Elsevier

Cretaceous Research

Volume 41, April 2013, Pages 82-85
Cretaceous Research

A giant tooth from the Late Cretaceous (middle Campanian–lower Maastrichtian) of Patagonia, Argentina: An enormous titanosaur or a large toothed titanosaur?

https://doi.org/10.1016/j.cretres.2012.10.004Get rights and content

Abstract

The tooth MML-Pv 1030 comes from the Upper Cretaceous (middle Campanian–lower Maastrichtian) strata of the Allen Formation at Salitral de Santa Rosa, Río Negro, Argentina and is the biggest titanosaur tooth yet described. The specimen is a cylindrical chisel-like tooth, its length is 75 mm, mesiodistally 15 mm and labiolingually 11 mm. The wear facet is single on the lingual side of the tooth, which has an oval outline with a low angle (10°) with respect to the axial axis of the tooth. This tooth is 32% greater in length than the longest tooth registered in a titanosaurid (Nemegtosaurus), and twice the tooth size of taxa as Tapuiasaurus, Bonitasaura and Pitekunsaurus. Detailed descriptions of the tooth morphology and a highlight of comparative relationships among known titanosaur teeth are provided. Finally, different aspects are suggested related to morphology and feeding behavior.

Introduction

Titanosaurs are a group of herbivorous dinosaurs that comprise nearly half of all sauropod genera. This group of neosauropods developed a highly specialized dentition that could be related to a distinct and specialized feeding behavior (Calvo, 1994; García and Cerda, 2010a). The numerous cylindrical chisel-like teeth, with acute wear facets allow to infer a specialized mechanism of consumption of plant material. The titanosaur dentition restricted to the front of the snout is practically constant (Pm 4, M 7–8/D 10–13), not only among different taxa, but also with respect to its ontogeny (García and Cerda, 2010a, b; García et al., 2010). Despite its morphological specialization and its large tooth development (four replacement teeth and several generations of teeth) their dentition and the feeding mechanisms are poorly understood.

In this paper, the biggest titanosaur tooth yet discovered is described. This record sheds light on titanosaur diversity, at least with respect to skull and dentition size.

Section snippets

Geological context

The unit that yielded the tooth is the Allen Formation, whose age was estimated by Ballent (1980) as middle Campanian–lower Maastrichtian. This geologic unit is widely exposed at Río Negro and Neuquén Provinces but the quarry of the MML-PV 1030 teeth is in Salitral de Santa Rosa area, approximately 120 km west from Lamarque city, Río Negro Province.

Systematic paleontology

Dinosauria Owen, 1842

Saurischia Seeley, 1888

Sauropoda Marsh, 1878

Titanosauria Bonaparte and Coria, 1993

Gen. et sp. Indet.

Fig. 1, Fig. 2A, B

Description

The MML-PV 1030 tooth (Fig. 1A) is a cylindrical and thick chisel-like tooth, bearing a slight lingual curvature. Its total length is 75 mm. though the base of the root is incomplete. The dental crown length is 56 mm. The labial side is slightly more curved than lingual side, similarly to that of other titanosaur tooth (Kellner, 1996; Upchurch, 1998; García and Cerda, 2010a). The crown has the margins mesiodistally parallel, one of the main differences with the mesiodistally expanded crown of

Discussion and conclusion

The largest titanosaur tooth that has been reported is the second upper left tooth of Nemegtosaurus mongoliensis Nowinski (Wilson, 2005). The MML-Pv 1030 tooth is 32% greater in length, 9.1% greater mesiodistally and 40% greater labiolingually than that of the Asian taxon. Meanwhile with taxa as Rapetosaurus, Tapuiasaurus, Pitekunsaurus, Petrobrasaurus and Bonitasaura the difference is 38–46% greater in length (Curry Rogers and Forster, 2004; Zaher et al., 2011; Filippi and Garrido, 2008;

Acknowledgments

Funds from The Jurassic Foundation (to the Author) provided financial support for different aspects of the research. I gratefully acknowledge the logistics assistance of the Daniel Cabaza and Museo Municipal de Lamarque. María Soledad Fernandez, Julio Varela and Jose O'Gorman, are thanked for field support. Luis M. Chiappe and Sebastian Apesteguía substantially improved this work with useful comments and critical reviews.

References (37)

  • P. Upchurch

    The phylogenetic relationships of sauropod dinosaurs

    Zoological Journal of the Linnean Society

    (1998)
  • S. Apesteguía

    Successional structure in continental tetrapod faunas from Argentina along the Cretaceous

  • S. Apesteguía

    Bonitasaura salgadoi gen. et sp. nov.: a beaked sauropod from the Late Cretaceous of Patagonia

    Naturwissenschaften

    (2004)
  • S.C. Ballent

    Ostrácodos de ambiente salobre de la Formación Allen (Cretácico Superior) en la provincia de Río Negro (Republica Argentina)

    Ameghiniana

    (1980)
  • P.M. Barrett et al.

    Feeding mechanisms of Diplodocus

    GAIA

    (1994)
  • J.F. Bonaparte et al.

    Un nuevo y gigantesco saurópodo titanosaurio de la Formación Río Limay (albiano – Cenomaniano) de la provincia de Neuquén, Argentina

    Ameghiniana

    (1993)
  • J.O. Calvo

    Jaw mechanics in sauropod dinosaurs

    Gaia

    (1994)
  • J.O. Calvo et al.

    Rinconsaurus caudamirus gen. et sp. nov., a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina

    Revista Geológica de Chile

    (2003)
  • K. Carpenter et al.

    Preliminary description of a Brachiosaurus skull from Felch Quarry 1, Garden Park, Colorado

    Modern Geology

    (1998)
  • K. Curry Rogers et al.

    The Skull of Rapetosaurus krausei (Sauropoda: Titanosauria) from the Late Cretaceous of Madagascar

    Journal of Vertebrate Paleontology

    (2004)
  • G.M. Erickson

    Daily deposition of dentine in juvenile Alligator and assessment of tooth replacement rate using incremental line counts

    Journal Morphology

    (1996)
  • L.S. Filippi et al.

    Pitekunsaurus macayai gen. et sp nov., tiranosaurio (Saurischia, Sauropoda) del Cretácico Superior de la Cuenca Neuquina, Argentina

    Ameghiniana

    (2008)
  • L.S. Filippi et al.

    A new sauropod titanosaur from the Plottier Formation (Upper Cretaceous) of Patagonia (Argentina)

    Geologica Acta

    (2011)
  • A.R. Fiorillo

    Dental microwear patterns of the sauropod dinosaurs Camarasaurus and Diplodocus: evidence for resource partitioning in the Late Jurassic of North America

    Historical Biology

    (1998)
  • P.A. Gallina et al.

    Cranial anatomy phylogenetic position of the titanosaurian sauropod Bonitasaura salgadoi

    Acta Paleontologica Polonica

    (2011)
  • P.A. Gallina et al.

    Primitive broad-crowned titanosaurs in the Uppermost Cretaceous

    Ameghiniana

    (2010)
  • R.A. García et al.

    Dentición de titanosaurios (Dinosauria, Sauropoda) del Cretácico Superior de la provincia de Río Negro, Argentina: morfología, inserción y reemplazo

    Ameghiniana

    (2010)
  • R.A. García et al.

    Dentition and histologyin titanosaurian dinosaur embryos from Upper Cretaceous of Patagonia, Argentina

    Palaeontology

    (2010)
  • Cited by (7)

    View all citing articles on Scopus
    View full text