Distribution: North America, Europe, Asia, Africa, and Australia.
Family MASTODONSAURIDÆ Huxley, 1863.
Huxley, Quart. Jour. Geol. Soc., XIX, p. 65, 1863.
Lydekker, R., Cat. Fossil Reptilia Amphibia, pt. IV, p. 141, 1890.
Skull triangular, and more or less elongated, with the cranial bones very strongly sculptured, the occipital condyles ossified ([49]), and large palatal vacuities; dentine of teeth with very complex plications ([502]); no bony rings ([242]) in sclerotic; and no ventral scutes. Bodies of vertebræ ([49]) fully ossified in the adult. There are large palato-vomerine tusks on the inner side of the maxillary teeth; and the palatines run parallel to the maxilla. The mandible has a large postarticular process; and there is a small inner series of mandibular teeth. In the type genus the pubes are separate from the ischia, and do not enter into the formation of the acetabulum; and the sacral ribs form kidney-shaped disks ([393]).
Represented in North America by a single tooth from the Carboniferous of Kansas. Described by Williston as Mastodonsaurus sp. (Kans. Univ. Quart., VI, pp. 209-210, pl. XXI). Represented in the Triassic of Wyoming by Anaschisma browni, Branson ([49]).
Mastodonsaurus sp. indet.
Williston, Kans. Univ. Quart., VI, p. 209, 1897.
The specimen preserved comprises the entire crown of a single vomerine (?) tooth, 38 mm. in length by 14 mm. in diameter at base ([pl. 21 , fig. 6]) . The immediate tip had been partly worn away in life, but was acuminate. It is composed of a dense blackish material, with the exterior smooth, shining black. It has about 20 narrow flutings, nearly straight, running from the base to the tip, separating shallow grooves. A transverse section of the base shows a narrow pulp-cavity not more than 5 mm. in diameter which extends in about the same proportional width to beyond the middle of the tooth, and in all probability to near the apex. The cross-section of the tooth throughout is nearly or quite circular.
A hemisection of the tooth was made near the middle, showing a structure most remarkably like that of Mastodonsaurus; so nearly alike, in fact, that there is no difference from the large figure given by Owen of a section of Mastodonsaurus ([502]).