Pseudopalatus pristinus Mehl, 1928

Nesbitt, Sterling J., 2011, The Early Evolution Of Archosaurs: Relationships And The Origin Of Major Clades, Bulletin of the American Museum of Natural History 2011 (352), pp. 1-292 : 19

Pseudopalatus pristinus Mehl, 1928

AGE: Mid-late Norian, Late Triassic; most specimens from Petrified Forest National Park, Arizona fall within 30 m of the Black Forest Bed which has been radiometrically dated at 213 ± 1.7 Ma ( Riggs et al., 2003) .

OCCURRENCE: Petrified Forest Member of the Chinle Formation, Arizona ; Bull Canyon Formation of the Dockum Group, New Mexico and Texas.

HOLOTYPE: U. of Mo. 525 VP, nearly complete skull.

REFERRED MATERIAL: UCMP 27235, partial skull and partially articulated postcranium, including much of the pes and manus; UCMP 34249, complete skull; various other isolated Pseudopalatus pristinus elements from the Canjilon Quarry (UCMP V2816); UCMP 34253, complete presacral column, sacrals, and anterior caudal vertebrae.

REMARKS: Pseudopalatus pristinus occurs throughout the upper half of the Chinle Formation and Dockum Group and stands alone as one of the most completely known derived phytosaurs. As a result, it is constantly cited as biostratigraphically useful (see Lucas, 1998a). Additionally, Zeigler et al. (2002, 2003) proposed that Pseudopalatus pristinus represents a sexual morph opposite Pseudopalatus buceros . Here, I score material referable to Pseudopalatus from the Canjilon Quarry (UCMP V2816), particularly the articulated specimens UCMP 27235 and UCMP 34253 and the complete well preserved skull UCMP 34249.

KEY REFERENCES: Mehl, 1928; Ballew, 1989; Long and Murry, 1995; Hungerbühler, 2002.