Prenocephale
Encyclopedia
Prenocephale was a small pachycephalosaurid dinosaur
genus
from the Late Cretaceous
(from the Campanian
through to the Maastrichtian
) and was similar in many ways to its close relative, Homalocephale
, which may simply represent Prenocephale juveniles. Adult Prenocephale probably weighed around 130 kilograms (286.6 lb) and measured around 2.4 metres (7.9 ft) long. Unlike the flattened wedge-shaped skull of Homalocephale (a possible juvenile trait also potentially seen in early growth stages of Pachycephalosaurus
), the head of Prenocephale was rounded and sloping. The dome had a row of small, bony spikes and bumps. It lived in what is now Mongolia
; but in high upland forests, not the dry deserts of Mongolia today.
Like some other pachycephalosaurs, Prenocephale is known only from skulls, and a few other small bones. For this reason, reconstructions usually depict Prenocephale as sharing the basic body plan common to all of the other Pachycephalosauria
: a stout body with a short, thick neck, short forelimbs and tall hind legs.
The head of Prenocephale was comparable to that of Stegoceras
, albeit with closed supratemporal fenestrae. Also, the paired grooves above the supraorbitals/prefrontals (along with a posterior parietal
that restricts the frontal dome) are absent in Prenocephale. This differentiates the species from Stegoceras, as such features are common in the latter. It has been suggested that Prenocephales supposed relatives, Sphaerotholus
and Homalocephale
, are all synoynms of Prenocephale. If this is the case, Prenocephale would have also lived in North America as well as in Mongolia.
ry teeth and muzzle are not as wideset as in its relative Stegoceras
, indicating different feeding preferences, possibly that Prenocephale was a more selective forager. Some scientists suggest that it may have been an omnivore
, eating both plants and insects. However, most experts agree that Prenocephale (and the other pachycephalosaurs) browsed on leaves and fruit.
, a large clade
of herbivorous/omnivorous dinosaurs from the Late Cretaceous. Initially, the species P. brevis, P. edmontonensis, and P. goodwini were identified as Stegoceras
, but are now referrable to Prenocephale.
It has also been proposed by Robert Sullivan that P. brevis, P. edmontonensis, and P. goodwini, come together to form a clade with the Asian taxa P. prenes as a currently unresolved sister group. Tylocephale
, has been interpreted as the sister taxon to the Prenocephale clade
. The species Sphaerotholus buchholtzae, could be a subjective junior synonym of P. edmontonensis. They all possess a distinct row of nodes on the squamosal
and parietal areas of the skull roof.
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...
genus
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...
from the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
(from the 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 ...
through to the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
) and was similar in many ways to its close relative, Homalocephale
Homalocephale
Homalocephale is a genus of dinosaur belonging to the pachycephalosaurid family, which lived during the late Cretaceous period of what is now Mongolia, 80 million years ago. The genus was described in 1974 by Osmólska & Maryañska, and consists of a single species, H...
, which may simply represent Prenocephale juveniles. Adult Prenocephale probably weighed around 130 kilograms (286.6 lb) and measured around 2.4 metres (7.9 ft) long. Unlike the flattened wedge-shaped skull of Homalocephale (a possible juvenile trait also potentially seen in early growth stages of Pachycephalosaurus
Pachycephalosaurus
Pachycephalosaurus is a genus of pachycephalosaurid dinosaur. It lived during the Late Cretaceous Period of what is now North America. Remains have been excavated in Montana, South Dakota, and Wyoming. It was an herbivorous or omnivorous creature which is only known from a single skull and a few...
), the head of Prenocephale was rounded and sloping. The dome had a row of small, bony spikes and bumps. It lived in what is now Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
; but in high upland forests, not the dry deserts of Mongolia today.
Description
Pachycephalosauria
Pachycephalosauria is a clade of ornithischian dinosaurs. Well-known genera include Pachycephalosaurus, Stegoceras, Stygimoloch, and Dracorex. Most lived during the Late Cretaceous Period, in what is now North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls...
: a stout body with a short, thick neck, short forelimbs and tall hind legs.
The head of Prenocephale was comparable to that of Stegoceras
Stegoceras
Stegoceras is a genus of plant-eating pachycephalosaurid dinosaur that lived in what is now North America during the Late Cretaceous period....
, albeit with closed supratemporal fenestrae. Also, the paired grooves above the supraorbitals/prefrontals (along with a posterior parietal
Parietal
Parietal may refer to:*Parietal placentation*Parietal lobe of the brain*Parietal bone of the skull*Parietal scales of a snake lie in the general region of the parietal bone*Parietal cell in the stomach*Parietal pleura...
that restricts the frontal dome) are absent in Prenocephale. This differentiates the species from Stegoceras, as such features are common in the latter. It has been suggested that Prenocephales supposed relatives, Sphaerotholus
Sphaerotholus
Sphaerotholus is a genus of pachycephalosaurid dinosaur from the Upper Cretaceous of the western United States. To date, two species have been described: the type species, S. goodwini, from the Den-na-zin Member of the Kirtland Formation of San Juan County, New Mexico, and a second species, S...
and Homalocephale
Homalocephale
Homalocephale is a genus of dinosaur belonging to the pachycephalosaurid family, which lived during the late Cretaceous period of what is now Mongolia, 80 million years ago. The genus was described in 1974 by Osmólska & Maryañska, and consists of a single species, H...
, are all synoynms of Prenocephale. If this is the case, Prenocephale would have also lived in North America as well as in Mongolia.
Diet
As with most of its relatives, scientists do not yet know what these dinosaurs ate. However the premaxillaPremaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
ry teeth and muzzle are not as wideset as in its relative Stegoceras
Stegoceras
Stegoceras is a genus of plant-eating pachycephalosaurid dinosaur that lived in what is now North America during the Late Cretaceous period....
, indicating different feeding preferences, possibly that Prenocephale was a more selective forager. Some scientists suggest that it may have been an omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
, eating both plants and insects. However, most experts agree that Prenocephale (and the other pachycephalosaurs) browsed on leaves and fruit.
Classification
Prenocephale is a member of the PachycephalosauriaPachycephalosauria
Pachycephalosauria is a clade of ornithischian dinosaurs. Well-known genera include Pachycephalosaurus, Stegoceras, Stygimoloch, and Dracorex. Most lived during the Late Cretaceous Period, in what is now North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls...
, a large clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of herbivorous/omnivorous dinosaurs from the Late Cretaceous. Initially, the species P. brevis, P. edmontonensis, and P. goodwini were identified as Stegoceras
Stegoceras
Stegoceras is a genus of plant-eating pachycephalosaurid dinosaur that lived in what is now North America during the Late Cretaceous period....
, but are now referrable to Prenocephale.
It has also been proposed by Robert Sullivan that P. brevis, P. edmontonensis, and P. goodwini, come together to form a clade with the Asian taxa P. prenes as a currently unresolved sister group. Tylocephale
Tylocephale
Tylocephale is a genus of pachycephalosaurid dinosaur from the Late Cretaceous Period. It was a herbivorous dinosaur estimated to have been about 1.4 metres in length...
, has been interpreted as the sister taxon to the Prenocephale clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
. The species Sphaerotholus buchholtzae, could be a subjective junior synonym of P. edmontonensis. They all possess a distinct row of nodes on the squamosal
Squamosal
The squamosal is a bone of the head of higher vertebrates. It is the principal component of the cheek region in the skull, lying below the temporal series and otic notch and bounded anteriorly by postorbital. Posteriorly, the squamosal articulates with the posterior elements of the palatal complex,...
and parietal areas of the skull roof.