''Zephyrosaurus'' (meaning "westward wind lizard") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

orodromine Orodrominae is a subfamily of thescelosaurid dinosaurs known from the Cretaceous of North America and Asia. Distribution Orodromines were a mostly North American based group with fossils from Canada and United States only. ''Albertadromeus'', a ...

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 ...

. It is based on a partial skull and

postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

l fragments discovered in the

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ag ...

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0 ...

-age

Lower Cretaceous Lower may refer to: * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also *Nizhny Nizhny (russian: Ни́жний; masculine), Nizhnyaya (; feminine), or Nizhneye (russian: Н� ...

Cloverly Formation The Cloverly Formation is a geological formation of Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on th ...

of Carbon County,

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

, USA. New remains are under description, and tracks from

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean t ...

and

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are ...

, also in the US, have been attributed to animals similar to ''Zephyrosaurus''. It lived approximately 113 mya.

Discovery and history

Hans-Dieter Sues Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC. He receiv ...

named his new genus in recognition of the fossil being found in western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

, and Charles R. Schaff, who found the specimen. MCZ 4392, the type specimen, is composed of jaw fragments, the

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skul ...

and associated bones, several partial

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

e, and rib fragments. He found the new genus to represent a previously unknown lineage of hypsilophodont (a taxon now considered not natural), similar in some respects to '' Hypsilophodon''. Because of the fragmentary nature of the type, and lack of additional remains, ''Zephyrosaurus'' had not attracted much attention until recently, when two separate events brought it more recognition. First, Martha Kutter, in a 2003 abstract, reported on new remains of this genus under study at the Sam Noble Oklahoma Museum of Natural History, including the remains of at least seven individuals with bones from all regions of the body. Then, Stanford ''et al.'' (2004) published on dinosaur tracks from the Patuxent Formation of Maryland and Virginia, which they named ''Hypsiloichnus marylandicus'' and attributed to an animal akin to ''Zephyrosaurus'' based on the proportions of the hands and feet.

Description

''Zephyrosaurus'' is still very incompletely known. Among other distinctive characteristics, it had a steep face, a raised knob on the upper jaw, and a larger knob on the

cheekbone In the human skull, the zygomatic bone (from grc, ζῠγόν, zugón, yoke), also called cheekbone or malar bone, is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is si ...

. Some of the bones may have allowed movement within the skull (cranial kinesis) as well. Like other orodromines, it had

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for fo ...

teeth.

Classification

Several studies have suggested that ''Zephyrosaurus'' and '' Orodromeus'' are closely related, mostly by virtue of both having bosses on their cheeks. Other studies have had difficulty classifying it, due to the sparseness of the original material. ''

Oryctodromeus ''Oryctodromeus'' (meaning "digging runner") was a genus of small orodromine thescelosaurid dinosaur. Fossils are known from the Late Cretaceous Blackleaf Formation of southwestern Montana and the Wayan Formation of southeastern Idaho, USA, bo ...

'' also shares several characteristics with ''Zephyrosaurus'' and ''Orodromeus'', some of which may be related to

burrow An Eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of s ...

ing. Phylogenetic analysis in the 2010s has classified ''Zephyrosaurus '' as part of the

Thescelosauridae Thescelosauridae is a clade of neornithischians from the Cretaceous of Asia, North America and possibly South America. The group was originally used as a name by Charles M. Sternberg in 1937, but was not formally defined until 2013, where it was ...

family.

Paleobiology

''Zephyrosaurus'' would have been a small, swift, bipedal

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

. Like ''Orodromeus'' and ''Oryctodromeus'', it may have burrowed as well.

References

External links

Press release
for ''Hypsiloichnus marylandicus''.

on what would become ''Hypsiloichnus marylandicus''.
Photograph of a ''Hypsiloichnus marylandicus'' footprint
fro
The Paleontology Portal

''Zephyrosaurus''
in The Natural History Museum's Dino Directory. {{Taxonbar, from=Q187013 Early Cretaceous dinosaurs of North America Fossil taxa described in 1980 Taxa named by Hans-Dieter Sues Cloverly fauna Paleontology in Montana Ornithischian genera