Carcharhinus isodon, the Finetooth Shark, is an extant taxon of the Western Atlantic and Gulf of Mexico (sub-tropical waters). Individuals are small (<2 m) inhabiting nearshore (0-20m) waters and often schooling; they feed on small teleosts and cephalopods. (Ref Compagno 1984, Compagno et al 2005, Garrick 1985 & FishBase.org). The dentition is largely grasping in design; cutting provided by slightly broadened uppers with a complete cutting-edge. Teeth number 15-16 per quadrate and are relatively homodont with a decrease in cusp height distally. [Bigelow & Schroeder (1948: 305) and Garrick (1985: 9) figure the isodon dentition-design.]

This tooth-design was not included by Purdy et al (2001) as present at Lee Creek and to the authors' knowledge, it hasn't been formally reported from the fossil record (although included on elasmo.com since 2000). The presented examples were recovered by the senior author from Pungo River Formation tailings. Their small size and narrow upright unserrate cusp makes these teeth quite distinct from most other Lee Creek carcharhinid teeth. In the first 10 or so file positions, there is neither a mesial nor distal notch; more posterior positions may display a distal notch. Shoulders, particularly the distal may faintly display a wavy cutting-edge. Much less common than the similarly-sized C. macloti (maybe 1:100), it is currently not possible to differentiate lower teeth with any degree of confidence.

References

Bigelow, H. and W. C. Schroeder 1948. Part 1. Sharks; in Fishes of the western North Atlantic. Sears Foundation for Marine Research, Yale University, New Haven.
Compagno, L.,1984. FAO Species Catalogue, Vol 4, parts 1 & 2 Sharks of the World. United Nations Development Program.
Compagno, L.,1988. Sharks of the Order Carcharhiniformes. Princeton University Press, Princeton, NJ. 486 pp , 35 plates.
Compagno, L,, Dando & M., Fowler, S., 2005. Sharks of the World. Harper Collins, 368 p.
FishBase.org Sep. 2008.
Garrick, J., 1985. Additions to a Revision of the Shark Genus Carcharhinus: Synonymy of Aprionodon and Hypoprion, and Description of a New Species of Carcharhinus (Carcharhinidae). NOAA Technical Report NMFS 34. 26 pp
Purdy, R., Schneider, V., Appelgate, S., McLellan, J., Meyer, R. & Slaughter, R., 2001. The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina. In: Geology and Paleontology of the Lee Creek Mine, North Carolina, III. C. E. Ray & D. J. Bohaska eds. Smithsonian Contributions to Paleobiology, No 90. Smithsonian Institution Press, Washington D.C. pp. 71-202.