. Bulletin. Natural history. Text-fig. 94. Lateral view of left quadrate. A. Tylosaurus proriger (reconstructed after YPM 3990 and AMNH 4909, X s/j). B. Tylosaurus nepaeoticus (YPM 3992, X s/t). articulating surface of quadrate, then ascends to terminate lateral to and slightly below infrastapedial process. Discussion. The type of "Macrosaurtis" proriger unfortunately has not been found. Thus far it has been possible to distinguish only two species of Tylosaurus from the Niobrara Chalk, one of which may be characterized by a premaxillomaxillary suture that extends at least as far bac
. Bulletin. Natural history. Text-fig. 94. Lateral view of left quadrate. A. Tylosaurus proriger (reconstructed after YPM 3990 and AMNH 4909, X s/j). B. Tylosaurus nepaeoticus (YPM 3992, X s/t). articulating surface of quadrate, then ascends to terminate lateral to and slightly below infrastapedial process. Discussion. The type of "Macrosaurtis" proriger unfortunately has not been found. Thus far it has been possible to distinguish only two species of Tylosaurus from the Niobrara Chalk, one of which may be characterized by a premaxillomaxillary suture that extends at least as far back, as the fourth maxillary tootli. From Cope's (1869-1870, pi. 12 figs. 22-24) figures this would seem to be its condition in the type of T. proriger, as it surely is in the specimen from Butte Creek that Cope referred to this species (AMNH 1493; Co]x?. 1872c, p. 175). One of the points by which Cope (1874, p. 38) separated the type of T. nepaeolicus from T. proriger was the relatively advanced posi- tion of its external nares, thus intimating that in the latter species the external nares were more posteriorly situated and that the premaxillo-maxillary suture was also extended further posteriorly. It seems safe therefore to assume that die correct name has been applied to the species diagnosed above. Tylosaurus nepaeolicus (Cope 1874) (Text-figs. 15, 93A, 94B, 95) Liodon nepaeolicus Cope, 1874, p. 37. Tylosaurus nepaeolicus, Merriam, 1894, p. 24. Type. AMNH 1565, from ". . die gray shale of the Niobrara Cretaceous, a half mile south of the Solomon River, Kansas," (Cope, 1874, p. 38) collected by B. F. Mudge. Type specimen includes a partial skull and one vertebra. Distribution. Smoky Hill Member, Niobrara Formation, Kansas. Additional References. Cope, 1875, p. 168, pi. 35 figs. 11-15. Owen, 1879, p. 55. Merriam, 1894, p. 24, pi. 4 fig. 7. Williston, 1898b, p. 176; 1910, p. 539, figs. 5-10. Stern- berg, 1908, p. 113, fig. I. Huene, 1910, p. 297, figs. 5-10, pi. 1, pi.
Size: 1188px × 2104px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookc, bookcentury1900, bookdecade1920, booksubjectnaturalhistory
