José Patricio O'Gorman- Dr.
- Research Assistant at National University of La Plata
José Patricio O'Gorman
- Dr.
- Research Assistant at National University of La Plata
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Introduction
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Publications
Publications (87)
ABSTRACT—A new elasmosaurid, Vegasaurus molyi, gen. et sp. nov., from Vega Island, James Ross Archipelago, Antarctica, is described. The holotype and only specimen of this species (MLP 93-I-5-1) was collected from the lower Maastrichtian Cape Lamb Member of the Snow Hill Island Formation. Vegasaurus molyi is the only Antarctic elasmosaurid and one...
The Museo de La Plata (MLP, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata) houses the Antarctica's largest fossil vertebrate collection. This collection is a major international research resource and constitutes one of Antarctica's most important records of vertebrate history and evolution. The principal focus of this col...
The Rhomaleosauridae were a clade of Jurassic plesiosaurians, characterized by triangular skulls, an elongated preorbital region, marked premaxillary-maxillary constriction, and intermediate body proportions that fall between pliosauromorphs and plesiosauromorphs. Despite recent progress in the study of dental replacement in plesiosaurians, the rep...
Elasmosaurids comprise some of the most extreme morphotypes of plesiosaurs. Thus, the study of their neck and vertebrae elongation patterns plays a crucial role in understanding the anatomy of elasmosaurids. In this study, the taphonomic distortion of the holotype of Elasmosaurus platyurus and its effects on the vertebral length index (VLI) values...
Los plesiosaurios constituyen uno de los grupos de reptiles marinos con mayor cantidad de registros durante el Mesozoico. Con el objetivo de estudiar los factores que afectaron a este clado y a su registro a lo largo de su historia, se testeó la correlación entre la abundancia de registros, la diversidad táxica, la diversidad filogenética y la disp...
A new elasmosaurid, Chubutinectes carmeloi gen. et sp. nov., from the Chubut Province, Argentina, is described. The holotype and only specimen of this species (MPEF-PV 5232) was collected from the La Colonia Formation. Chubutinectes carmeloi gen. et sp. nov. is among the few upper Maastrichtian elasmosaurids from the Southern Hemisphere whose postc...
The distal end of a left ulna found in the southeastern margin of the Somún Curá Plateau, Chubut Province (Argentina), was collected from the Maastrichtian (Upper Cretaceous) of the La Colonia Formation. Based on the torsion and the cylindrical section of the shaft, the complete development of both condyles, and the distal extension of the tubercul...
Polycotylidae Cope, 1869 is a clade of short-necked plesiosaurians that achieved a cosmopolitan distribution by the Late Cretaceous. Here, the material previously referred to Polycotylidae/Pliosauridae from the Upper Cretaceous of New Zealand is reviewed, concluding that only 2.4% and 7.7% respectively of the total plesiosaurians specimens recovere...
Polycotylids were a clade of shorth-necked plesiosaur that achieved a worldwide distribution and a peak of diversity during the Albian-Turonian, reaching the K/Pg mass extinction with a relative low diversity. One of the youngest polycotylids worldwide recorded is Sulcusuchus erraini, from Los Alamitos and La Colonia formations (Patagonia). Here, a...
The Snow Hill Island Formation (SHIF; late Campanian-early Maastrichtian) crops out in the northeast of the Antarctic Peninsula and constitutes the basal part of the late Campanian-early Maastrichtian sedimentary succession of the James Ross Basin (NG Sequence). Its major exposures occur at the James Ross and Vega islands. Several fossil-bearing lo...
Elasmosaurids are among the most frequently recorded marine reptile fossils from the Campanian–Maastrichtian strata of Antarctica. Here, we describe one of the earliest quarried specimens, MLP 82-I-28-1, which is identified as a non-aristonectine elasmosaurid and phylogenetically nested within Weddellonectia. An ancestral states analysis of dorsal...
The holotype specimen of Alexandronectes zealandiensis is analyzed using digital reconstruction based on CT scans. Additional information regarding internal anatomy or obscured details are added. Additional features include: ectopterygoid rhombic in shape with posterior end pointed, a feature shared only with Aristonectes quiriquinensis;
pterygoid...
Se realiza un recuento de los registros de plesiosaurios de Perú y se describe material referido a plesiosauria depositado en el Museo de Historia Natural de la UNMSM.El registro de plesiosaurios de Perú se extiende entre el Valanginiano-Hauteriviano (Cretácico Inferior) hasta el Maastrictiano (Cretácico Superior). En relación con la posición taxon...
Elasmosaurids are a cosmopolitan group of plesiosaurians that radiated during the Late Cretaceous. A new specimen of the small sized elasmosaurid Kawanectes lafquenianum is described here. New features of the basicranium and palate are added: basioccipital tubers with distal end deeply excavated, basioccipital ventral flat plate below occipital con...
New ichthyosaur remains from the Upper Jurassic of Antarctica, recovered from the Ameghino (=Nordenskjöld) Formation are described. These three new specimens represent the first unambiguous records of ichthyosaurs in this continent. Based on the morphology of the humerus, we refer one of the specimens to Ophthalmosauridae, the dominant ichthyosaur...
Elasmosaurids are one of the most abundant fossil marine reptile groups identified from the Upper Cretaceous strata of Antarctica. However, the documented record of intact elasmosaurid skull remains is scarce. In this study, we describe the first non-aristonectine elasmosaurid skeleton from Antarctica that preserves an associated lower jaw. This sp...
During the last summer 2020 field trip carried out under the Argentine Antarctic Program (IAA-DNA), new geological and palaeontological data of the Maastrichtian López de Bertodano Formation (Upper Cretaceous), James Ross Basin was recovered. This transgressive/regressive sequence is well exposed in the Sandwich Bluff Member of Vega Island and in t...
Although knowledge of Mesozoic marine reptiles from Antarctica has improved considerably in recent years, associated and well-preserved skeletal material of these animals remains uncommon. Here we describe a largely complete, closely associated plesiosaur pelvic girdle recovered from the uppermost Cretaceous (Maastrichtian) Sandwich Bluff Member of...
The holotype of the elasmosaurid Aphrosaurus furlongi from the Maastrichtian levels of the Moreno Formation is redescribed and considered a valid species based on one autapomorphy, a deep trough in the ventral surface of vertebral centra of the posterior cervicals, and the following combination of features: wide and short clavicle-interclavicle com...
O’Gorman, J.P. 27 November, 2019. First record of Kawanectes lafquenianum (Plesiosauria, Elasmosauridae) from the La Colonia Formation of Argentina, with comments on the mandibular morphology of elasmosaurids. Alcheringa XX, XX–XX. ISSN 0311-5518
The elasmosaurid plesiosaur Kawanectes lafquenianum is recorded from the upper Campanian–Maastrichtian...
Recientemente, la colecta de nuevos elasmosáuridos antárticos ha incrementado el conocimiento del grupo. Sin embargo, también es relevante la redescripción de ejemplares históricos, tales como el MLP 82-I-28-1. Este espécimen procede la Isla Marambio (= Seymour), Formación López de Bertodano (Maastrichtiano–Daniano) y fue, a principios de la década...
Los registros de ictiosaurios hallados en Antártida son escasos, encontrándose únicamente tres referencias en la literatura. Las dos primeras mencionan la presencia de una mandíbula de ictiosaurio hallada en las inmediaciones de Longing Gap, sin figurar ni describir el material. El reporte más reciente está basado en el molde de un diente parcialme...
We report the first plesiosaur remains (Diapsida, Sauropterygia) from Peru, recovered from Lower Cretaceous rocks cropping out in Morro Solar, within Lima city (La Herradura Formation, Valanginian-Hauterivian). The material is restricted to an undetermined propodium, fragmentary vertebrae and ilium, being identified as a Plesiosauria, with putative...
Antarctica has significant environmental, scientific, historic and intrinsic values, all of which are worth protecting into the future. West Antarctica has a discrete number of places of scientific interest that exhibit great potential as natural heritage sites, its geodiversity is of fundamental importance to scientific values of the continent, and t...
The Maastrichtian–Danian López de Bertodano Formation comprises a thick sequence of marine deposits that is well exposed on Seymour (= Marambio) and Vega islands. The López de Bertodano Formation yielded vertebrates such as chondrichthyans, teleosts, marine reptiles (plesiosaurs and mosasaurs) and dinosaurs (including birds). On the last three Anta...
Aristonectines show a highly derived morphology among elasmosaurid plesiosaurs, including some species with large body size. A new postcranial skeleton is described from the uppermost Maastrichtian levels of the López de Bertodano Formation, Seymour Island (= Marambio), Antarctica, being referred to as cf. Aristonectes sp; the most striking feature...
A new genus and species of elasmosaurid, Leivanectes bernardoi gen. et sp. nov., from the upper Aptian levels of the Paja Formation of Villa de Leiva (Boyacá Colombia) is described. The new elasmosaurid is characterized by a short mandibular symphysis, bears only three alveoli (there are five in Callawayasaurus colombiensis), has an enlarged premax...
The last twenty million years (Maastrichtian-Santonian) of Southern Hemisphere plesiosaur history is especially well recorded in the Weddellian Province (Patagonia; Western Antarctica and New Zealand). The oldest Late Cretaceous plesiosaurs, two specimens referred to Polycotylidae indet., come from the Santonian levels of the Santa Marta Formation,...
Elasmosaurids are a monophyletic group of cosmopolitan plesiosaurs with extremely long necks. Although abundant elasmosaurid material has been collected from the Upper Cretaceous of Antarctica, skull material is extremely rare. Here, new elasmosaurid cranial material from the lower Maastrichtian levels of the Cape Lamb Member (Snow Hill Island Form...
This paper presents the detailed description of a remarkable skull and partial postcranial skeleton of a very juvenile elasmosaurid referred to Tuarangisaurus keyesi (CD 427), from the upper Campanian-lower Maastrichtian levels of the Tahora Formation, New Zealand. The following points are discussed: i) the conspecific status of CD 427 with T. keye...
Most species of the genus Pliosaurus Owen, 1842 come from the Northern Hemisphere, however, a growing number of new specimens are now available from the Southern Hemisphere. Here, a new species of Pliosaurus is described, the second for the genus from the Southern Hemisphere, collected from the upper Tithonian (Jurassic) levels of the Vaca Muerta F...
During the Jurassic two main marine pathways might act as dispersion routes for vertebrates and invertebrates between Laurasia and Gondwana: the Caribbean Seaway (between North and South America) and the Trans-Erythraean Seaway (splitting Africa from India, Madagascar). The former has proven to be of relevance as a dispersion route for marine verte...
Elasmosaurid plesiosaurs remains are frequently collected across the Marambio Group (Santonian-Danian), Antarctica. Notwithstanding, finding of informative cranial material is extremelyrare. A new specimen (MLP 15-I-7-6), from the Cape Lamb Member of the Snow Hill Island Formation (lower Maastrichtian) in Vega Island (Fig. 1.A, B) allows studyingth...
This paper redescribes the holotype skull of the aristonectine elasmosaur Morturneria seymourensis from the upper Maastrichtian of Seymour Island, Antarctica. This description supports the validity of the genus Morturneria, distinct from the genus Aristonectes from Chile and Argentina. The paroccipital process of Morturneria is plesiomorphic, simil...
O’Gorman, J.P., Panzeri, K.M., Fernández, M.S., Santillana, S., Moly, J.J. & Reguero, M. XX.XX.2017. A new elasmosaurid from the upper Maastrichtian López de Bertodano Formation: new data on weddellonectian diversity. Alcheringa xx, xxx–xxx. ISSN 0311-5518.
Elasmosaurids are one of the most frequently recorded marine reptiles from the Weddellian Pr...
Nowadays, notothenioids are the teleostean group that dominates marine Antarctic waters. However, during the Mesozoic a diverse ichthyofauna inhabited the sea that surrounded Antarctic. We present the preliminary results of the last two Argentinian Antarctic field expedition to the Late Jurassic of Antactic Peninsula (Longing Gape) and Cretaceous-P...
The systematics of elasmosaurids are not well resolved partially because of the scarcity of well-preserved skull material. Among Weddellian elasmosaurids, one exception to this is the holotype of Tuarangisaurus keyesi from upper Campanian–lower Maastrichtian levels of the Maungataniwha Sandstone Member of the Tahora Formation, Mangahouanga Stream,...
Research carried out on austral plesiosaurs from the Weddellian Biogeographic Province in the decade since the last attempt to characterise the New Zealand elasmosaurid, Mauisaurus haasti Hector, 1874 (On the Fossil Reptilia of New Zealand. Transactions and Proceedings of the New Zealand Institute 6: 333–358), has prompted a reappraisal of this tax...
The evolution of the axial skeleton of vertebrates, particularly regionalization and the changes in the limits of each region is yet to be completely understood. The features of this process are more difficult to follow in groups with strong changes in the number of vertebrae as is the case of plesiosaurs. In this work we record the osseous correla...
O’Gorman, J.P. & Coria, R.A. September 2016. A new elasmosaurid specimen from the upper Maastrichtian of Antarctica: new evidence of a monophyletic group of Weddellian elasmosaurids. Alcheringa 41, xxx–xxx. ISSN 0311-5518
A new fossil elasmosaurid specimen, MLP 15-I-7-48, from the upper Maastrichtian Sandwich Bluff Member of the López de Bertodano...
Perinatal specimens give valuable information about the first stages of vertebrate ontogeny. Here, the morphology and palaeohistology of an aristonectine perinatal specimen from Seymour Island (Isla Marambio), López de Bertodano Formation are analysed. The palaeohistological analysis shows incomplete endochondral ossification (retention of a calcif...
During December 2015 / February 2016, within the activities of the ―Vertebrate Paleontology of the James Ross Basin, Antarctic Peninsula‖ project of the Instituto Antártico Argentino, principal fossiliferous localities of Marambio (=Seymour) Island, northeast Antarctic Peninsula (marine late Cretaceous, K-Pg and Paleogene outcrops), and Cape Longin...
The elasmosaurid Fresnosaurus drescheri, Welles from the contact between the Tierra Loma/Marca members of the Moreno Formation (Maastrichtian), California, USA is reviewed. Most of the features included in Welles's original diagnosis are considered related only to the juvenile ontogenetic stage of the holotype and only specimen. The new diagnosis i...
A fragmentary plesiosaur skull from lower Maastrichtian levels of the Conway Formation, New Zealand, is redescribed. Originally regarded as pertaining to two separate individuals, we argue that they represent a single individual belonging to a new aristonectine elasmosaurid, Alexandronectes zealandiensis gen. et sp. nov. This new taxon has common m...
Resumen
During the late Campanian and early Maastrichtian, Northern Patagonia suffered the first stage of the Atlantic marine ingression that reached the Neuquén Basin. The Allen and La Colonia formations show the early stages of this change, and were deposited in a complex asso- ciation of marginal marine environments, including coastal and marin...
A new species of an edaphodontid holocephalian, Edaphodon snowhillensis, sp. nov., is described based on a complete dentition collected in the late Campanian Herbert Sound Member of the Snow Hill Island Formation of James Ross Island, Antarctica. The dentition consists of paired vomerine, mandibular, and palatine tooth plates, which are almost comp...
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A femur with an hemispherical articular head was regarded as autapomorphic of Mauisaurus haasti Hector, 1874, from the late Campanian of New Zealand. The review of three Maastrichtian taxa, Aristonectes quiriquinensis from Chile, Aristonectes sp. from Ant...
New observations on the holotype of the Maastrichtian aristonectine elasmosaurid Aristonectes parvidens Cabrera from Chubut Province, Argentina, reveals features that were not previously described while resulting in new interpretations. Quantitative comparison with non-aristonectine elasmosaurids demonstrates that the increase in the number of alve...
The systematics of the Late Cretaceous non-aristonectine elasmosaurids from Argentinean Patagonia are poorly known as there is no valid species currently recognized. Here a new non-aristonectine elasmosaurid: Kawanectes lafquenianum nov. comb. from the late Campanian-early Maastrichtian Allen Formation is diagnosed. K. lafquenianum is a distinctive...
O’Gorman, J.P., Otero, R.A. & Hiller, N., 2014. A new record of an aristonectine elasmosaurid (Sauropterygia, Plesiosauria) from the Upper Cretaceous of New Zealand: implications for the Mauisaurus haasti Hector, 187418.
Hector, J., 1874. On the fossil Reptilia of New Zealand. Transactions and Proceedings of the New Zealand Institute 6, 333–358.Vie...
Pliosaurus patagonicus sp. nov., from the middle Tithonian, Vaca Muerta Formation, Neuquen Province, Argentina, is described on an autapomorphic trait -i.e., the distance between the posterior functional alveolus and coronoid eminence (300 mm) equivalent to the last fourteen alveoli- and a unique combination of characters: short and robust mandibul...
The occurrence of a large gastrolith set associated with a specimen referred to Aristonectes sp. is reported here for the first time. The specimen MLP 89-III-3-1 comes from Seymour Island (Is. Marambio), Antarctic Peninsula, López de Bertodano Formation (upper Maastrichtian). The gastrolith cluster is composed of 793 elements (534 in their presumed...
The holotype of Tuarangisaurus? cabazai Gasparini, Salgado and Casadio, 2003 (Elasmosauridae, Plesiosauria) from the Upper Maastrichtian Jagüel Formation (northern Patagonia, Argentina) is redescribed, its taxonomic status is reconsidered, and its phylogenetic relationships analysed. We conclude that it must be referred as an aristonectin elasmosau...
ABSTRACT—This paper describes a new species of elasmosaurid plesiosaur,Aristonectes quiriquinensis, sp. nov., based on a partial skeleton recovered from upper Maastrichtian beds of the Quiriquina Formation of central Chile. The material described here consists of two skeletons, one collected near the village of Cocholgue, and a second juvenile spec...
Sulcusuchus erraini, from the upper Campanian–lower Maastrichtian of Patagonia, Argentina, is the only polycotylid from the Southern Hemisphere for which the skull and mandible are known. The diagnosis of the species and genus is emended based on new observations.Sulcusuchus is characterized by the following autapomorphies: (1) deep and broad rostr...
Elasmosaur postcranial remains from the La Colonia Formation (Campanian–Maastrichtian), Chubut Province, Patagonia, Argentina, are described. The new material has small dimensions and caudal vertebrae with parapophyses strongly projected laterally—characters shared with some Elasmosauridae indet. from the coeval Allen Formation, Río Negro Province,...
A partial, postcranial skeleton of a juvenile individual referred to Aristonectes cf. parvidens from the upper Maastrichtian López de Bertodano Formation, Isla Marambio (Seymour Island), Antarctica, is described. Additionally, two juvenile specimens, also referred to A. cf. parvidens from the Allen Formation (upper Campanian–lower Maastrichtian) an...
José P. O'Gorman, Eduardo Olivero & Daniel A. Cabrera. iFirst article. Gastroliths associated with a juvenile elasmosaur (Plesiosauria, Elasmosauridae) from the Snow Hill Island Formation (upper Campanian–lower Maastrichtian), Vega Island, Antarctica. Alcheringa, 1–12. ISSN 0311-5518.One of the unresolved problems concerning the palaeobiology of pl...
Elasmosaurs are recorded for the first time in the Lachman Crags Member
(Beta Member) of the Santa Marta Formation (lower Campanian) and in
the Herbert Sound Member of the Snow Hill Island Formation (upper
Campanian). These are the first elasmosaurids from James Ross Island,
Antarctic Peninsula. These records greatly improve our knowledge of the
ta...
Se confirma la presencia de Elasmosauridae y Polycotylidae en el Campaniano–Maastricthiano en el Norte de Patagonia, tal como fuera previamente señalado por Gasparini y Salgado (2000) y Salgado et al. (2007a). El material del área del Salitral de Santa Rosa de la Formación Allen es compa rable al proveniente de la misma unidad en Lago Pellegrini. P...
Plesiosaurs are recorded for the first time from the lower section of Mata Amarilla Formation,
Santa Cruz Province, Patagonia, Argentina. The stratigraphic succession consists of mudstones and siltstones
interbedded with medium to fine-grained sandstone, deposited in a littoral environment during
the Cenomanian-Santonian; therefore the material is...
