Fig. 80. P. leptognathus, rear portion of skull—
½ natural size; shaded areas are matrix.
The dental formula is
- 3 1 4 3
- ———
- 3 1 4 3
as in Adinotherium, the chief difference being that the teeth are less hypsodont than in the Santa Cruz genus. Little is known as yet of the skeleton, but when more is known probably more distinctive characters will appear. Ameghino made two species, P. leptognathus which we also found, and P. angustidens a much smaller form.
Proadinotherium leptognathus Ameghino
P. leptognathus Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 625.
P. leptognathus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 467.
Fig. 81. Left lower jaw with
incisor 3 and molar 2—
½ natural size.
Of this species we found on the Chico del Chubut River, west of Puerto Visser, three specimens; the back of a skull as far forward as molar 2, and two lower jaws. In general, the species is very similar, even to size, to Adinotherium ovinum of the Santa Cruz.