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Examination of a historic collection of isolated cranial and appendicular hadrosaurid material from the lower Kirtland Formation of the San Juan Basin, New Mexico

Published online by Cambridge University Press:  27 July 2016

Mateusz Wosik
Affiliation:
Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 2C6, Canada 〈m.wosik@mail.utoronto.ca〉
Merrilee F. Guenther
Affiliation:
Department of Biology, Elmhurst College, Elmhurst, Illinois 60126, USA 〈guentherm@elmhurst.edu〉

Abstract

The Field Museum of Natural History collection contains several isolated hadrosaurid specimens collected by Charles H. Sternberg from the lower Kirtland Formation of the San Juan Basin, New Mexico, that have been previously overlooked. Cranial elements described herein consist of a dentary and three jugals while appendicular material is limited to two humeri and two pubes. Many of the specimens preserve taxonomically informative characters that show strong affinities with Kritosaurini but are distinct from Kritosaurus navajovius (Brown, 1910) suggesting that the saurolophine-dominated San Juan Basin diversity is greater than currently recognized. Future examination of currently unprepared material will add to our developing understanding of the ambiguous hadrosaurid diversity of the San Juan Basin.

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Articles
Copyright
Copyright © 2016, The Paleontological Society 
Figure 0

Figure 1Stratigraphic distribution of hadrosaurid taxa and key specimens in the San Juan Basin, New Mexico (modified from Sullivan and Lucas, 2014). Prieto-Márquez (2013) considered A. horneri as a junior synonym of K. navajovius. LVA=North American Land Vertebrate Age; Hadrosaur Biostrat=Hadrosaur Biostratigraphy.

Figure 1

Table 1Selected measurements (in millimeters) of FMNH hadrosaurid Sternberg material. DCC=depth of caudal constriction; DCVF=depth of caudoventral flange; DPCL=length of deltopectoral crest; DPCW=width of deltopectoral crest; DRC=depth of rostral constriction; DW=distal width; MW=midshaft width; PCW=width of proximal constriction; PPBW=width of prepubic blade; PPW=width of pubic process; PW=proximal width; TL=total length; NW=width of minimum constriction of neck.

Figure 2

Figure 2Right dentary (PR 2248) in (1) medial; (2) medial illustration; and (3) lateral views. AF=angular facet; CP=coronoid process; DB=dental battery; OP=occlusal plane; PEM=proximal edentulous margin.

Figure 3

Figure 3Right jugals. PR 1203a in (1) lateral; (2) medial; and (5) medial illustration views. PR 1203b in (3) lateral and (4) medial views. PR 1252 in (6) lateral and (7) medial views. CVF=caudoventral flange; IF=infratemporal fenestra; OF=orbital fenestra; OM=orbital margin; PP=postorbital process; QJF=quadratojugal flange; RP=rostral process.

Figure 4

Figure 4Right humeri. PR 1300 in (1) lateral and (2) medial views. PR 1301 in (3) lateral and (4) medial views. AH=articular head; DPC=deltopectoral crest; HS=humeral shaft; RC=radial condyle; UC=ulnar condyle.

Figure 5

Figure 5Left pubes. (1) PR 1202 in lateral view; (2) PR 1290 in lateral view. AM=acetabular margin; IP=ischial peduncle; PB=prepubic blade; PC=proximal constriction; PP=pubic process (iliac peduncle); PPP=postpubic process.