''Cylindroteuthis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

belemnite Belemnitida (or belemnites) is an extinct order (biology), order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous (And possibly the Eocene). Unlike squid, belemnites had an internal skeleton that made up the cone ...

that lived from the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

to the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

. Its fossils have been found in Asia, Europe, North America, and New Zealand.

Taxonomical history

''Cylindroteuthis'' was first described in 1879 by Claude-Emile Bayle. A belemnite originally described as the ''Cylindroteuthis'' species ''C. confessa'' has been re-described as ''

Mesoteuthis ''Mesoteuthis'' is a genus of belemnite, an extinct group of cephalopods. Taxonomical history A belemnite originally described as ''Cylindroteuthis confessa'' has been re-described as ''Mesoteuthis soloniensis''. See also * Belemnite Bel ...

soloniensis''.

Paleobiology

''Cylindroteuthis'' is a common find from several Jurassic formations. Specimen length ranges from . The most commonly preserved part of the animal is its guard, or

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

, which was composed of

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

. The guard would not have been found on the exterior of ''Cylindroteuthis'', as traces of

blood vessel Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...

s have been discovered on some guards, suggesting that it was an internal feature. The guard housed a

phragmocone The phragmocone is the chambered portion of the shell of a cephalopod. It is divided by septa into camerae. In most nautiloids and ammonoids, the phragmocone is a long, straight, curved, or coiled structure, in which the camerae are linked by ...

, which allowed ''Cylindroteuthis'' to maintain

buoyancy Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of t ...

in water. Some better-preserved specimens have features similar to modern

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

, such as ten arm-like appendages and an

ink sac An ink sac is an anatomical feature that is found in many cephalopod mollusks used to produce the defensive cephalopod ink. With the exception of nocturnal and very deep water cephalopods, all Coleoidea (squid, octopus and cuttlefish) which dwell ...

, intact.

Distribution

''Cylindroteuthis'' has been recovered from the Temaikan Boatlanding Bay formation of

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

. Three species of ''Cylindroteuthis'' (''C. knoxvillensis'', ''C. cf. newvillensis'', and ''C. venusta'') have been described from the

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

region. In addition, about 2350 belemnite guards (including those of ''Cylindroteuthis'') have been recovered from Lower Cretaceous formations of northeastern

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

, suggesting the presence of a sort of "immigration route" for belemnites. The findings also suggest the existence of a "proto Gulf-stream" as early as the

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...

. Another species, ''C. cf. obeliscoides'' is associated with the early Cretaceous One Tree Formation of

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

.Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 93-94

Species List:

The genus contains thirteen species * ''Cylindroteuthis clavicula'' * ''Cylindroteuthis cuspidata'' * ''Cylindroteuthis gelida'' * ''Cylindroteuthis glennensis'' * ''Cylindroteuthis jacutica'' * ''Cylindroteuthis knoxvillensis'' * ''Cylindroteuthis newvillensis'' * ''Cylindroteuthis occidentalis'' * ''Cylindroteuthis oweni'' * ''Cylindroteuthis porrecta'' * ''Cylindroteuthis porrectiformis'' * ''Cylindroteuthis puzosi'' * ''Cylindroteuthis venusta''

References

* ''Fossils'' (Smithsonian Handbooks) by David Ward (Page 163)

External links

''Cylindroteuthis''
in the

Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

{{Taxonbar, from=Q4119243 Belemnites Jurassic cephalopods Cretaceous cephalopods Prehistoric cephalopod genera Fossil taxa described in 1879 Mesozoic cephalopods of Asia Mesozoic cephalopods of North America Cretaceous cephalopods of Europe Mesozoic cephalopods of Europe Early Jurassic genus first appearances Early Cretaceous genus extinctions