''Platypelta'' is an
extinct genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of herbivorous
ankylosaurid
Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s within the subfamily
Ankylosaurinae
Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pina ...
. It is known from the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
Dinosaur Park Formation
The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group), a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the Late Cretaceous, between about 76. ...
(early Late
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...
stage, about 77.5-76.5 Ma ago) of southern
Alberta
Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...
,
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
is ''Platypelta coombsi''.
Discovery and naming
![Euoplocephalus tutus pelvis](https://upload.wikimedia.org/wikipedia/commons/a/a0/Euoplocephalus_tutus_pelvis.jpg)
In 1914,
Barnum Brown
Barnum Brown (February 12, 1873 – February 5, 1963), commonly referred to as Mr. Bones, was an American paleontologist. Named after the circus showman P. T. Barnum, he discovered the first documented remains of ''Tyrannosaurus'' during a career ...
and
Peter Kaisen
Peter may refer to:
People
* List of people named Peter, a list of people and fictional characters with the given name
* Peter (given name)
** Saint Peter (died 60s), apostle of Jesus, leader of the early Christian Church
* Peter (surname), a su ...
, working for the
American Museum of Natural History, in Alberta at the Sand Creek near the
Red Deer River
The Red Deer River is a river in Alberta and a small portion of Saskatchewan, Canada. It is a major tributary of the South Saskatchewan River and is part of the larger Saskatchewan-Nelson system that empties into Hudson Bay.
Red Deer River h ...
, eight miles southeast of Steveville, excavated an ankylosaur skeleton, specimen AMNH 5337. In 1971, it was referred to ''
Euoplocephalus
''Euoplocephalus'' ( ) is a genus of very large, herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, ''Euoplocephalus tutus''.
The first fossil of ''Euoplocephalus'' was found in 1897 i ...
tutus'' by
Walter Preston Coombs. In 2001 however,
Paul Penkalski
Paul may refer to:
*Paul (given name), a given name (includes a list of people with that name)
* Paul (surname), a list of people
People
Christianity
*Paul the Apostle (AD c.5–c.64/65), also known as Saul of Tarsus or Saint Paul, early Chri ...
concluded that this skeleton was nearly identical to another exemplar, AMNH 5403, and that both likely represented a separate taxon.
[Penkalski, P., 2001, "Variation in specimens referred to ''Euoplocephalus tutus''", pp 261-298 in: Carpenter, K. (ed.): ''The Armored Dinosaurs'' Bloomington (Indiana University Press)] In 2013,
Victoria Megan Arbour
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
and
Philip Currie continued to refer AMNH 5337 (and AMNH 5403) to ''
Euoplocephalus
''Euoplocephalus'' ( ) is a genus of very large, herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, ''Euoplocephalus tutus''.
The first fossil of ''Euoplocephalus'' was found in 1897 i ...
'', suggesting that differences from other skulls referred to ''
Euoplocephalus
''Euoplocephalus'' ( ) is a genus of very large, herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, ''Euoplocephalus tutus''.
The first fossil of ''Euoplocephalus'' was found in 1897 i ...
'' could be due to changes occurring with growth and development.
They also noted that AMNH 5337 differed from ''
Scolosaurus
''Scolosaurus'' is an extinct genus of ankylosaurid dinosaurs within the subfamily Ankylosaurinae. It is known from the lower levels of the Dinosaur Park Formation and upper levels of the Oldman Formation in the Late Cretaceous (latest middle Cam ...
'' and ''
Dyoplosaurus
''Dyoplosaurus'' (meaning “double-armoured lizard”) is a monospecific genus of ankylosaurid dinosaur from Alberta that lived during the Late Cretaceous (middle Campanian, ~76.5–75 Ma) in what is now the Dinosaur Park Formation. ''Dyoplosau ...
'' in the pelvic region.
In 2018, Penkalski published a study containing a
cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
analyses of such forms. In it, AMNH 5337 and AMNH 5403 were recovered in a joint different position from ''Euoplocephalus tutus'' specimens CMN 210, UALVP 31, and AMNH 5406. He named a separate genus for AMNH 5337 and AMNH 5403: ''Platypelta'', with as type species ''Platypelta coombsi''. The generic name is derived from Greek ''platys'', "wide", and ''plate'', "small shield", in reference to the broad osteoderms. The
specific name honors Walter P. Coombs Jr., who pioneered the study of ankylosaurs in the late twentieth century.
The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...
, AMNH 5337, was found in a layer of the Dinosaur Park Formation at an altitude of 667 metres, which indicates an age of about 76,8 million years. It consists of a skeleton with skull, lacking the tail and hindlimbs. It represents a mature and aged individual, in view of fused ribs, a fused shoulder girdle, rough articulation surfaces and rough armour.
Specimens AMNH 5403, CMN 8876, ROM 788, and ROM 813 were referred to ''Platypelta''.
AMNH 5403 consists of the severely compressed front half of a skeleton including the skull.
A short tail club has been stored with this skeleton, but Penkalski doubted the connection, pointing out that the club was not marked nor mentioned in the accession catalogue.
CMN 8876 is a skull preserving a single tooth. ROM 788 is a tail club. ROM 813 is a skeleton lacking the skull but containing the entire rump, forelimbs and hindlimbs. Apart from a large number of osteoderms, it preserves skin impressions. It has been secured on three blocks that have not been fully prepared to conserve the impressions. Penkalski already in 2001 suggested it represented a taxon different from ''Euoplocephalus''.
Description
''Platypelta'' is a rather large ankylosaurid. In 2018, its length was estimated at six metres.
According to Penkalski, ''Platypelta'' is typified by a number of traits. Some of the armour plates on its rump are large, exceeding twenty-five centimetres in length, and have a rough top surface with a sharp keel continuing into a pointy beak-shape. The snout is constricted just in front of the eye sockets. The upper beak, of the snout, is rounded and relatively small. The
vomer
The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right max ...
s at their front side overlap the rear underside of the fused
premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
e. At the rear of the skull, the
occipital condyle
The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra.
The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...
is large. The squamosal horns, at the rear corners of the skull roof, are low and rough with a broad base and a pitted point extending to behind. The tooth crowns are strongly ornamented. In the lower arm, the
ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
is long and lightly built. In the pelvis, the front blade of the ilium only lightly bends to below. The foot is robust with arched claws. On the first cervical halfring, the transverse armour band protecting the top front of the neck, the paired middle osteoderms are elongated and partly keeled with a conical projection. On the first cervical halfring, the lateral, or side, osteoderms have a bent but not wavy keel of which the point sticks out to the rear.
Phylogeny
''Platypelta'' was in 2018 placed, within the
Ankylosauridae
Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pa ...
, in the
Ankylosaurinae
Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pina ...
. More precisely it was a member of the
clade Ankylosaurini
Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pinac ...
. In the evolutionary tree it was placed above ''
Scolosaurus
''Scolosaurus'' is an extinct genus of ankylosaurid dinosaurs within the subfamily Ankylosaurinae. It is known from the lower levels of the Dinosaur Park Formation and upper levels of the Oldman Formation in the Late Cretaceous (latest middle Cam ...
'' and below ''
Dyoplosaurus
''Dyoplosaurus'' (meaning “double-armoured lizard”) is a monospecific genus of ankylosaurid dinosaur from Alberta that lived during the Late Cretaceous (middle Campanian, ~76.5–75 Ma) in what is now the Dinosaur Park Formation. ''Dyoplosau ...
''.
See also
*
Timeline of ankylosaur research
This timeline of ankylosaur research is a chronological listing of events in the history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a club ...
*
2018 in paleontology
Flora Plants
Fungi
Cnidarians
Research
* New three dimensionally phosphatized microfossils of coronate scyphozoan '' Qinscyphus necopinus'', including a new type of fossil embryo, are described from the Cambrian (Fortunian) Kuanchuanpu ...
References
{{Taxonbar, from=Q50355971
Ankylosaurids
Late Cretaceous dinosaurs of North America
Fossil taxa described in 2018
Paleontology in Alberta
Campanian genus first appearances
Campanian genus extinctions
Ornithischian genera