[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Ornithopod teeth from Alaska



From: Ben Creisler
bh480@scn.org

A new online paper:

Caleb Marshall Brown and Patrick Druckenmiller (2011) 
Basal ornithopod (Dinosauria: Ornithischia) teeth from 
the Prince Creek Formation (early Maastrichtian) of 
Alaska.
Canadian Journal of Earth Sciences (advance online 
publication)
doi:10.1139/e11-017
http://www.nrcresearchpress.com/doi/abs/10.1139/e11-017


Abstract
A diverse and prolific record of polar dinosaurs comes 
from the Upper Cretaceous (Campanian?Maastrichtian) 
sediments of the Prince Creek Formation exposed on 
Alaska?s North Slope. Previous assignment of basal 
ornithopod material from this formation has been based 
solely on teeth, which have either been referred 
to "hypsilophodontid" indet. or Thescelosaurus sp. Here, 
we re-examine this material and describe several new 
specimens, including five isolated premaxillary teeth and 
three cheek teeth. The premaxillary teeth are most 
similar to those of Thescelosaurus, whereas the cheek 
teeth are more similar to its sister taxon Parksosaurus, 
for which premaxillary teeth are unknown. Referral of 
this new material to Thescelosaurus would represent the 
oldest occurrence of this taxon and considerably extend 
its stratigraphic range. A more likely possibility is 
that the premaxillary teeth are referable to 
Parksosaurus, an interpretation that is more parsimonious 
from a stratigraphic perspective. Intriguingly, one cheek 
tooth previously referred to as "hypsilophodontid" cannot 
be referred to either Thescelosaurus or Parksosaurus. 
Previously, faunal comparisons of the Prince Creek 
Formation have largely been made with non-contemporaneous 
formations, including the Campanian-aged Judith River and 
Aguja formations, or to the latest Maastrichtian Hell 
Creek Formation. On the basis of age and faunal 
similarities, a more appropriate comparison should be 
made with coeval rocks of the Horseshoe Canyon. This 
study expands our knowledge of Cretaceous ornithischian 
diversity at polar paleolatitudes and underscores the 
importance of small, rare, or easily misidentified 
fossils in paleoecological studies.

----------------