Late Cretaceous vertebrates from bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae)

Abstract

,4bstraet: A large and diverse collection of vertebrate remains from the Campanian-Maastrichtian Allen Formation (Malargiie Group) a t the Bajo de Santa Rosa locality (Rio Negro Province, Argentina) is described hore. The vertebrates arc represented hv: chondrichthvans: di~iomvstid siluriform. le~isosteid, cf oercichthvid and titanosaurid dinosaurs. A now small salt,asaurine tit&saurid, I3onatitan reigigen. el sp. no"., is described. It is diagnosed by the following association of characters: 1) longitudinal groovo located an the suture between pariotals that continues posteriorly over the supraoccipital to the foramen magnum; 2) basisphcnoid tubera long and narrow; 3) dorsalto middle caudal vertebrae with deep oval to circular pits present on both sides of the prespinal lamina; 4) anterior caudal vertebra with spino-postzygapophysiat and spino-prezygapophysiai laminae; 5) neural arch of anterior caudals with deep interzygapophysial fossae with numerous pits; 6 ) anterior caudal vertebra with an accessom sub-horizontal lamina extendine from the antero-ventral oortion of the " postzygapophysis to the mid-portion of tho spino-prezygapophysial lamina; and finally, 7) anterior caudal vertobra with a prominent axial crest on the ventral surftaee of tho cerntrum. The first rocord of sphenodonts and cf carcharodontosaurid theropods is recognized for the upper Late Cretaceous ofpatagonia, as well as the earliest record of perichthylds (Pereiformes). The vertebrate record is mainly composed of terrestrial and freshwater tawa, but a few marine elements are found (olasmosaurids) indicating a marine influence during the deposition of the Allen hrmation in the arca of Baio de Santa Rosa. The vertebrate remains s u~~o r t a Cam~anian-and extra Patagonlan South Amencan records Key words: Late Cretdecous, osteichthyans, chondnchtllyans, anurans, turtles, sphenodonts, plesiosaur^, oph~d-ians, dmosaurs, Patagonla particular those of Argentina, is opening new windows, not only for the infornlation based on new taxa, but also for the evolutionary, paleobiogeographic, biochronoiogical, and compositional aspects of the Late Cretaceous continental assemblages which populated this continent. The fossil remains recovered fkom the CampanianMaastrichtian South American formations such as Los Blanquitos iSalta Province, Argentina; e.g., Powell, 1979,20031, Lecho (Salta Province, Argentina; e.g., Bonaparte & Powell, 1980; Chiappe, 19931 . , " ince, Argentina; e.g., Bonaparte et a;., Bonaparte, 1986a Bonaparte, ,1987 Bonaparte, , 1990 Bonaparte, , 1992 Bonaparte, , 1994 Bonaparte, ,2002 Baez, 1987; Broin, 1987;Albino, 1986 Albino, , 1994Cione, 1987; Salgado et al., 1997b), Loncoche (Mendoza Province, Argentina; e.g., Wichmann, 1927; Gonaaez Riga, 1999), Allen (Rio Negro and La Pampa, Provinces, Argentina; e.g., Powell, 1987b, Gasparini & Salgado, 2000 Salgado & Aspilicueta, 2000;Coria, 2001.), L a Colonia (Chubut Province, Argentina; e.g., Ardolino & Franchi, 1996; Albino, 2000 In addition, Campanian-Masstrichtian noiiSou...

Considerations on the neural laminae of the sauropod dinosaurs and their morpho-functional meaning

“…1 En las caudales anteriores de algunos titanosaurios, es muy probable que los divertí-culos aéreos se hayan dispuesto sobre la espina neural a ambos lados de la prsl. Esto puede inferirse a partir de la presencia de orificios (probablemente neumáticos) en esa área (Bonatitan, Martinelli & Forasiepi, 2004, fig. 16; Neuquensaurus, Salgado et al 2005, fig.…”

A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and palaeobiogeography of the tuatara ( Sphenodon )

“…This material helps to bridge a gap in the rhynchocephalian fossil record of nearly 70 Mya between the Late Pleistocene ( Worthy & Grant-Mackie 2003) and the Late Cretaceous (Apesteguía & Novas 2003;Martinelli & Forasiepi 2004;Apesteguía 2005a,b). It also represents the first direct evidence that a rhynchocephalian was present on New Zealand prior to the Pleistocene.…”

“…Crook 1975, p. 338;Rich 1975, p. 50;Robb 1977, p. 4) were based on a misidentified Holocene prey accumulation of the laughing owl Sceloglaux albifacies ( Worthy & Holdaway 1996). Outside New Zealand, apart from a problematic lepidosaur specimen from the Palaeocene of Morocco (Augé & Rage 2006), the next most recent records of rhynchocephalians are from the Late Cretaceous Allen (Martinelli & Forasiepi 2004;Apesteguía & Rougier 2007) and Los Alamitos formations (Apesteguía 2005b) of Argentina (ca 70 Mya).…”

New Insights on theAristonectes parvidens(Plesiosauria, Elasmosauridae) Holotype: News on an Old Specimen

“…En la misma localidad pero provenientes de la Formación Allen (Campaniano superiorMaastrichtiano inferior) se hallaron restos referibles a Polycotylidae (Salgado et al, 2007b). Otros materiales fragmentarios han sido registrados en la Formación Allen, los cuales son relevantes a la hora de discutir el ambiente de depositación de dicha formación, hacer correlaciones y realizar inferencias sobre estadios ontogenéticos de los individuos (Martinelli y Forasiepi, 2004;O'Gorman et al, 2011). En 2011 nuevos hallazgos provenientes de la Formación La Colonia (Chubut) confirmaron la presencia de elasmosáuridos en esta unidad, la que había sido mencionada por Gasparini y de la Fuente (2000) y Gasparini et al (2001); estos nuevos materiales permitieron ampliar el conocimiento sobre la morfología y paleobiología de los elasmosáuridos patagónicos y complementar los resultados del estudio de Cerda y Salgado (2008) sobre diversos aspectos de los gastrolitos de plesiosaurios (O'Gorman et al, 2012c).…”

“…Sin embargo dado que esta división no es observada en todos los afloramientos de la Fm. Allen, es probable que esta formación corresponda, en conjunto, a un mosaico de ambientes marino marginales a continentales costeros, dada la abundancia de macro y microfósiles continentales (Martinelli y Forasiepi, 2004, Carignano y Varela, 2010.…”