Lurdusaurus ('heavy lizard') is a genus of large ornithopod dinosaur that lived in the Aptian stage of the Early Cretaceous, sometime between 121 and 112 million years ago.

Temporal range: Early Cretaceous, 121–112 Ma
Lurdusaurus forelimb
Forelimb, Royal Belgian Institute of Natural Sciences
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Clade: Styracosterna
Clade: Hadrosauriformes
Genus: Lurdusaurus
Taquet & Russell, 1999
L. arenatus
Binomial name
Lurdusaurus arenatus
Taquet & Russell, 1999


The generic name is derived from the Latin lurdus, "heavy" while the specific name of the type species, arenatus means "sandy", being a reference to the Tenere desert.[1]


In 1965 Philippe Taquet discovered the remains of an ornithopod in rock layers of the Elrhaz Formation, in the Tenere desert of Niger, it consists of a partial skeleton with a fragmentary skull belonging to single individual which was given the catalogue number GDF 1700, the remains sat undescribed until 1988 when paleontologist Souad Chabli coined the name "Gravisaurus tenerensis" in her unpublished dissertation on the animal,[2] however since the name was never published it is invalid, the remains were later briefly described and formally given the name Lurdusaurus arenatus by Taquet and Dale Russell in 1999, a name with similar etymology to "Gravisaurus tenerensis".


Based on the known specimen, Lurdusaurus arenatus had an unusually heavy built compared to other iguanodonts. Their forelimbs were proportionally short and powerfully constructed as were their hands which bore an enlarged thumb claw, their hindlimbs as well were massive and proportionally short, specially the lower leg, the foot was unusually constructed in that the foot bones (metatarsals) lacked solid contact with each other suggesting the presence of a fleshy pad that supported most of the weight.[1] Their necks were relatively longer than in their relatives due to their neck vertebra being both more numerous and comparatively elongated.[1] The type specimen would have been about 2 m (6.6 ft) tall at the hips and it was estimated to have approached 9 m (30 ft) in length while weighing 5.5 t (6.1 short tons) based on the circumference of its limb bones,[1] lower weight and length estimates have been estimated, however.[3] Due to their unusual body plan, the describers Taquet and Russell suggested that they would have looked superficially like an ankylosaur.[1]


Lurdusaurus arenatus thumb spike
Original thumb spike of Lurdusaurus arenatus in Paris


Paleontologist Tom Holtz has speculated that, based on its bodily proportions and spreading hands, Lurdusaurus arenatus may have led an aquatic or semiaquatic lifestyle, similar to a hippopotamus.[4]


The fossils of Lurdusaurus arenatus were found in the Elrhaz Formation, dating from the late Aptian to the early Albian of the Early Cretaceous period,[5] approximately 112 million years ago.[6] The stratigraphy of the formation and its aquatic fauna suggest that it was an inland fluvial environment, entirely freshwater in nature with a humid tropical climate.[5][6][7] The named dinosaur fauna of the region apart from Lurdusaurus consisted of Ouranosaurus, the sauropod Nigersaurus, the spinosaurid Suchomimus,[5] the carcharodontosaurid Eocarcharia and the abelisaurid Kryptops.[8] The waters moreover were inhabited by the semionotid fish Pliodetes as well as the giant crocodile relative, Sarcosuchus.[5]


  1. ^ a b c d e Taquet, P.; Russell, D. A. (1999). "A massively-constructed iguanodont from Gadoufaoua, Lower Cretaceous of Niger". Annales de Paléontologie. 85 (1): 85–96. doi:10.1016/s0753-3969(99)80009-3.
  2. ^ Chabli, S., 1988, Étude anatomique et systématique de Gravisaurus tenerensis n. g., n. sp. (Dinosaurien, Ornithischien) du gisement de Gadoufauoua (Aptien du Niger). Ph.D. dissertation, Université de Paris VII. UFR de Biologie et des Sciences de la nature 164 pp
  3. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 288
  4. ^ Thomas R., Holtz Jr.; Rey, Luis (2007). Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. New York: Random House. ISBN 9780375824197.
  5. ^ a b c d Sereno, Paul C.; Wilson, Jeffrey A.; Witmer, Lawrence M.; Whitlock, John A.; Maga, Abdoulaye; Ide, Oumarou; Rowe, Timothy A. (2007). "Structural Extremes in a Cretaceous Dinosaur". PLoS ONE. 2 (11): e1230. doi:10.1371/journal.pone.0001230. PMC 2077925. PMID 18030355.
  6. ^ a b Sereno, Paul C.; Larson, Hans C. E.; Sidor, Christian A.; Gado, Boubé (2001). "The Giant Crocodyliform Sarcosuchus from the Cretaceous of Africa". Science. 294 (5546): 1516–9. doi:10.1126/science.1066521. PMID 11679634.
  7. ^ De Broin, France; Taquet, Philippe (1966). "Découverte d'un Crocodilien nouveau dans le Crétacé inférieur du Sahara". C. R. Acad. Sci. Paris (in French). 262 (D).
  8. ^ Sereno, Paul. C.; Brusatte, Stephen L. (2008). "Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger". Acta Palaeontologica Polonica. 53 (1): 15–46. doi:10.4202/app.2008.0102.

Ankylopollexia is an extinct clade of ornithischian dinosaurs that lived from the Late Jurassic to the Late Cretaceous. It is a derived clade of iguanodontian ornithopods and contains the subgroup Styracosterna.

The name stems from the Greek word, “ankylos”, mistakenly taken to mean stiff, fused (in fact the adjective means bent or curved; used of fingers, it can mean hooked), and the Latin word, “pollex”, meaning thumb. Originally described in 1986 by Sereno, this most likely synapomorphic feature of a conical thumb spine defines the clade.First appearing around 156 million years ago, in the Jurassic, Ankylopollexia became an extremely successful and widespread clade during the Cretaceous, and were found around the world. The group died out at the end of the Maastrichtian. Even though they grew to be quite large, comparable to some carnivorous dinosaurs, they were universally herbivorous. Most ankylopollexians were bipedal.


The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous.The Aptian partly overlaps the upper part of the regionally used (in Western Europe) stage Urgonian.

The Selli Event, also known as OAE1a, was one of two oceanic Anoxic events in the Cretaceous period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.


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).


Brachylophosaurini is a tribe of saurolophine hadrosaurs with known material being from N. America and potentially Asia. It contains at least four taxa; Acristavus (from Montana and Utah), Brachylophosaurus (from Montana and Alberta), Maiasaura (also from Montana), and Probrachylophosaurus (also from Montana). A hadrosaur from the Amur river, Wulagasaurus, might be a member of this tribe, but this is disputed. The group was defined by Terry A. Gates and colleagues in 2011.The clade Brachylophosaurini was defined as "Hadrosaurine ornithopods more closely related to Brachylophosaurus, Maiasaura, or Acristavus than to Gryposaurus or Saurolophus".


Canardia is an extinct genus of aralosaurin lambeosaurine dinosaur known from the Late Cretaceous Marnes d’Auzas Formation (late Maastrichtian stage) of Toulouse, Haute-Garonne Department, southern France. The type species Canardia garonnensis was first described and named by Albert Prieto-Márquez, Fabio M. Dalla Vecchia, Rodrigo Gaete and Àngel Galobart in 2013.


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


Elrhazosaurus is a genus of basal iguanodontian dinosaur, known from isolated bones found in Lower Cretaceous rocks of Niger. These bones were initially thought to belong to a species of the related dryosaurid Valdosaurus, but have since been reclassified.


Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include Camptosaurus, Dryosaurus, Iguanodon, Tenontosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodontians were one of the first groups of dinosaurs to be found. They are among the best known of the dinosaurs, and were among the most diverse and widespread herbivorous dinosaur groups of the Cretaceous period.


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


Koshisaurus is a monospecific genus of basal hadrosauroid from the Kitadani Formation in Japan. The discovery of the genus suggests that hadrosauroids had higher diversity along the eastern margin of Asia in the Early Cretaceous. "Koshi" means an old Japanese regional name including Fukui prefecture where fossils of the genus were discovered.


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.


Lambeosaurinae is a group of crested hadrosaurid dinosaurs.


Lapampasaurus is an extinct genus of hadrosaurid known from the Late Cretaceous Allen Formation (late Campanian or early Maastrichtian stage) of La Pampa Province, Argentina. It contains a single species, Lapampasaurus cholinoi.The generic name refers to the Argentine province of La Pampa. The specific name honours the late collector José Cholino. The material includes cervical, dorsal, sacral and caudal vertebrae, the forelimb girdle, and the partial hindlimb.


Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Durlston Bay, Dorset, United Kingdom. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage (approximately 143 million years ago). It was first described by Richard Owen, who in 1874 assigned it to Iguanodon as the type specimen of the new species I. hoggii, the specific name honouring naturalist A.J. Hogg who had originally collected the fossil in 1860. The bone was damaged during initial preparation but was freed from the surrounding rock matrix by an acid bath between 1975 and 1977. David Norman and Paul Barrett subsequently transferred the species to Camptosaurus in 2002, but this was challenged, and in 2009 Peter Galton assigned the species to the new genus Owenodon. Galton interpreted the genus as an iguanodontoid more derived than Camptosaurus but less derived than Lurdusaurus.


Penelopognathus ("wild duck jaw") is a genus of dinosaur which lived during the Early Cretaceous. It was an iguanodont ancestral to hadrosaurids. Fossils have been found in the Bayin-Gobi Formation in what is now China. The type species, Penelopognathus weishampeli, was described by Godefroit, Li, and Shang in 2005, based on fragmentary jaw fossils.


Plesiohadros is an extinct genus of hadrosauroid dinosaur. It is known from a partial skeleton including the skull collected at Alag Teg locality, from the Campanian Djadochta Formation of southern Mongolia. The type species is Plesiohadros djadokhtaensis.


Rhabdodontomorpha is a clade of basal iguanodont dinosaurs. This group was named in 2016 in the context of the description, based on Spanish findings, of an early member of the Rhabdodontidae. A cladistic analysis was conducted in which it was found that Muttaburrasaurus was the sister species of the Rhabdodontidae sensu Weishampel. Therefore, Paul-Emile Dieudonné, Thierry Tortosa, Fidel Torcida Fernández-Baldor, José Ignacio Canudo and Ignacio Díaz-Martínez defined Rhabdodontomorpha as a nodal clade: the group consisting of the last common ancestor of Rhabdodon priscus Matheron, 1869 and Muttaburrasaurus langdoni Bartholomai and Molnar, 1981; and all its descendants. Within the clade are included also Zalmoxes and Mochlodon.The group consists of small to large plant eaters from Europe and Gondwana. It must have split from other iguanodont groups during the Middle Jurassic.


Tsintaosaurini is a tribe of basal lambeosaurine hadrosaurs native to Eurasia. It currently contains only Tsintaosaurus (from China) and Pararhabdodon (from Spain ).Koutalisaurus, also known from late Cretaceous Spain and formerly referred to Pararhabdodon

, may also be a tsintaosaurin because of its association with the latter genus; some recent work also suggests it may indeed be referrable to Pararhabdodon.


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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