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Crocodiles (Crocodilia)

Age – Late Cretaceous; Commonality – very uncommon; Size – teeth: 1/8-7/8 inches, Osteoderms: ~1/2-1 inches (fragments), ~1-2 inches (complete), Vertebrae: 1/2-2 inches (centrums)

The typical slender crocodile teeth are probably from fish-eating crocs such as Thoracosaurus neocesariensis. These teeth have faint carinae, a relatively deep but narrow basal indentation, usually a circular base, concentric circles in the base (info from Plax on TheFossilForum), and most of the time a smooth crown (sometimes some posterior croc teeth have ridges). There are rumors that massive Deinosuchus teeth can be found, but so far there hasn’t been any clear evidence for this (comment of Steve B.).

Osteoderms were bony plates that were under the crocodiles’ skin. They provided protection and also helped the crocs regulate their temperature. They are flat and have many relatively deep dimples. They can sometimes be confused with Trionyx sp. turtle shell pieces (crocs have deeper dimples and the dimple pattern is less evenly distributed). Also, Trionyx sp. shell pieces possess the typical porous bone structure unlike the croc osteoderms.

Most NJ crocodile remains are teeth and osteoderms. Other material is much rarer. The vertebrae can be confused with mosasaur vertebrae, but are more elongated and seem to have heavier process attachments.

Teeth

Lateral View

Anterior View

Posterior View

Basal View

Anteriormost tooth. This position seems to be less common than the position the two below are from.

Lateral View

Lateral View

Anterior/Posterior View

Basal View

Occlusal View

Anterior (but not anteriormost) tooth. This one is the typical tooth form seen.

Lateral View

Lateral View

Anterior/Posterior View

Basal View

Occlusal View

Another anterior tooth from a similar position as the one above. This one has a tiny bit of in vivo wear visible at the crown apex. It is basically at the maximum size for New Jersey Croc teeth at 5/8 inches.

Lateral View

Lateral View

Anterior/Posterior View

Basal View

Occlusal View

This tooth came from a posterior position. These seem to be less common than anterior teeth.

There is definitely more than one species present, which coupled with variation and wear makes it hard to even attribute a tooth to a position. In sharks you would likely figure out the species before the position; in Croc teeth, however, a species level identification is impractical most of the time in NJ because of not many associated remains, but since Croc teeth of different species are very similar, there is a chance one can be assigned to a position.

Lateral View

Lateral View

Anterior View

Posterior View

Basal View

EDIT: this tooth is actually a Pachyrhizodus. Will be moved to the according page.

Osteoderms

External surface

Internal surface

This is a fairly large chunk of osteoderm at ~1 inch. Crocodile osteoderms are dimpled on one side and are smooth on the other. They are usually always fragmentary. The osteoderms, which were located under the skin, served as body armor and helped regulate the crocodilian’s body temperature.

External surface

Internal surface

This osteoderm shows the dimples more clearly. It is easy to confuse Croc osteoderms with Trionyx sp. turtle shell pieces. The turtle shell pieces are more bony, are thicker, and have shallower, more even dimples.

External surface

Internal surface

This osteoderm is probably about half complete. The line running on the external surface is the middle of the osteoderm.

Vertebra

Dorsal View

Ventral View

Anterior View

Posterior View

Caudal-Lateral View

Possible juvenile Croc vertebra (there is a small chance it could actually be from one of the small terrestrial reptiles). Croc vertebrae generally have larger joint stubs than Mosasaur verts. Information about it possibly belonging to a terrestrial reptile is from Steve B.

Skull Fragment

External surface

Internal surface

Skull fragments are similar to osteoderms, but have more irregular divots and have a backside that has a different surface texture. This one has a piece on the backside that would have jointed to the rest of the skull. Usually the pieces of Croc skull are from the top of the skull (that is why they resemble the “regular” Croc osteoderms). 

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