Cameroceras
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Cameroceras Temporal range: Middle Ordovician – Wenlock 470–425 Ma |
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| Partial internal mold of C. inaequabile, Upper Ordovician of northern Kentucky | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Endocerida |
| Family: | Endoceratidae |
| Genus: |
Cameroceras Conrad, 1842 |
| Type species | |
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†Cameroceras trentonense Conrad, 1842 |
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| Species | |
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Cameroceras ("chambered horn") is a genus of extinct, giant orthoconic cephalopod that lived mainly during the Ordovician period. It first appears during the middle Ordovician, around 470 million years ago, and was a fairly common component of the fauna in some places during the period, inhabiting the shallow seas of Laurentia, Baltica and Siberia. Its diversity and abundance became severely reduced following the Ordovician–Silurian extinction events, and the last remnants of the genus went extinct sometime during the Wenlock.
Cameroceras is a cephalopod, a taxon of molluscs that includes the octopuses, squids and cuttlefish. From comparison with living cephalopods, particularly the shelled chambered nautilus, some inferences about the biology of Cameroceras can be made. The head of the animal would have been soft muscular tissue situated at the opening of the hard cone-like shell, with the mantle (main body) lying within the shell for protection. Tentacles would have grown from the base of the head like in a modern nautilus, and these tentacles would have been used to seize and manipulate prey. At the base of these tentacles within the buccal mass (analogous to the mouth) a hard keratinous beak would have bitten into the bodies of its prey, and is assumed to have been strong enough to breach the prey's exoskeleton or shell. Within the beaks of modern cephalopods a radula, or ‘toothed’ tongue is used to rasp out soft tissue from within the prey's shell.
Cameroceras is widely regarded as one of if not the largest orthocone cephalopods to ever exist. Unfortunately only estimates for the upper size of the animal exist. The partial shell of one giant Cameroceras yielded a total length estimated at the time at nearly 30 feet (9 m). This estimate has since been revised downward quite a bit; Frey (1995) gives a length of up to 6 m. Regardless of this estimate's degree of accuracy, this gargantuan cephalopod is thought to be among the largest known Paleozoic molluscs.
Cameroceras has become a "wastebasket taxon" in which large orthoconic endocerids such as Endoceras, Vaginoceras, and Meniscoceras were originally placed. This makes it extremely difficult to describe Cameroceras as a distinct genus. Although the type species Cameroceras trentonense was first described by Conrad in 1842, since then the generic term has had variable meaning.
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