''Stegopelta'' (meaning "roofed shield") is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
struthiosaurin nodosaurid
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia.
Description
Nodosaurids, like their close relatives the ankylosaurids, wer ...
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 ...
. It is based on a partial skeleton from the
latest Albian-
earliest Cenomanian-age
Lower
Lower may refer to:
*Lower (surname)
*Lower Township, New Jersey
*Lower Receiver (firearms)
*Lower Wick
Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...
and
Upper 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'', the ...
Belle Fourche Member of the
Frontier Formation
The Frontier Formation is a sedimentary geological formation whose strata date back to the Late Cretaceous. The formation's extents are: northwest Colorado, southeast Idaho, southern Montana, northern Utah, and western Wyoming. It occurs in many ...
of
Fremont County,
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
, USA.
History
![Stegopelta armor plates and teeth](https://upload.wikimedia.org/wikipedia/commons/7/77/Stegopelta_armor_plates_and_teeth.jpg)
In 1905,
Samuel Wendell Williston
Samuel Wendell Williston (July 10, 1852 – August 30, 1918) was an American educator, entomologist, and paleontologist who was the first to propose that birds developed flight cursorially (by running), rather than arboreally (by leaping from tr ...
described FMNH UR88, a partial
armored dinosaur skeleton
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...
consisting of a
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
fragment, seven cervical and two dorsal
vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...
e, part of a
sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30.
The sacrum situates at the upper, back part ...
and both
ilia, caudal vertebrae, parts of the
scapula
The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...
e, both
humeral heads, portions of an
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 ...
and both
radii
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
, a
metacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
, partial
tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
,
metatarsal
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...
, and
armor
Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...
including a
shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
spine and neck ring.
[Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.). ''Lower and Middle Cretaceous Terrestrial Ecosystems''. ''New Mexico Museum of Natural History and Science Bulletin'' 14:249-270.] The specimen was in poor condition, as it had eroded from a slope and been walked on by
cattle
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...
.
Ankylosauria
Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. ...
ns being very poorly known, Williston compared his new genus to ''
Stegosaurus
''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been foun ...
'', and the armor to that of ''
Glyptodon
''Glyptodon'' (from Greek for 'grooved or carved tooth': γλυπτός 'sculptured' and ὀδοντ-, ὀδούς 'tooth') is a genus of glyptodont (an extinct group of large, herbivorous armadillos) that lived from the Pleistocene, around 2.5 ...
'';
[ like that ]mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
, ''Stegopelta'' had a fused section of armor (in its case over the pelvis
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton).
The ...
). Roy Lee Moodie redescribed it in 1910, and considered it to be close to, if not the same as, ''Ankylosaurus
''Ankylosaurus'' is a genus of armored dinosaur. Its fossils have been found in geological formations dating to the very end of the Cretaceous Period, about 68–66 million years ago, in western North America, making it among the last of the n ...
''.[
The genus fell into obscurity. Walter Coombs synonymized it with the more famous but equally poorly known '']Nodosaurus
''Nodosaurus'' (meaning "knobbed lizard") is a genus of herbivorous nodosaurid ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found exclusively in the Frontier Formation in Wyoming.
Description
''Nodosaurus'' grew ...
'' in his 1978 redescription of the Ankylosauria. It was reinstated as a valid genus by Ken Carpenter and James Kirkland (1998), who recognized it as having distinct vertebral and armor characteristics.[ Tracy Ford took this farther in 2000, assigning it to a new ]subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
in 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–Pal ...
based on armor characteristics, which he called Stegopeltinae. Also included was ''Glyptodontopelta
''Glyptodontopelta'' (meaning "''Glyptodon'' shield") is a monospecific genus of nodosaurid dinosaur from New Mexico that lived during the Late Cretaceous (lower to upper Maastrichtian, 69 to 66 Ma) in what is now the Naashoibito member of the O ...
''.[Ford, T.L. (2000). A review of ankylosaur osteoderms from New Mexico and a preliminary review of ankylosaur armor. In: Lucas, S.G., and Heckert, A.B. (eds.). ''Dinosaurs of New Mexico''. ''New Mexico Museum of Natural History and Science Bulletin'' 17:157-176.] This has not been generally accepted, but most recent reviews have accepted ''Stegopelta'' as a distinct genus with uncertain affinities.[Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). ''The Armored Dinosaurs''. Indiana University Press:Bloomington, 455-483. ][Vickaryous, M.K., Maryańska, T., and Weishampel, D.B. (2004). Ankylosauria. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria'' (second edition). University of California Press:Berkeley, 363-392. ]
Paleobiology
Because it is so poorly known, at this point all that can be said about the habits and life of ''Stegopelta'' is that it was a slow quadruped
Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...
al herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
that fed low to the ground and relied on its armor for defense.[
Its armor included a fused region over the sacrum, and shoulder spines that may have been split, as seen in '']Edmontonia
''Edmontonia'' is a genus of panoplosaurin nodosaurid dinosaur from the Late Cretaceous Period. It is part of the Nodosauridae, a family within Ankylosauria. It is named after the Edmonton Formation (now the Horseshoe Canyon Formation in Canada) ...
''.[
]
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 ...
References
External links
Article about the discovery of ''Stegopelta landerensis'' on ''DinosaurusBlog''
(in Czech)
Early Cretaceous dinosaurs of North America
Nodosaurids
Late Cretaceous dinosaurs of North America
Fossil taxa described in 1905
Taxa named by Samuel Wendell Williston
Paleontology in Wyoming
Campanian genus extinctions
Ornithischian genera
{{Ankylosaurian stub