34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



CLAENODON ACROGENIUS," new species 

 Plate 7, figures i, 6 



Type.— Right ramus of mandible with Pi, Mi, and M3, U.S.N.M. 

 No. 20634. 



Horison and locality. — Bison basin Tiffanian, saddle locality at 

 south rim of Bison basin, sec. 28, T. 27 N., R. 95 W., Fremont 

 County, Wyo. 



Specific characters. — Size comparable to the very largest indi- 

 viduals of Claenodon ferox. Jaw very deep, particularly beneath posi- 

 tion of anterior premolars. Canine large and anterior premolars sepa- 

 rated by a marked diastema. P2 possibly absent or reduced to single 

 rooted tooth. 



Discussion. — Claenodon acrogenius is represented by approximately 

 seven specimens in the collections of the National Museum and pos- 

 sibly by a molar talonid in the University of Wyoming collection. 

 Among the referred specimens are the posterior portions of three 

 other lower jaws with one molar each, two maxillary fragments ex- 

 hibiting M^, one of which also includes most of P*, and an isolated P4. 



Although the size of the teeth in this material is within, or nearlj 

 within, the upper limits of the size range for Claenodon ferox as 

 recognized in the Torre j on materials, the depth of the jaw, as shown 

 in the type specimen, appears to be exceedingly great, particularly to- 

 ward the forward extremity. Moreover, the type specimen has a large 

 saberlike canine, as indicated by the root portion, and a diastema of 

 very considerable length anterior to P3. Pi is close to the canine and 

 P2 is missing. A short distance posterior to Pi there is a depression 

 that may have been an alveolus for a root of P2. It is uncertain, of 

 course, but this tooth may have been lost during the life of the animal 

 and the alveoli nearly obliterated. In any case, the length of the 

 diastema between Pi and P3 is very mucli greater than would be 

 required for a P2. 



The two molars preserved in this jaw are much worn and do not 

 include Mo. These teeth are a little smaller than those in the other 

 more fragmentary deep-jawed specimens and are interpreted as repre- 

 senting the smaller size group of C. acrogenius as shown in the 

 histogram. 



MEASUREMENTS IN MILLIMETERS OF TYPE OF Clacnodon acrogcnius, 



U.S.N.M. NO. 20634 



Length of cheek tooth series, posterior margin of alveolus of canine to 



posterior margin of Ms 87.* 



Diastema between Pi and Ps 15.O 



1^ From Greek, akrogcneios =:^f/ith prominent chin. 



