Monday, April 30, 2012

[Paleontology • 2010] Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods

Two Suchomimus swim to the bottom of an estuary to catch fish. 


Spinosaurs were large theropod dinosaurs showing peculiar specializations, including somewhat crocodile-like elongate jaws and conical teeth. Their biology has been much discussed, and a piscivorous diet has been suggested on the basis of jaw as well as tooth morphology and stomach contents. Although fish eating has been considered plausible, an aquatic or semiaquatic lifestyle has seldom been suggested because of the apparent lack of corresponding adaptations in the postcranial skeleton of spinosaurs, which on the whole is reminiscent of that of other large terrestrial theropods. On the basis of the oxygen isotopic composition of their phosphatic remains compared with those of coexisting terrestrial theropod dinosaurs and semiaquatic crocodilians and turtles, we conclude that spinosaurs had semiaquatic lifestyles, i.e., they spent a large part of their daily time in water, like extant crocodilians or hippopotamuses. This result sheds light on niche partitioning between large predatory dinosaurs, since spinosaurs coexisted with other large theropods such as carcharodontosaurids or tyrannosaurids. The likely ichthyophagy and aquatic habits of spinosaurids may have allowed them to coexist with other large theropods by reducing competition for food and territory.

Spinosaurus aegyptiacus – Kem Kem Assemblage 

Amiot, R.; Buffetaut, E.; Lécuyer, C.; Wang, X.; Boudad, L.; Ding, Z.; Fourel, F.; Hutt, S.; Martineau, F.; Medeiros, A.; Mo, J.; Simon, L.; Suteethorn, V.; Sweetman, S.; Tong, H.; Zhang, F.; and Zhou, Z. (2010). "Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods". Geology 38 (2): 139–142. doi:10.1130/G30402.1.

[Paleontology • 1986] สยามโมซอรัส สุธีธรนี | Siamosaurus suteethorni • Unusual theropod dinosaur teeth from the Upper Jurassic of Phu Wiang, northeastern Thailand

สยามโมซอรัส สุธีธรนี | Siamosaurus suteethorni

Siamosaurus Tooth 

Thailand Stamp: 1997 Dinosaurs 
Miniature sheet featuring dinosaurs with Phuwiangosaurus sirindhornae, Siamotyrannus isanensis, Siamosaurus suteethorni and Psittacosaurus sattayaraki

Buffetaut, E.; and Ingevat, R. (1986). Unusual theropod dinosaur teeth from the Upper Jurassic of Phu Wiang, northeastern Thailand. Rev. Paleobiol. 5: 217-220.

[Paleontology • 2012] Ichthyovenator laosensis | Sail-Backed Fish Hunter of Laos • The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the Early Cretaceous of Laos

A restoration of Ichthyovenator laosensis
by Michel Fontaine. From Allain et al., 2012.

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.

 Keywords: Cretaceous, Savannakhet basin, Theropoda, Spinosauridae, Asia

Allain, R., Xaisanavong, T., P. Richir and Khentavong, B. (In press). The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the Early Cretaceous of Laos. Naturwissenschaften (advance online publication)

Fig. 1 Twelfth dorsal vertebra (BK 10-01) of I. laosensis.

Fig. 2 Reconstruction and morphology of the sinusoidal dorsosacral sail of the holotype of I. laosensis (MDS BK10-01 to BK10-08).

Fig. 4 Pelvis of the holotype of I. laosensis.

Spinosauridae Stromer 1915
  Baryonychinae Charig and Milner 1986
  Ichthyovenator laosensis gen et sp nov.

Etymology : The generic name is derived from ichthos (ancient Greek word for fish), and from venator (Latin word for “hunter”). The generic name is in reference to the predominantly piscivorous diet of Spinosauridae. The specific name is derived from the name Laos.

Holotype : Partially articulated skeleton, curated at the Dinosaur Museum, Savannakhet (MDS BK10-01 to 15), including the antepenultimate dorsal vertebra, the neural spine of the last dorsal vertebra, the first and the second caudal vertebrae, five incomplete sacral vertebrae found in articulation, ilia, the right pubis, ischia, and a posterior dorsal rib (Figs. 1, 2. 3 and 4) (See ESM, for a complete description of the bones).

mission DinOsavan 2012 au Laos

Fig. 5: Time-calibrated result of the phylogenetic analysis showing the interrelationships of I. laosensis within theropoda. Numerous synapomorphies place Ichthyovenator within the Baryonychinae as the sister-group of (Suchomimus + Baryonyx). 

[Paleontology • 2012] Ostafrikasaurus crassiserratus • An early spinosaurid dinosaur from the Late Jurassic of Tendaguru (Tanzania) and the evolution of the spinosaurid dentition

The tooth of Ostrafrikasaurus as seen from the front (A), tongue side (B), back (c) and cheek side (d). From Buffetaut, 2011.

Ostafrikasaurus crassiserratus
Buffetaut, 2012

Buffetaut, E. 2012. "An early spinosaurid dinosaur from the Late Jurassic of Tendaguru (Tanzania) and the evolution of the spinosaurid dentition". Oryctos 10: 1-8.

[Paleontology • 2011] Oxalaia quilombensis • A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil

A life restoration of Oxalaia quilombensis.
(Image: Elaine Machado)


A new spinosaurid taxon, Oxalaia quilombensis gen. et sp. nov., is described based on the anterior part of a snout and a fragment of a maxilla. These specimens were collected at the Laje do Coringa site, Late Cretaceous (Cenomanian) of the São Luis Basin. Unlike Cristatusaurus and Suchomimus, Oxalaia quilombensis lacks serrations on the teeth. The new species differs from Angaturama limai by having the anterior part of the premaxillae more expanded and by lacking a sagittal premaxillary crest. It further differs from Spinosaurus cf. S. aegyptiacus and the Algerian spinosaurid by the rounder shape of the terminal expansion. Furthermore, xalaia quilobensis has one functional tooth followed by two replacement teeth, a feature not previously observed in theropods. Oxalaia quilombensis appears to be more closely related to the spinosaurids found in North Africa than to the Brazilian members of this clade and thus further increases the diversity of these enigmatic predatory dinosaurs in this country.

Key words: Dinosauria, Spinosauridae, Oxalaia quilombensis, Cenomanian, Brazil.

sensu Sereno et al. 1998
Oxalaia gen. nov.
Etymology: The generic name comes from Oxalá, the most respected masculine deity in the African pantheon, introduced in Brazil during slavery.

Type species: Oxalaia quilombensis sp. nov.
Diagnosis: as for the type and only species. Oxalaia quilombensis sp. nov.
Etymology: The generic name is derived from the Portuguese expression quilombo, the place where the quilombola (the descendants of former Brazilian slaves) live. The Cajual Island, where the specimens of this
new taxon were collected, is one of these places.

 Kellner, Alexander W.A.; Sergio A.K. Azevedeo, Elaine B. Machado, Luciana B. Carvalho and Deise D.R. Henriques (2011). "A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil". Anais da Academia Brasileira de Ciências 83 (1): 99–108. doi:10.1590/S0001-37652011000100006 

[Paleontology • 1942/2008] Sinopliosaurus fusuiensis • An Early Cretaceous spinosaur theropod from southern China

Teeth from the Early Cretaceous Napai Formation of Fusui County, Guangxi Zhuang Autonomous Region (South China), initially described as the sauropterygian Sinopliosaurus fusuiensis, are redescribed as belonging to a spinosaurid theropod closely allied to Siamosaurus suteethorni, from the Early Cretaceous of Thailand. This identification extends to China the geographical range of Asian spinosaurs, previously reported from Thailand and Japan.

Indeterminate Spinosauridae
"Sinopliosaurus" fusuiensis Young, 1942 
Buffetaut, E.; Suteethorn, V.; Tong, H.; and Amiot, R. (2008). "An Early Cretaceous spinosaur theropod from southern China". Geological Magazine 145 (5): 745–748. doi:10.1017/S0016756808005360.

[Paleontology • 1964] Chilantaisaurus tashuikouensis • theropod dinosaur from the Early Cretaceous of Alanshan, People's Republic of China

Chilantaisaurus tashuikouensis Hu, 1964

Hu, S.-Y. (1964). "Carnosaurian remains from Alashan, Inner Mongolia." Vertebrata PalAsiatica, 8: 42–63. [In Chinese, with English summary]
Benson, R.B.; and 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". Geological Magazine published online (6). doi:10.1017/S0016756808005475.

[Paleontology • 1996] Irritator challengeri • A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil

Irritator challengeri Martill et al., 1996

Martill, D. M.; Cruickshank, A. R. I.; Frey, E.; Small, P. G.; Clarke, M. (1996). "A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil". Journal of the Geological Society 153: 5. doi:10.1144/gsjgs.153.1.0005.

[Paleontology • 1998] Cristatusaurus lapparenti • New data on spinosaurid dinosaurs from the Early Cretaceous of the Sahara

Cristatusaurus lapparenti Taquet and Russell, 1998

 Taquet, P. and Russell, D.A. (1998). "New data on spinosaurid dinosaurs from the Early Cretaceous of the Sahara". Comptes Rendus de l'Académie des Sciences à Paris, Sciences de la Terre et des Planètes 327: 347-353

[Paleontology • 1998] Suchomimus tenerensis • A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Ténéré Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.

Sereno, P.C.; Beck, A.L.; Dutheil, D.B.; Gado, B.; Larsson, H.C.E.; Lyon, G.H.; Marcot, J.D.; Rauhut, O.W.M.; Sadleir, R.W.; Sidor, C.A.; Varricchio, D.D.; Wilson, G.P; and Wilson, J.A. 1998. A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids. Science 282 (5392): 1298–1302. DOI: 10.1126/science.282.5392.1298

[Paleontology • 1915] Spinosaurus aegyptiacus 'spine lizard' • Large theropod dinosaur of Africa

Spinosaurus aegyptiacus Stromer, 1915

Stromer, E. (1915). "Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. II. Wirbeltier-Reste der Baharije-Stufe (unterstes Cenoman). 3. Das Original des Theropoden Spinosaurus aegyptiacus nov. gen., nov. spec" (in German). Abhandlungen der Königlich Bayerischen Akademie der Wissenschaften, Mathematisch-physikalische Klasse. 28 (3): 1–32.

Results of the explorations of Prof. E. Stromers in the deserts of Egypt. II vertebrate remains of Baharije level (lowest Cenomanian). Third The original theropod Spinosaurus aegyptiacus nov. Gen., nov. spec.

[Paleontology • 1986] Baryonyx walkeri • a remarkable new fish-eating theropod dinosaur from England

Baryonyx walkeri Charig & Milner, 1986

Charig, A.J. and Milner, A.C. (1997). "Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey." Bulletin of the Natural History Museum of London, 53: 11–70.
Charig, A.J. & Milner, A.C. (1986) Baryonyx, a remarkable new theropod dinosaur. Nature, 324, 359–361.

Sunday, April 29, 2012

[Mammalogy • 2011] Nuralagus rex | Minorcan Giant Lagomorph • an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain)

We describe a new insular endemic lagomorph from the Late Neogene karstic deposits of Minorca (Balearic islands, Spain). Nuralagus rex, gen. et sp. nov., is characterized by an array of odd traits unknown for lagomorphs. Most outstanding are the gigantic size (average 12 kg), the robust postcranial skeleton with unique morphological traits (short manus and pes with splayed phalanges, short and stiff vertebral column with reduced extension/flexion capabilities), and the relatively small size of sense-related areas of the skull (tympanic bullae, orbits, braincase, and choanae). These morphological traits denote an important decrease in locomotor and neurological activities and, hence, a decrease in metabolic energy expenditure, which is concordant with the ecological conditions of the insular environment characterized by absence of predators and low levels of resource supply. Our discovery enhances the importance of the frequently neglected fossil record for our understanding evolution on islands, because it provides the perspective of time and adds valuable data from fossil insular ecosystems unaffected by anthropogenic alterations.

Nuralagus rex — Giant Extinct Rabbit was the King of Minorca

Reconstruction & Holotype

Josep Quintana, Meike Köhler & Salvador Moyà-Solà. 2011. Nuralagus rex, gen. et sp. nov., an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain). Journal of Vertebrate Paleontology. 31 (2): 231–240. doi:10.1080/02724634.2011.550367.