In the course of examining material from fissure deposits of earlyPermian age collected from a limestone quarry near Fort Sill, Oklahoma,the author recovered several tooth-bearing fragments of smallpelycosaurs. The fragments were examined, compared with descriptions ofknown kinds appearing in the literature, and determined to be new generawithin the Nitosauridae (Edaphosauria) and Sphenacodontidae(Sphenacodontia).
Appreciation is expressed to Prof. Theodore H. Eaton, Jr., forpermission to examine the collections of the University of Kansas fromFort Sill, and for the financial assistance furnished by his NationalScience Foundation grant (NSF-G8624). I am grateful both to Prof. Eatonand Mr. Dale L. Hoyt for their suggestions regarding this manuscript.The accompanying figures have been drawn by the author.
(delos, Gr., evident; rhynchos, Gr., neuter, nostril; priscus, L.,ancient. Delorhynchus is masculine because of the ending that itacquires when transliterated into Latin.)
Type specimen.—Fragmentary left maxilla, bearing four teeth, KU11117.
Referred specimens.—Fragmentary right maxilla having four teeth, KU11118; fragmentary left maxilla having four teeth, the most posterior ofwhich has been broken, KU 11119.
Horizon and locality.—A fissure deposit in the Arbuckle limestone atthe Dolese Brothers Limestone Quarry, approximately six miles north ofFort Sill, in sec. 31, T. 4 N, R. 11 W, Comanche County, Oklahoma. Thesesediments are of early Permian age, possibly equivalent to the Arroyoformation, Lower Clear Fork Group of Texas (Vaughn, 1958: 981).
Diagnosis.—Small; marginal teeth conical, slender and recurved attips; marginal tooth-row without caniniform enlargement; narial openingenlarged and bordered dorsally, posteriorly and ventrally by maxilla;maxilla with foramen opening laterally at posteroventral corner ofnaris.
Description (based on 3 maxillary fragments, see Table 1).—Each ofthe maxillary fragments bears four thecodont teeth. These are conical,slender and sharply pointed; in their distal third they are slightlyrecurved, laterally compressed, and have anterior and posteriornon-serrated cutting edges. In medial aspect at their bases, the teethare longitudinally striated. The bases of the teeth[Pg 300] are circular in