Compagno (2005:269) includes 24 species as present in modern oceans. These are small (usually <1 meter rarely over 1.5) sharks of the continental/insular shelf with a world wide (cold temperate to tropical) distribution (regionalized by species). Most taxa have low-crowned pavement-like dentitions (durophagous, crushing design), although some have more cuspidate crowns. Currently present off the US east coast is Mustelus canis (MITCHILL, 1815) which prefers muddy/sandy bottoms (usually to 200 meters) and feeds largely on crustaceans.
Cappetta (1987:116) when discussing this tooth-designed referred to it as convergent with the (rhino)batoids. He noted the crown has a transverse ridge, labial face which overhangs the roots with marginal folds and a lingual face with a distinct uvula. The root is large with a lingual protuberance and broad nutrient groove. He noted two species
Mustelus vanderhoefti HERMAN, 1982 from the Middle Eocene of Belgium
Mustelus whitei CAPPETTA 1976 from the Ypresian of England
Probably because of their small size, usually less than 1.5 mm in length, there isn't a particularly good fossil record in the US.
Case (1994:118, pl 13 fig 276-81) erected Mustelus rodgersi for Mustelus teeth from the Tuscahoma Fm. (Late Palaeocene) of Mississippi. These were large by the taxon's standards (3 mm) and he noted they were devoid of cusps and had a coronal ridge with slight crenulations.
Müller (1999: 46-47) included as Mustelus sp a single specimen from the Piney Point Fm. (Ypresian, VA) and multiple teeth from the Mio-Pliocene (St. Marys Fm, MD, Eastover Fm., VA and Yorktown of NC).
Purdy et (al 2001:140) included as Mustelus sp teeth of this design from the Pungo River Fm (Units 1-5, Early-Middle Miocene of NC). They noted these small teeth (1-1.3 mm) as similar to the Recent M. canis. The accompanying specimens (Figs. & ) were found in basal Yorktown 2 sands.
Parmley et al (2003:168) reported Mustelus cf vanderhoefti from the Late Eocene of Georgia.
Cappetta, H., 1987. Chondrichthyes II. Mesozoic and Cenozoic Elasmobranchii. In: Handbook of Paleoichthyologie, vol. 3b, Gustav Fischer Verleg, Stuttgart, 193 pp.
Case, G., 1994. Fossil Fish Remains fron the Late Paleocene Tuscahoma and Early Eocene Bashi Formations of Meridian, Lauderdale County, Mississippi. Palaeontographica Abt. A, 230, pp 97-138.
Compagno, L,, Dando & M., Fowler, S., 2005. Sharks of the World. HarperCollins, 368 p.
Müller, A. 1999. Ichthyofaunen aus dem atlantischen Tertiär der USA. Leipziger Geowissenschafteb, Leipzig, 9/10: 1-360.
Parmley, D., Cicimurri, D. & Campbell, R., 2003. Late Eocene sharks of the Hardie Mine local fauna of Wilkinson County, Georgia Georgia Journal of Science, 61(3):153-179
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.