10.5061/DRYAD.V9S4MW6QS
Cullen, Thomas
0000-0002-4261-1323
Field Museum of Natural History
Simon, D. Jade
University of Toronto
Benner, Elizabeth
University of Toronto
Evans, David
Royal Ontario Museum
Morphology and osteohistology of a large-bodied caenagnathid (Theropoda:
Oviraptorosauria) from the Hell Creek Formation (Montana): implications
for size-based classifications and growth reconstruction in theropods
Dryad
dataset
2019
Caenagnathidae
osteohistology
theropod
osteocyte lacunar density
Natural Sciences and Engineering Research Council
https://ror.org/01h531d29
2020-03-10T00:00:00Z
2020-03-10T00:00:00Z
en
https://doi.org/10.1002/spp2.1302
8053462394 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Oviraptorosaurs, like many coelurosaurians, are frequently diagnosed using
incomplete or fragmentary skeletal remains, with factors such as body size
often used to assign material to a particular taxon or as a basis for
describing new species. Here we describe a partial skeleton, ROM VP 65884,
from the Hell Creek Formation (Montana), and through morphological and
phylogenetic comparisons identify it as belonging to Caenagnathidae, and
likely referable to Anzu wyliei. We perform multi-element
osteohistological sampling of the tibia, fibula, manual phalanx, rib, and
gastralium of ROM VP 65884 so as to determine the ontogenetic status of
the individual, and to perform a detailed assessment of the intra-skeletal
variation present in a series of histological proxies for growth and
development. Skeletochronological analysis suggests ROM VP 65884 was still
actively growing at time of death. Lacunar area was variable, but
consistent with values reported for other dinosaurs and vertebrates.
Osteocyte lacunar densities (OLD) were found to be relatively similar to
the few previous measurements known from coelurosaurian dinosaurs, and
preserved no ontogenetic pattern. OLD was much higher in sampled rib and
gastralia elements when compared to limbs, and the high variability in OLD
overall lends further support against the hypothesis of this feature
acting as a proxy for mass-specific growth rate. Our results stress the
importance of using osteohistological analyses to constrain variation and
permit ontogenetic assessment, and suggest caution be taken when using
size as a determinant for referral of disassociated elements to specific
or new coelurosaur taxa.