Description
Original diagnose after Cicimurri & Knight (2019) p. 11 [27380]: Nearly 400 specimens are referred to the new species, which differs from Recent Isogomphodon oxyrhynchus (Müller and Henle 1841) in that all teeth have smooth cutting edges extending from the apex to the very base of the crown. In contrast, the upper teeth of the extant species are weakly serrated and edges of lower anterior teeth are often limited to the upper half of the crown. In addition, the Eocene teeth have shorter cusps, many exhibit very convex lateral shoulders (especially more lateral positions), and the root lobes are more elongated and divergent (Herman et al. 1991, Compagno et al. 2005). The new species differs from the fossil species I. acuarius (Probst 1879), I. lerichei (Darteville and Casier 1943), I. caunellensis (Cappetta 1970), and I. gracilis (Jonet 1966) in being smaller in overall size. Additionally, the Dry Branch species has narrower upper anterior teeth and complete cutting edges on all teeth when compared to I. caunellensis, and the convexity of the lateral shoulders of anterior teeth appears to be more pronounced than on I. acuarius (Cappetta 1970, Case 1980, Müller 1999). The transition from main cusp to lateral shoulders appears to be slightly more angular on teeth of I. lerichei (Darteville and Casier 1943).

Remarks
shark-references Species-ID=15461;
valid after Cicimurri & Knight (2019) p. 11 [27380];

References