Figure 1 from the origninal description (Rickart, 1976) Phrynosoma adinognathus (a) dorsal, ventral and lateral views of referred frontal KUMVP no. 25261 (b) labial and lingual views of holotype dentary no. 25258 (c) labial and lingual views of paratype dentary KUVP 25260 (d) diagram- matic cross-section through proximal end of dentary. Scale line = 2 mm.
REPTILIA (Reptiles) SQUAMATA (PART) (Other Lizards) PHRYNOSOMATIDAE (Sand and Spiny Lizards)

Thick-jawed Horned Lizard
Phrynosoma adinognathus Rickart 1976

Conservation Status:


Homed lizard somewhat larger than Phrynosoma douglassi general dimensions of dentary and juncture of rami on lingual surface similar, but much more robust on fossil. Dorsal surface of frontal more uniformly convex.

Pleistocene (Aftonian?). University of Kansas Meade County Locality no. 9; east of State Lake on east side of Crooked Creek, Meade County, Kansas. T. 33S., R. 28W. NW 1/4 of NE 1/4 of S. 21 (370 10' N, 1000 22' W). Borchers local fauna.
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  • Occurrence Summary:  
  • 6
  • 6
    Museum Vouchers 
  • 0
    Other Observations 
Some county occurrences indicated below may be too imprecise to map above.
County Breakdown: County Name (# occurrences):
Meade (6);

Natural History:

Phrynosoma adinognathus is uniquely different from other known spe- cies. The material available suggests a form similar to P. douglassi, but larger and more heavily built. The skull also appears to have been more arched than in living species. The specific name is from the Greek adinos, meaning "thick," and gnathos or "jaw;" referring to the extreme thickness of the bone of the dentary.

1976 Rickart, Eric A. A new horned lizard (Phrynosoma adinognathus) from the early Pleistocene of Meade County, Kansas, with comments on the herpetofauna of the Borchers locality. Herpetologica 32(1):64-67
Contains the original description of Phrynosoma adinognathus.
1985 Schultze, Hans-Peter, L. Hunt, J. Chorn, and A. M. Neuner. Type and figured specimens of fossil vertebrates in the collection of the University of Kansas Museum of Natural History. Part II. Fossil amphibians and reptiles. University of Kansas Museum of Natural History, Miscellaneous Publication (77):1-66
Also check on several listed names not in KHA as KS taxa.
1987 Montanucci, Richard R. A phylogenetic study of the horned lizards, genus Phrynosoma, based on skeletal and external morphology. Natural History Museum of Los Angeles County, Contributions in Science (390):1-36
1993 Bell, Christopher J. Fossil lizards from the Elsinore Fault Zone, Riverside County, California. PaleoBios 15(2):18-26
Brief mention on the lack of knowledge regarding the squamosal horn patterns of P. adinognathus and P. holmani.
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Travis W. Taggart © 1999-2024 — w/ Sternberg Museum of Natural History, Fort Hays State University