Kritosaurini

Kritosaurini is a clade of saurolophine hadrosaurid dinosaurs from the Late Cretaceous.

Kritosaurini
Temporal range: 83–66 Ma
Gryposaurus incurvimanus
Gryposaurus notabilis skeleton at the Royal Ontario Museum
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Family: Hadrosauridae
Subfamily: Saurolophinae
Tribe: Kritosaurini
Prieto-Márquez, 2014
Type species
Kritosaurus navajovius
Subtaxa

Discovery and naming

The first member of the group discovered and named was Kritosaurus; it was named by paleontologist Barnum Brown in 1910.[1] Four years later, Canadian paleontologist Lawrence Lambe would name Gryposaurus.[2] The similarity between the two taxa was immediately recognized, and throughout the twentieth century the validity of the latter genus was doubted, with it being suggested both species were the same.[3][4] Only in the 1990s were they definitively identified as distinct.[5] Around this time, related hadrosaurs Naashoibitosaurus[6] and Secernosaurus[7] were discovered, and the modern interpretation of the group started to develop.[8]

Kritosaurini as a tribe was first proposed by Michael Brett-Surman in 1989.[8] It was first defined as a clade in 2014 by Albert Prieto-Márquez as "The most exclusive clade of hadrosaurids containing Kritosaurus navajovius Brown, 1910, Gryposaurus notabilis Lambe, 1914, and Naashoibitosaurus ostromi Hunt & Lucas, 1993".[9]

See also

Notes

  1. ^ Brown, Barnum (1910). "The Cretaceous Ojo Alamo beds of New Mexico with description of the new dinosaur genus Kritosaurus". Bulletin of the American Museum of Natural History. 28 (24): 267–274.
  2. ^ Lambe, Lawrence M. (1914). "On Gryposaurus notabilis, a new genus and species of trachodont dinosaur from the Belly River Formation of Alberta, with a description of the skull of Chasmosaurus belli". The Ottawa Naturalist. 27 (11): 145–155.
  3. ^ Brown, Barnum (1914). "Cretaceous Eocene correlation in New Mexico, Wyoming, Montana, Alberta". Geological Society of America Bulletin. 25: 355–380. doi:10.1130/gsab-25-355.
  4. ^ Gilmore, Charles W. (1916). "Contributions to the geology and paleontology of San Juan County, New Mexico. 2. Vertebrate faunas of the Ojo Alamo, Kirtland and Fruitland Formations". United States Geological Survey Professional Paper. 98-Q: 279–302.
  5. ^ Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska Halszka (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561. ISBN 978-0-520-06727-1.
  6. ^ Hunt, Adrian P.; Lucas, Spencer G. (1993). "Cretaceous vertebrates of New Mexico". In Lucas, S.G.; Zidek, J. (eds.). Dinosaurs of New Mexico. New Mexico Museum of Natural History and Science Bulletin, 2. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 77–91.
  7. ^ Brett-Surman, M. K. (1979). "Phylogeny and palaeobiogeography of hadrosaurian dinosaurs". Nature. 277 (5697): 560–562.
  8. ^ a b Brett-Surman, Michael Keith. (1989). "A revision of the Hadrosauridae (Reptilia: Ornithischia) and their evolution during the Campanian and Maastrichtian". Faculty of the Graduate School of Arts and Sciences of the George Washington University.
  9. ^ Prieto-Márquez, A. (2014). "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.
"Tanius" laiyangensis

"Tanius" laiyangensis is a dubious species of kritosaurin hadrosaur from the Late Cretaceous Wangshi Group of Shandong, China. It was originally described in 1976 as the third species in the genus Tanius, based on a sacrum and partial ilium. The type species of the genus, Tanius sinensis, was later found to be a basal hadrosauroid as opposed to be a member of Hadrosauridae. T. laiyangensis was, after its description, variously considered a nomen dubium or a synonym of the lambeosaur Tsintaosaurus. In 2019, T. laiyangensis was re-evaluated, and found to be an indeterminate kritosaur, unrelated to the true Tanius. Material from the same formation, initially referred to the edmontosaur Laiyangosaurus, was also identified as being from a kritosaur, and so possibly belonged to the same species. It is the first recognized kritosaur to be found in Asia, and its closest relative was found to be Secernosaurus from Argentina.

Acristavus

Acristavus is a genus of saurolophine dinosaur. Fossils have been found from the Campanian Two Medicine Formation in Montana and Wahweap Formation in Utah, United States. The type species A. gagslarsoni was named in 2011. Unlike nearly all hadrosaurids except Edmontosaurus, Acristavus lacked ornamentation on its skull. The discovery of Acristavus is paleontologically significant because it supports the position that the ancestor of all hadrosaurids did not possess cranial ornamentation, and that ornamentation was an adaptation that later arose interdependently in the subfamilies Saurolophinae and Lambeosaurinae. It is closely related to Brachylophosaurus and Maiasaura, and was assigned to a new clade called Brachylophosaurini.

Aralosaurini

Aralosaurini is a tribe of basal lambeosaurine hadrosaurs endemic to Eurasia. It currently contains Aralosaurus (from the Aral sea of Kazakhstan) and Canardia (from Toulouse, Southern France).

Bonapartesaurus

Bonapartesaurus is an extinct genus of herbivorous ornithopod dinosaur belonging to Hadrosauridae, which lived in the area of the modern Argentina during the Campanian and Maastrichtian stages of the Late Cretaceous.

Edmontosaurini

Edmontosaurini are a tribe of saurolophine hadrosaurs that lived in the Northern Hemisphere during the Late Cretaceous period. It currently contains Edmontosaurus (from the United States and Canada), Ugrunaaluk (from Alaska, U.S.), and Shantungosaurus (from Shandong, China), though Anatosaurus might be a distinct genus. Kerberosaurus and Kundurosaurus from Russia could also be members though are more likely saurolophins.

Elasmaria

Elasmaria is a clade of iguanodont ornithopods known from Cretaceous deposits in South America, Antarctica, and Australia.

Galleonosaurus

Galleonosaurus (meaning "galleon lizard" as the upper jaw bone resembles an upturned galleon) is a genus of basal ornithopod dinosaur from the Wonthaggi Formation of the Gippsland region of Victoria, Australia. The type and only species is G. dorisae, described by Herne et al. in 2019.

Gryposaurus

Gryposaurus (meaning "hooked-nosed (Greek grypos) lizard"; sometimes incorrectly translated as "griffin (Latin gryphus) lizard") was a genus of duckbilled dinosaur that lived about 83 to 74 million years ago, in the Late Cretaceous (late Santonian to late Campanian stages) of North America. Named species of Gryposaurus are known from the Dinosaur Park Formation in Alberta, Canada, and two formations in the United States: the Lower Two Medicine Formation in Montana and the Kaiparowits Formation of Utah.

Gryposaurus is similar to Kritosaurus, and for many years the two were thought to be synonyms. It is known from numerous skulls, some skeletons, and even some skin impressions that show it to have had pyramidal scales projecting along the midline of the back. It is most easily distinguished from other duckbills by its narrow arching nasal hump, sometimes described as similar to a "Roman nose," and which may have been used for species or sexual identification, and/or combat with individuals of the same species. A large bipedal/quadrupedal herbivore around 9 meters (30 feet) long, it may have preferred river settings.

Jaxartosaurus

Jaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan.

Kritosaurus

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" (referring to the arrangement of the cheek bones in an incomplete type skull), but is often mistranslated as "noble lizard" in reference to the presumed "Roman nose" (in the original specimen, the nasal region was fragmented and disarticulated, and was originally restored flat).

Kundurosaurus

Kundurosaurus is an extinct genus of saurolophine hadrosaurid dinosaur known from the Latest Cretaceous (probably Late Maastrichtian stage) of Amur Region, Far Eastern Russia. It contains a single species, Kundurosaurus nagornyi.

Laiyangosaurus

Laiyangosaurus ("Laiyang lizard") is a genus of saurolophine hadrosaurid from the Late Cretaceous of China. It is known from one species, L.youngi, found in the Laiyang Basin within the province of Shandong.

Naashoibitosaurus

Naashoibitosaurus (from Navajo naʼashǫ́ʼii bitooh—"lizard creek") 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.

Prosaurolophus

Prosaurolophus (; meaning "before Saurolophus", in comparison to the later dinosaur with a similar head crest) is a genus of hadrosaurid (or duck-billed) dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure. Around 9 m (30 ft), its fossils have been found in the late Campanian-age Upper Cretaceous Dinosaur Park Formation in Alberta, and the roughly contemporaneous Two Medicine Formation in Montana, dating to around 75.5-74.0 million years ago. Its most recognizable feature is a small solid crest formed by the nasal bones, sticking up in front of the eyes.

The type species is P. maximus, described by American paleontologist Barnum Brown of the American Museum of Natural History in 1916. A second species, P. blackfeetensis, was described by Jack Horner of the Museum of the Rockies in 1992. The two species were differentiated mainly by crest size and skull proportions.

Rhinorex

Rhinorex is a genus of kritosaurin hadrosaur from the Late Cretaceous Neslen Formation, in central Utah. Its exact placement in time is uncertain, though it probably dates to 75 million years ago and was discovered in estuarine sediments.It is likely a close relative of Gryposaurus, and indeed some have suggested that it falls within the genus Gryposaurus, as the phylogenetic analysis indicates.It is found in a very similar time and place as Gryposaurus monumentensis and Gryposaurus sp. This would challenge the idea of provincialism in Late Cretaceous Laramidian faunas. It may be that Rhinorex lived in more coastal environments than Gryposaurus. The holotype specimen BYU 13258 is composed of a partial but mostly articulated skeleton, which includes the skull, the vertebral column and a partial pelvis.

Saurolophinae

Saurolophinae is a subfamily of hadrosaurid dinosaurs. It has since the mid-20th century generally been called the Hadrosaurinae, a group of largely non-crested hadrosaurs related to the crested sub-family Lambeosaurinae. However, the name Hadrosaurinae is based on the genus Hadrosaurus which was found in more recent studies to be more primitive than either lambeosaurines or other traditional "hadrosaurines", like Edmontosaurus and Saurolophus. As a result of this, the name Hadrosaurinae was dropped or restricted to Hadrosaurus alone, and the subfamily comprising the traditional "hadrosaurines" was renamed the Saurolophinae. Recent phylogenetic work by Hai Xing indicates that Hadrosaurus is placed within the monophyletic group containing all non-lambeosaurine hadrosaurids. Under this view, the traditional Hadrosaurinae is resurrected, with the Hadrosauridae being divided into two clades: Hadrosaurinae and Lambeosaurinae.

Saurolophinae was first defined as a clade in a 2010 phylogenetic analysis by Prieto-Márquez. Traditionally, the "crestless" branch of the family Hadrosauridae had been named Hadrosaurinae. However, the use of the term Hadrosaurinae was questioned in a comprehensive study of hadrosaurid relationships by Albert Prieto-Márquez in 2010. Prieto-Márquez noted that, though the name Hadrosaurinae had been used for the clade of mostly crestless hadrosaurids by nearly all previous studies, its type species, Hadrosaurus foulkii, has almost always been excluded from the clade that bears its name, in violation of the rules for naming animals set out by the ICZN. Prieto-Márquez (2010) defined Hadrosaurinae as only the lineage containing H. foulkii, and used the name Saurolophinae instead for the traditional grouping.The cladogram below follows Godefroit et al. (2012) analysis.

The following cladogram was recovered in the 2013 phylogenetic analysis by Prieto-Márquez (the relationships within Lambeosaurinae and between basal hadrosauroids aren't shown).

Secernosaurus

Secernosaurus (meaning "severed lizard") is a genus of herbivorous dinosaur. Secernosaurus was a hadrosaur, a "duck-billed" dinosaur which lived during the Late Cretaceous. Its fossils have been found in the Lago Colhué Huapi and Los Alamitos Formations of Argentina.

Tanius

Tanius (meaning "of Tan") is a genus of hadrosauroid dinosaur. It lived in the Late Cretaceous of China. The type species, named and described in 1929 by Carl Wiman, is Tanius sinensis. The generic name honours the Chinese paleontologist Tan Xichou ("H.C. Tan"). The specific epithet refers to China. In 2010 Gregory S. Paul estimated the length of Tanius at seven metres and the weight at two tonnes.

Xuwulong

Xuwulong is a genus of hadrosauroid dinosaur from the Early Cretaceous period. It lived during the early Cretaceous period (Aptian-Albian age) in what is now Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. It is known from the holotype – GSGM F00001, an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle from Xinminpu Group. Xuwulong was named by You Hailu, Li Daqing and Liu Weichang in 2011 and the type species is Xuwulong yueluni.

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