Agujaceratops

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Agujaceratops
Temporal range: Late Cretaceous, 77  Ma
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Agujaceratops skull.jpg
Partial holotype skull, Texas Science & Natural History Museum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Neornithischia
Clade: Ceratopsia
Family: Ceratopsidae
Subfamily: Chasmosaurinae
Genus: Agujaceratops
Lucas, Sullivan & Hunt, 2006
Type species
Agujaceratops mariscalensis
(Lehman, 1989)
Species
  • A. mariscalensis(Lehman, 1989)
  • A. mavericusLehman et al., 2016
Synonyms

Agujaceratops (meaning "horned face from Aguja") is a genus of horned dinosaur from the Late Cretaceous (Campanian) of west Texas. It is a chasmosaurine (long-frilled) ceratopsian. Two species are known, Agujaceratops mariscalensis, and A. mavericus.

Contents

Discovery and species

Restoration of Agujaceratops mariscalensis Agujaceratops life restoration.jpg
Restoration of Agujaceratops mariscalensis
Size comparison of Agujaceratops mariscalensis to a human Agujaceratops mariscalensis size chart.jpg
Size comparison of Agujaceratops mariscalensis to a human
Juvenile Agujaceratops skeleton as reproduced by Triebold Paleontology in Woodland Park, Colorado, USA Agujaceratops-Triebold-800px.png
Juvenile Agujaceratops skeleton as reproduced by Triebold Paleontology in Woodland Park, Colorado, USA

In 1938, three dinosaur bone beds were excavated, and ceratopsian material was collected from Big Bend National Park (Texas) by William Strain. This material was studied by Lehman in 1989 and named Chasmosaurus mariscalensis. It is known only from the holotype UTEP  P.37.7.086 a partial adult skull which includes a braincase, left supraorbital horncore, left maxilla and a right dentary. Additional material was associated with the holotype, but not considered to be part of it. [1] All specimens of Agujaceratops were collected from the lower part of the Upper Shale member of the Aguja Formation, dating to about 77 million years ago, [2] in the Big Bend National Park, Brewster County. Additional material was recovered from elsewhere in west Texas, including a nearly complete skull from Rattlesnake Mountain designated TMM 43098-1.

Originally described as Chasmosaurus mariscalensis by Lehman in 1989, subsequent analysis resulted in the taxon being put in its own genus. Agujaceratops was named by Spencer G. Lucas, Robert M. Sullivan and Adrian Hunt in 2006, and the type species is Agujaceratops mariscalensis. [3]

Later, Lehman and colleagues revisited the Agujaceratops material and found substantial variation. They described the Rattlesnake Mountain skull as a new species, Agujaceratops mavericus. [4]

Description

Agujaceratops mariscalensis brow horn Agujaceratops mariscalensis postorbital horn by Nick Longrich.jpg
Agujaceratops mariscalensis brow horn

Agujaceratops was a relatively large horned dinosaur, reaching 4.3 metres (14 ft) in length and 1.5 metric tons (1.7 short tons) in body mass. [5] It was similar to other chasmosaurines such as Pentaceratops in having a short nose horn, long brow horns, and an elongate frill circled by small hornlets. The back of the frill has a strong notch, as in Pentaceratops and Chasmosaurus , giving it a heart shape, with three or four pairs of spike-like hornlets. The edges of the frill bear numerous low, blunt hornlets, giving it a strongly scalloped appearance. The brow horns are oriented up and out, and curve backwards in side view. [4]

Agujaceratops mariscalensis squamosal Agujaceratops squamosal by Nick Longrich.jpg
Agujaceratops mariscalensis squamosal

Two species are known, Agujaceratops mariscalensis and A. mavericus. A. mariscalensis has shorter brow horns and a shorter frill. [4]

Ecology

Like other ceratopsids, Agujaceratops was a four-legged plant eater. The elaborate frill and horns suggest a complex social life, perhaps involving displays towards and fights with other members of the species over territory or mating. Multiple individuals are found in a single quarry. It is unclear whether this represents animals brought together by a drought or flood event, or perhaps a herd. Although it is common to find multiple individuals of centrosaurine ceratopsids together - large bonebeds are known for Centrosaurus and Pachyrhinosaurus , for example - bonebeds are rarer for chasmosaurines.[ citation needed ]

At the time, the Aguja Formation lay along the western margin of the Western Interior Seaway. The habitat Agujaceratops lived in (at least where the fossil material was found) may have been a swamp, due to the nature of the sediments.[ citation needed ]

Agujaceratops lived alongside a fauna that included the feathered dinosaur Leptorhynchos gaddisi and the small pachycephalosaur Texacephale . Predators would have included tyrannosaurs and the giant crocodilian Deinosuchus riograndensis.[ citation needed ]

See also

Related Research Articles

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Chasmosaurus is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings (fenestrae) in its frill. With a length of 4.3–4.8 metres (14.1–15.7 ft) and a weight of 1.5–2 tonnes —or anywhere from 2,200 to nearly 5,000 lbs., give or take—Chasmosaurus was of a slightly smaller to ‘average’ size, especially when compared to larger ceratopsians.

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<i>Sinoceratops</i> Extinct genus of dinosaurs

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<i>Vagaceratops</i> Extinct genus of reptiles

Vagaceratops is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during the Late Cretaceous period in what is now Alberta. Its fossils have been recovered from the Upper Dinosaur Park Formation. It is sometimes included in the genus Chasmosaurus as Chasmosaurus irvinensis instead of being recognized as its own genus.

<i>Titanoceratops</i> Extinct genus of dinosaurs

Titanoceratops is a controversial genus of herbivorous ceratopsian dinosaur. It was a giant chasmosaurine ceratopsian that lived in the Late Cretaceous period in what is now New Mexico. Titanoceratops was named for its large size, being one of the largest known horned dinosaurs and the type species was named T. ouranos, after Uranus (Ouranos), the father of the Greek titans. It was named in 2011 by Nicholas R. Longrich for a specimen previously referred to Pentaceratops. Longrich believed that unique features found in the skull reveal it to have been a close relative of Triceratops, classified within the subgroup Triceratopsini. However, other researchers have expressed skepticism, and believe "Titanoceratops" to simply be an unusually large, old specimen of Pentaceratops.

<i>Nasutoceratops</i> Extinct genus of dinosaurs

Nasutoceratops is genus of ceratopsid dinosaur that lived in North America during the Late Cretaceous period, about 76.0–75.5 million years ago. The first known specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument (GSENM) from 2006 onwards, including a subadult skull with a partial postcranial skeleton and rare skin impressions and two other partial skulls. In 2013, the subadult was made the holotype of the new genus and species Nasutoceratops titusi; the generic name means "large-nosed horned face", and the specific name honors the paleontologist Alan L. Titus for his work at the GSENM. The dinosaur was noted for its large nose in news reports, and later featured in Jurassic World films.

<i>Judiceratops</i> Extinct genus of dinosaurs

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<i>Bravoceratops</i> Extinct genus of dinosaurs

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<span class="mw-page-title-main">Timeline of ceratopsian research</span>

This timeline of ceratopsian research is a chronological listing of events in the history of paleontology focused on the ceratopsians, a group of herbivorous marginocephalian dinosaurs that evolved parrot-like beaks, bony frills, and, later, spectacular horns. The first scientifically documented ceratopsian fossils were described by Edward Drinker Cope starting in the 1870s; however, the remains were poorly preserved and their true nature was not recognized. Over the next several decades, Cope named several such genera and species. Cope's hated rival, Othniel Charles Marsh, also described ceratopsian remains. In 1887, Marsh mistook a Triceratops horn for one belonging to a new species of prehistoric Bison. Marsh also named the eponymous genus Ceratops in 1888. The next year, he named the most famous ceratopsian, Triceratops horridus. It was the discovery of Triceratops that illuminated the ceratopsian body plan, and he formally named the Ceratopsia in 1890.

<i>Yehuecauhceratops</i> Extinct genus of dinosaurs

Yehuecauhceratops is a genus of horned centrosaurine ceratopsid dinosaur from the Late Cretaceous of Coahuila, Mexico. It contains a single species, Y. mudei, described from two partial specimens by Rivera-Sylva et al. in 2016 and formally named by Rivera-Sylva et al. in 2017. It was a small centrosaurine with a body length of 3 metres (9.8 ft), making it smaller than Agujaceratops and Coahuilaceratops, the other two ceratopsids in its environment; the three may have been ecologically segregated. A ridge bearing a single roughened projection near the bottom of the squamosal bone, which probably supported a small horn, allows Yehuecauhceratops to be distinguished from other centrosaurines. Its affinities to nasutoceratopsin centrosaurines, such as Avaceratops and Nasutoceratops, are supported by various morphological similarities to the former.

<i>Terminocavus</i> Genus of ceratopsid dinosaurs (fossil)

Terminocavus is a genus of ceratopsid dinosaur from the late Cretaceous Period of what is now North America. The genus contains a single species, the type species Terminocavus sealeyi, known from a parietal and some other associated fragments. The holotype specimen was discovered in the Kirtland Formation of New Mexico in 1997, and was later described and named in a 2020 study. It was similar in anatomy to Pentaceratops and Anchiceratops, which it was closely related to, but had a distinctive heart-shaped upper frill with very narrow notch. It has been hypothesized to form an anagenetic series with several other chasmosaur species.

References

  1. Lehman, T. M. (1989). "Chasmosaurus mariscalensis, sp. Nov., a new ceratopsian dinosaur from Texas". Journal of Vertebrate Paleontology. 9 (2): 137–162. Bibcode:1989JVPal...9..137L. doi:10.1080/02724634.1989.10011749.
  2. Longrich, N. R.; Sankey, J.; Tanke, D. (2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA". Cretaceous Research. 31 (2): 274. Bibcode:2010CrRes..31..274L. doi:10.1016/j.cretres.2009.12.002.
  3. Lucas, S.G.; Sullivan, R.M.; Hunt, A.P. (2006). "Re-evaluation of Pentaceratops and Chasmosaurus (Ornithischia: Ceratopsidae) in the Upper Cretaceous of the Western Interior" (PDF). New Mexico Museum of Natural History and Science Bulletin. 35: 367–370.
  4. 1 2 3 Lehman, T.M.; Wick, S.L.; Barnes, K.R. (2016). "New specimens of horned dinosaurs from the Aguja Formation of West Texas, and a revision of Agujaceratops". Journal of Systematic Palaeontology. 15 (8): 641–674. doi:10.1080/14772019.2016.1210683. S2CID   88907183.
  5. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2 ed.). Princeton: Princeton University Press. p. 297. ISBN   978-0-691-16766-4.