Unquillosaurus

Unquillosaurus Temporal range: Maastrichtian ~72 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Maniraptoriformes
Clade:	Maniraptora
Genus:	†Unquillosaurus Powell, 1979
Species:	†U. ceibalii
Binomial name
†Unquillosaurus ceibalii Powell, 1979

Unquillosaurus (meaning "Unquillo river lizard") is a genus of large theropod dinosaur from the Late Cretaceous Los Blanquitos Formation of Salta Province, Argentina. Its precise classification is uncertain, but most researchers consider it as a maniraptoran. The genus contains a single species, U. ceibalii, known only from a single fossilized pubis (a pelvic bone).

The holotype, PVL 3670-11, was found at Arroyo-Morterito in the Los Blanquitos Formation, dating to the Maastrichtian.^[1] The specimen, which consists of a left pubis measuring 51.4 centimetres (1 ft 8.2 in) long, was re-studied by Fernando Novas and Federico Agnolin in 2004, who concluded that the orientation of the pubis had been misinterpreted: it pointed backwards, as was shown by the fossil still being attached to a displaced part of the pubic peduncle of the ilium.^[1]

The type species Unquillosaurus ceibalii was described by Jaime Eduardo Powell in 1979. The generic name, "Unquillosaurus," is derived from the river Unquillo and the Greek word, "sauros," meaning "lizard." The specific name, "ceibalii," refers to the town El Ceibal.^[2]

Powell originally assigned Unquillosaurus as a large theropod of uncertain taxonomic placement.^[2] In 2004, Novas and Agnolín concluded from the opisthopubic pelvic anatomy that Unquillosaurus was part of the Maniraptora or at least Maniraptoriformes, and likely closely related to either the Avialae or the bird-like Alvarezsauridae; perhaps it was itself a bird, a basal member of the Metornithes.^[1] In 2006, Martínez and Novas stated that Unquillosaurus probably belonged to the maniraptoran clade Dromaeosauridae.^[3] In 2012, however, Carrano and colleagues considered Unquillosaurus as a member of the Carcharodontosauridae, noting that the animal has many similarities to Giganotosaurus.^[4] In 2013, Agnolín and Novas interpreted Unquillosaurus as a very large averaptoran instead, suggesting that the distal pubis shows condition of a coelurosaur and different from that of a carnosaur.^[5] In a 2016 study about the phylogeny of theropods found in Argentina, Unquillosaurus is considered as a maniraptoran.^[6] As of the 2020s, no reliable records of carcharodontosaurids beyond the Turonian age were known.^[7]

Unquillosaurus is known from the Los Blanquitos Formation. The abelisaurid theropod Guemesia is also known from this formation,^[8] as well as fossils of what may belong to a species of Titanosaurus.^[9]

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Maniraptora

Kingdom: Animalia Phylum: Chordata Clade: Dinosauria Clade: Theropoda Clade: Maniraptoriformes
Avemetatarsalia see Avemetatarsalia Theropoda see Theropoda Maniraptora see below↓

Maniraptora
Maniraptora †Elopteryx? †Fukuivenator? †Kakuru? †Migmanychion †Yaverlandia? †Alvarezsauroidea Achillesaurus Aorun? Bannykus Bonapartenykus Haplocheirus Patagonykus Shishugounykus Tugulusaurus? Xiyunykus Alvarezsauridae Achillesaurus? Alnashetri Alvarezsaurus Bonapartenykus? Bradycneme Heptasteornis Patagonykus? Parvicursorinae Dzharaonyx Jaculinykus Khulsanurus Kol? Nemegtonykus Ondogurvel Parvicursor Qiupanykus Trierarchuncus Ceratonykini Albinykus Ceratonykus Xixianykus Mononykini Albertonykus Linhenykus Mononykus Shuvuuia †Therizinosauria Eshanosaurus? Falcarius Fukuivenator? Jianchangosaurus Lingyuanosaurus Therizinosauroidea Alxasaurus Beipiaosaurus Enigmosaurus Martharaptor Suzhousaurus Therizinosauridae Erliansaurus Erlikosaurus Nanshiungosaurus Neimongosaurus Nothronychus Paralitherizinosaurus Segnosaurus Therizinosaurus Pennaraptora †Oviraptorosauria see Oviraptorosauria Paraves see below↓

Paraves
Paraves †Imperobator †Palaeopteryx? †Pneumatoraptor †Rahonavis †Scansoriopterygidae? Ambopteryx Epidexipteryx Scansoriopteryx Yi †Anchiornithidae Anchiornis Aurornis Caihong Eosinopteryx Fujianvenator Liaoningvenator? Ostromia Pedopenna Serikornis Xiaotingia Yixianosaurus †Archaeopterygidae Alcmonavis? Archaeopteryx Wellnhoferia Anchiornithidae? †Dromaeosauridae see Dromaeosauridae †Troodontidae see Troodontidae Avialae †Alcmonavis †Balaur? †Cretaaviculus? †Fukuipteryx †Overoraptor †Rahonavis? †Yandangornis †Zhongornis †Anchiornithidae? †Archaeopterygidae? †Scansoriopterygidae? †Jeholornithiformes Dalianraptor? Jeholornis Jixiangornis? Kompsornis Neimengornis Pygostylia †"Proornis" †Omnivoropterygidae? Omnivoropteryx Sapeornis †Confuciusornithidae Changchengornis Confuciusornis Eoconfuciusornis Yangavis †Jinguofortisidae Chongmingia Cratonavis Jinguofortis Ornithothoraces †Enantiornithes see Enantiornithes Euornithes see below↓

Euornithes
Euornithes †Archaeorhynchus †Bellulornis †Brevidentavis †Changmaornis †Changzuiornis †Chaoyangia †Dingavis †Eogranivora †Gansus †Gargantuavis? †Hollanda †Horezmavis †Iteravis †Jianchangornis †Jiuquanornis †Juehuaornis †Kaririavis †Khinganornis †Meemannavis †Platanavis †Vorona †Wyleyia? †Xinghaiornis †Yumenornis †Zhongjianornis †Schizoouridae Mengciusornis Schizooura †Patagopterygiformes Alamitornis Kuszholia? Patagopteryx †Ambiortiformes Ambiortus Apsaravis? Palintropus? †Hongshanornithidae Archaeornithura Hongshanornis Longicrusavis Parahongshanornis Tianyuornis †Songlingornithidae Hollanda? Piscivoravis? Songlingornis Yanornis? Yixianornis? †Yanornithidae Abitusavis Similiyanornis Yanornis Ornithurae †Antarcticavis? †Apatornis †Cerebavis †Gallornis †Guildavis †Iaceornis †Kookne †Limenavis †Tingmiatornis †Ichthyornithes Ichthyornis Janavis †Hesperornithes Baptornis Brodavis Chupkaornis Enaliornis Judinornis Pasquiaornis Potamornis Hesperornithidae Asiahesperornis Canadaga Fumicollis Hesperornis Parahesperornis †Vegaviidae Australornis? Maaqwi? Neogaeornis? Polarornis Vegavis †Cimolopterygidae Ceramornis Cimolopteryx Lamarqueavis? Aves / Neornithes see below↓

Aves / Neornithes
Palaeognathae see Palaeognathae Neognathae Neoaves Galloanserae Anserimorphae see Anserimorphae Pangalliformes see Pangalliformes Incertae sedis †Asteriornis †Perplexicervix †Qinornis? †Dromornithidae Barawertornis Dromornis Genyornis Ilbandornis †Gastornithiformes Brontornis? Gastornis Dromornithidae? †Pelagornithidae Aequornis Caspiodontornis Cyphornis Dasornis Gigantornis Laornis? Lutetodontopteris Macrodontopteryx Manu? Odontopteryx Odontoptila Osteodontornis Palaeochenoides Pelagornis Proceriavis? Protodontopteryx Protopelicanus? Pseudodontornis Tympanonesiotes

• See also: Archaeornithes
• Carinatae
• Deinonychosauria
• Odontognathae
• Odontornithes
• Sauriurae
• Unenlagiidae
• Category