''Gravitholus'' (meaning 'heavy dome') was 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 pachycephalosaurid

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 ...

from the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

period (

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. Campanian s ...

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

, around 75

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

). It was a

pachycephalosaur Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachyc ...

, and like other pachycephalosaurids the skull roof formed a thick dome made of dense bone, which may have been used in head-butting contests over mates or territory. It lived in what is now

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, and was described in 1979 by W. P. Wall and

Peter Galton Peter Malcolm Galton (born 14 March 1942 in London) is a British vertebrate paleontologist who has to date written or co-written about 190 papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosaur ...

. 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 specimen ...

is ''Gravitholus albertae''. There is some debate amongst paleontologists as to whether the animal represents a distinct genus, or if it may be synonymous with ''

Stegoceras ''Stegoceras'' is a genus of pachycephalosaurid (dome-headed) dinosaur that lived in what is now North America during the Late Cretaceous period, about 77.5 to 74 million years ago (mya). The first specimens from Alberta, Canada, were describe ...

''. Recent publications indicate it may be a valid genus. ''Gravitholus'' is one of several pachycephalosaurids known from Dinosaur Park, including ''

Stegoceras validum ''Stegoceras'' is a genus of pachycephalosaurid (dome-headed) dinosaur that lived in what is now North America during the Late Cretaceous period, about 77.5 to 74 million years ago (mya). The first specimens from Alberta, Canada, were describe ...

'', ''

Hanssuesia sternbergi ''Hanssuesia'' is a genus of pachycephalosaurid dinosaurs from the late Cretaceous period. It lived in what is now Alberta and Montana, and contains the single species ''Hanssuesia sternbergi''. ''Hanssuesia'' is based on a skull dome originall ...

'', and '' Foraminacephale brevis''. It is unclear whether all of these species would have lived in the area at the same time. A 2020 CSVP abstract found ''Gravitholus'' and ''Hanssuesia'' to be synonymous with ''Stegoceras.''

References

*Wall, W.P. & Galton, P.M. (1979). "Notes on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America, with comments on their status as ornithopods". ''Canadian Journal of Earth Sciences''. 16:1176-1186 * Maryanska, T., Chapman, R.E., and Weishampel, D.B. (2004). "Pachycephalosauria". In D. B. Weishampel, P. Dodson & H. Osmólska (eds.), ''The Dinosauria'' (second edition). University of California Press, Berkeley 464-477

External links

''Gravitholus'' at the Paleobiology Database

Late Cretaceous dinosaurs of North America Fossil taxa described in 1979 Pachycephalosaurs Taxa named by Peter Galton Paleontology in Alberta Campanian genus first appearances Campanian genus extinctions Ornithischian genera {{pachycephalosaur-stub

See also

References

External links