely horse - like head . It had small tusks which it used to uproot plants , and spoon - shaped incisors ideal for pulling and cropping water plants . " Elomeryx " had five - toed hind legs and four - toed front legs , resulting in wide feet which made it easier to walk on soft mud . It probably had similar habits to the modern hippopotamus , to which it may have been related . The transition between the end of the Eocene and the beginning of the Oligocene is marked by large - scale extinction and floral and faunal turnover ( although minor in comparison to the largest mass extinctions ). Most of the affected organisms were marine or aquatic in nature . They included the last of the ancient cetaceans , the ___MASK85___ . Grasslands are ___MASK46___ where the vegetation is dominated by grasses ( ___MASK33___ ), however sedge ( Cyperaceae ) and rush ( Juncaceae ) families can also be found . Grasslands occur naturally on all continents except Antarctica . Grasslands are found in most ecoregions of the Earth . For example , there are five terrestrial ecoregion classifications ( subdivisions ) of the temperate grasslands , savannas , and shrublands biome ( ecosystem ), which is one of eight terrestrial ecozones of the Earth ' s surface . Animals are multicellular , eukaryotic organisms of the kingdom Animalia ( also called ___MASK9___ ). The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the choanoflagellates . Sponges are the most basal clade of animals . Animals are motile , meaning they can move spontaneously and independently at some point in their lives . Their body plan eventually becomes fixed as they develop , although some undergo a process of metamorphosis later in their lives . All animals are heterotrophs : they must ingest other organisms or their products for sustenance . Kenya , officially the Republic of Kenya , is a country in Africa and a founding member of the East African Community ( EAC ). Its capital and largest city is Nairobi . Kenya ' s territory lies on the equator and overlies the East African Rift covering a diverse and expansive terrain that extends roughly from Lake ___MASK75___ to Lake Turkana ( formerly called Lake Rudolf ) and further south - east to the Indian Ocean . It is bordered by Tanzania to the south and southwest , Uganda to the west , South Sudan to the north - west , Ethiopia to the north and Somalia to the north - east . Kenya covers , and had a population of approximately 45 million people in July 2014 . Africa is the world ' s second - largest and second - most - populous continent . At about 30 . 3 million km² ( 11 . 7 million square miles ) including adjacent islands , it covers 6 % of Earth ' s total surface ___MASK91___ and 20 . 4 % of its total land ___MASK91___ . With 1 . 1 billion people as of 2013 , it accounts for about 15 % of the world ' s human population . The continent is surrounded by the Mediterranean Sea to the north , both the Suez Canal and the Red Sea along the Sinai Peninsula to the northeast , the Indian Ocean to the southeast , and the Atlantic Ocean to the west . The continent includes Madagascar and various archipelagos . It contains 54 fully recognized sovereign states ( countries ), nine territories and two " de facto " independent states with limited or no recognition . ___MASK100___ ( French : ) is the capital and most populous city of France . It has an area of and a population in 2013 of 2 , 229 , 621 within its administrative limits . The city is both a commune and department , and forms the centre and headquarters of the Île - de - France , or ___MASK100___ Region , which has an area of and a population in 2014 of 12 , 005 , 077 , comprising 18 . 2 percent of the population of France . The pygmy ___MASK59___ (" ___MASK81___ liberiensis " or " Hexaprotodon liberiensis ") is a small hippopotamid which is native to the forests and swamps of West Africa , primarily in Liberia with small populations in Sierra Leone , Guinea , and Ivory Coast . The Paleogene ( or ; also spelled Palaeogene or Palæogene ; informally Lower Tertiary ) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( ___MASK18___ ) to the beginning of the Neogene Period ___MASK18___ . It is the beginning of the Cenozoic Era of the present Phanerozoic Eon . The Paleogene is most notable for being the time during which mammals diversified from relatively small , simple forms into a large group of diverse animals in the wake of the Cretaceous  Paleogene extinction event that ended the preceding Cretaceous Period . Anthracotheriidae is a family of extinct , ___MASK59___ - like artiodactyl ungulates related to hippopotamuses and whales . The oldest genus , Elomeryx , first appeared during the middle Eocene in Asia . They thrived in Africa and Eurasia , with a few species ultimately entering North America during the Oligocene . They died out in Europe and Africa during the Miocene , possibly due to a combination of climatic changes and competition with other artiodactyls , including pigs and true hippopotamuses . The youngest genus , Merycopotamus , died out in Asia during the late Pliocene . The family is named after the first genus discovered , Anthracotherium , which means `` coal beast '' , as the first fossils of it were found in Paleogene - aged coal beds in France . Fossil remains of the anthracothere genus were discovered by the Harvard University and Geological Survey of Pakistan joint research project ( Y - GSP ) in the well - dated middle and late Miocene deposits of the Pothohar Plateau in northern Pakistan . In life , the average anthracothere would have resembled a skinny ___MASK59___ with a comparatively small , narrow head and most likely ___MASK84___ - like in general appearance . They had four or five toes on each foot , and broad feet suited to walking on soft mud . They had full sets of about 44 teeth with five semicrescentric cusps on the upper molars , which , in some species , were adapted for digging up the roots of aquatic plants . Porpoises are a group of fully aquatic marine mammals that are sometimes referred to as mereswine , all of which are classified under the family Phocoenidae , parvorder ___MASK3___ ( toothed whales ). There are six extant species of porpoise . They are small toothed whales that are very closely related to oceanic dolphins . The most obvious visible difference between the two groups is that porpoises have shorter beaks and flattened , spade - shaped teeth distinct from the conical teeth of dolphins . Porpoises , and other cetaceans , belong to the clade Cetartiodactyla with even - toed ungulates , and their closest living relatives are the hippopotamuses , having diverged from them about 40 million years ago . The Sahara (", ' the Greatest Desert ') is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic . Its ___MASK91___ of is comparable to the ___MASK91___ of the United States . Sub - Saharan Africa is , geographically , the ___MASK91___ of the continent of Africa that lies south of the Sahara desert . According to the UN , it consists of all African countries that are fully or partially located south of the Sahara . It contrasts with North Africa , whose territories are part of the League of Arab states within the Arab world . Somalia , Djibouti , Comoros and Mauritania are geographically in Sub - Saharan Africa , but are likewise Arab states and part of the Arab world .