Panoplosaurus

Panoplosaurus (meaning "completely armoured lizard") is a genus of nodosaurid dinosaur. It was one of the last known nodosaurids, living during the Late Cretaceous in what is now North America; fossils have been located in Alberta, Canada.

Panoplosaurus
Temporal range: Late Cretaceous, 76 Ma
Panoplosaurus
Holotype skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Clade: Eurypoda
Suborder: Ankylosauria
Family: Nodosauridae
Genus: Panoplosaurus
Lambe, 1919
Type species
Panoplosaurus mirus

Discovery

The first fossil was found in 1917 by Charles M. Sternberg in Quarry 8, near Little Sandhill Creek. The type species Panoplosaurus mirus was named by Lawrence M. Lambe in 1919. The generic name is derived from Greek pan, "completely" and hoplon, "armour". The specific name means "wondrous" in Latin.[1]

Dinosaur park formation fauna
Depiction of megaherbivores in the Dinosaur Park Formation, Panoplosaurus on the far right

This holotype, CMN 2759, was discovered in the Dinosaur Park Formation dating from the late middle Campanian, 76 million years ago.[2] It consists of the complete skull with lower jaws, the cervical vertebrae, some dorsal vertebrae and some ribs. Part of the bony armour scutes or osteoderms were preserved. Later two more large specimens were found, again containing skulls but also providing some information about the shoulder girdle and front limbs: ROM 1215[3] and RTMP 83.25.2.

Description

Panoplosaurus was 5 to 7 metres (16 to 23 ft) long,[4][5] around 2 metres (6.6 ft) tall, and had an estimated weight of 1.5–1.6 tonnes (1.7–1.8 short tons).[4][6] It was heavily armoured, even by the standards of other nodosaurs, probably with traverse bands of studded plates covering its back and tail, although the tail likely lacked the club found in ankylosaurids. Larger paired ovals of bony armour covered the neck, shoulders and front limbs. These ovals were keeled, possessing a prominent curved ridge on the outer surface. Spikes on the shoulder, that some other nodosaurids featured, were absent. The armour on the head was fused into a compact helmet-like shield; these plates had a lumpy surface. Also bony cheek scutes were present.[7]

The skull was short and wide at the back. The head of the holotype specimen is particularly rounded; the other two skulls are longer and flatter, perhaps reflecting age or gender differences. The animal had a relatively narrow snout, perhaps to aid in rooting about for low growing plants to eat and indicating a selective diet of highly nutritious food. Although the coracoid was slender and not fused to the scapula, the forelegs were particularly heavy, and had attachments for large muscles, which may suggest that the animal would have been surprisingly maneuverable in life, possibly being able to make defensive charges like a modern rhinoceros.[8] The hand perhaps had only three fingers. The pelvis was attached to four sacral vertebrae with short sacral ribs.

Classification

Originally assigned to the Ankylosauridae, Panoplosaurus is today considered a member of the Nodosauridae as a close relative of Edmontonia from the same formation. In 1971 Walter Coombs even referred the species of Edmontonia to a subgenus within Panoplosaurus, creating a Panoplosaurus (Edmontonia) longiceps and a Panoplosaurus (Edmontonia) rugosidens but this has found no lasting acceptance.

See also

References

  1. ^ Lambe, L.M., 1919, "Description of a new genus and species (Panoplosaurus mirus) of an armoured dinosaur from the Belly River Beds of Alberta", Transactions of the Royal Society of Canada, series 3 13: 39-50
  2. ^ Arbour, V.M., V. M.; Burns, M. E.; Sissons, R. L. (2009). "A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus". Journal of Vertebrate Paleontology. 29 (4): 1117–1135. doi:10.1671/039.029.0405.
  3. ^ Sternberg, C.M., 1921, "A supplementary study of Panoplosaurus mirus", Transactions of the Royal Society of Canada, Third Series 4: 93-102
  4. ^ a b Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 237
  5. ^ Holtz, Thomas R. Jr. (2011) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.
  6. ^ Brown, C.M., Evans, D.C., Campione, N.E., O'Brien, L.J., Eberth, D.A. 2013. Evidence for Taphonomic Size Bias in the Dinosaur Park Formation (Campanian, Alberta), A Model Mesozoic Terrestrial Alluvial-Paralic System. Paleogeo. Paleoclim. Paleoeco. Vol. 372:108–122.
  7. ^ Carpenter, K. 1990. "Ankylosaur systematics: example using Panoplosaurus and Edmontonia (Ankylosauria: Nodosauridae):, In: Carpenter, K. & Currie, P. J. (eds) Dinosaur Systematics: Approaches and Perspectives. Cambridge University Press, Cambridge, pp. 281-298
  8. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 159. ISBN 1-84028-152-9.

External links

1919 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1919.

Acantholipan

Acantholipan is a genus of herbivorous nodosaurid dinosaur from Mexico from the early Santonian age of the Late Cretaceous. It includes one species, Acantholipan gonzalezi.

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, Pinacosaurus, Euoplocephalus, and Saichania.

Bienosaurus

Bienosaurus (meaning "Bien's lizard") is a genus of thyreophoran dinosaur from the Lower Jurassic (probably Sinemurian) Lower Lufeng Formation in Yunnan Province in China.

Denversaurus

Denversaurus (meaning "Denver lizard") is a genus of herbivorous nodosaurid ankylosaurian dinosaur from the Late Cretaceous (late Maastrichtian) of western North America. Although at one point treated as a junior synonym of Edmontonia by some taxonomists, current research indicates that it is a distinct nodosaurid genus.

Dongyangopelta

Dongyangopelta is an extinct genus of nodosaurid ankylosaurian dinosaur known from the "middle" Cretaceous Chaochuan Formation (Albian or Cenomanian stage) of Dongyang, Zhejiang Province, China. Dongyangopelta was first named by Rongjun Chen, Wenjie Zheng, Yoichi Azuma, Masateru Shibata, Tianliang Lou, Qiang Jin and Xingsheng Jin in 2013 and the type species is Dongyangopelta yangyanensis. It differs from Zhejiangosaurus, the second nodosaurid from southeast China, in the characters of presacral rod, ilium, and femur. Donyangopelta is distinguishable from Zhejiangosaurus only on the basis of the morphology of its pelvic shield.

Edmontonia

Edmontonia was an armoured dinosaur, part of the nodosaur family from the Late Cretaceous Period. It is named after the Edmonton Formation (now the Horseshoe Canyon Formation in Canada), the unit of rock it was found in.

List of Appalachian dinosaurs

This is a list of dinosaurs whose remains have been recovered from Appalachia. During the Late Cretaceous period, the Western Interior Seaway divided the continent of North America into two landmasses; one in the west named Laramidia and Appalachia in the east. Since they were separated from each other, the dinosaur faunas on each of them were very different. For example, nodosaurs were common in Appalachia, but they were rare in Laramidia, and there were only specialized forms, such as Edmontonia and Panoplosaurus. This is an example of how isolated faunas develop differently.

Mongolostegus

Mongolostegus is a genus of stegosaur from the Early Cretaceous (Aptian-Albian) of Mongolia. The type and only species is M. exspectabilis, known from a single specimen previously under the nomen nudum Wuerhosaurus mongoliensis.

Nodosauridae

Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period of what are now North America, Europe, Asia, Africa, and Antarctica.

Nodosaurinae

Nodosaurinae is a group of ankylosaurian dinosaurs named in 1919 by Othenio Abel.

Nodosaurus

Nodosaurus (meaning "knobbed lizard") is a genus of herbivorous ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found in North America.

Pawpawsaurus

Pawpawsaurus, meaning "Pawpaw Lizard", is a nodosaurid ankylosaur from the Cretaceous (late Albian) of Tarrant County, Texas, discovered in May 1992. The only species yet assigned to this taxon, Pawpawsaurus campbelli, is based on a complete skull (lacking mandibles) from the marine Paw Paw Formation (Wachita Group).

Polacanthinae

Polacanthinae is a grouping of ankylosaurs, possibly primitive nodosaurids. Polacanthines are late Jurassic to early Cretaceous in age, and appear to have become extinct about the same time a land bridge opened between Asia and North America.Polacanthines were somewhat more lightly armoured than more advanced ankylosaurids and nodosaurids. Their spikes were made up of thin, compact bone with less reinforcing collagen than in the heavily armoured nodosaurids. The relative fragility of polacanthine armour suggests that it may have been as much for display as defense.

Propanoplosaurus

Propanoplosaurus is a genus of herbivorous nodosaurid dinosaur from the Early Cretaceous Patuxent Formation of Maryland, USA. Its type specimen is a natural cast and partial natural mold of a hatchling.

From 1994 onwards Ray Stanford uncovered an ichnofauna in Maryland near the border with Washington D.C.. Along with dinosaur footprints the impressions of a neonate nodosaurid were found.The type species Propanoplosaurus marylandicus was named and described by Stanford, David Weishampel and Valerie DeLeon in 2011. The generic name combines the Latin prefix pro~ with the name of the genus Panoplosaurus because the new species lived earlier than — but resembled much — this already described nodosaurid. The specific name refers to Maryland.The holotype, USNM 540686, was found in the Patuxent Formation, dating from the late Aptian. It consists of the impressions of the back of the head together with a natural cast of the ribcage, some vertebrae, the right forelimb, the right femur and a right foot. The animal is shown lying on its back. The authors rejected the possibility the specimen represented a pseudofossil or an embryo. The specimen is the first nodosaurid skeleton from the eastern seaboard from which previously only nodosaurid teeth named as Priconodon were known, and the first neonate dinosaur from that region.The specimen has a preserved length of thirteen centimetres. The total length of the individual was estimated as between twenty-four and twenty-eight centimetres. Only the skull shows osteoderms and the authors suggest this was a common developmental stage of all nodosaurids, together with a long middle section of the snout which is characterised by a unique cross-pattern of the bone plates, probably formed by the triangular osteoderms of the maxillae.Propanoplosaurus was by the describers assigned to the Nodosauridae.

Sauropelta

Sauropelta ( SAWR-o-PEL-tə; meaning 'lizard shield') is a genus of nodosaurid dinosaur that existed in the Early Cretaceous Period of North America. One species (S. edwardsorum) has been named although others may have existed. Anatomically, Sauropelta is one of the most well-understood nodosaurids, with fossilized remains recovered in the U.S. states of Wyoming, Montana, and possibly Utah. It is also the earliest known genus of nodosaurid; most of its remains are found in a section of the Cloverly Formation dated to 108.5 million years ago.

It was a medium-sized nodosaurid, measuring about 5.2 metres (17.1 ft) long. Sauropelta had a distinctively long tail which made up about half of its body length. Although its body was smaller than a modern black rhinoceros, Sauropelta was about the same mass, weighing in at about 1,500 kilograms (3,300 lb). The extra weight was largely due to its extensive covering of bony armor, including the characteristically large spines projecting from its neck.

Silvisaurus

Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the middle Cretaceous period.

Tatisaurus

Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary.

Tianzhenosaurus

Tianzhenosaurus (Tianzhen + Greek sauros="lizard") is a genus of ankylosaurid dinosaurs discovered in Tianzhen County, at Kangdailiang near Zhaojiagou Village, in Shanxi Province, China, in the Late Cretaceous Huiquanpu Formation. Thus far, a virtually complete skull and postcranial skeleton have been assigned to the genus, which is monotypic (T. youngi Pang & Cheng, 1998).

This was a medium-sized ankylosaurian, the skull measuring 28 cm (11 in) in length, with a total body length around 4 m (13 ft).

Vickaryous et al. (2004) placed Tianzhenosaurus within the Ankylosauridae, nested as the sister group to Pinacosaurus. Some authors have suggested that Tianzhenosaurus is actually a junior synonym of Saichania chulsanensis.

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