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A New Basal Titanosaur (Dinosauria, Sauropoda) from the Lower Cretaceous of Brazil

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A New Basal Titanosaur (Dinosauria, Sauropoda) from the Lower Cretaceous of Brazil Journal of South American Earth Sciences 75 (2017) 74e84 Contents lists available at ScienceDirect Journal of South American Earth Sciences journal homepage: www.elsevier.com/locate/jsames A new basal titanosaur (Dinosauria, Sauropoda) from the Lower Cretaceous of Brazil * Ismar de Souza Carvalho a, , Leonardo Salgado b, Rafael Matos Lindoso c, Hermínio Ismael de Araújo-Júnior d, Francisco Cezar Costa Nogueira e, Jose Agnelo Soares f a Universidade Federal do Rio de Janeiro, Departamento de Geologia, CCMN/IGEO 21. 949-900 Cidade Universitaria-Ilha do Fundao,~ Rio de Janeiro, Brazil b Instituto de Investigacion en Paleobiología y Geología, UNRN-Conicet, Av. General Roca 1242, 8332 General Roca, Río Negro Argentina c Instituto Federal de Educaçao,~ Ci^encia e Tecnologia do Maranhao,~ Rua da Tecnologia, nº 215eVila Amorim, Ze Doca, 65.365-000, Maranhao,~ Brazil d Universidade do Estado do Rio de Janeiro, Faculdade de Geologia, Departamento de Estratigrafia e Paleontologia, Rua Sao~ Francisco Xavier, 524, 2º andar, Sala 2032A, Maracana,~ 20.550-013, Rio de Janeiro, Rio de Janeiro, Brazil e Universidade Federal de Campina Grande, Unidade Acad^emica de Engenharia Mecanica,^ Avenida Aprígio Veloso, 812. Bairro Universitario, 58.429-140, Campina Grande, Paraíba, Brazil f Universidade Federal de Campina Grande, Unidade Acad^emica de Mineraçao~ e Geologia, Avenida Aprígio Veloso, 882eBloco BY. Bairro Universitario, 58.429-900, Campina Grande, Paraíba, Brazil article info abstract Article history: Although dinosaurian ichnofaunas are common in the Northeastern Brazilian Interior Basins, osteological Received 24 August 2016 remains are poorly represented in these areas. One of the main challenges in vertebrate paleontology in Received in revised form the Lower Cretaceous of this region is to recognize body-fossils, which can unveil the anatomy, functional 19 January 2017 morphology and paleoecological aspects of the dinosaurian fauna recorded until now only by footprints Accepted 30 January 2017 and trackways. The discovery of a new dinosaur specimen in the Rio Piranhas Formation of the Triunfo Available online 3 February 2017 Basin opens new perspectives into the comprehension of paleogeographical and temporal distribution of the titanosaur sauropods. Titanosaurs are common in Upper Cretaceous rocks of Brazil and Argentina. Keywords: Triunfo Basin The age of the Rio Piranhas Formation is considered to range from Berriasian to early Hauterivian. Thus, Titanosauria the description of this new species opens new viewpoints concerning the paleobiogeographical aspects Triunfosaurus leonardii gen. et sp. nov of these sauropod dinosaurs. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Cenomanian) strata (Medeiros and Schultz, 2001, 2002; Castro et al., 2007; Freire et al., 2007; Lindoso et al., 2013; Medeiros Titanosaurs were the most common and diversified group of et al., 2014). neosauropods throughout the Cretaceous (Curry Rogers, 2005). Intriguingly, the fossil record of these sauropods in the Lower Although their remains are present in almost all continents, in Cretaceous (Berriasian to Hauterivian) of Equatorial deposits of South America their fossil record is more abundant and complete Brazil are represented almost entirely by footprints (Leonardi, 1979; (Santucci and Bertini, 2001; Powell, 2003; Poropat et al., 2016). In Carvalho, 1996, 2000; Leonardi and Carvalho, 2000, 2007; Leonardi Brazil, titanosaurs are best recorded in the Upper Cretaceous de- and Santos, 2004). The only titanosaur species described from this posits of the Bauru Basin, being represented mostly by body fossils interval comes from the Sanfranciscana Basin (Aptian, Areado (Kellner and Azevedo, 1999; Campos et al., 2005; Kellner et al., Group) (Zaher et al., 2011). Recently, the first titanosaur body fossil 2005, 2006; Santucci and Bertini, 2006; Salgado and Carvalho, has been discovered from the Rio do Peixe Basin complex (Ghilardi 2008; Santucci and Arruda-Campos, 2011; Bandeira et al., 2016). et al., 2016). Among the interior basins situated in the Northeastern In the Sao~ Luís-Grajaú Basin, northern South America, titanosaurs Brazil, those located in the region of Rio do Peixe, specially Sousa are badly preserved in the lower-Upper Cretaceous (Albian- and Triunfo, stand out due to their prolific dinosaur fossil record, in particular on their paleoichnological aspects (Carvalho, 2001; Leonardi and Carvalho, 2002). Footprints and trackways, mainly of large theropods, sauropods and ornithopods and invertebrate * Corresponding author. ichnofossils, such as traces and burrows produced by arthropods E-mail address: [email protected] (I.S. Carvalho). http://dx.doi.org/10.1016/j.jsames.2017.01.010 0895-9811/© 2017 Elsevier Ltd. All rights reserved. I.S. Carvalho et al. / Journal of South American Earth Sciences 75 (2017) 74e84 75 and annelids, are also common (Fernandes and Carvalho, 2001; levels in marls. The lithostratigraphic terms used in the Triunfo Carvalho et al., 2017). Basin are the same as for the Sousa Basin. The total thickness of The paleontological-geological relevance of Sousa and Triunfo these deposits is unknown. Besides the breccias and conglomerates basins lies on the abundance of dinosaurian ichnofaunas that near the faulted margins, there are coarse arkosic sandstones and represent an extensive Lower Cretaceous megatracksite (Viana medium-fine quartzose sandstones with an argillaceous matrix or et al., 1993; Carvalho, 2000; Leonardi and Carvalho, 2000, 2002) siliceous cement in the Antenor Navarro Formation. The main established during the early stages of the South Atlantic opening. In sedimentary structures are cross-channel and planar stratification this area, 37 sites and approximately 96 individual stratigraphic (Mabesoone and Campanha, 1973; Carvalho and Leonardi, 1992; levels preserve occurrences of more than 535 individual dinosau- Mabesoone, 1994; Carvalho, 2000). rian trackways, as well as rare tracks and traces of the vertebrate As the basin is an asymmetric graben, the finer-grained lithol- mesofauna (Leonardi, 1989, 1994; Leonardi and Carvalho, 2000; ogies are distributed in the south-southeast region of the basin, Carvalho et al., 2013). On the other hand, dinosaur remains are where tilting was greater than elsewhere. Such deposits are poorly represented in these basins. Then, one of the main chal- referred to the Sousa Formation, which comprises shales and lenges in the vertebrate paleontology in northeastern Brazil is to mudstones interbedded with sandstones and siltstones. The main find dinosaur body-fossils, which can unveil the anatomy, func- sedimentary structures are ripple marks, climbing ripples, mud- tional morphology and paleoecological aspects of the dinosaurian cracks, convolute lamination and liquefaction features (Carvalho, fauna recorded until now only by footprints and trackways 2000). (Carvalho, 2004; Carvalho et al., 1993a,b). The last macroclastic succession is the Rio Piranhas Formation, This paper presents a new species of a titanosaur from the Lower composed of coarse grained immature sandstones, medium Cretaceous (Berriasian to lower Hauterivian) of Brazil and one of grained sandstones, breccias and polymictic conglomerates. oldest worldwide. Additionally, it provides new insights regarding Trough-cross bedding is common with paleocurrents mainly from the pattern of distribution of this successful group of sauropods in N/NW to S/SE. This unit interfingers with the Antenor Navarro and the equatorial Gondwana. Sousa formations. The origin of this basin, like others in the interior of Northeastern Brazil, was a result of reactivation of basement transcurrent faults. Deposition of coarse grained sediments on the 2. The Triunfo Basin margins occurred under the strong influence of tectonic activity. The tilted blocks created a pronounced rupture in terrain topog- 2.1. Geological and paleontological setting raphy, and in the southern part of the basin, the decrease in gradient favored the establishment of meandering fluvial and Located in the west of Paraíba State in the counties of Uiraúna, lacustrine environments (Machado et al., 1990; Lima Filho, 1991; Poço, Brejo das Freiras, Triunfo and Santa Helena, this basin of Mabesoone et al., 2000). 480 km2 is an asymmetric graben that was controlled by a north- Excepting the dinosaur footprints, which are located close to the west transcurrent fault system (Fig. 1). The Precambrian basement northern margin, the fossiliferous localities are in the central-south is composed of igneous (granites, gabbros and diorites) and meta- region of the basin. The paleoenvironmental interpretation sug- morphic (migmatites, gneisses, quartzites and marbles) rocks (ANP, gests coalescing alluvial fans and an anastomosing fluvial system. 2008; Carvalho, 2000). Cordoba et al. (2008) concluded e based on the analysis of sysmic In the basin, the main lithologies are clastic rocks: breccias, sections e that Rio Piranhas Formation is chronocorrelated to the conglomerates, sandstones, siltstones, shales and mudstones. Sousa Formation. Furthermore, the relatively rare footprints and Limestones are rare, occurring as nodules or as centimeter-thick Fig. 1. Location of Triunfo Basin, northeastern Brazil (black area on the right); Triunfo town, Paraíba State (1); Areias Farm, Paraíba State, site where the fossils comes from (2). 76 I.S. Carvalho et al. / Journal of South American Earth Sciences 75 (2017) 74e84 trackways identified in this unit are similar to those of Sousa For- recovered in the
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