Enchodus petrosus Cope
Enchodus ferox Leidy
|Description: These early salmon-like fish are represented by teeth, jaw segments.
The most common salmonoid at Big Brook is E. petrosus. There are three different types of teeth that E. petrosus possessed the palatine teeth (upper and lower fangs), upper lateral teeth, and the lower lateral teeth. The upper palatine teeth are usually 2 to 5 cm (about .75 to 2 in) in length, while the lower palatine teeth are about 1 to 3 cm (about .5 to 1.25 in) in length. These palatine teeth are widest at their crescent shaped root bases and gradually taper to a sharp or dull point depending on wear during life and stream action. The convexed and smooth enamel surfaces are marked with fine striations on half to two thirds of the tooth and have small growth cracks. Two cutting surfaces can be observed at the intersection of the anterior and posterior surfaces. The upper lateral teeth are usually about half the length of the palatine teeth and are more stout. They have a lens shaped cross section and have two cutting edges. The other teeth from the lower lateral are about the same size as the upper lateral teeth but only have one cutting edge. The other side is rounded to give the tooth a teardrop shaped cross-section. All these teeth are fairly smooth with no striations.
The palatine teeth of E. gladiolus have a tear drop shaped cross section, a slight curve from side to side and most distinctive of all, a small barb on the tip of the tooth. These teeth are also striated on the rounded side of the tooth.
The palatine teeth of E. ferox are almost the same as E. petrosus except for the presence of small serrations on the carinae of the tooth. The authors have never found this type of tooth and doubt the existence of E. ferox at Big Brook. It would appear that the teeth described and depicted by Fowler as E. serratus would be those of the upper lateral and lower lateral teeth of E. petrosus since complete specimens have been found in other localities in the Mid-west.
The jaw sections of these fish are fairly common at Big Brook but not quite as common as the teeth. The palatine jaw sections, rarely with the one palatine tooth still attached, is a robust and stout, right angel shaped jaw segment that has parallel grooves beneath the root base of the palatine tooth. The upper lateral jaw section in life contained about 6 irregular spaced, irregular sized teeth along its thin strip of bone. These teeth usually are separated from the upper lateral jaw section due to conditions before and after fossilization. The lower lateral jaw segment in life contains about 14 teeth, which unlike the upper lateral teeth, uniformly taper down in size from the front of the jaw to the back.
Commonality: The most common Cretaceous fish of the Atlantic Coastal Plain is that of E. petrosus. The teeth are very common while the jaw sections are common. E. gladiolus is somewhat common and E. ferox, if found at Big Brook, is rare.
Similar fossils: The teeth only very vaguely resemble shark teeth. Attention to the description given above should serve to differentiate between them. The lower lateral teeth of E. petrosus resemble the palatine teeth of E. gladiolus. E. gladiolus teeth have barbs on the tips of the teeth and are striated. The jaw sections might look like the concretions but these lack the bony structure.
Size: This fish had a body length of 1 to 2 meters (about 3 to 6 feet) or more.
Notes: The streamlined body of Enchodus coupled with an interlocking jaw full of elongated and sharp teeth places this predatorily salmonoid at the top of its class. This genus had worldwide distribution during the Late Cretaceous but seems to have gone into decline during the Late Paleocene.
|Isolated Palatine Fang|
|Isolated Palatine Fang|
|Isolated Lateral Tooth|
|Right Upper Palatine Jaw
|Right UpperPalatine Jaw
|Right Lower Palatine Jaw
|Laterial Jaw Fragment
with tooth base
|Articular Jaw Bone|
|Reconstruction of E. petrosus
Jaws and Teeth