Cameroceras

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Cameroceras
Cameroceras trentonese captures a Cyclostomiceras

Cameroceras trentonese captures a Cyclostomiceras

Temporal occurrence
Ordovician
approx. 470 to approx. 440 million years
Locations
Systematics
Molluscs (mollusca)
Cephalopods (cephalopoda)
Nautiloidea
Endocerida
Endoceratidae
Cameroceras
Scientific name
Cameroceras
Conrad , 1842

Cameroceras is a genus of the family Endoceratidae from the class of the cephalopods (Cephalopoda). The species of the genus lived in the Ordovician .

features

The housing of Cameroceras is long to extremely long (up to approx. 9 m). The cross-section is rounded to slightly flattened dorsoventral, with a maximum diameter of just under 30 cm. The phragmocone , d. H. the chambered rear part of the housing took up at least 2/3 to about 3/4 of the total length. The attachment of the septa to the inner chamber wall ("lobe line") is almost straight, or only with a flat sinus on the abdominal side. In the adult animal, the Sipho took up about half the diameter of the case. It is located on the edge of the housing, more rarely a little away from the edge, but not centrally on the animal's belly. The septal necks are holochoanitic. The posterior parts of the siphon are filled with conical endosiphonal deposits. The endocones are simple and save a thin endosiphonal tube which is located in the middle of the siphon line. The appearance of the apical tip is unknown as no complete specimens have been found. Presumably, however, it resembles the genera Nanno and Suecoceras , which in turn are based only on the apical parts of endosiphonal deposits. Endosiphonal deposits often recrystallize in calcite during the animal's lifetime and therefore have a higher fossilization potential than the remaining parts of the phragmocone, which consist of the more easily soluble aragonite and therefore have a higher potential for fossilization . U. can be found in isolation.

Way of life

Little is known about the way of life and also about the organization of the soft tissues of Cameroceras . So far, no specimens with fossilized remains of the soft tissues or stomach contents have been found. About the soft tissue organization and the way of life can therefore only be speculated or analogy to the recent nautilus can be drawn. The species of Cameroceras have moved forward using the principle of recoil. With some probability the deposits in the rear part of the siphon served to take a horizontal swimming position. However, they have further reduced the buoyancy of the phragmocone. Even in the recent nautilus , 90% of the buoyancy generated by the phragmocone through the air-filled chambers is compensated by the weight of the phragmocone, the rest of the buoyancy is neutralized by the soft tissues. Due to the endosiphonal deposits, this ratio is likely to have been significantly higher in Cameroceras . This means that the soft body was relatively small in relation to the housing. The species of the genus Cameroceras could safely move only slowly due to the large inertial mass of the housing. Rapid changes of direction were not possible.

Today's nautilus feeds on the carrion and exuvia of crustaceans. This way of life is also conceivable for the slowly moving species of Cameroceras . They could also have predatory feeds on larger, benthonic trilobites.

Systematics

The genus Cameroceras was first described by Timothy Abbott Conrad in 1842 . The type species is Cameroceras trentonense . There are currently around 40 species belonging to the genus Cameroceras .

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literature

  • Curt Teichert : Endoceratoidea. In: Curt Teichert, Bernhard Kummel , Walter C. Sweet, HB Stenzel, William M. Furnish, Brian F. Glenister, Heinrich K. Erben , Raymond Cecil Moore , DEN Zeller (eds.): Treatise on Invertebrate Paleontology. Part K: Mollusca. 3: Cephalopoda - General Features Endoceratoidea - Actinoceratoidea - Nautiloidea - Bactritoidea. Geological Society of America et al., New York NY et al. 1964, K160-K189.
  • Curt Teichert, Bernhard Kummel: Size of endoceroid cephalopods. In: Museum of Comparative Zoology at Harvard College, Cambridge. Breviora. 128, December 20, 1960, ISSN  0006-9698 , pp. 1-7, online .

Individual evidence

  1. ^ Charles Hepworth Holland : The nautiloid cephalopods: a strange success. In: Journal of the Geological Society London. Vol. 144, No. 1, 1987, ISSN  0016-7649 , pp. 1-15, doi : 10.1144 / gsjgs.144.1.0001 .
  2. ↑ John A. Chamberlain: Locomotion of Nautilus. In: W. Bruce Saunders, Neil H. Landman: Nautilus. The Biology and Paleobiology of a Living Fossil. Plenum Press, New York NY et al. 1987, ISBN 0-306-42709-5 , pp. 489-525.

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