A chance fossil discovery in Montana a decade ago has led to the
identification of an audacious new species of horned dinosaur. The
international research team that described the plant-eating dinosaur was
led by a scientist at the Canadian
Museum of Nature. The results are published today in the online science journal PLOS ONE.
The museum now houses the specimen in its national fossil collection,
which includes some of the best examples of horned dinosaurs in the
world. Museum palaeontologist Dr. Jordan Mallon completed the scientific
analysis that pinned down the dinosaur as a new species. It is one
among a growing number of newly discovered ceratopsids (four-legged
dinosaurs generally characterized by horns on the face and elaborate
head frills).
Mallon has bestowed the scientific name Spiclypeus shipporum (spi-CLIP-ee-us ship-OR-um) on the dinosaur, which lived about 76 million year ago.Spiclypeus is
a combination of two Latin words meaning "spiked shield," referring to
the impressive head frill and triangular spikes that adorn its margins.
The name shipporum honours the Shipp family, on whose land the fossil was found near Winifred, Montana.
About half of the skull, as well as parts of the dinosaur's legs, hips
and backbone had been preserved in the silty hillside that once formed
part of an ancient floodplain.
"This is a spectacular new addition to the family of horned dinosaurs
that roamed western North America between 85 and 66 million years ago,"
explains Mallon, who collaborated with researchers in Canada and the
United States. "It provides new evidence of dinosaur diversity during
the Late Cretaceous period from an area that is likely to yield even
more discoveries."
What sets Spiclypeus shipporum apart from other horned dinosaurs such as the well-known Triceratops is
the orientation of the horns over the eyes, which stick out sideways
from the skull. There is also a unique arrangement to the bony "spikes"
that emanate from the margin of the frill--some of the spikes curl
forward while others project outward.
"In this sense, Spiclypeus is
transitional between more primitive forms in which all the spikes at
the back of the frill radiate outward, and those such asKosmoceratops in which they all curl forward," says Mallon.
While the fossil now has a scientific moniker, it is more commonly known
by its nickname "Judith," after the Judith River geological formation
where it was found. Until it was purchased by the museum in 2015, the
fossil had remained in the official possession of Dr. Bill Shipp, who
found it while exploring his newly acquired property in 2005.
Shipp invested time and money to excavate and prepare the bones, aided by volunteers and palaeontologists including the PLOS ONE study
co-authors Chris Ott and Peter Larson. "Little did I know that the
first time I went fossil hunting I would stumble on a new species,"
explains Shipp, a retired nuclear physicist who became a fossil
enthusiast after moving to his dinosaur rich area of Montana. "As a
scientist, I'm really pleased that the Canadian Museum of Nature has
recognized the dinosaur's value, and that it can now be accessed by
researchers around the world."
Apart from the horns and frill bones that helped define Judith as a new
species, close examination of some of its other bones reveal a story of a
life lived with pain. Judith's upper arm bone (humerus) shows distinct
signs of arthritis and osteomyelitis (bone infection)--determined
following analysis by Dr. Edward Iuliano, a radiologist at the Kadlec
Regional Medical Cener, in Richland, Washington.
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