Abstract
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.
Similar content being viewed by others
References
Allain R (2002) Discovery of megalosaur (Dinosauria, Theropoda) in the Middle Bathonian of Normandy (France) and its implications for the phylogeny of basal Tetanurae. J Vertebr Paleontol 22:548–563
Allain R, Taquet P, Battail B, Dejax J, Richir P, Veran M, Sayarath P, Khenthavong B, Thamvirith P, Hom B (1997) Pistes de dinosaures dans les niveaux du Crétacé inférieur de Muong Phalane, province de Savannakhet (Laos). C R Acad Sci Paris 325:815–821
Allain R, Taquet P, Battail B, Dejax J, Richir P, Veran M, Limon-Duparcmeur F, Vacant R, Mateus O, Sayarath P, Khenthavong B, Phouyavong S (1999) Un nouveau genre de dinosaure sauropode de la Formation des Grès supérieurs (Aptien-Albien) du Laos. C R Acad Sci Paris 329:609–616
Amiot R, Buffetaut E, Lécuyer C, Wang X, Boudad L, Ding Z, Fourel F, Hutt S, Martineau F, Medeiros MA, Mo J, Simon L, Suteethorn V, Sweetman S, Tong H, Zhang F, Zhou Z (2010) Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods. Geology 38:139–142
Bailey JB (1997) Neural spine elongation in dinosaurs: sailbacks or buffalo-backs? J Paleontol 71:1124–1146
Benson RBJ (2010) A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the United Kingdom and the relationships of Middle Jurassic theropods. Zool J Linn Soc Lond 158:882–935
Benson RBJ, Xu X (2008) The anatomy and systematic position of the theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the early cretaceous of Alanshan, People’s Republic of China. Geol Mag 145:778–789
Benson RBJ, Carrano MT, Brusatte SL (2010) A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic. Naturwissenschaften 97:71–78
Britt BB (1991) Theropods of Dry Mesa Quarry (Morrison Formation, Late Jurassic), Colorado, with emphasis on the osteology of Torvosaurus tanneri. Brigham Young Univ Geol Stud 37:1–72
Brusatte SL, Sereno PC (2008) Phylogeny of Allosauroidea (Dinosauria: Theropoda): comparative analysis and resolution. J Syst Palaeontol 6:155–182
Brusatte SL, Benson RBJ, Xu X (2010) The evolution of large-bodied theropod dinosaurs during the Mesozoic in Asia. J Iberian Geol 36:275–296
Buffetaut E (1991) On the age of the Cretaceous dinosaur-bearing beds of southern Laos. Newsl Stratigr 24:59–73
Buffetaut E, Ingavat R (1986) Unusual theropod dinsoaur teeth from the upper Jurassic of Phu Wiang, northeastern Thailand. Rev Paleobiol 5:217–220
Buffetaut E, Suteethorn V, Tong H (1996) The earliest known tyrannosaur from the Lower Cretaceous of Thailand. Nature 381:689–691
Buffetaut E, Martill DM, Escuillié F (2004) Pterosaurs as part of a spinosaur diet. Nature 430:33
Buffetaut E, Suteethorn V, Tong H, Amiot R (2008) An early cretaceous spinosaurid theropod from southern China. Geol Mag 145:745–748
Buffetaut E, Cuny G, Le Loeuff J, Sutheethorn V (2009) Late Palaeozoic and Mesozoic continental ecosystems of SE Asia: an introduction. Geol Soc London, Spec Pub 315:1–5
Camp CL (1936) A new type of small bipedal dinosaur from the Navajo sandstone of Arizona. Bull Univ California Dept Geol Sci 24:39–53
Carrano MT, Hutchinson JH, Sampson SD (2005) New information on Segisaurus halli, a small theropod dinosaur from the early Jurassic of Arizona. J Vertebr Paleontol 25:835–849
Charig AJ, Milner AC (1986) Baryonyx, a remarquable new theropod dinosaur. Nature 324:359–361
Charig AJ, Milner AC (1997) Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bull Nat Hist Mus 53:11–70
Currie PJ, Zhao XJ (1994) A new carnosaur (Dinosauria: Theropoda) from the Jurassic of Xinjiang, People’s Republic of China. Can J Earth Sci 30:2037–2081
Dal Sasso C, Maganuco S, Buffetaut E, Mendez MA (2005) New information on the skull of the enigmatic theropods Spinosaurus, with remarks on is size and affinities. J Vertebr Paleontol 25:888–896
de Broin F (2004) A new Shachemydinae (Chelonii, Cryptodira) from the lower cretaceous of Laos: preliminary data. C R Palevol 3:387–396
Galton PM, Jensen JA (1979) A new large theropod dinosaur from the UpperJurassic of Colorado. Brigham Young Univ Geol Stud 26:1–12
Gauthier J (1986) Saurischian monophyly and the origin of birds. In: Padian K (ed) The origin of birds and the evolution of flight. Mem California Acad Sci. 8:1–55
Goloboff P (1999) NONA (No Name) ver. 2. Tucumán, Argentina
Hasegawa Y, Buffetaut E, Manabe M, Takakuwa Y (2003) A possible spinosaurid tooth from the Sebayashi formation (Lower Cretaceous), Gunma, Japan. Bull Gunma Mus Nat Hist 7:1–5
Hoffet JH (1937) Note sur la géologie du Bas-Laos. Bull Serv Geol Indochine 24:1–22
Hoffet JH (1942) Description de quelques ossements de Titanosauriens du Senonien du Bas-Laos. C R Séances Cons Rech Sci Indochine 1942:51–57
Hoffet JH (1944) Description des ossements les plus caracteristiques appartenant a des Avipelviens du Senonien du Bas-Laos. Bull Cons Rech Sci Indochine 1944:179–186
Holtz TR, Chapman RE, Lamanna MC (2004a) Mesozoic biogeography of Dinosauria. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria, 2nd edn. University of California Press, Berkeley, pp 627–642
Holtz TR, Molnar RE, Currie PJ (2004b) Basal Tetanurae. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria, 2nd edn. University of California Press, Berkeley, pp 71–110
Hone DWE, Xu X, Wang DA (2010) A probable baryonychine tooth from the late cretaceous of Henan Province, China. Vertebrata PalAsiatica 48:19–26
Hu SY (1964) Carnosaurian remains from Alashan, inner Mongolia. Vertebrata Palasiatica 8:42–63
Hutchinson JH (2001) The evolution of pelvic osteology and soft tissues on the line to extant birds (Neornithes). Zool J Linn Soc Lond 131:123–168
Huttenlocker AK, Rega E, Sumida SS (2010) Comparative anatomy and osteohistology of hyperelongate neural spines in the sphenacodontids Sphenacodon and Dimetrodon (Amniota: Synapsida). J Morphol 271:1407–1421
Ingavat R, Janvier P, Taquet P (1978) Découverte en Thaïlande d'une portion de fémur de dinosaure sauropode (Saurischia, Reptilia). CR Soc Geol France 3:140–141
Marsh OC (1881) Principal characters of American Jurassic dinosaurs. Part V. Am J Sc 21:417–423
Milner A, Buffetaut E, Suteethorn V (2007) A tall–spined spinosaurid theropod from Thailand and the biogeography of spinosaurs. J Vert Paleontol 27:118A
Naish D (2011) Theropod dinosaurs. In: Batten DJ (ed) English wealden fossils. The Palaeontological Association, London, pp 526–559
Nixon KC (1999–2002) WinClada 1.00.08. Ithaca, N.Y., Nixon KC
O’Connor PM (2007) The postcranial axial skeleton of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the late cretaceous of Madagascar. Mem Soc Vert Paleontol 8:127–162
Ortega F, Escaso F, Sanz JL (2010) A bizarre, humped Carcharodontosauria (Theropoda) from the Lower Cretaceous of Spain. Nature 467:203–206
Owen R (1842) Report on British fossil reptiles. Part II. Rep Br Assoc Adv Sci 1841:60–204
Owen R (1855) Monograph of the fossil Reptilia of the Wealden and Purbeck formations. Part II. Dinosauria. Palaeontogr Soc Monogr 8:1–54
Racey A, Goodall JGS (2009) Palynology and stratigraphy of the Mesozoic Khorat Group red bed sequences from Thailand. Geol Soc Lond Spec Pub 315:69–83
Rauhut OWM (2003) The interrelationships and evolution of basal theropod dinosaurs. Spec Pap Paleontol 69:1–215
Rayfield EJ, Milner AC, Xuan VB, Young PG (2007) Functional morphology of spinosaur ‘crocodile-mimic’ dinosaurs. J Vertebr Paleontol 27:892–901
Russell DA (1994) The role of Central Asia in dinosaurian biogeography. Canadian Journal of Earth Sciences 30:2002–2012
Sereno PC, Beck AL, Dutheil DB, Gado B, Larsson HCE, Lyon GH, Marcot JD, Rauhut OWM, Sadleir RW, Sidor CA, Varricchio D, Wilson GP, Wilson JA (1998) A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids. Science 282:1298–1302
Sha J (2007) Cretaceous trigonioidid (non-marine Bivalvia) assemblages and biostratigraphy in Asia with special remarks on the classification of Trigonioidacea. J Asian Earth Sci 29:62–83
Smith AG, Smith DG, Funnell BM (1994) Atlas of Mesozoic and Cenozoic. Cambridge University Press, Cambridge
Smith JB, Lamanna MC, Mayr H, Lacovara KJ (2006) New information regarding the holotype of Spinosaurus aegyptiacus Stromer, 1915. J Paleontol 80:400–406
Smith ND, Makovicky PJ, Hammer WR, Currie PJ (2007) Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zool J Linn Soc Lond 151:377–421
Stovall JW, Langston W (1950) Acrocanthosaurus atokensis, a new genus and species of lower cretaceous Theropoda from Oklahoma. Am Midl Naturalist 43:696–728
Stromer E (1915) Ergebnisse der Forschungsreisen Prof E. Stromer in den Wüsten Ägyptens. II Wirbeltier-Reste der Baharïje-Stufe (unterstes Cenoman) 3: Das Original des theropoden Spinosaurus aegyptiacus nov gen nov spec. Abhandl K Bayer Akad Wiss Math-phys Kl 28:1–32
Stromer E (1934) Ergebnisse der Forschungsreisen Prof Stromers in den Wüsten Ägyptens II Wirbeltier-Reste der Baharije-Stufe (unterstes Cenoman) 13: Dinosauria. Abhandl Bayer Akad Wiss Math Naturwiss Abt 22:1–79
Sues HD, Frey E, Martill DM, Scott DM (2002) Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the lower cretaceous of Brazil. J Vertebr Paleontol 22:535–547
Taquet P (1984) Une curieuse spécialisation du crâne de certains dinosaures carnivores du Crétacé: le museau long et étroit des spinosauridés. C R Acad Sci Paris II 299:217–222
Taquet P (1994) Chercheur d’os au Laos. In : Commune d’Oberhausbergen (ed.), Josué H. Hoffet, d’Oberhausbergen au Laos, pp 49-62
Taquet P, Russell DA (1998) New data on spinosaurid dinosaurs from the early cretaceous of the Sahara. C R Acad Sci Paris 327:347–353
Taquet P, Battail B, Dejax J, Richir P, Veran M (1995) First discovery of dinosaur footprints and new discoveries of dinosaur bones in the lower cretaceous of the Savannakhet Province, Laos. In: IGCP Symposium on Geology of SE Asia, Hanoi. J Geol 5–6:167
Tykoski RS, Rowe T (2004) Ceratosauria. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria, 2nd edn. University of California Press, Berkeley, pp 47–70
Xu X, Clark JM, Forster CA, Norell MA, Erickson GM, Eberth DA, Jia C, Zhao Q (2006) A basal tyrannosauroid dinosaur from the late Jurassic of China. Nature 439:715–718
Xu X, Clark JM, Mo J, Choiniere J, Forster CA, Erickson GM, Hone DWE, Sullivan C, Eberth D, Nesbitt SJ, Zhao Q, Hernandez R, Jia CK, Han FL, Guo Y (2009) A Jurassic ceratosaur from China helps clarify avian digital homologies. Nature 459:940–944
Yates AM (2006) A new theropod dinosaur from the early jurassic of South Africa and its implications for the early evolution of theropods. Palaeontol Afr 41:105–122
Zhao XJ, Currie PJ (1993) A large crested theropod from the Jurassic of Xinjiang, People’s Republic of China. Can J Earth Sci 30:2027–2036
Zhao XJ, Benson RBJ, Brusatte SL, Currie PJ (2010) The postcranial skeleton of Monolophosaurus jiangi (Dinosauria: Theropoda) from the Middle Jurassic of Xinjiang, China, and a review of Middle Jurassic Chinese theropods. Geol Mag 147:13–27
Acknowledgments
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.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by: Robert Reisz
Electronic supplementary material
Below is the link to the electronic supplementary material.
ESM 1
(PDF 10532 kb)
Rights and permissions
About this article
Cite this article
Allain, R., Xaisanavong, T., Richir, P. et al. The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the early cretaceous of Laos. Naturwissenschaften 99, 369–377 (2012). https://doi.org/10.1007/s00114-012-0911-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00114-012-0911-7