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Re: Baby Chasmosaurus found in Alberta (news story)

From: Ben Creisler

A news release from the University of Alberta:


On Mon, Nov 25, 2013 at 10:09 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> From: Ben Creisler
> bcreisler@gmail.com
> Here's the abstract from the SVP meeting:
> Technical Session III (Wednesday, October 30, 2013, 3:15 PM)
> CURRIE, Philip, University of Alberta, Edmonton, AB, Canada, T6G 2E9;
> HOLMES, Robert, University of Alberta, Edmonton, AB, Canada; RYAN,
> Michael, Cleveland Museum of Natural History, Cleveland, OH, United
> States; COY, Clive, University of
> Alberta, Edmonton, AB, Canada; KOPPELHUS, Eva, University of Alberta,
> Edmonton, AB, Canada
> The smallest known articulated ceratopsid skeleton (lacking only the
> forelimbs) is a juvenile chasmosaurine that was collected in 2010 from
> the lowermost part of the Dinosaur Park Formation in Dinosaur
> Provincial Park, Alberta. At 1.5 m in total length, it falls below the
> size range of even adult basal neoceratopsians and large
> psittacosaurids. Cranial bones have striated, porous bone texture;
> many are coossified despite its small size. The frill is relatively
> short and narrow. The back of the frill is rectangular, lacks a
> posterior embayment, and is relatively narrower than those of either
> equivalent-sized basal neoceratopsians or adult ceratopsids. There are
> no cranial epiossifications, and the squamosal is capped at the
> posterolateral corner by the parietal. The margins of the elongate
> squamosals are thick and scalloped. Narrow and elongate openings may
> represent the parietal fenestrae, and there is a pronounced midline
> sagittal crest that extends almost to the back of the frill. The
> preserved short, knoblike postorbital horn has a round base and there
> is no development of sinuses from below. An incipient horncore is
> present on the nasals over the posterior one-half of the external
> nares. There are 18 maxillary tooth positions, which is at least four
> more than in any similar-sized basal neoceratopsians, but is fewer
> than what is found in more mature ceratopsids. All of the cranial
> features are consistent with its identification as Chasmosaurus sp.
> Postcranially, skin on the flank of the body comprised a basement of
> pebbles with large feature scales. The syncervical is composed of
> three fused vertebrae. There are 32 articulated caudals, of which the
> fifth to twentieth appear to have short, robust, free caudal ribs. The
> narrow pelvis suggests the body was tall and narrow. Ossified tendons
> are present in the neck and trunk. The pedal unguals are broad but
> taper acutely. Ontogenetic hind limb proportions scale isometrically,
> and as in more mature ceratopsids, the tibia/fibula and metatarsals
> are relatively short in contrast with those of more basal
> ceratopsians. Recovery in the phylogenetic analysis of the specimen as
> a basal chasmosaurine is a reflection of juvenile characters that have
> a significant impact on character coding. For example, as in basal
> ceratopsians the palpebral is not fully incorporated into the orbital
> rim. Those characters used in phylogenetic analyses of ceratopsids
> that are size or age-dependent can now be identified, redefined to be
> more useful, or dropped.
> On Mon, Nov 25, 2013 at 8:22 AM, Ben Creisler <bcreisler@gmail.com> wrote:
>> From: Ben Creisler
>> bcreisler@gmail.com
>> A news story of interest:
>> http://www.livescience.com/41486-smallest-intact-baby-ceratopsid-found.html