Kirtland Formation

Last updated
Kirtland Formation
Stratigraphic range: Campanian (typically Kirtlandian)
75–73.5  Ma
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Kirtland Formation.jpg
Kirtland Formation at its type location south of Kirtland, New Mexico
Type Geological formation
Sub-unitsHunter Wash, Farmington and De-na-zin Members
Underlies Ojo Alamo Formation
Overlies Fruitland Formation
Thickness594 m (1,949 ft)
Lithology
Primary Sandstone
Other Shale, mudstone, conglomerate
Location
Coordinates 36°42′29″N108°21′00″W / 36.708°N 108.350°W / 36.708; -108.350
Approximate paleocoordinates 42°36′N76°18′W / 42.6°N 76.3°W / 42.6; -76.3
RegionFlag of New Mexico.svg  New Mexico
CountryFlag of the United States.svg  USA
Extent San Juan Basin
Type section
Named forKirtland Post Office
Named byC.M. Bauer
Year defined1916
Usa edcp relief location map.png
Lightgreen pog.svg
Kirtland Formation (the United States)
USA New Mexico relief location map.svg
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Kirtland Formation (New Mexico)
Kirtland Formation outcrops near Coal Creek Kirtland Formation Outcrops Near Coal Creek by Nick Longrich.jpg
Kirtland Formation outcrops near Coal Creek

The Kirtland Formation (originally the Kirtland Shale) is a sedimentary geological formation. [1]

Contents

Description

The Kirtland Formation is the product of alluvial muds and overbank sand deposits from the many channels draining the coastal plain that existed on the inland seashore of North America, in the late Cretaceous period. It overlies the Fruitland Formation. It is found in the San Juan Basin in the states of New Mexico and Colorado, in the United States of America.

The base of the Kirtland Formation and its lowest sub-unit, the Hunter Wash member, has been dated to 75.02 ± 0.13 Ma. [2] Together with the upper part of the underlying Fruitland Formation, this contains fossils representing the Hunter Wash local fauna. The border between the Hunter Wash member and overlying Farmington member dates to approximately 74 million years ago. The top of the Farmington member and bottom of the overlying De-na-zin member has been radiometrically dated to 73.83 ± 0.18 Ma ago. The top of the De-na-zin member, which contains the Willow Wash local fauna, has been dated to 73.49 ± 0.25 Ma ago. [1]

Overlying the De-na-zin member is a unit called the Naashoibito member This has often been considered to be part of the Kirtland formation, but more recently has been transferred back to the overlying Ojo Alamo Formation, which it had originally been part of. [1]

History of investigation

The formation was named by C.M. Bauer in 1916 for exposures near the Kirtland Post Office. [3]

Stratigraphy

Upper Cretaceous stratigraphy of the San Juan Basin San Juan Basin Upper Cretaceous stratigraphy PeerJ e5435 fig 1.png
Upper Cretaceous stratigraphy of the San Juan Basin

Vertebrate paleofauna

Saurischians

Saurischians of the Kirtland Formation
GenusSpeciesMemberMaterialNotesImages

Alamosaurus [4]

A. sanjuanensis [4]

Specimens actually from the Naashoibito member of the Ojo Alamo Formation [5]
Alamosaurus Alamosaurus.jpg
Alamosaurus
Bistahieversor Bistahieversor.jpg
Bistahieversor
Saurornitholestes Saurornitholestes MOR1.jpg
Saurornitholestes
Struthiomimus Struthiomimus altus.JPG
Struthiomimus

Aublysodon [6]

A. mirandus [6]

  • Hunter Wash [6]
Remains are now referred to Bistahieversor , although these remains may possibly have come from the Fruitland Formation. [7]
Bistahieversor [8] B. sealeyi [8]
  • Hunter Wash [8]
An articulated skull and undescribed postcranial skeleton of an adult individual, and an incomplete skull and postcranial skeleton of a juvenile individual. [8] A eutyrannosaur tyrannosauroid also known from the Fruitland Formation. [8]
Caenagnathidae [9] Indeterminate [9] A nearly complete right tibia [9] Indeterminate caenagnathid remains. [9]

Daspletosaurus [6]

Indeterminate [6]

  • Hunter Wash [8]
Remains are now referred to Bistahieversor , although these remains may possibly have come from the Fruitland Formation. [7]
Dromaeosauridae [10] Indeterminate [10] Numerous isolated teeth. [10] Indeterminate dromaeosaurid remains. [10]
Ornithomimidae [10] Indeterminate [10] A distal end of a phalanx, and [two] partial manual unguals. [10] Indeterminate ornithomimid remains. [10]
Saurornitholestes [11] S. sullivani [11] A nearly complete frontal. [11] A saurornitholestine dromaeosaurid, sister taxa to Saurornitholestes langstoni. [11]
" Saurornitholestes ""S." robustus [12] A nearly complete frontal. [12] Originally assigned to Saurornitholestes, actually a troodontid. [13]
cf. Struthiomimus [10] cf. S. altus [10] A centrum of a dorsal vertebra, distal portion of a metatarsal, and proximal phalanx. [10] Indeterminate remains that may belong to Struthiomimus altus. [10]
Tyrannosauridae [10] Indeterminate [10] A partial skeleton, dentary, metatarsal, and numerous teeth. [10] Indeterminate tyrannosaurid material. [10]

Ornithischians

Ornithischians reported from the Kirtland Formation
GenusSpeciesMemberMaterialNotesImages

Ahshislepelta [14]

A. minor [14] A partial girdle, scapulocoracoids, humerus, proximal portion of the radius, cervical and/or dorsal vertebrae, complete and fragmentary thoracic osteoderms, and other unidentifiable postcranial fragments. [14] An ankylosaurine ankylosaurid part of the Hunter Wash Member. [14]
Bisticeratops New Mexico Pentaceratops.jpg
Bisticeratops
Kritosaurus Kritosaurus.jpg
Kritosaurus
Naashoibitosaurus Naashoibitosaurus.jpg
Naashoibitosaurus
Nodocephalosaurus (right) Akainacephalus and nodocephalosaurus skulls.jpg
Nodocephalosaurus (right)
Pentaceratops Pentaceratops sternbergii holotype AMNH6325.jpg
Pentaceratops
Sphaerotholus Sphaerotholus.png
Sphaerotholus
Stegoceras Royal Tyrrell Museum Stegoceras.jpg
Stegoceras
Terminocavus Terminocavus.png
Terminocavus
Navajoceratops Navajoceratops.png
Navajoceratops
Titanoceratops Titanoceratops.jpg
Titanoceratops
Ziapelta Ziapelta sanjuanensis.png
Ziapelta

Anasazisaurus [15]

A. horneri [15] An incomplete skull consisting of premaxillae, nasals, maxilla, lacrimal, jugal, prefrontal, postorbital, squamosal, frontal, parietal, and fragment of dentary with teeth. [15] A kritosaurin hadrosaurid from the De-Na-Zin Member. [15]
Bisticeratops [16] B. froeseorum [16] A nearly complete skull. [16] A chasmosaurine ceratopsid, originally identified as a specimen of Pentaceratops . [16]
Kritosaurus [15] K. navajovius [15] [Two] incomplete skulls, an atlas, axis and cervical vertebrae. [15] A kritosaurin hadrosaurid also known from the Cerro del Pueblo Formation of Mexico. [15]
Naashoibitosaurus [15] N.ostromi [15] A skull lacking the premaxillae and mandible, a partial humerus, cervical vertebrae and dorsal vertebrae. [15] A kritosaurin hadrosaurid, distinct from Kritosaurus. [15]
Nodocephalosaurus [17] N. kirtlandensis [17] A partial skull. [17] An ankylosaurine ankylosaurid that has cranial ornamentation similar to Akainacephalus, an ankylosaur from the Kaiparowits Formation. [17] [18]
Parasaurolophus [19] P. tubicen [19] [Two] incomplete and fragmentary skulls. [19] A lambeosaurine hadrosaurid known from partial cranial remains. [19]

Pentaceratops [20]

P. fenestratus [20]
  • De-na-zin Member [21]
A crushed but nearly complete skull, mandible, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, chevrons, scapulae, coracoids, radii, ulnae, ischia, ilia, pubes, femora, tibiae, astragali, manual phalanxes and manual unguals. [21] A junior synonym of Pentaceratops sternbergii, diagnostic characteristics of the species were pathologies.

P. sternbergi [20]

A crushed but nearly complete skull, mandible, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, chevrons, scapulae, coracoids, radii, ulnae, ischia, ilia, pubes, femora, tibiae, astragali, manual phalanxes and manual unguals. [21] A chasmosaurine ceratopsid also known from the Fruitland Formation. [21]
Sphaerotholus [23] S. goodwini [23] A partial skull lacking the facial and palatal elements. [23] A pachycephalosaurine pachycephalosaurid also known from the Hell Creek and Horseshoe Canyon Formation. [23]
Stegoceras [24] S. novomexicanum [24] An incomplete parietal. [24] A basal pachycephalosaurid also known from the upper Fruitland Formation. [24]
Terminocavus [25] T. sealeyi [25] A parietal, partial squamosal, jugal, epijugal, partial quadratojugal, partial sacrum and vertebral fragments. [25] A chasmosaurine ceratopsid that has been hypothesized to form an anagenetic series with several other chasmosaur species, including Navajoceratops. [25]
Navajoceratops [25] N. sullivani [25]
  • Hunter Wash
A parietal, squamosal fragments, fused jugal\epijugal and other unidentified cranial fragments. [25] A chasmosaurine ceratopsid that has been hypothesized to form an anagenetic series with several other chasmosaur species, including Terminocavus. [25]
Titanoceratops [26] T. ouranos [26] A partial skull, syncervical vertebrae, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, ribs, humeri, radius, femora, tibiae, fibula, ilia, ischia, and ossified tendons. [26] Possibly represents a junior synonym of Pentaceratops, holotype may possibly have come from the Fruitland Formation. [26]

Ziapelta [27]

Z. sanjuanensisA complete skull, [two] first cervical half-rings, fragmentary second cervical half ring, and numerous fragmentary osteoderms. [27] An ankylosaurine ankylosaurid closely related to Scolosaurus.

Pterosaurs

Pterosaurs of the Kirtland Formation
GenusSpeciesLocationMemberAbundanceNotesImages

Navajodactylus [28]

N. boerei [28]

  • Hunter Wash Member [28]

Partial phalanx and ulna fragment [28]

A possible azhdarchid pterosaur known from fragmentary remains. [28]

Crurotarsans

Crurotarsans of the Kirtland Formation [21]
GenusSpeciesLocationMemberAbundanceNotesImages

Brachychampsa

B. montana

  • De-na-zin

Member of the Willow Wash local fauna.

Brachychampsa NT small.jpg

Denazinosuchus

D. kirtlandicus

  • De-na-zin

Member of the Willow Wash local fauna.

Leidyosuchus [29]

Indeterminate [29]

  • De-na-zin

Member of the Willow Wash local fauna.

Turtles

Turtles of the Kirtland Formation [21]
GenusSpeciesLocationMemberAbundanceNotesImages

Basilemys

B. nobilis

  • De-na-zin

Member of the Willow Wash local fauna.

Denazinemys

D. nodosa

  • De-na-zin

Member of the Willow Wash local fauna.

Neurankylus

N. baueri

  • De-na-zin

Member of the Willow Wash local fauna.

Plastomenus

P. robustus

  • De-na-zin

Member of the Willow Wash local fauna.

Thescelus

T. hemispherica

  • De-na-zin

Member of the Willow Wash local fauna.

Bony fish

Bony fishes of the Kirtland Formation [21]
GenusSpeciesLocationMemberAbundanceNotes

Melvius

M. chauliodous

  • De-na-zin

Member of the Willow Wash local fauna.

Cartilaginous fish

Cartilaginous fish of the Kirtland Formation [21]
GenusSpeciesLocationMemberAbundanceNotes

Myledaphus

M. bipartitus

  • De-na-zin

Member of the Willow Wash local fauna.

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

See also

Related Research Articles

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

Pentaceratops is a genus of herbivorous ceratopsid dinosaur from the late Cretaceous Period of what is now North America. Fossils of this animal were first discovered in 1921, but the genus was named in 1923 when its type species, Pentaceratops sternbergii, was described. Pentaceratops lived around 76–73 million years ago, its remains having been mostly found in the Kirtland Formation in the San Juan Basin in New Mexico. About a dozen skulls and skeletons have been uncovered, so anatomical understanding of Pentaceratops is fairly complete. One exceptionally large specimen later became its own genus, Titanoceratops, due to its more derived morphology, similarities to Triceratops, and lack of unique characteristics shared with Pentaceratops.

<i>Parasaurolophus</i> Hadrosaurid ornithopod dinosaur genus from Late Cretaceous Period

Parasaurolophus is a genus of hadrosaurid "duck-billed" dinosaur that lived in what is now western North America and possibly Asia during the Late Cretaceous period, about 76.5–73 million years ago. It was a large herbivore that could reach over 9 metres (30 ft) long and weigh over 5 metric tons, and were able to move as a biped and a quadruped. Three species are universally recognized: P. walkeri, P. tubicen, and the short-crested P. cyrtocristatus. Additionally, a fourth species, P. jiayinensis, has been proposed, although it is more commonly placed in the separate genus Charonosaurus. Remains are known from Alberta, New Mexico, and Utah, as well as possibly Heilongjiang if Charonosaurus is in fact part of the genus. The genus was first described in 1922 by William Parks from a skull and partial skeleton found in Alberta.

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

Kritosaurus is an incompletely known genus of hadrosaurid (duck-billed) dinosaur. It lived about 74.5-66 million years ago, in the Late Cretaceous of North America. The name means "separated lizard", but is often mistranslated as "noble lizard" in reference to the presumed "Roman nose".

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

Anasazisaurus is a genus of saurolophine hadrosaurid ("duckbill") ornithopod dinosaur that lived about 74 million years ago, in the Late Cretaceous Period. It was found in the Farmington Member of the Kirtland Formation, in the San Juan Basin of New Mexico, United States. Only a partial skull has been found to date. It was first described as a specimen of Kritosaurus by Jack Horner, and has been intertwined with Kritosaurus since its description. It is known for its short nasal crest, which stuck out above and between its eyes for a short distance.

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

Nodocephalosaurus is a monospecific genus of ankylosaurid dinosaur from New Mexico that lived during the Late Cretaceous in what is now the De-na-zin member of the Kirtland Formation. The type and only species, Nodocephalosaurus kirtlandensis, is known only from a partial skull. It was named in 1999 by Robert M. Sullivan. Nodocephalosaurus has an estimated length of 4.5 metres and weight of 1.5 tonnes. It is closely related and shares similar cranial anatomy to Akainacephalus.

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

Naashoibitosaurus is a genus of hadrosaurid dinosaur that lived about 73 million years ago, in the Late Cretaceous, and was found in the Kirtland Formation of the San Juan Basin in New Mexico, United States. Only a partial skeleton has been found to date. It was first described as a specimen of Kritosaurus by Jack Horner, and has been intertwined with Kritosaurus since its description.

<span class="mw-page-title-main">Fruitland Formation</span> Geological formation in New Mexico and Colorado

The Fruitland Formation is a geologic formation found in the San Juan Basin in the states of New Mexico and Colorado, in the United States of America. It contains fossils dating it to the Campanian age of the late Cretaceous.

<span class="mw-page-title-main">Aguja Formation</span> Geological formation in North America

The Aguja Formation is a geological formation in North America, exposed in Texas, United States and Chihuahua and Coahuila in Mexico, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. Fossil palms have also been unearthed here.

<span class="mw-page-title-main">Menefee Formation</span> Geologic formation in New Mexico and Colorado

The Menefee Formation is an upper Santonian to lower Campanian geologic formation found in Colorado and New Mexico, United States.

<span class="mw-page-title-main">Ojo Alamo Formation</span> Geologic formation in New Mexico

The Ojo Alamo Formation is a geologic formation in New Mexico spanning the Mesozoic/Cenozoic boundary. Non-avian dinosaur fossils have controversially been identified in beds of this formation dating from after the Cretaceous–Paleogene extinction event, but these have been explained as either misidentification of the beds in question or as reworked fossils, fossils eroded from older beds and redeposited in the younger beds.

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

Ojoceratops is a genus of ceratopsian dinosaur which lived in what is now New Mexico, United States. Ojoceratops fossils have been recovered from strata of the Ojo Alamo Formation, dating to the late Cretaceous period. The type species is Ojoceratops fowleri.

<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.

Dinosaur paleobiogeography is the study of dinosaur geographic distribution, based on evidence in the fossil record.

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

Ahshislepelta is a monospecific genus of ankylosaur dinosaur from New Mexico that lived during the Late Cretaceous in what is now the Hunter Wash Member of the Kirtland Formation. The type and only species, Ahshislepelta minor, is known only from an incomplete postcranial skeleton of a small subadult or adult individual. It was named in 2011 by Michael Burns and Robert M. Sullivan. Based on the size of the humerus, Ahshislepelta is larger than Pinacosaurus mephistocephalus but smaller than Talarurus and Pinacosaurus grangeri.

Chedighaii hutchisoni was a bothremydid turtle that lived during the Late Cretaceous. It was named in 2006 by Gaffney et al. for a specimen, KUVP 14765, consisting only of a skull. The specimen was found in the San Juan Basin of New Mexico in the Hunter Wash Member of the Kirtland Formation. The formation is one of many formations that are from the Kirtlandian land-vertebrate age, and date from 74.0 million years ago. The holotype skull is nearly complete. No skeleton or carapace is known, but the material of "Naiadochelys" ingravata might be assignable to C. hutchisoni.

Denazinemys was a genus of baenid turtle that lived in the Late Cretaceous of New Mexico. The holotype specimen, which D. nodosa was based on, USNM 8345, consists of a partial carapace and plastron. It came from the De-na-zin Member of the Kirtland Formation, and therefore, Denazinemys lived in the Kirtlandian land-vertebrate age. Many specimens other than the holotype have been assigned to Denazinemys.

Melvius is a genus of vidalamiin amiid fish from the Late Cretaceous. The type species, Melvius thomasi, was described by Bryant in 1987 from Hell Creek Formation. A second species Melvius chauliodous, was named and described by Hall and Wolburg in 1989 from Kirtland Formation, and it is now considered to be one of the index taxa of the Kirtlandian land-vertebrate age. Both species of Melvius were very large at its size. A vertebral remain of M. thomasi would belongs to fish with standard length of 161 cm (5.28 ft), and there are some specimens exceeds height of that vertebra. Total length of this species would be at least 193–205 cm (6.33–6.73 ft). However, M. thomasi would be a “dwarf” compared to M. chauliodous, a specimen of M. chauliodous with abdominal centra which is 6.57 cm (2.59 in) wide would indicate standard length over 2 m (6.6 ft), and there is even larger abdominal centra which is 7.3 cm (2.9 in) wide.

<span class="mw-page-title-main">Robert M. Sullivan</span> Vertebrate paleontologist

Robert Michael "Bob" Sullivan is a vertebrate paleontologist, noted for his work on fossil lizards and dinosaurs.

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

Menefeeceratops is a genus of ceratopsid dinosaur from the Menefee Formation in New Mexico, United States. It is potentially the oldest known member of the ceratopsids, as well as the centrosaurine subfamily, related to animals including Yehuecauhceratops and Crittendenceratops. The type and only species is Menefeeceratops sealeyi, known from a partial, non-articulated skeleton.

References

  1. 1 2 3 Sullivan & Lucas 2006.
  2. Fowler 2017.
  3. Bauer 1916.
  4. 1 2 Weishampel, Dodson & Osmólska 2004, pp. 580–581, 3.3 New Mexico, United States; 10. Lower Kirtland Formation and 11. Upper Kirtland Formation.
  5. Jasinski & Sullivan 2011.
  6. 1 2 3 4 5 Carr & Williamson 2010, p. 1, Systematic Paleontology.
  7. 1 2 Carr & Williamson 2010, p. 1, Systematic Paleontology; Referred Specimens.
  8. 1 2 3 4 5 6 Carr & Williamson 2010, p. 1, Systematic Paleontology; Holotype.
  9. 1 2 3 4 5 Funston, G. F.; Williamson, T. E.; Brusatte, S. L. (2024). "A caenagnathid tibia (Theropoda: Oviraptorosauria) from the upper Campanian Kirtland Formation of New Mexico". Cretaceous Research . 158 (in press). 105856. Bibcode:2024CrRes.15805856F. doi:10.1016/j.cretres.2024.105856.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Lucas, Spencer G.; Mateer, Niall J.; Hunt, Adrian P.; O'Neill, F. Michael (1987). Dinosaurs, the age of the Fruitland and Kirtland Formations, and the Cretaceous-Tertiary boundary in the San Juan Basin, New Mexico.
  11. 1 2 3 4 5 Jasinski 2016.
  12. 1 2 3 Sullivan 2006, p. 253, Abstract.
  13. Evans et al. 2014.
  14. 1 2 3 4 5 Burns & Sullivan 2011.
  15. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Prieto-Márquez, A. (2013). "Skeletal morphology of Kritosaurus navajovius (Dinosauria:Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini". Journal of Systematic Palaeontology. 12 (2): 133–175. doi:10.1080/14772019.2013.770417. S2CID   84942579.
  16. 1 2 3 4 5 Dalman SG, Jasinski SE, Lucas SG (2022). "A new chasmosaurine ceratopsid from the Upper Cretaceous (Campanian) Farmington Member of the Kirtland Formation, New Mexico". New Mexico Museum of Natural History and Science Bulletin. 90: 127–153.
  17. 1 2 3 4 5 Sullivan, R. (1999). "Nodocephalosaurus kirtlandensis, gen et sp nov., a new ankylosaurid dinosaur (Ornithischia; Ankylosauria) from the Upper Cretaceous Kirtland Formation (Upper Campanian), San Juan Basin, New Mexico". Journal of Vertebrate Paleontology. 19 (1): 126–139. Bibcode:1999JVPal..19..126S. doi:10.1080/02724634.1999.10011128.
  18. Jelle P. Wiersma; Randall B. Irmis (2018). "A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA". PeerJ. 6: e5016. doi: 10.7717/peerj.5016 . PMC   6063217 . PMID   30065856.
  19. 1 2 3 4 5 Sullivan & Williamson 1999.
  20. 1 2 3 Weishampel, Dodson & Osmólska 2004, p. 580, 3.3 New Mexico, United States; 10. Lower Kirtland Formation.
  21. 1 2 3 4 5 6 7 8 Sullivan & Lucas 2006, p. 11, Table 1.
  22. Sullivan & Lucas 2006, p. 10, Kirtlandian Index Fossils.
  23. 1 2 3 4 5 Williamson Thomas E.; Carr Thomas D. (2002). "A new genus of highly derived pachycephalosaurian from western North America". Journal of Vertebrate Paleontology. 22 (4): 779–801. doi:10.1671/0272-4634(2002)022[0779:angodp]2.0.co;2. S2CID   86112901.
  24. 1 2 3 4 5 Steven E. Jasinski; Robert M. Sullivan (2011). "Re-evaluation of pachycephalosaurids from the Fruitland-Kirtland transition (Kirtlandian, late Campanian), San Juan Basin, New Mexico, with a description of a new species of Stegoceras and a reassessment of Texascephale langstoni" (PDF). Fossil Record 3. New Mexico Museum of Natural History and Science, Bulletin. 53: 202–215.
  25. 1 2 3 4 5 6 7 8 9 Fowler, D.W.; Freedman Fowler, E.A. (2020). "Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico". PeerJ. 8: e9251. doi: 10.7717/peerj.9251 . PMC   7278894 . PMID   32547873.
  26. 1 2 3 4 Longrich, N.R. (2011). "Titanoceratops ouranos, a giant horned dinosaur from the Late Campanian of New Mexico". Cretaceous Research. 32 (3): 264–276. Bibcode:2011CrRes..32..264L. doi:10.1016/j.cretres.2010.12.007.
  27. 1 2 3 4 Arbour et al. 2014.
  28. 1 2 3 4 5 Sullivan & Fowler 2011.
  29. 1 2 Listed as "cf. Leidyosuchus sp."

Bibliography