A new hadrosaurid (Dinosauria: Ornithischia) from the Late Cretaceous of northern Patagonia and the radiation of South American hadrosaurids

Here we describe a new hadrosaurid from the Upper Cretaceous (Campanian–Maastrichtian) Allen Formation of Río Negro Province, north-west Patagonia. The new taxon is based on cranial and postcranial elements from subadult and adult specimens. The new taxon may have reached 8–9 m in total body length, and it is diagnosed by a unique combination of characters, including a very low maxilla with respect to the dentary, and a dentary with a prominent and elongate anterior process with a deep groove on its anterior end, among other features. The new taxon is known from well-preserved elements and constitutes one of the most complete hadrosaurids known from South America. Features of the teeth, cranial and postcranial bones of the new taxon overlap with those of other hadrosaurid specimens previously recorded from this continent. This new evidence allows us to recognize that Secernosaurus koerneri, Bonapartesaurus rionegrensis and ‘Kritosaurus’ australis are valid taxa. The latter can be distinguished from the other South American taxa, as well as from Kritosaurus from North America. Thus, a new generic name is proposed for the species ‘Kritosaurus’ australis. Phylogenetic analysis recovers a new clade of South American hadrosaurids composed of the new taxon, ‘Kritosaurus’ australis, Bonapartesaurus and Secernosaurus. The new South American clade is tentatively nested among Kritosaurini and is supported by several traits, including an ilium with a subhorizontal ridge separating the preacetabular notch from the pubic pedicle, a longitudinal ridge on the dorsal surface of the postacetabular process, and a twisted distal end of the postacetabular process. The recovery of a monophyletic clade of South American hadrosaurids indicates that the history of the clade on Gondwanan landmasses is far from well understood, and new discoveries may change the current picture of the taxonomy and phylogenetic relationships of southern duck-billed dinosaurs. http://zoobank.org/urn:lsid:zoobank.org:pub:6C6F0056-9D3A-4097-A10E-2E33C9DB76B9

[1]  S. Rozadilla,et al.  The sauropod record of Salitral Ojo del Agua: An Upper Cretaceous (Allen Formation) fossiliferous locality from northern Patagonia, Argentina , 2021, Cretaceous Research.

[2]  J. Alvarado-Ortega,et al.  Tlatolophus galorum, gen. et sp. nov., a parasaurolophini dinosaur from the upper Campanian of the Cerro del Pueblo Formation, Coahuila, northern Mexico , 2021 .

[3]  S. Rozadilla,et al.  Ornithischian remains from the Chorrillo Formation (Upper Cretaceous), southern Patagonia, Argentina, and their implications on ornithischian paleobiogeography in the Southern Hemisphere , 2021 .

[4]  M. Lamanna,et al.  New hadrosaurid (Dinosauria: Ornithopoda) fossils from the uppermost Cretaceous of central Patagonia and the influence of paleoenvironment on South American hadrosaur distribution , 2021 .

[5]  N. Jalil,et al.  The first duckbill dinosaur (Hadrosauridae: Lambeosaurinae) from Africa and the role of oceanic dispersal in dinosaur biogeography , 2021 .

[6]  David C Evans,et al.  Cranial variation in Gryposaurus and biostratigraphy of hadrosaurines (Ornithischia: Hadrosauridae) from the Dinosaur Park Formation of Alberta, Canada , 2020, Canadian Journal of Earth Sciences.

[7]  A. Fiorillo,et al.  Re-examination of the cranial osteology of the Arctic Alaskan hadrosaurine with implications for its taxonomic status , 2020, PloS one.

[8]  À. Galobart,et al.  Adynomosaurus arcanus, a new lambeosaurine dinosaur from the Late Cretaceous Ibero-Armorican Island of the European archipelago , 2019, Cretaceous Research.

[9]  Jordan C. Mallon,et al.  Supplementary cranial description of the types of Edmontosaurus regalis (Ornithischia: Hadrosauridae), with comments on the phylogenetics and biogeography of Hadrosaurinae , 2017, PloS one.

[10]  J. Powell,et al.  Bonapartesaurus rionegrensis, a New Hadrosaurine Dinosaur from South America: Implications for Phylogenetic and Biogeographic Relations with North America , 2017, Journal of Vertebrate Paleontology.

[11]  M. Fabbri,et al.  Redescription of a remarkably large Gryposaurus notabilis (Dinosauria: Hadrosauridae) from Alberta, Canada , 2017 .

[12]  R. Coria,et al.  Revisiting the Hadrosaurid (Dinosauria: Ornithopoda) Diversity of the Allen Formation: A Re-Evaluation of Willinakaqe salitralensis from Salitral Moreno, Río Negro Province, Argentina , 2016, Ameghiniana.

[13]  G. Erickson,et al.  Anatomy and osteohistology of the basal hadrosaurid dinosaur Eotrachodon from the uppermost Santonian (Cretaceous) of southern Appalachia , 2016, PeerJ.

[14]  J. Horner,et al.  A New Brachylophosaurin Hadrosaur (Dinosauria: Ornithischia) with an Intermediate Nasal Crest from the Campanian Judith River Formation of Northcentral Montana , 2015, PloS one.

[15]  Z. Gasparini,et al.  Late Cretaceous reptilian biota of the La Colonia Formation, central Patagonia, Argentina: Occurrences, preservation and paleoenvironments , 2015 .

[16]  Xing Xu,et al.  A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) with Transitional Features from the Late Cretaceous of Henan Province, China , 2014, PloS one.

[17]  À. Galobart,et al.  Diversity, Relationships, and Biogeography of the Lambeosaurine Dinosaurs from the European Archipelago, with Description of the New Aralosaurin Canardia garonnensis , 2013, PloS one.

[18]  R. Casamiquela.  SOBRE UN DINOSAURIO HADROSAURIDO DE LA ARGENTINA , 2013 .

[19]  A. McDonald,et al.  Osteology of the Basal Hadrosauroid Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation of Utah , 2012, PloS one.

[20]  P. Godefroit,et al.  Osteology and Relationships of Olorotitan arharensis, A Hollow-Crested Hadrosaurid Dinosaur from the Latest Cretaceous of Far Eastern Russia , 2012 .

[21]  Federico L. Agnolin,et al.  Vertebrados de la Formación Paso del Sapo (Campaniano/Maastrichtiano), Provincia de Chubut, Argentina , 2012 .

[22]  F. Agnolin,et al.  A new global palaeobiogeographical model for the late Mesozoic and early Tertiary. , 2012, Systematic biology.

[23]  P. Godefroit,et al.  A New Saurolophine Dinosaur from the Latest Cretaceous of Far Eastern Russia , 2012, PloS one.

[24]  A. Prieto-mÁrquez,et al.  The skull and appendicular skeleton of Gryposaurus latidens, a saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the early Campanian (Cretaceous) of Montana, USA , 2012 .

[25]  P. Bell.  Cranial Osteology and Ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia with Comments on Saurolophus osborni from Canada , 2011 .

[26]  J. Horner,et al.  New Unadorned Hadrosaurine Hadrosaurid (Dinosauria, Ornithopoda) from the Campanian of North America , 2011 .

[27]  J. Calvo,et al.  A new hadrosauroid (Dinosauria: Ornithopoda) from the Allen Formation (Late Cretaceous) of Patagonia, Argentina , 2010 .

[28]  R. Holmes,et al.  The first complete description of the holotype of Brachylophosaurus canadensis Sternberg, 1953 (Dinosauria: Hadrosauridae) with comments on intraspecific variation , 2010 .

[29]  A. Prieto-mÁrquez,et al.  Global historical biogeography of hadrosaurid dinosaurs , 2010 .

[30]  S. Salisbury,et al.  A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities , 2010 .

[31]  A. Prieto-mÁrquez,et al.  A Re-Evaluation of Secernosaurus koerneri and Kritosaurus australis (Dinosauria, Hadrosauridae) from the Late Cretaceous of Argentina , 2010 .

[32]  A. Prieto-mÁrquez,et al.  The Braincase and Skull Roof of Gryposaurus notabilis (Dinosauria, Hadrosauridae), with a Taxonomic Revision of the Genus , 2010 .

[33]  Ckan Ial.  TERESA MARYANSKA and HALSZKA OSM 6 LSKA CRANIAL ANATOMY OF SAUROLOPHUS ANGUSTIROSTRIS WITH COMMENTS ON THE ASIAN HADROSAURIDAE ( DINOSAURIA ) , 2009 .

[34]  Pablo A. Goloboff,et al.  TNT, a free program for phylogenetic analysis , 2008 .

[35]  Terry A. Gates,et al.  A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the late Campanian Kaiparowits Formation, southern Utah, USA , 2007 .

[36]  R. Reisz,et al.  ANATOMY AND RELATIONSHIPS OF LAMBEOSAURUS MAGNICRISTATUS, A CRESTED HADROSAURID DINOSAUR (ORNITHISCHIA) FROM THE DINOSAUR PARK FORMATION, ALBERTA , 2007 .

[37]  M. Brett-Surman,et al.  Discussion of character analysis of the appendicular anatomy in Campanian and Maastrichtian North American hadrosaurids - Variation and ontogeny , 2007 .

[38]  JEFFREY A. Wilson.  ANATOMICAL NOMENCLATURE OF FOSSIL VERTEBRATES: STANDARDIZED TERMS OR ‘LINGUA FRANCA’? , 2006 .

[39]  Terry A. Gates,et al.  A HISTORICAL AND BIOGEOGRAPHICAL EXAMINATION OF HADROSAURIAN DINOSAURS , 2006 .

[40]  A. Prieto-mÁrquez,et al.  NEW INFORMATION ON THE CRANIUM OF BRACHYLOPHOSAURUS CANADENSIS (DINOSAURIA, HADROSAURIDAE), WITH A REVISION OF ITS PHYLOGENETIC POSITION , 2005 .

[41]  A. Forasiepi,et al.  Late Cretaceous vertebrates from bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae) , 2004 .

[42]  J. Wagner.  The hadrosaurian dinosaurs (ornithiscia: hadrosauria) of Big Bend National Park, Brewster County, Texas, with implications for late Cretaceous paleozoogeography , 2001 .

[43]  M. Reguero,et al.  THE FIRST DUCK-BILLED DINOSAUR (FAMILY HADROSAURIDAE) FROM ANTARCTICA , 2000 .

[44]  P. Vickers-Rich,et al.  A PROBABLE HADROSAUR FROM SEYMOUR ISLAND, ANTARCTIC PENINSULA , 1999 .

[45]  D. Grigorescu,et al.  Telmatosaurus transsylvanicus from the late Cretaceous of Romania: the most basal hadrosaurid dinosaur , 1993 .

[46]  F. D. Broin.  The Late Cretaceous fauna of Los Alamitos, Patagonia, Argentina. IV: Chelonia , 1987 .

[47]  G. Rougier,et al.  The Late Cretaceous fauna of Los Alamitos, Patagonia, Argentina. VII: The hadrosaurs , 1987 .

[48]  M. Brett-Surman.  Phylogeny and palaeobiogeography of hadrosaurian dinosaurs , 1979, Nature.

[49]  B. Norford.  The Palatal Structure of some Canadian Hadrosauridae (Reptilia: Ornithischia): Discussion , 1973 .

[50]  R. S. Lull,et al.  Hadrosaurian Dinosaurs of North America , 1942 .

[51]  C. Sternberg.  The systematic position of Trachodon , 1936 .

[52]  B. Brown.  Corythosaurus casuarius, a new crested dinosaur from the Belly River Cretaceous ; with Provisional classification of the family Trachodontidae. Bulletin of the AMNH ; v. 33, article 35. , 1914 .

[53]  H. Seeley.  I. On the classification of the fossil animals commonly named Dinosauria , 1888, Proceedings of the Royal Society of London.

[54]  O. C. Marsh.  Principal characters of American Jurassic dinosaurs, Part V , 1881, American Journal of Science.

[55]  O. C. Marsh.  Principal characters of American Jurassic dinosaurs , 1878, American Journal of Science.