Palaeoscincus asper, Lambe, 1902

Lambe L. M., 1902, New genera and species from the Belly River Series (mid-Cretaceous), Geological Survey of Canada Contributions to Canadian Palaeontology 3, pp. 25-81 : 54

Palaeoscincus asper . Sp. nov.

Plate XVII, fig. 5 .

The tooth for which the above name is proposed is in the form of a laterally compressed cone, with a serrate edge and rugose sides. The root was evidently cylindrical but has been broken off close to the base of the crown.

One side of the crown is more rugosely striated and flatter than the other which is decidedly convex. The trenchant edge has eighteen serrations, fifteen only of which are seen in a side view, as the last three on the right (as figured) are paired with three others of equally small size. The groove separating these three pairs is deep and decided. The other end of the tooth is flattened in an almost vertical direction; here the serrations curve toward the side of the greater rugosity. The broad apical denticle is the one that shows the most wear. The base of the crown is evenly rounded below to meet the fang.

This tooth differs materially from others of the genus described by Leidy and Marsh. The serrations are more numerous, the sides more conspicuously ridged, Whilst the double row of denticles at one end of the cutting edge, besides being novel, is most interesting and instructive, in that it is suggestive of a progressive step toward the development of a double row of tubercles such as is found in the molars of the Multituberculates.

The specific name here suggested has reference to the rough sides of the crown of the tooth.

Measurements

Figures

PLATE XVII. Fig. 1.? Monoclonius dwasoni, Lambe, side view of’! nasal horn core; one-half the natural size. outlines of the at “ ” and “ b " Fig. 2. Sectional same a 3. Monoclonius canadensis, Lambe, right Orbital horn core, obliquely from behind; one-halfe Fig. natural size. Page 63. o, orbit. sectional outline at “ ”. Fig. 4. The same, a 5. Palaeoscincus Lambe, side view of tooth; four times natural size. Page 54. Fig. asper,