Avaceratops ‭(‬Ava horned face‭)

Short Info

Avaceratops ‭(‬Ava horned face‭)

Phonetic : A-vah-seh-rah-tops.

Named By : Peter Dodson‭ ‬-‭ ‬1986

Diet : Herbivore

Size : Estimated 2.4 – 4.5 meters long

Type of Dinosaur : Ceratopsian

Type Species : A.‭ ‬lammersi‭ (‬type‭)

Found in : USA,‭ ‬Montana‭ ‬-‭ ‬Judith River Formation

When it Lived : Late Cretaceous, 80-75 million years ago

Avaceratops is one of the genus of small herbivore ceratopsian dinosaurs that lived in the latter part of the Campanian in the Late Cretaceous Period in what is today currently the Northwest United States. The majority of fossils originate out of the Judith River Formation.


Academy of Natural Sciences, Philadelphia - IMG 7431
Daderot, Public domain, via Wikimedia Commons


Avaceratops was first discovered by Dodson believed to be an extremely small species. The holotype was estimated by Dodson to be 2.3 metres (7.5 feet) and believed that it was close to reaching adult size. The second skull (which is not necessarily related to Avaceratops),[2MOR 692 is a size at 4.2 metres (14 feet). Paul in 2010 put the weight of the four-metre long animal at one ton. Another alteration in the appearance of Avaceratops that was triggered by MOR 692 was that of the eyebrow hairs. The horns were initially believed to be rather small, however this was only speculation as the holotype did not have preserved the horns. The skull that was discovered showed postorbital horn horns that had dimensions in the range of 25 cm (9.8 in.).

Avaceratops is distinguished by its frill that runs along the rear on the back of the skull. The squamosal, which is located in end of the frill is quite large and constantly curving, instead of an edge that is stepped. An elevated area on the bottom of the squamosal separates the squamosal into equal portions and more derivate species have a larger top section. The squamosal can be separated from parietal bones at rear of the skull through the small indentation. Parietals have no indentation in the middle of the frill’s rear. The parietals also are not fenestrae-free, which is typical of other genera, with the exception of Triceratops and result in a solid frill however, damages to the Holotype may allow the possibility of a small gap to appear.

First remains from Avaceratops were discovered in the fossil collection of Eddie Cole in the Judith River Formation of Montana in the year 1981 on the property belonging to the Careless Creek Ranch, owned by rancher Arthur J. Lammers. They were found scattered throughout the remnants of a stream bed that was prehistoric. The Avaceratops specimen was probably to be buried in the sandbar when the body was swept downstream by current. The bones, which were which are displayed in Cole’s shop for fossils was discovered in October of 1981. examined by Peter Dodson who in July 1982, while accompanying Cole to the site , discovered additional bones. The bones were found in 1984 were extracted in 1984 by Anthony Fiorillo.

The fossil was officially classified and named by Dodson in 1986, and was described as the species of type Avaceratops lammersi. The first cetropsid that was named after Pachyrhinosaurus was named in the year 1950. The genus is named after Ava Cole, Eddie’s wife. The epithet specifically honors Lammers family members. Lammers family. In the year 1990, George Olshevsky emended the name to A. lammersorum. This was done with the precise name as a genitive plural, as it was used to refer to multiple individuals. But, Dodson objected against this modification, arguing that the genitive singular could be a reference to one family name. In 1990 Thomas Lehman renamed A. lammersi into Monoclonius lammersi. The name Monoclonius lammersi has received no support.

The Holotype, ANSP 15800, consists of a skeleton that is only partially complete, including an upper skull the lower jaw left and vertebrae, as well as a complete shoulder girdle, and the majority of elements of hindlimbs as well as forelimbs. The specimen could be either a juvenile or subadult person, with Dodson in 1986 was inclined to think the specimen to be fully mature. Kenneth Carpenter made a reconstruction of the skull, a casting of which was made by Leroy Glenn combined with restored parts of the postcranial skull to make a mount which in 1986 was displayed at the Academy of Natural Sciences in Philadelphia The replica of this skeleton mount was given to the Upper Musselshell Valley Historical Museum in Harlowton.

In 1993, Paul Penkalski referred two earlier found squamosals as Avaceratops, USNM 4802 and USNM 2415, from larger people. in 1999 Penkalski along with Dodson described another skull, MOR 692 that was also from an older person. The specimen is comprised of the upper skullas well as the brow and nose Horns. However, the attribution that the former is Avaceratops is doubted due to variations in chronological positions as well as skull morphology and the absence of intermediate forms. therefore, Avaceratops is depicted by the skull specimen of the type.

Avaceratops was discovered by Dodson in 1986, assigned as part of the Ceratopsidae of the Ceratopsia (both names are originated of Ancient Greek for ‘horned face’), a group of herbivorous dinosaurs sporting parrot-like beaks that thrived in what is now North America and Asia, in the Cretaceous Period.

In addition to being in the category of ceratopsian There isn’t much certainty about the taxonomic status of Avaceratops. Since most of the skeleton is found in juveniles, and because juveniles exhibit ancestral traits more clearly A cladistic study could indicate a base, low, location within the evolution tree. This is why Avaceratops is often left out of such studies. Penkalski as well as Dodson have concluded in the year 1999 that Avaceratops likely was a basal member within the Centrosaurinae but it was possible that it was a basal part from the Ceratopsinae or was just outside the clade that is formed from both of the groups. A phylogenetic study conducted by Sampson and co. (2013) concluded the fact that Avaceratops is the taxon that was sister to the newly formed Genus Nasutoceratops which was which was first described as such in the year 2013. The clade that consists of Avaceratops along with Nasutoceratops was called the Nasutoceratopsini in the year 2016.

Avaceratops, as with the majority of ceratopsians were herbivores. The Cretaceous was a time when flowers are “geographically limited on the landscape” which means it’s probable that the dinosaur ate on the dominant species of the time including cycads, ferns and conifers. It could have utilized the razor-sharp ceratopsian beak to eat away at the needles or leaves. Avaceratops’ habitat Avaceratops was densely forested and flooded.

Source: Wikipedia