. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. CM. B Figure 25. Dinnebitodon amarali, MCZ 8830. A) contact between right maxilla, palatine, and premaxilla on the palate as pre- served. B) sutural contact between left jugal and maxilla in ventral view. than its predecessor. The coronoid process slopes backward and its height equals the distance from the ventral projection of the symphysis to the angular process. The ar- ticular process is proportionately large. MCZ 8845 and MCZ 8848 possibly rep- resent very young specimens of either Dinnebitodon or Kayentatheriiim
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. CM. B Figure 25. Dinnebitodon amarali, MCZ 8830. A) contact between right maxilla, palatine, and premaxilla on the palate as pre- served. B) sutural contact between left jugal and maxilla in ventral view. than its predecessor. The coronoid process slopes backward and its height equals the distance from the ventral projection of the symphysis to the angular process. The ar- ticular process is proportionately large. MCZ 8845 and MCZ 8848 possibly rep- resent very young specimens of either Dinnebitodon or Kayentatheriiim. Two tiny dentaries, MCZ 8849 (length from symphysis to angle about 6 mm) and MNA V3241 (Fig. 26B) are probably the smallest known non-mammalian synapsid jaws. They already show all the structural features characteristic of tritylodontid jaws. MCZ 8849 holds a large procumbent incisor and two postcanine teeth. The an- terior cheek-tooth is raised well above the more posterior one and its anterolingual cusp is displaced forward relative to the anterobuccal cusp as on some teeth of Oli- gokyphiis (Kuhne, 1956: 80). MCZ 8849 and MNA V3241 represent extremely im- mature individuals, perhaps hatchlings. Their affinities cannot be de- termined at present owing to the absence of clearly diagnostic features. One of the specimens described by D. M. Kermack (1982: 7) but not included in her hypodigm for Kayentatherium wellesi was a fragment of a very large dentary. Kermack left its taxonomic status uncer- tain because of the considerable size dif- ference to the holotype of K. wellesi (UCMP 83671). As Kermack herself not- ed, comparable size differences are found among modern crocodiles. The larger sample for Kayentatherium used in this studv clearly demonstrates a range in skull length from'about 80 mm (USNM 317203; Fig. 24) to about 260 mm (MCZ 8812; Fig. 1) without any structural differences of diagnostic significance. Dodson (1975: 317) observed a range in skull length in
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