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Saurolophus skin impressions show species distinctions

From: Ben Creisler

New in PLoS ONE:

Bell, P.R. (2012)
Standardized Terminology and Potential Taxonomic Utility for
Hadrosaurid Skin Impressions: A Case Study for Saurolophus from Canada
and Mongolia.
PLoS ONE 7(2): e31295

The characterization of palaeospecies typically relies on hard-tissue
anatomy, such as bones or teeth that is more readily fossilized than
soft parts. Among dinosaurs, skin impressions are commonly associated
with partial and complete hadrosaurid skeletons, and consist of
non-imbricating tubercles or scales. Skin impressions from various
parts of the body of two species of the hadrosaurine Saurolophus (S.
angustirostris from Mongolia and S. osborni from Canada) are described
from multiple specimens. These species, recently validated on
osteological grounds, can be differentiated based solely on
soft-tissue anatomy, namely scale shape and pattern. This study
demonstrates for the first time the applicability of soft-tissue
(i.e., scale impressions) as a means to differentiate species within
the Dinosauria. Differences are most spectacular in the tail, where S.
angustirostris is differentiated by the presence of vertical bands of
morphologically distinct scales, a grid-like arrangement of circular
feature-scales, and tabular scales along the dorsal midline.
Preliminary results indicate scale architecture remained consistent
throughout ontogeny in S. angustirostris. These results support
previous assertions that hadrosaurid scale architecture has a positive
phylogenetic signal. As such, future taxonomic descriptions should
include, where possible, the standardized description of skin
impressions including the position and orientation of these
impressions on the body.