Plinthicus, COPE, 1869

Adnet, Sylvain, Cappetta, Henri, Guinot, Guillaume & Sciara, Giuseppe Notarbartolo Di, 2012, Evolutionary history of the devilrays (Chondrichthyes: Myliobatiformes) from fossil and morphological inference, Zoological Journal of the Linnean Society 166 (1), pp. 132-159 : 141

GENUS † PLINTHICUS COPE, 1869

Included species: † Plinthicus stenodon ( Cope, 1869) ; † Plinthicus kruibekensis Bor, 1990 .

Occurrences: Genus known from the Rupelian of the Boom Clay Formation, Belgium ( Bor, 1990) and Late Chattian of South Carolina, USA ( Cicimurri & Knight, 2009), until the middle Miocene of southern France ( Cappetta, 1970) and of Maryland and North Carolina, USA ( Cope, 1869; Müller, 1999; Purdy et al., 2001).

Remarks: The extinct genus † Plinthicus Cope, 1869 was tentatively placed in the mobulids ( Cappetta, 1987; Cappetta & Stringer, 2002) although these teeth recall those of some rhinopterids ( Purdy et al., 2001; Cicimurri & Knight, 2009). The largest species † P. stenodon ( Cope, 1869) appears to have had a rhinopterid-type dentition with multiple, weakly interlocked columns of teeth. Most striking in these teeth is the 45° angle of recline seen in lateral profile, the concave occlusal surface, and the labiolingually compressed root with regular and fine root lamellae. The species † P. kruibekensis Bor, 1990 is known from a unique tooth that strongly differs from the younger species by a flat occlusal surface (as in some Mobula ), a concave lingual face (as in † Mo. fragilis ), and anastomosing enameloid laminae on the labial and lingual faces of crown.