| Muensterellidae Temporal range: | |
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| Fossil of Muensterella scutellaris | |
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| Family: | †Muensterellidae Roger, 1952 |
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†Enchoteuthinae | |
Muensterellidae is a family of stem-octopod cephalopods from the Late Jurassic to Late Cretaceous.
Muensterellidae is one of two families in the superfamily Muensterelloidea along with the Patelloctopodidae. The muensterelloids are characterized by having a roughly spoon-shaped end of the gladius called the patella. This type of gladius is likely ancestral to the gladius remnants of modern octopuses. [1] [2]
The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.
An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
Subclass Coleoidea, or Dibranchiata, is the grouping 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 cuttlebone, gladius, or shell that is used for buoyancy or support. Some species have lost their cuttlebone altogether, while in some it has been replaced by a chitinous support structure. A unique trait of the group is the ability to edit their own RNA.
Grimpoteuthis is a genus of pelagic finned or cirrate octopods known as the dumbo octopuses. The name "dumbo" originates from their resemblance to the title character of Disney's 1941 film Dumbo, having a prominent ear-like fin which extends from the mantle above each eye. There are 17 species recognized in the genus. Prey include crustaceans, bivalves, worms and copepods. The average life span of various Grimpoteuthis species is 3 to 5 years.
Cirrina or Cirrata is a suborder and one of the two main divisions of octopuses. Cirrate octopuses have a small, internal shell and two fins on their head, while their sister suborder Incirrina has neither. The fins of cirrate octopods are associated with a unique cartilage-like shell in a shell sac. In cross-section, the fins have distinct proximal and distal regions, both of which are covered by a thin surface sheath of muscle.
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.
Trachyteuthis is a genus of fossil cephalopod, comprising five species: T. hastiformis, T. latipinnis, T. nusplingensis, T. teudopsiformis, T. covacevichi and T. chilensis.
Pohlsepia mazonensis is a species of fossil organism with unknown affinity. Although it was originally identified as an extinct cephalopod, later studies denied that interpretation. The species is known from a single exceptionally preserved fossil discovered in the late Carboniferous (Pennsylvanian) Francis Creek Shale of the Carbondale Formation, north-east Illinois, United States.
Palaeoctopus newboldi is an extinct basal octopod that lived in the Late Cretaceous, approximately 89 to 71 million years ago. Fossil material assigned to this species originates from the Mount Hajoula region in Lebanon. The holotype was found below the Old Covent, Sahel-el-Alma, Mount Lebanon and is deposited at the Natural History Museum in London. It might belong to the Cirrina or be more basal in the Octopoda. Specimens from the Turonian of Vallecino, Mexico, originally described as P. pelagicus, are reinterpreted to be portions of a coelacanth.
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. Examination of gladius remains has yielded an estimated mantle length close to or equal to that of the modern giant squid. Fossil remains have been found in parts of the one-time Western Interior Seaway of North America, including Late Cretaceous rocks in Kansas, Colorado, Wyoming, South Dakota, North Dakota, and Manitoba Province. One species, T. longa, is traditionally recognized. In 2019, due to poor preservation of holotype specimen, genus Tusoteuthis is likely to be invalid, and it is considered that later described species are better to include in genus Enchoteuthis instead.
Styletoctopus is an extinct genus of octopus. The genus consists of the single species Styletoctopus annae, which lived approximately 95 million years ago. Very few octopus species appear in the fossil record, as octopuses consist of soft tissue that usually decomposes before it has time to fossilize.
Keuppia is an extinct genus of octopus.
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.
Octopodoidea is a superfamily of the suborder Incirrata containing all extant octopods except for the cirrate octopodes, argonauts, and the vampire squid.
Plesioteuthis is an extinct genus of squids, belonging to the family Plesioteuthididae. This genus was first described in 1859, and its fossils were found in the well-known Solnhofen field in Germany.
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.
Patelloctopodidae is a family of stem-octopod cephalopods from the Middle and Late Jurassic of Europe. Five genera are currently placed in the family, Etchesia, Muenstellerina,Patelloctopus,Pearciteuthis and Tyrionella, Patelloctopodidae is one of two families in the superfamily Muensterelloidea along with the Muensterellidae. They are thought to be the group from which modern octopus arose.