Belemnotheutis

Belemnotheutis
Live reconstruction
Temporal occurrence
Middle Jura to Upper Jura
approx. 161 to approx. 145 million years
Locations
Europe (Germany, England, Poland)
Systematics
Cephalopods (cephalopoda) Octopus (coleoidea) Belemnoidea Belemnites (Belemnitida) Belemnotheutidae Belemnotheutis
Scientific name
Belemnotheutis
Pearce , 1842

Belemnotheutis is a genus of belemnoid cuttlefish that lived in the Upper Middle Jurassic and Upper Jurassic about 161 to 145 million years ago. Well preserved specimens were removed from the English Oxfordton (from the chronostratigraphic stage of Calloviums ) and the Solnhofen (from the stage of the Tithonian described).

features

The hard parts of belemnotheutis consist of the chambered cuttlebone , with a small aragonite rostrum and the relatively wide, bounded on the back side Proostrakum . The dorsal rostrum has two typical longitudinal ridges diverging forwards. The apical angle of the phragmocone is around 20 degrees . The siphon line is on the edge of the abdomen. The animals had ten tentacles that were only moderately long and were provided with 30 to 40 pairs of chitinous , opposing hooks. They had relatively large eyes , and it is very likely that they already had lenticular eyes like today's squids, which have been preserved as prints. The muscular jacket , which made up over half of the entire animal, was limited to the abdominal side, the muscles were attached to the side panels of the proostracum. The animals reached a maximum length of 30 centimeters.

Diet and Enemies

Some copies of belemnotheutis were fossilized remains of goiter and stomach found. The remains contain fish scales and bones and prove that the genus fed on fish ( piscivorie ). The chitinous hooks of Belemnotheutis and other belemnoid squids were found relatively frequently in the stomach contents of ichthyosaurs , so these squids formed at least part of the diet of those diapsid reptiles . John E. Pollard calculated after assessing the number of fishing hooks in the stomach contents of an ichthyosaur from the Jurassic that this belemnoide 760-2430 squid have eaten had, although not in this example to the genus belemnotheutis included because the genre until the Middle Jurassic occurred .

Systematics

Belemnotheutis is the type genus of the family Belemnotheutidae in the order Belemnitida within the Belemnoidea .

So far, three types are known:

• Belemnotheutis antiqua Pearce, 1842, Callovium, England
• Belemnotheuthis polonica Makowski, 1952, Callovium, Poland, and
• Belemnotheutis mayri Engeser & Reitner, 1981, Tithonium, Southern Germany

Spelling of the name

The spelling originally chosen by the first writer Joseph Chaning Pearce is Belemnotheutis . This was later unjustifiably changed by some authors to Belemnoteuthis because the ending -teuthis was used more often at that time. According to the priority rule , however, this spelling is a secondary incorrect spelling, which, however, has often found its way into the secondary literature. But there is no reason to change the priority of Belemnotheutis over Belemnoteuthis, for example by submitting an application to the Commission for Zoological Nomenclature (ICZN) (cf. also the discussion in Donovan and Crane, 1990).

swell

literature

• Desmond T. Donovan and MD Crane: The type material of the Jurassic Cephalopod Belemnotheutis. Palaeontology, 35 (2): 273-296, London 1992 PDF
• Joseph Chaning Pearce: On the mouth of ammonites, and of fossils contained in laminated beds of the Oxford Clay, discovered in cutting the Great Western Railway, near Christian Malford in Wiltshire. Proceedings of the Geological Society of London, 3: 592-594, London 1842.

Individual evidence

1. ↑ Ronald Boettcher: About the food of a Leptopterygius (Ichthyosauria, Reptilia) from the southern German Posidonia schist (Lower Jura) with remarks about the stomach of the Ichthyosaurs. Stuttgart Contributions to Natural History Series B (Geology and Paleontology), 155: 19 S., Stuttgart 1989 (online)
2. ^ John E. Pollard: The gastric contents of an ichthyosaur from the Lower Lias of Lyme Regis, Dorset. Palaeontology, 11: 376-388, London 1968 PDF .
3. ^ H. Makowski: La faune Callovienne de Luków en Pologne. Palaeontologia polonica, 4: 1-64, Warsaw 1952
4. ↑ Theo Engeser & Joachim Reitner: A new copy by Belemnoteuthis mayri Engeser & Reitner, 1981 (Coleoidea, Cephalopoda) from the Solnhofen limestone (Untertithonium) of Wintershof, Bavaria . Archeopteryx, 10: 13-17; Eichstätt, 1992 PDF  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
5. ^ Desmond T. Donovan and MD Crane: The type material of the Jurassic Cephalopod Belemnotheutis. Palaeontology, 35 (2): 273-296, London 1992 PDF p. 280