Panoplosaurus
Encyclopedia
Panoplosaurus 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
.
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
.
This holotype
, CMN 2759, was discovered in the Dinosaur Park Formation
dating from the late middle Campanian
, 76 million years ago. 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 osteoderm
s were conserved. Later two more large specimens were found, again containing skulls but also providing some information about the shoulder girdle and front limbs: ROM 1215 and RTMP 83.25.2.
Panoplosaurus was 5.5 to 7.5 m (18 to 24.6 ) long, around 2 metres (6.6 ft) tall, and would have weighed approximately 3.5 tonnes (3.9 ST). 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.
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
. The hand perhaps had only three fingers. The pelvis was attached to four sacral vertebrae with short sacral ribs.
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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of nodosaurid
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe.-Characteristics:...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
. It was one of the last known nodosaurids, living during the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
in what is now North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
; fossils have been located in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.
The first fossil was found in 1917 by Charles M. Sternberg in Quarry 8, near Little Sandhill Creek. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the 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
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
.
This holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, CMN 2759, was discovered in the Dinosaur Park Formation
Dinosaur Park Formation
The Dinosaur Park Formation is the uppermost member of the Judith River Group, a major geologic unit in southern Alberta. It was laid down over a period of time between about 76.5 and 75 million years ago. The formation is made up of deposits of a high-sinuosity fluvial system, and is capped...
dating from the late middle Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
, 76 million years ago. 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 osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s were conserved. Later two more large specimens were found, again containing skulls but also providing some information about the shoulder girdle and front limbs: ROM 1215 and RTMP 83.25.2.
Panoplosaurus was 5.5 to 7.5 m (18 to 24.6 ) long, around 2 metres (6.6 ft) tall, and would have weighed approximately 3.5 tonnes (3.9 ST). 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.
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
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
, 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
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
. The hand perhaps had only three fingers. The pelvis was attached to four sacral vertebrae with short sacral ribs.
Originally assigned to the Ankylosauridae
Ankylosauridae
An ankylosaurid is a member of the Ankylosauridae family of armored dinosaurs that evolved 125 million years ago and became extinct 65 million years ago during the Cretaceous-Tertiary extinction event...
, Panoplosaurus is today considered a member of the Nodosauridae
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe.-Characteristics:...
as a close relative of Edmontonia
Edmontonia
Edmontonia was an armoured dinosaur, a part of the nodosaur family from the Late Cretaceous Period. It is named after the Edmonton Formation , the unit of rock it was found in.-Description:...
from the same formation. In 1971 Walter Coombs even referred the species of Edmontonia to a subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
within Panoplosaurus, creating a Panoplosaurus (Edmontonia) longiceps and a Panoplosaurus (Edmontonia) rugosidens but this has found no lasting acceptance.