Palaeoscincus, Leidy, 1856

Marsh, O. C., 1892, Notes on Mesozoic vertebrate fossils, American Journal of Science 260, pp. 171-176 : 173-174

Palaeoscincus, Leidy, 1856 .

A new reptilian genus and species, Palaeoscincus costatus , was proposed by Dr. Leidy in 1856 for a single tooth found by Dr. Hayden in the Judith Basin. This tooth was more fully described and figured by Leidy in 1859.* The specimen showed well-marked characters, and many similar teeth have since been found, both in the Judith Basin and in various other localities of the Laramie.

A smaller species, apparently of the same genus, is not uncommon in the Ceratops beds of Wyoming, and a characteristic tooth is shown on Plate III, figure 3 . This may be taken as the type specimen, and the species it represents may he called Palaeoscincus latus . The crown of the tooth in this species is broader and the apex more pointed than in the first species described, and this is clearly shown in comparing the present figures on Plate III with those given by Leidy.

The tooth from the Laramie described by Cope in 1882 as a mammalian premolar and as the type of the generic name Meniscoessus evidently belongs to the above or an allied genus, and all three are unquestionably the teeth of Dinosaurian reptiles pertaining to the order Stegosauria . On Plate IV, figure 1 , a very small but typical tooth of Stegosaurus from the Jurassic is represented. The allied genus Diracodon , also Jurassic, has similar teeth.

Figures

Plate III. Figure 1.—Sternal bone of Claosaurus annectens. One-eighth natural size. a, seen from above; b, seen from below. Figure 2.—Left coracoid of Cimolopteryx rarus, Marsh. Natural size, a, front view; b, inuer view; c, back view; cl, lower eud. Figure 3.—Tooth of Palaeoscincus latus, Marsh, a, natural size; b, c, d, twice natural size. Figure 4.—Tooth of Aublysodon mirandus, Leidy. Natural size, a, front view, with sections; b, side view. (After Leidy.) Figure 5.—Tooth of Aublysodon amplus, Marsh. Natural size, a, side view; b, back view; c, front view. Figure 6.—Tooth of Aublysodon cristatus, Marsh. Twice natural size, a, side view; b, back view; c, front view .

Plate IV. Figure 1.—Tooth of Stegosaurus ungulatus, Marsh, a, natural size; b, c, d, twice natural size. Figure 2.—Left fore leg of the same species. Figure 3.—Left hiud leg of the same species. Figures 2 and 3 are one-sixteenth natural size. Letters as in Plate II.