Morrosaurus is an extinct genus of herbivorous ornithischian dinosaur member of the Euornithopoda, that lived in the late Cretaceous in the Antarctica. The only known species is the type Morrosaurus antarcticus. 
Rozadilla et al. 2015
In 2002 the Argentine paleontologist Fernando Novas reported the discovery of a partial skeleton of a euornithopod in Antarctica. In 2015 these remains were the basis for naming the type species Morrosaurus antarcticus, named and described by Sebastian Rozadilla, Federico Lisandro Agnolin, Fernando Emilio Novas, Alexis Rolando Aranciaga Mauro, Matthew J. Motta, Juan Manuel Lirio Marcelo and Pablo Isasi. The genus name refers to the site of El Morro on James Ross Island, where the remains of the species were found. The specific name refers to Antarctica. His name was mentioned in 2015 in the electronic version of the publication Cretaceous Research.
The holotype specimen MACN Pv 197, was found in a layer of the Snow Hill Island Formation (Cape Lambe, previously assigned to the Lopez de Bertodano Formation), dating to the Maastrichtian age. The remains consists in a right hind leg, including the top of the femur, the lower end of the femur, the upper part of the tibia, the underside of the tibia, the upper half of the foot, the bottom of the midfoot and the top of the first joint of the third toe.
The type specimen corresponds to a medium-sized animal. The descriptors were able to establish some distinctive features. Two of these are autapomorphies, i.e. derived features that are unique. In bottom view, the greater trochanter of the femur has an undulating profile with a thick edge output and a main thin edge. The fourth metatarsal bone has a triangular profile with a rearward projection that wraps around it and the third metatarsal.
In addition, there is a unique combination of two features that by themselves are not unique features. In the femur, the lesser trochanter is inclined diagonally, right next to the greater trochanter. In the tibia, medial malleolus has a triangular outline view showing a front concave surface.
Morrosaurus was classified in the group Iguanodontia, as a basal member of Euiguanodontia. This in turn formed a clade with other ornithopods of Patagonia and Antarctica, particularly Trinisaura, Gasparinisaura, Anabisetia, Notohypsilophodon, Talenkauen and Macrogryphosaurus in a group called Elasmaria, whose members are distinguished by their adaptation to a running lifestyle which would be reflected by the narrow foot with a thin fourth metatarsal which indicates a high speed running; subsequently expanded chevrons, a feature that is associated with a greater surface area for attachment of the lateral muscles of the tail, which would give good control of the movements of this; and a curved humerus which demonstrates the absence of a deltopectoral ridge and therefore that the front leg was not used for walking. It cannot be determined, however, if Morrosaurus itself possessed these characteristics due to their limited remains. The existence of this clade may indicate that Patagonia, Antarctica and Australia shared the same type of fauna. The exact phylogenetic relationships within this clade could not be identified, except for Gasparinisaura, which proved to be the most basal member of group.
Anabisetia ( AH-nə-bee-SET-ee-ə) is a genus of iguanodont dinosaur from the Late Cretaceous Period of Patagonia, South America. It was a small bipedal herbivore, around 2 metres (6 ft 7 in) long.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).Canardia
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
Elasmaria is a clade of iguanodont ornithopods known from Cretaceous deposits in South America, Antarctica, and Australia.Gasparinisaura
Gasparinisaura (meaning "Gasparini's lizard") is a genus of herbivorous ornithopod dinosaur from the Late Cretaceous.
The first fossils of Gasparinisaura were in 1992 found in Argentina, near Cinco Saltos in Río Negro Province. The type species, Gasparinisaura cincosaltensis, was named and described in 1996 by Rodolfo Coria and Leonardo Salgado. The generic name honours Argentine palaeontologist Zulma Brandoni de Gasparini. The specific name refers to Cinco Saltos.Huxleysaurus
Huxleysaurus (meaning "Huxley's lizard") is a genus of herbivorous styracosternan ornithopod dinosaur.Iguanodontia
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
Jaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan.Jintasaurus
Jintasaurus (Chinese: 金塔龙; pinyin: Jīntǎ lóng) is a genus of hadrosauriform dinosaur described by Hai-Lu You (尤海鲁, Yóu Hǎilǔ) and Da-Qing Li (李大庆, Lǐ Dàqìng) in 2009. The type species is J. meniscus. Jintasaurus lived during the Early Cretaceous of what is now Gansu, northwestern China. The fossils were discovered in Jinta County, Jiuquan, Gansu, China. The discovery supports the theory that hadrosaurs originated in Asia. The holotype and only known specimen includes the postorbital skull, lacking the jugal and quadratojugal.Kritosaurini
Kritosaurini is a clade of saurolophine hadrosaurid dinosaurs from the Late Cretaceous.Lapampasaurus
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.Notohypsilophodon
Notohypsilophodon (meaning "southern Hypsilophodon") is a genus of euornithopod dinosaur from the Late Cretaceous of Argentina. It was described as the only "hypsilophodont" known from South America, although this assessment is not universally supported, and Gasparinisaura is now believed to have been a basal euornithopod as well.Pareisactus
Pareisactus (from the Greek "pareisaktos", meaning "intruder", referring to being represented as a single element among hundreds of hadrosaurid bones) is a genus of rhabdodontid ornithopod dinosaur from the Late Cretaceous Conquès Member of the Tremp Formation in the Southern Pyrenees of Spain. The type and only species is P. evrostos, known only from a single scapula.Plesiohadros
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.Snow Hill Island Formation
The Snow Hill Island Formation is a Late Campanian geologic formation found on James Ross Island, James Ross Island group, Antarctica. Remains of a paravian theropod Imperobator antarcticus have been recovered from it, as well as the Elasmarian ornithopods Trinisaura santamartaensis and Morrosaurus antarcticus, the Nodosaurid Antarctopelta oliveroi, and the shark Notidanodon sp.. Alongside these described genera are also the remains of indeterminate elasmosaurs, and lithostrotian titanosaurs.
In the Herbert Sound Member of the Snow Hill Island Formation, bivalves, ammonites, and fish were found.Talenkauen
Talenkauen (meaning "small skull" in Aonikenk, referring to the proportionally small skull) is a genus of basal iguanodont dinosaur from the Cenomanian-age Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma in the Austral Basin of Santa Cruz, Argentina. It is based on MPM-10001, a partial articulated skeleton missing the rear part of the skull, the tail, and the hands. Its most unusual feature is the presence of several thin mineralized plates along the sides of the ribs.Trinisaura
Trinisaura is an extinct genus of ornithopod dinosaur known from the lower levels of the Late Cretaceous Snow Hill Island Formation (lower Campanian stage) of James Ross Island, Antarctica. It contains a single species, Trinisaura santamartaensis.The species was in 2013 named by Rodolfo Aníbal Coria e.a. The generic name honours the geologist Trinidad Diaz. The specific name refers to the Santa Marta Cove site where the specimen was in 2008 found by Coria and Juan José Moly. That same year, the find was reported in the scientific literature.The holotype, MLP-III-1-1, consists of a partial skeleton lacking the skull, of a subadult individual about 1.5 metres (4.9 ft) in length.Tsintaosaurini
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
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.