, Volume 99, Issue 5, pp 369–377 | Cite as

The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the early cretaceous of Laos

  • Ronan AllainEmail author
  • Tiengkham Xaisanavong
  • Philippe Richir
  • Bounsou Khentavong
Original Paper


Spinosaurids are among the largest and most specialized carnivorous dinosaurs. The morphology of their crocodile-like skull, stomach contents, and oxygen isotopic composition of the bones suggest they had a predominantly piscivorous diet. Even if close relationships between spinosaurids and Middle Jurassic megalosaurs seem well established, very little is known about the transition from a generalized large basal tetanuran to the specialized morphology of spinosaurids. Spinosaurid remains were previously known from the Early to Late Cretaceous of North Africa, Europe, and South America. Here, we report the discovery of a new spinosaurid theropod from the late Early Cretaceous Savannakhet Basin in Laos, which is distinguished by an autapomorphic sinusoidal dorsosacral sail. This new taxon, Ichthyovenator laosensis gen. et sp. nov., includes well-preserved and partially articulated postcranial remains. Although possible spinosaurid teeth have been reported from various Early Cretaceous localities in Asia, the new taxon I. laosensis is the first definite record of Spinosauridae from Asia. Cladistic analysis identifies Ichthyovenator as a member of the sub-clade Baryonychinae and suggests a widespread distribution of this clade at the end of the Early Cretaceous. Chilantaisaurus tashouikensis from the Cretaceous of Inner Mongolia, and an ungual phalanx from the Upper Jurassic of Colorado are also referred to spinosaurids, extending both the stratigraphical and geographical range of this clade.


Cretaceous Savannakhet basin Theropoda Spinosauridae Asia 



Field expeditions in the Savannakhet Basin were supported by the “Fondation de France”, the French Ministry of Foreign Affairs, the Laotian National Authority for Science and Technology, the Savannakhet Province, and the ‘Formation et Recherche au Laos’ Association. The Dinosavan Project is also supported by the National Geographic Society. We thank B. Ledimet, A. Soukrany, M. Veran, N. Ouprasay, and S. Phanvilay for assistance during fieldwork and preparation of the specimen, and M. Fontaine for the live reconstruction of Ichthyovenator in Fig. 6. We thank P. Taquet and A Thiollier who initiated paleontological researches in Laos; M. Carrano, L. Ferrer, and P. Sereno for helpful data on Segisaurus and Suchomimus; K. Padian, S. Chapman, and A. Milner for access to specimens in their care. We also thank Roger Benson and two anonymous referees for their thorough and constructive reviews.

Supplementary material

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ESM 1 (PDF 10532 kb)


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Ronan Allain
    • 1
    Email author
  • Tiengkham Xaisanavong
    • 2
  • Philippe Richir
    • 1
  • Bounsou Khentavong
    • 2
  1. 1.Département Histoire de la Terre, Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements (CR2P)Muséum National d’Histoire NaturelleParis cedex 05France
  2. 2.Science and Technology OfficeSavannakhet Dinosaur MuseumSavannakhetRépublique Démocratique Populaire Lao

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