CHAPTER VII. 



A DESCRIPTION OF EDAPHOSAURUS COPE. 



By S. W. WiLLisTON AND E. C. Case. 



The detailed history of the genus Edaphosaurus has been given by Case * 

 and need not be repeated here. Briefly, the genus was described by Cope in 1882, 

 based upon a fairly complete but crushed skull and a single vertebra, the axis. 

 The characters presented by this specimen were deemed of sufficient importance 

 by Cope to warrant the erection of the family Edaphosauridae, in which, however, 

 he erroneously associated the cotylosaurian genus Pantylns Cope, a genus having 

 somewhat similar palatal teeth, but differing widely in other respects. In 1884 he 

 referred a second species, E. microdus Cope, to the same genus, based upon some 

 fragments of the plates bearing the teeth and a series of vertebrae. Two years 

 later, however. Cope transferred the latter species to his new genus Naosaurus, 

 where it has since remained. 



Until recently no additional specimens have been referred with certainty to 

 Edaphosaurus, and the identity of the two genera, Edaphosaurus and Naosaurus, has 

 been in doubt. Six years ago, however, Case discovered in the Texas deposits 

 typical Naosaurus vertebrae associated with a mandibular dental plate, which 

 pretty nearly convinced him of the identity of the two genera, as shown by the 

 following quotation from his cited work, page 45 : 



"If this association is a true one, as seems certain, the name Naosaurus must be given 

 up, as it is preoccupied by Edaphosaurus, and the subfamily Naosaurinffi will disappear, 

 and the members will be placed in the family Edaphosauridae. It may seem that there is 

 undue hesitancy in uniting the two genera on the evidence cited, but to any one familiar 

 witli the occurrence of bones in the Texas beds the possibility of accidental association is 

 so evident that the greatest conservatism seems the best course. * * * Tq me it seems 

 extremely probable that the two genera must be united." 



As will be seen. Case was quite right in his opinion ; the evidence is now posi- 

 tive that the two genera are closely allied if not identical, and the name Naosaurus 

 must be abandoned, unless it should be foimd that the typical species N. claviger 

 Cope is generically different from Edaphosaurus in ways that are yet unknown. 

 That the genus belongs in the family Edaphosauridse is, in any event, definitely 

 proven. In some ways it is unfortunate that the identity or close relationship 

 of the two genera was not more strongly insisted upon by Case; it might, perhaps, 

 have prevented the incorrect restorations of Naosaurus which have gained currency 

 in textbooks and popular works. The following, to the best of our present knowl- 

 edge, is the correct synonymy of the genus and species: 



EDAPHOSAURID/E. 



Cope, Proc. Amer. Phil. Soc, xx, 1882, p. 450; ibid, 1883, p. 631; Pal. BulLs. 35, 36. Case, Revision 

 of the Pelycosauria, 1907, 68. 



Edaphosaiirus. 



Cope, Proc. Amer. Phil. Soc., xx, 1882, p. 448. Case, Revision of the Pelycosauria, 1907. p. 69. 

 Naosaurus Cope, Amer. Nat. xx, 1886, p. 544; ibid, xxi, 1878, p. 319; Proc. Amer. Phil. Soc. 

 XIV, 1878, 44 {Dimetrodon). Case, Revision of the Pelycosauria, 1907, p. 58. 



* Revision of the Pelycosauria, Cam. Inst. Washington, Publication 55, 1907, p. 34. 



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