Hanssuesia
Encyclopedia
Hanssuesia is a genus
of pachycephalosaurid dinosaur
from the late Cretaceous
period. It lived in what is now Alberta
and Montana
.
Hanssuesia based on material originally named Troodon sternbergi by Barnum Brown
and Erich Maren Schlaikjer
in 1943. Later, it was transferred to Stegoceras as S. sternbergi by Williamson and Carr, 2002 and by Ryan and Evans, 2005. The genus was first named by Robert M. Sullivan in 2003
and the type species
is Hanssuesia sternbergi. H. sternbergi is known from 7 specimens (mainly from frontoparietals) which were collected from two formations of the Belly River Group
of Alberta, Canada
, the Dinosaur Park Formation
(late Campanian
, 76.5–75 ma) in the Dinosaur Provincial Park
, and the Oldman Formation
(middle Campanian, 77.5-76.5 ma), as well as from the upper Judith River Formation
of Montana, USA (late Campanian
, 76–75 ma).
Like other pachycephalosaurs, Hanssuesia had a thick skull roof
. However, Hanssuesia is distinguished from other pachycephalosaurs by having a depressed parietal
region, wide frontoparietal dome, broad nasal characteristics, reduced prefontal lobes, and a reduced parietosquamosal
shelf.
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 pachycephalosaurid 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...
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...
period. It lived in what is now 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...
and Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
.
Hanssuesia based on material originally named Troodon sternbergi by Barnum Brown
Barnum Brown
Barnum Brown , a paleontologist born in Carbondale, Kansas, and named after the circus showman P.T. Barnum, discovered the second fossil of Tyrannosaurus rex during a career that made him one of the most famous fossil hunters working from the late Victorian era into the early 20th century.Sponsored...
and Erich Maren Schlaikjer
Erich Maren Schlaikjer
Erich Maren Schlaikjer was an American geologist and dinosaur hunter. Assisting Barnum Brown, he co-described Pachycephalosaurus and what is now Montanoceratops. Other discoveries include Miotapirus and a new species of Mesohippus....
in 1943. Later, it was transferred to Stegoceras as S. sternbergi by Williamson and Carr, 2002 and by Ryan and Evans, 2005. The genus was first named by Robert M. Sullivan in 2003
2003 in paleontology
-New taxa:-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-New taxa:-Non-mammalian:-newly named:-Conifers:-Angiosperms:...
and 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...
is Hanssuesia sternbergi. H. sternbergi is known from 7 specimens (mainly from frontoparietals) which were collected from two formations of the Belly River Group
Belly River Group
The Belly River Formation is a stratigraphical unit of Late Cretaceous age in the Western Canadian Sedimentary Basin.It takes the name from the Belly River, a tributary of the Oldman River in southern Alberta, and was first described in outcrop on the banks of the Oldman River and Bow River by...
of Alberta, 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 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...
(late 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 ...
, 76.5–75 ma) in the Dinosaur Provincial Park
Dinosaur Provincial Park
Dinosaur Provincial Park is a UNESCO World Heritage Site located about two and a half hours drive southeast of Calgary, Alberta, Canada or , about a half hour drive, northeast of Brooks....
, and the Oldman Formation
Oldman Formation
The Oldman Formation is the middle member of the Judith River Group, a major geologic unit in southern Alberta. The formation is widely recognized as bearing a great number of well preserved dinosaur skeletons, as well as other fossils.-Age:...
(middle Campanian, 77.5-76.5 ma), as well as from the upper Judith River Formation
Judith River Formation
The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous, between 80 and 75 million years ago, corresponding to the "Judithian" land vertebrate age...
of Montana, USA (late 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 ...
, 76–75 ma).
Like other pachycephalosaurs, Hanssuesia had a thick skull roof
Skull roof
The skull roof , or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes and all land living vertebrates. The bones are derived from dermal bone, hence the alternative name dermatocranium...
. However, Hanssuesia is distinguished from other pachycephalosaurs by having a depressed parietal
Parietal bone
The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
region, wide frontoparietal dome, broad nasal characteristics, reduced prefontal lobes, and a reduced parietosquamosal
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,...
shelf.