parent_taxon tusoteuthis
___MASK11___ is an order of cephalopods comprising one known extant species (" Vampyroteuthis infernalis ") and many extinct taxa . Physically , they somewhat resemble octopuses , but the eight arms are united by a web of skin , and two smaller cilia are also present . The giant squid ( genus Architeuthis ) is a deep - ocean dwelling squid in the family ___MASK95___ . Giant squid can grow to a tremendous size due to deep - sea gigantism : recent estimates put the maximum size at for females and for males from the posterior fins to the tip of the two long tentacles ( second only to the colossal squid at an estimated , one of the largest living organisms ). The mantle is about long ( more for females , less for males ), and the length of the squid excluding its tentacles ( but including head and arms ) rarely exceeds . Claims of specimens measuring or more have not been scientifically documented . The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago ( ___MASK82___ ) to the beginning of the Paleogene Period ___MASK82___ . It is the last period of the Mesozoic Era . The Cretaceous Period is usually abbreviated K , for its German translation " Kreide " ( chalk ). The Jurassic ( from Jura Mountains ) is a geologic period and system that spans 56 . 3 million years from the end of the Triassic Period million years ago ( ___MASK82___ ) to the beginning of the Cretaceous Period ___MASK82___ . The Jurassic constitutes the middle period of the Mesozoic Era , also known as the Age of Reptiles . The start of the period is marked by the major Triassic  Jurassic extinction event . Two other extinction events occurred during the period : the Pliensbachian / Toarcian event in the Early Jurassic , and the Tithonian event at the end ; however , neither event ranks among the " Big Five " mass extinctions . 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 ( ___MASK82___ ) to the beginning of the Neogene Period ___MASK82___ . 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 . The colossal squid (" ___MASK50___ hamiltoni ", from Greek " mesos " ( middle ), " onycho " ( claw , nail ), and " teuthis " ( squid )), sometimes called the Antarctic or giant cranch squid , is believed to be the largest squid species in terms of mass . It is the only known member of the genus " ___MASK50___ ". It is known from only a few specimens , and current estimates put its maximum size at long and weighing possibly up to 750 kg ( 1 , 650 lb ), based on analysis of smaller and immature specimens , making it the largest known invertebrate . Tusoteuthis is a genus of Cretaceous cephalopod molluscs . One species , T . longa , has been identified so far , and examination of gladius remains has yielded an estimated mantle length close to or equal to that of the modern giant squid . Recent studies suggest a closer relationship to the vampire squid than the modern day giant squid . Tusoteuthis is assumed to have preyed on other cephalopods , fish , and possibly even small marine reptiles . Despite its size , which was around 20 to 35 feet ( 6 to 11 metres ) long with tentacles fully outstretched , Tusoteuthis was still preyed on by other animals , especially the many , various predatory fish of the Western Interior Seaway . A fossil of the predatory salmonid , Cimolichthys nepaholica , was found with the gladius of T . longa in its gullet . The back portion of the gladius was in the stomach region , while the mouth of C . nepaholica had remained opened , suggesting that the fish had died in the middle of swallowing the squid , tail first . Researchers strongly suspect that as the fish was swallowing Tusoteuthis , the head and / or tentacles remained outside the mouth , thus blocking the gills of the fish , and suffocating it as it swallowed its prey . The vampire squid (" ___MASK90___ infernalis ", lit . " vampire squid of Hell ") is a small , deep - sea cephalopod found throughout the temperate and tropical oceans of the world . Unique retractile sensory filaments justify the vampire squid ' s placement in its own order : ___MASK11___ ( formerly Vampyromorpha ), which shares similarities with both squid and octopodes . As a phylogenetic relict it is the only known surviving member of its order , first described and originally classified as an octopus in 1903 by German teuthologist Carl Chun , but later assigned to a new order together with several extinct taxa . A fish is any member of a group of organisms that consist of all gill - bearing aquatic craniate animals that lack limbs with digits . They form a sister group to the tunicates , together forming the ___MASK84___ . Included in this definition are the living ___MASK86___ , lampreys , and cartilaginous and bony fish as well as various extinct related groups . Tetrapods emerged within lobe - finned fishes , so cladistically they are fish as well . However , traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods ( i . e ., the amphibians , reptiles , birds and mammals which all descended from within the same ancestry ). Because in this manner the term " fish " is defined negatively as a paraphyletic group , it is not considered a formal taxonomic grouping in systematic biology . The traditional term pisces ( also ichthyes ) is considered a typological , but not a phylogenetic classification . In zoology , a tentacle is a flexible , mobile , elongated organ present in some species of animals , most of them invertebrates . In ___MASK17___ anatomy , tentacles usually occur in one or more pairs . Anatomically , the tentacles of animals work mainly like muscular hydrostats . Most forms of tentacles are used for grasping and feeding . Many are sensory organs , variously receptive to touch , vision , or to the smell or taste of particular foods or threats . Examples of such tentacles are the " eye stalks " of various kinds of snails . Some kinds of tentacles have both sensory and manipulatory functions . A cephalopod ( pronounced or ) is any member of the molluscan class ___MASK15___ ( Greek plural , " kephalópoda "; " head - feet "). These exclusively marine animals are characterized by bilateral body symmetry , a prominent head , and a set of arms or tentacles ( muscular hydrostats ) modified from the primitive molluscan foot . Fishermen sometimes call them inkfish , referring to their common ability to squirt ink . The study of cephalopods is a branch of malacology known as teuthology . Malacology is the branch of invertebrate zoology that deals with the study of the ___MASK91___ ( mollusks or molluscs ), the second - largest phylum of animals in terms of described species after the arthropods . Mollusks include snails and slugs , clams , ___MASK78___ and squid , and numerous other kinds , many ( but by no means all ) of which have shells . One division of malacology , conchology , is devoted to the study of mollusk shells . Malacology derives from Greek , " malakos ", " soft "; and , "- logia ".