| Eromangateuthis Temporal range: | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Family: | † Plesioteuthididae |
| Genus: | † Eromangateuthis Fuchs, 2019 [1] |
| Species: | †E. soniae |
| Binomial name | |
| †Eromangateuthis soniae (Wade, 1993) [2] | |
| Synonyms | |
| |
Eromangateuthis is an extinct genus of large plesioteuthidid cephalopod from the Cretaceous of Australia and possibly Canada.
Eromangateuthis soniae is known from several gladii found in the Allaru Formation of Queensland [1] [2] and a potential gladius from the Northumberland Formation of British Columbia. [3] It was originally described in 1993 as Boreopeltis soniae, [2] but was moved to its own genus in 2019 based on multiple differences between it and the type species of Boreopeltis. [1] The generic name is derived from the Eromanga Basin in which it was discovered and the Ancient Greek teuthís (τευθίς, 'squid'). [1] One gladius suggests it had a mantle length of 1.2 meters. [1] This makes Eromangateuthis the largest known plesioteuthidid, with a mantle length over twice as long as the second largest, Boreopeltis ifrimae. [4]
A squid is a mollusc with an elongated soft body, large eyes, eight arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida. 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.
A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.
The vampire squid is a small cephalopod found throughout temperate and tropical oceans in extreme deep sea conditions. The vampire squid uses its bioluminescent organs and its unique oxygen metabolism to thrive in the parts of the ocean with the lowest concentrations of oxygen. It has two long retractile filaments, located between the first two pairs of arms on its dorsal side, which distinguish it from both octopuses and squids, and places it in its own order, Vampyromorphida, although its closest relatives are octopods. As a phylogenetic relict, it is the only known surviving member of its order.
Coleoidea or Dibranchiata is one of the two subclasses of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less". Unlike its extant sister group Nautiloidea, whose members have a rigid outer shell for protection, the coleoids have at most an internal shell called cuttlebone or gladius that is used for buoyancy or as muscle anchorage. Some species, notably incirrate octopuses, have lost their internal shell altogether, while in some it has been replaced by a chitinous support structure.
Octopodiformes is a superorder of the subclass Coleoidea, comprising the octopuses and the vampire squid. All living members of Octopodiformes have eight arms, either lacking the two tentacles of squid or modifying the tentacles into thin filaments. Octopodiformes is often considered the crown group of octopuses and vampire squids, including all descendants of their common ancestor. Some authors use the term Vampyropoda for the same general category, though others use "Vampyropoda" to refer to the total group. Another term is Octobranchia, referring to cephalopods without prominent tentacles.
Cephalopods, which include squids and octopuses, vary enormously in size. The smallest are only about 1 centimetre (0.39 in) long and weigh less than 1 gram (0.035 oz) at maturity, while the giant squid can exceed 10 metres (33 ft) in length and the colossal squid weighs close to half a tonne (1,100 lb), making them the largest living invertebrates. Living species range in mass more than three-billion-fold, or across nine orders of magnitude, from the lightest hatchlings to the heaviest adults. Certain cephalopod species are also noted for having individual body parts of exceptional size.
Tusoteuthis is an extinct genus of large enchoteuthine cephalopod that lived during the Cretaceous. Although often called a squid, it is now thought to be more closely related to modern octopuses. Although many specimens from Western Interior Seaway of North America were described, at 2019, only one, poorly preserved specimen from Kansas is recognized as Tusoteuthis. One species, T. longa, is traditionally recognized. In 2019, due to poor preservation of holotype specimen, Tusoteuthis was considered likely to be a nomen dubium, and it was proposed that later described species are better to included in genus Enchoteuthis instead.
Belemnotheutis is an extinct coleoid cephalopod genus from the middle and upper Jurassic, related to but morphologically distinct from belemnites. Belemnotheutis fossils are some of the best preserved among coleoids. Remains of soft tissue are well-documented in some specimens, even down to microscopic muscle tissue. In 2008, a group of paleontologists even recovered viable ink from ink sacs found in several specimens.
The Allaru Formation, also known as the Allaru Mudstone, is a geological formation in Queensland, Australia, whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The cephalopods have a long geological history, with the first nautiloids found in late Cambrian strata.
Belemnitida is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard. The chitinous hooks were usually no bigger than 5 mm (0.20 in), though a belemnite could have had between 100 and 800 hooks in total, using them to stab and hold onto prey.
The gladius, or pen, is a hard internal bodypart found in many cephalopods of the superorder Decapodiformes and in a single extant member of the Octopodiformes, the vampire squid. 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. Some species, like the bigfin reef squid, still has a gladius with some degree of mineralization.
Muensterella is a fossil stem-octopod known from a handful of specimens from the Late Jurassic lithographic limestones of southern Germany and the upper Cretaceous of Germany and Texas. Another indeterminate specimen of the Genus is known from the Tithonian Nordenskjöld Formation of Antarctica.
Boreopeltis is an extinct genus of plesioteuthidid cephalopod, with 4 known species.
Muensterelloidea is a superfamily of stem-octopod cephalopods from the Early Jurassic to Late Cretaceous. Two families are currently identified, Muensterellidae, and Patelloctopodidae. The clade is the ancestral group from which modern octopus arose.
Enchoteuthis is an extinct genus of large enchoteuthine cephalopod that lived during the Cretaceous. Although it and its relative Tusoteuthis are often compared to squid, both are now thought to be more closely related to modern octopuses. Examination of gladius remains initially yielded an estimated mantle length about 2 m based on specimen once described as Tusoteuthis longa, close to or equal to that of the modern giant squid, although reclassification of this genus as a muensterelloid results in a much shorter total length, about 3 m (10 ft). Three species are currently recognized as valid: E. melanae, E. tonii, and E. cobbani.
The Teudopseina is a clade of stem-octopods that first evolved in the Toarcian, 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.
Syllipsimopodi is an extinct member of the cephalopod subclass Coleoidea originally interpreted to belong to the clade Vampyropoda, which includes octopuses (Octopoda) and vampire squids (Vampyromorphida). The type and only known species is Syllipsimopodi bideni, named in honor of US President Joe Biden, and to raise awareness of his climate change policies. The holotype fossil was found in the Bear Gulch Limestone deposit in the US state of Montana in 1988, and donated that year to the Royal Ontario Museum by B. Hawes, designated ROMIP 64897. The species lived during the (Carboniferous) Mississippian subperiod, 330.3 to 323.4 million years ago, pushing back the group of cephalopods by 81.9 million years.
Antarcticeras is an extinct genus of enigmatic cephalopod from the Eocene of Antarctica. It contains a single species, A.nordenskjoeldi. It is either considered the last of the "orthocone"-type cephalopods, the only member of its subclass Paracoleoidea & a descendant of the orthoceratids, and a remarkable example of convergent evolution with coleoid cephalopods, or an oegospid squid and a transitional form in the development of the modern squid gladius, of which it is the only preserved example.
Yezoteuthis is an extinct genus of very large oegopsid squid that inhabited the seas around Japan in the Late Cretaceous period. It contains a single species, Y. giganteus from the early Campanian Osousyunai Formation of the Yezo Group in Hokkaido. It is possibly the largest fossil coleoid ever described.