Avaceratops
Encyclopedia
Avaceratops is a genus
of small ceratopsia
n dinosaur
which lived during the late Campanian
during the Late Cretaceous
Period in what are now the Northwest United States
.
The first fossils of Avaceratops were found in the Judith River Formation
of Montana
, in 1981. They were preserved scattered through-out the remains of a prehistoric stream bed. This Avaceratops specimen was likely buried in the sandbar after its body was swept downstream by the current.
The original find was made by Eddie Cole and the fossils were formally named in 1986, by Peter Dodson
. It was named after Ava, Eddie's wife. The species epithet honors the Lammers family, who owned the land where the holotype
fossil was found.
within the Ceratopsia
(both names being derived from Ancient Greek
for 'horned face'), a group of herbivorous dinosaurs with parrot
-like beaks which thrived in what are now North America
and Asia
, during the Cretaceous
Period.
Apart from being a ceratopsian, little is certain about Avaceratops's taxonomic position. It is a smallish Ceratopsia
n with a solid frill (i.e. lacking fenestrae
which are typical of many other genera except Triceratops
), thus it may be somehow ancestral to Triceratops or occupy a position between the two subfamilies Centrosaurinae and Ceratopsinae. This latter opinion was the one reached by Penkalski and Dodson
in 1999.
. During the Cretaceous, flowering plants were "geographically limited on the landscape", so it is likely that this dinosaur fed on the predominant plants of the era: fern
s, cycad
s and conifers. It would have used its sharp ceratopsian beak to bite off the leaves or needles.
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 small ceratopsia
Ceratopsia
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...
n 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...
which lived during the 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 ...
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...
Period in what are now the Northwest United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Discoveries and species
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
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,...
, in 1981. They were preserved scattered through-out the remains of a prehistoric stream bed. This Avaceratops specimen was likely buried in the sandbar after its body was swept downstream by the current.
The original find was made by Eddie Cole and the fossils were formally named in 1986, by Peter Dodson
Peter Dodson
Peter Dodson is an American paleontologist who has published many papers and written and collaborated on books about dinosaurs. An authority on Ceratopsians, he has also authored several papers and textbooks on hadrosaurs and sauropods, and is a co-editor of The Dinosauria, widely considered the...
. It was named after Ava, Eddie's wife. The species epithet honors the Lammers family, who owned the land where the 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...
fossil was found.
Classification
Avaceratops belonged to the family CeratopsidaeCeratopsidae
Ceratopsidae is a speciose group of marginocephalian dinosaurs including Triceratops and Styracosaurus...
within the Ceratopsia
Ceratopsia
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...
(both names being derived from Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
for 'horned face'), a group of herbivorous dinosaurs with parrot
Parrot
Parrots, also known as psittacines , are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropical regions. The order is subdivided into three families: the Psittacidae , the Cacatuidae and the Strigopidae...
-like beaks which thrived in what are 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...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, during the 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.
Apart from being a ceratopsian, little is certain about Avaceratops's taxonomic position. It is a smallish Ceratopsia
Ceratopsia
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...
n with a solid frill (i.e. lacking fenestrae
Fenestrae
Fenestræ is a Latin word that means "window".* In histology, fenestræ are small pores in endothelial cells that allow for rapid exchange of molecules between sinusoid blood vessels and surrounding tissue...
which are typical of many other genera except Triceratops
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
), thus it may be somehow ancestral to Triceratops or occupy a position between the two subfamilies Centrosaurinae and Ceratopsinae. This latter opinion was the one reached by Penkalski and Dodson
Peter Dodson
Peter Dodson is an American paleontologist who has published many papers and written and collaborated on books about dinosaurs. An authority on Ceratopsians, he has also authored several papers and textbooks on hadrosaurs and sauropods, and is a co-editor of The Dinosauria, widely considered the...
in 1999.
Diet
Avaceratops, like all ceratopsians, was a herbivoreHerbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
. During the Cretaceous, flowering plants were "geographically limited on the landscape", so it is likely that this dinosaur fed on the predominant plants of the era: fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s, cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s and conifers. It would have used its sharp ceratopsian beak to bite off the leaves or needles.