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Gladius (cephalopod)
The gladius (plural: ''gladii''), or pen, is a hard internal bodypart found in many cephalopods of the superorder Decapodiformes (particularly squids) and in a single extant member of the Octopodiformes, the vampire squid (''Vampyroteuthis infernalis''). It is so named for its superficial resemblance to the Roman short sword of the same name, and is a vestige of the ancestral mollusc shell, which was external. The gladius is located dorsally within the mantle and usually extends for its entire length. Composed primarily of chitin, it lies within the shell sac, which is responsible for its secretion. Gladii are known from a number of extinct cephalopod groups, including teudopseids (''e.g.'' '' Actinosepia'', '' Glyphiteuthis'', '' Muensterella'', '' Palaeololigo'', '' Teudopsinia'', ''Teudopsis'', and ''Trachyteuthis''), loligosepiids (''e.g.'' '' Geopeltis'', '' Jeletzkyteuthis'', and '' Loligosepia''), and prototeuthids (''e.g.'' ''Dorateuthis'', '' Paraplesioteuthis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squid Gladius, Showing Measurement Of Rachis And Vane
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting these criteria. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin. Squid diverged from other cephalopods during the Jurassic and occupy a similar role to teleost fish as open water predators of similar size and behaviour. They play an important role in the open water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swallowing. Squid are rapid swimmers, moving by jet propulsion, and largely locate their prey by sight. They are among the most intelligent of invert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teudopseina
The Teudopseina is a clade of stem- octopods that first evolved in the Toarcian,Fuchs, Dirk & Weis, Robert. (2010). Taxonomy, morphology and phylogeny of Lower Jurassic teudopseid coleoids (Cephalopoda). Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 257. 351-366. 10.1127/0077-7749/2010/0083. considered the largest clade of gladius-bearing coleoids in the Mesozoic. Up to five families are known, among which the Trachyteuthidae, ''Trachyteuthis'' in particular, were the most abundant.Tree of Life Project: Teudopseina ''Tree of Life Web Project''. Retrieved 2022-01-15. Description The Teudopseina can be united by five primary traits. These are the presence of a |
Dorateuthis
''Dorateuthis'' is a genus of cephalopod with a gladius and soft-part anatomy preserved. Fossils of ''D. syriaca'' are found in Upper Santonian-aged shale of Late Cretaceous Lebanon Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to the north and east and Israel to the south, while Cyprus li .... References External links *Image: Prehistoric cephalopod genera Cretaceous cephalopods {{Cephalopod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachyteuthis
''Trachyteuthis'' is a genus of fossil cephalopod, comprising five species: ''T. hastiformis'', ''T. latipinnis'', ''T. nusplingensis'', ''T. teudopsiformis'', ''T. covacevichi'' and ''T. chilensis''. Taxonomy The taxonomic placement of ''Trachyteuthis'' is uncertain. Though often assigned to the order Vampyromorphida, the discovery of fossilised ''Trachyteuthis'' beaks in the Upper Jurassic limestone of Germany suggests a close phylogenetic relation to the Octopoda. It is clear that it does at least belong in the Coleoidea. It is thought to be very closely related to ''Teudopsis''. Distribution Fossils are scarce but have been reported from the Kimmeridge clay of the UK; the Solnhofen limestone of Germany, Jurassic deposits in Antarctica, and Oxfordian deposits in Chile. History First described in 1773 as the remnants of a fish, ''Trachyteuthis'' was considered comparable to a ''Sepia Sepia may refer to: Biology * ''Sepia'' (genus), a genus of cuttlefish Color * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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