Two thresher sharks are found in the mine. Both come from the Pungo River formation and although uncommon, dedicated searching should turn up one or two. Fine screening of the waste tailings will usually turn up several small specimens. In addition, tailings very rarely yield teeth that have been ascribed to Alopias grandis (LERICHE, 1942).

The common thresher, which in the fossil record goes by Alopias latidens (LERICHE, 1909), is indistinguishable from the modern species — Alopias vulpinus (BONNATERRE, 1788). To further the naming confusion, the other rarer one is the Big-eye thresher shark, Alopias aff. superciliosus (LOWE, 1839) which is the same as the modern species.

Teeth of both species are very similar with smooth cutting edges and rounded curved root lobes. The main difference between the two species is the presence of a nutritive groove in A. superciliosus and as juveniles, A. vulpinus/latidens tends to have slightly broader teeth. As the sharks grow, the teeth of both become very similar, growing much wider and the nutritive groove less obvious, often requiring oblique lighting to see. In fact, the easiest way to tell the modern jaws apart is to count the tooth rows as A. vulpinus has more teeth in its jaws.

Alopias vulpinus (BONNATERRE, 1788)
   aka A. latidens (LERICHE, 1909)

Fig. 1 - A. vulpinus aka latidens
Upper laterals, lower anterior & lateral. Pungo River specimens.

Alopias superciliosus (LOWE, 1839)

Fig. 2 - A. superciliosus
Upper lateral and lower anterior. Pungo River specimens.

"Alopias grandis" (LERICHE, 1942)

Teeth of this design have been previously reported as a rare component of Chesapeake Bay sediments. These teeth get much larger than those of other Alopias species - the figure 3 specimen measures 4.7 cm diagonally. They are best characterized by their alopiid-look, large size and articulated shoulders. (Specimens from the Chesapeake often have incipient serrations, refer to figure 4, a Lee Creek tooth.) Insufficient examples have been found or documented to speculate upon the dentition design. However, the authors have seen teeth with these characteristics from upper lateral & posterior and lower file positions.

There remains the question as to whether or not these teeth are even alopiid. Kent (1994) argued that they more likely represented upper laterals of "Isurus" hastalis. He noted the more angular root, weak labial overhang and the presence of a similar tooth in an associated hastalis dentition.

These authors are not arguing for or against the proper genus. These specimens are being presented as rare tooth-designs found in both Pungo River and Yorktown sediments of North Carolina. Purdy et al (2001) did not include this tooth design in the fauna.

Fig. 3 - "A. grandis"
Note ginzu-like shoulder design. Yorktown specimen.

Fig. 4 - "A. grandis"
Note incipient serration. Lee Creek specimen.
Fig. 5 - "A. grandis"
Lee Creek specimen.