Basal Neoceratopsiano de China

On a New Genus of Basal Neoceratopsian Dinosaur from the Early Cretaceous of Gansu Province, China.

YOU Hailu, LI Daqing, JI Qiang, Matthew C. LAMANNA and Peter DODSON

Abstract: A new genus and species of basal neoceratopsian dinosaur, Auroraceratops rugosus, is reported based on material from the Early Cretaceous Xinminpu Group in the Gongpoquan Basin of Gansu Province, China. Auroraceratops is represented by a nearly complete skull and low jaws, and different greatly from all other neoceratopsians by its considerable breadth of the nasals, fungiform expansion of the dorsal end of the lacrimal, highly developed rugosity of the jugal, dentary and surangular, and inflated, striated premaxillary teeth. The finding of Auroraceratops adds diversity and helps elucidate the evolution of basal neoceratopsian dinosaurs.

Lanzhousaurus magnidens

Lanzhousaurus magnidens gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world

Hai-lu You, Qiang Ji, Da-qing Li

Abstract: A new ornithopod dinosaur, Lanzhousaurus magnidens gen. et sp. nov., from the Early Cretaceous of the Lanzhou Basin, Gansu Province, China, possesses the largest teeth of any herbivorous dinosaur yet discovered. The dental morphology of Lanzhousaurus, in which only 14, ~4 cm-wide tooth families are preserved in the tooth row of the 1 m long lower jaw, augments the known morphological diversity of dinosaurs. Cladistic analysis recovers a close relationship between L. magnidens and Lurdusaurus arenatus from the Early Cretaceous of Africa. Together, these species represent a previously unrecognized, massively-constructed quadrupedal lineage in the evolution of ornithopod dinosaurs. This discovery also implies a close connection between Eurasia and Africa during the Early Cretaceous.

Paleoilustración

Amargasaurus cazaui
Bruno Hernández ®2005

Centrosaurus brinkmani

A new centrosaurine ceratopsid from the Oldman Formation of Alberta and its implications for centrosaurine taxonomy and systematics.
Ryan, M.R. and Russell, A.P. (2005). Can. J. Earth Sci. 42: 1369–1387.


Abstract: "Centrosaurus brinkmani" (sp. nov) is distinguished from "Centrosaurus apertus" by key features of its cranial ornamentation, including the shape and orientation of the postorbital horn and parietal ornamentation at parietal locus 3, the shape of the parietal ornamentation at locus 2, and the possession of accessory parietal ossifications developed as short spines on the caudal parietal ramus. This species is restricted to the Oldman Formation of southern Alberta and is the oldest ceratopsid represented by diagnostic material in Canada. Phylogenetic analysis of the Centrosaurinae suggests that the development of spike-like ornamentation at the parietal locus 3 parietal locus is inversely related to the development of the P1 parietal ornamentation."

Registro de impresiones de las patas delanteras en Titanosaurus

Manus-only titanosaurid trackway from Fumanya (Maastrichtian, Pyrenees): further evidence for an underprint origin

BERNAT VILA, ORIOL OMS AND A ANGEL GALOBART Vila, B., Oms, O. & Galobart, A . 2005 09 12: Manus-only titanosaurid trackway from Fumanya (Maastrichtian, Pyrenees): further evidence for an underprint origin. Lethaia, Vol. 38, pp. 211–218. Oslo. ISSN 0024-1164.

The origin of manus-only and manus dominated sauropod trackways has been a matter of intense debate since two hyphothesis exist: (a) manus-only and manus-dominated trackways result from a ‘swimming’ sauropod, and (b) they result from a selective underprint phenomenon that only leaves the manus recorded. Several new sauropod trackways are reported in the Fumanya tracksite area (Maastrichtian), in SE Pyrenees, where both tracks and undertracks are found on the same stratigraphic bedding surface. In one of the trackways, footprint morphology together with the trackway pattern displays a clear succession of manus-only impressions attributed to a sauropod dinosaur in a walking gait. The ichnological comparison between the manus-only trackway with the other complete trackway (manus-pes) display an identical distribution of the manus pattern. This fact clearly points towards an underprint phenomenon as the origin for manus-only trackways, since it is rather unlikely that the same pattern would completely match different locomotion behaviours such as walking and swimming. Therefore, we suggest an interpretation based on the differential loading between the hindfoot and the forefoot on an upper stratigraphic track-level, for the studied manus-only trackway. & Fumanya tracksite, manus-only trackways, titanosaurs, trackway pattern, underprint, Upper Cretaceous.

Funcion del pteroides en el vuelo de los Pterosaurus

High lift function of the pteroid bone and forewing of pterosaurs

Matthew T. Wilkinson1,*, David M. Unwin2 and Charles P. Ellington1 1Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK 2Institut fu¨ r Pala¨ontologie, Museum fu¨ r Naturkunde, Humboldt-Universita¨ t zu Berlin, Invalidenstrasse 43, Berlin 10115, Germany

The pteroid bone is a rod-like element found only in pterosaurs, the flying reptiles of the Mesozoic. It articulated at the wrist, and supported a membranous forewing in front of the inner part of the wing spar.
The function of this bone, particularly its orientation, has been much debated. It is widely believed that it pointed towards the body, and that the forewing was relatively narrow. An alternative hypothesis states that it was directed forwards during flight, resulting in a much broader forewing that acted as a leading edge flap. We tested scale models in a wind tunnel to determine the aerodynamic consequences of these conflicting hypotheses, and found that performance is greatly improved if the pteroid is directed forwards: the lift : drag ratios are superior and the maximum lift is exceptionally high in comparison with conventional aerofoils.

Antiguo dromaeosaurido de Sud América

The earliest dromaeosaurid theropod from South America

Peter J. Makovicky1, Sebastia´n Apesteguı´a2,4 & Federico L. Agnolı´n3

The evolutionary history of Maniraptora, the clade of carnivorous
dinosaurs that includes birds and the sickle-clawed Dromaeosauridae,
has hitherto been largely restricted to Late Jurassic and
Cretaceous deposits on northern continents. The stunning Early
Cretaceous diversity of maniraptorans from Liaoning, China1–3,
coupled with a longevity implied by derived Late Jurassic forms
such as Archaeopteryx, pushes the origins of maniraptoran
lineages back to Pangaean times and engenders the possibility
that such lineages existed in Gondwana. A few intriguing, but
incomplete, maniraptoran specimens have been reported from
South America4–8, Africa9 and Madagascar10. Their affinities
remain contested11–13, however, and they have been interpreted
as biogeographic anomalies relative to other faunal components of
these land-masses. Here we describe a near-complete, small
dromaeosaurid that is both the most complete and the earliest
member of the Maniraptora from South America, and which
provides new evidence for a unique Gondwanan lineage of Dromaeosauridae
with an origin predating the separation between
northern and southern landmasses.

Buitreraptor gonzalezorum

El reciente descubrimiento de un pequeño dinosaurio dromaeosaurido de 90 millones de años de antiguedad en la patagonia, demuestra que éstos animales, cercanamente emparentados con los raptores y las aves de empezaron a desarrollar mas tempranamente de lo que se creía.

Noticia completa en inglés

La garra terrible, para matar o escalar ?

Dinosaur killer claws or climbing crampons?

Phillip L. Manning1,*, David Payne2, John Pennicott2, Paul M. Barrett3 and Roland A. Ennos4

Dromaeosaurid theropod dinosaurs possess a strongly recurved, hypertrophied and hyperextensible ungual claw on pedal digit II. This feature is usually suggested to have functioned as a device for disembowelling herbivorous dinosaurs during predation. However, modelling of dromaeosaurid hindlimb function using a robotic model and comparison of pedal ungual morphology with extant analogue taxa both indicate that this distinctive claw did not function as a slashing weapon, but may have acted as an aid to prey capture.

Primer registro de Mosasaurios en Suecia

THE FIRST RECORD OF HAINOSAURUS (REPTILIA: MOSASAURIDAE) FROM SWEDEN

JOHAN LINDGREN
Department of Geology, GeoBiosphere Science Centre, Lund University, So¨lvegatan 12,
SE-223 62 Lund, Sweden, ,johan.lindgren@geol.lu.se.

ABSTRACT: Isolated marginal tooth crowns of the early Campanian mosasaur Hainosaurus Dollo, 1885, from the Kristianstad Basin and the Vomb Trough, southern Sweden, are described and illustrated. The teeth have been collected from a narrow stratigraphic interval corresponding to the highest belemnite zone in the lower part of the European two-fold division of the Campanian stage. A reexamination of dental and skeletal characters in two alleged species of Hainosaurus, ‘H.’ pembinensis Nicholls, 1988 and ‘H.’ gaudryi (The´venin, 1896), and detailed comparisons with the corresponding elements in H. bernardi Dollo, 1885 and Tylosaurus proriger (Cope, 1869a), strongly indicate that ‘H.’ pembinensis and ‘H.’ gaudryi are both Tylosaurus Marsh, 1872. Diagnostic features of Hainosaurus include a very small infrastapedial process on the quadrate (conspicuous protuberance in Tylosaurus), flattened, symmetrically bicarinate marginal teeth (asymmetric and conical in Tylosaurus), short and wide pygal centra, and anteriorly situated intermediate

Evolución en el sistema locomotor de los Plesiosaurios

Correlated trends in the evolution of the plesiosaur
locomotor system

F. Robin O’Keefe and Matthew T. Carrano

Abstract: This paper investigates trends in the evolution of body size and shape in the Plesiosauria, a diverse clade of Mesozoic marine reptiles. Using measures from well-preserved plesiosaur specimens, we document and interpret evolutionary patterns in relative head size, body size, and locomotor variables. Size increase is a significant trend in the clade as a whole, and in constituent clades. The trend in relative head size is of variance increase; observed head sizes are both smaller and larger than ancestral values. In the locomotor system, changes in propodial and girdle proportions appear concomitant with body size increase and are interpreted as allometric responses to the physical constraints of large body size. Other trends in the locomotor systemare significantly
correlated with both body size and relative head size. These locomotor trends evolved convergently in several clades of plesiosaurs, and may have had an ecomorphological basis, although data are lacking to constrain speculation on this point. The evolution of the locomotor systemin plesiosaurs sheds new light on the response of aquatic tetrapods to the physical constraints of foraging at large body size.

Analisis de la musculatura de extremidades posteriores del T-rex

Analysis of hindlimb muscle moment arms in Tyrannosaurus rex using a three-dimensional musculoskeletal computer model: implications for stance, gait, and speed.

John R. Hutchinson, Frank C. Anderson, Silvia S. Blemker, Scott L. Delp,
Paleobiology 31(4): 676-701.

Abstract. — Muscle moment arms are important determinants of muscle function; however, it is challenging to determine moment arms by inspecting bone specimens alone, as muscles have curvilinear paths that change as joints rotate. The goals of this study were to (1) develop a three-dimensional graphics-based model of the musculoskeletal system of the Cretaceous theropod dinosaur Tyrannosaurus rex that predicts muscle-tendon unit paths, lengths, and moment arms for a range of limb positions; (2) use the model to determine how the T. rex hindlimb muscle moment arms varied between crouched and upright poses; (3) compare the predicted moment arms with previous assessments of muscle function in dinosaurs; (4) evaluate how the magnitudes of these moment arms compare with those in other animals; and (5) integrate these findings with previous biomechanical studies to produce a revised appraisal of stance, gait, and speed in T. rex. The musculoskeletal model includes ten degrees of joint freedom (flexion/extension, ab/adduction, or medial/ lateral rotation) and 33 main muscle groups crossing the hip, knee, ankle, and toe joints of each hindlimb. The model was developed by acquiring and processing bone geometric data, defining joint rotation axes, justifying muscle attachment sites, and specifying muscle-tendon geometry and paths. Flexor and extensor muscle moment arms about all of the main limb joints were estimated, and limb orientation was statically varied to characterize how the muscle moment arms changed. We used sensitivity analysis of uncertain parameters, such as muscle origin and insertion centroids, to deterimine how much our conclusions depend on the muscle reconstruction we adopted. This shows that a specific amount of error in the reconstruction (e.g., position of muscle origins) can have a greater, lesser, similar, or no effect on the moment arms, depending on complex interactions between components of the musculoskeletal geometry. We found that more upright poses would have improved mechanical advantage of the muscles considerably. Our analysis shows that previously assumed moment arm values were generally conservatively high. Our results for muscle moment arms are generally lower than the values predicted by scaling data from extant taxa, suggesting that T. rex did not have the allometrically large muscle moment arms that might be expected in a proficient runner. The information provided by the model is important for determining how T. rex stood and walked, and how the muscles of a 4000–7000 kg biped might have worked in comparison with extant bipeds such as birds and humans. Our model thus strengthens the conclusion that T. rex was not an exceptionally fast runner, and supports the inference that more upright (although not completely columnar) poses are more plausible for T. rex. These results confirm general principles about the relationship between size, limb orientation, and locomotor mechanics: exceptionally big animals have a more limited range of locomotor abilities and tend to adopt more upright poses that improve extensor muscle effective mechanical advantage. This model builds on previous phylogenetically based muscle reconstructions and so moves closer to a fully dynamic, three-dimensional model of stance, gait, and speed in T. rex.

Icnitas del triasico medio en francia: reevaluación de la nomenclatura

The French Middle Triassic Dinosauroid trackways: palaeontological result and nomenclatural re-evaluation

Georges Gand, and Georges Demathieu

Numerous dinosauroid footprints which showing sometimes manus imprint mark were gathered, since 1960, from the lower sandstones Triassic formations of the eastern border of the Massif Central (France).
Tracks bearing levels are dated from palynological, micropalaeontological and palichnological data. They belong to the period upper Anisian-lower Ladinian. The paleontological results show bipedal digitigrade reptiles with erected, long hind limbs, having also pentadactyl mani and (II-IV) tridactyl feet. The osteological feet inferred structure is like that of Ceratosauria of Late Triassic age. The skeletons of first Dinosauria, diversified already well, are known in summit Ladinian and lower Carnien and those of their ancestors, Dinosauriformes, in Ladinian. And, for this reason, the aniso-ladinian dinosauroid footprints are ascribed to these last animals which thus appeared earlier, to Anisan even to late Olenekian. The chirotheroid hands show a "pseudosuchian" origin which possibly took place during the late Olenekian; feet modifications of these Crurotarsi being characterized by I and V digits reduction and a meso-tarsal joint. The Anisian-Ladinian dinosauroid footprints are ascribed to the ichnospecies Coelurosaurichnus perriauxi and Anchisauripus bibractensis. The discriminant analysis computed from these latter ichnospecies, and others from the German Triassic, French and USA Hettangian indicate that C. perriauxi and A. bibractensis can not be included into Grallator sensu Lull, 1953 or Coelurosaurichnus of Franconie. By this way, these taxa are well original and till now, there was no reason to change their nomenclature. Nevertheless because the numerous changes of Grallator which gathers now, most of dinosauroid footprints, it could be possible to include them into Grallator for the feet and into Atreipus when the manus trace is connected with the foot.

Theriosuchus (Atoposauridae, Crocodylomorpha)

A new species of Theriosuchus (Atoposauridae, Crocodylomorpha) from the Late Jurassic (Kimmeridgian) of Guimarota, Portugal

Daniela Schwarz and Steven W. Salisbury

A new species of an atoposaurid crocodilian, Theriosuchus guimarotae, is described from the Late Jurassic (Kimmeridgian) of Portugal. Theriosuchus guimarotae can be distinguished from other species of Theriosuchus by a lateral surface of squamosal bevelled ventrally; a rounded, caudally projecting and dorsally sculptured caudolateral corner of the squamosal; a premaxillomaxillary suture aligned caudomedially in dorsal aspect; a minimum space between the supratemporal foramina that comprises one third of the total width of the cranial table; a minimum width of the frontal between the orbits that comprises one third of the maximum width of the skull at the orbits; a dentition that comprises only pseudocaniniform and lanceolate-shaped teeth; the presence of an external mandibular fenestra and all vertebral bodies amphicoelous. Its osteology also sheds light on the diagnosis of Theriosuchus within Atoposauridae.
The material additionally includes specimens representative of several ontogenetic stages, each of which is discussed here. With its Late Jurassic age, T. guimarotae represents the oldest well-preserved material of Theriosuchus and reveals further knowledge about the palaeobiogeography of the genus in western Europe.

Ornitisquio "fabrosaurido" de Sud Africa

The ‘fabrosaurid’ ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho

RICHARD J. BUTLER

Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK, and Department of Palaeontology, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK

The Upper Elliot Formation of South Africa and Lesotho contains the world’s most diverse fauna of early Jurassic ornithischian dinosaurs. Nevertheless, despite four decades of work on this fauna there remains significant taxonomic confusion and many important specimens remain undescribed. A review of the non-heterodontosaurid (‘fabrosaurid’) ornithischians of the Upper Elliot Formation is presented, following re-examination of all known ornithischian material from the Elliot Formation. ‘ Fabrosaurus australis’ is based upon a single undiagnostic dentary, and is here considered a nomen dubium

Lesothosaurus diagnosticus is considered to be valid and is rediagnosed based upon a unique combination of plesiomorphic and derived characteristics. Stormbergia dangershoeki gen. et. sp. nov. is described from three partial skeletons including numerous postcranial material. Stormbergia dangershoeki is significantly larger than previously described Elliot Formation ornithischians, and can be recognized on the basis of a unique combination of characters, the most important of which is the possession of a distinctive tabshaped obturator process on the ischium. A preliminary systematic analysis is presented, the results of which differ significantly from other recent ornithischian phylogenies.
© 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005,

Hallan los fósiles de dos nuevas especies de reptiles voladores

Un equipo de científicos brasileños ha identificado en China dos especies de reptiles voladores que vivieron hace 120 millones de años y que, aparentemente, peleaban por el territorio con aves primitivas.

El descubrimiento de fósiles de estas dos especies hasta ahora no conocidas, del que también informa en su última edición la revista Nature, fue hecho en el marco de un acuerdo entre instituciones académicas de Brasil y China.

Las dos especies identificadas por los brasileños, el "Feilongus youngi" y el "Nurhachius ignaciobritoi", medían cerca de 2,5 metros de envergadura y se alimentaban básicamente de peces e insectos, dijeron los paleontólogos en una rueda de prensa en Río de Janeiro.

Ambos reptiles tenían una mandíbula de unos 33 centímetros de ancho, dientes afilados y alas de unos 2,4 metros, mientras que de la cabeza del "Feilongus" salían dos crestas.

Los fósiles fueron hallados en la región china de Liaoning, un rico yacimiento en donde han sido identificadas hasta ahora 2.000 ejemplares de 26 especies de aves primitivas y 140 ejemplares de 16 especies de "pterosauros" o reptiles voladores.

A partir de esa constatación los investigadores han elaborado una nueva teoría sobre la competencia y ocupación de esa zona por parte de aves primigenias y reptiles voladores durante el período cretácico.

Según el estudio, las regiones continentales eran dominadas por las aves y las zonas costeras por los reptiles voladores.

Ahora los investigadores tratan de descubrir si había enfrentamiento directo entre ambos grupos de animales, cuáles eras sus hábitos alimentarios y cuáles alimentos se disputaban.

El proyecto fue realizado en conjunto por investigadores del Instituto de Paleontología de Vertebrados y Paleonantropología de China, y por los brasileños Departamento Nacional de Producción Mineral y Museo Nacional de Brasil.

La investigación es resultado de un acuerdo de cooperación entre las academias de Ciencia de Brasil y China para investigar en conjunto las especies de reptiles voladores localizados por científicos chinos.

El equipo fue dirigido por el brasileño Alexander Kellner, del Museo Nacional de Río de Janeiro.

Paleoblog

Excelentes fotos y artículos en este blog de Michael Ryan.

Un par de fotos como muestra de una expe en Mongolia.

Impresión de piel de Hadrosaurus que muestra arrugas

Huella de Hadrosaurus en la formación Nemegt

Pequeños huevos de dinosaurio

Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition

Abstract: We report on very small fossil eggs from the Lower Cretaceous of Thailand, one of them containing a theropod embryo, which display a remarkable mosaic of characters. While the surficial ornamentation is typical of non-avian saurischian dinosaurs, the three-layered prismatic structure of the eggshell is currently known only in extant and fossil eggs associated with birds. These eggs, about the size of a goldfinch's, mirror at the reproductive level the retention of small body size that was paramount in the transition from non-avian theropods to birds. The egg-layer may have been a small feathered theropod similar to those recently found in China.

Patrones filogenéticos en Microestructuras del esmalte en dientes de dinosaurios

Phylogenetic Patterns of Enamel Microstructure in Dinosaur Teeth
Sunny H. Hwang Division of Paleontology, American Museum of Natural History, New York, New York 10024

ABSTRACT: The tooth enamel microstructure of all the dinosaur taxa that are adequately represented in the American Museum of Natural History collections were analyzed using scanning electron microscopy. This study aims to determine whether or not better sampling within a major nonmammalian amniote (hereafter referred to descriptively as “reptile”) clade will unearth phylogenetic patterns in enamel microstructure in addition to those
dictated by tooth function. While interest in reptile enamel microstructure has increased in the past few years, intensive sampling focused on just one monophyletic reptile clade was not previously implemented. This study reveals that phylogenetic constraints play a larger
role in shaping enamel microstructure in reptiles than previously thought. Within many monophyletic dinosaur clades the combination of enamel types and enamel features
within a tooth "the schmelzmuster" is the same in all the taxa due to their common ancestry, and their schmelzmusters are diagnostic of their respective clades.
While distantly related taxa with similar teeth and diets have similar schmelzmusters due to functional constraints, phylogenetic constraints keep those schmelzmusters distinct from one another. An interesting finding of this analysis is that the enamel complexity of a taxon does
not necessarily coincide with the position of the taxon on a phylogenetic tree; more derived taxa do not necessarily have more derived enamel and more primitive taxa do not necessarily have more primitive enamel.

Oviraptor del sur de China

A new oviraptorid (Theropoda: Oviraptorosauria) from the Upper Cretaceous of the Nanxiong Basin, Guangdong Province of southern China.
Lü, J. and Zhang, B.-K. 2005.
Acta Palaeontologica Sinica 44(3): 412-422.

ABSTRACT: "Shixinggia oblita" gen. et sp. nov. herein described was collected from Shixing County, Nanxiong Basin of Guangdong Province, southern China, by the Beijing Natural History Museum in 1995. It is characterized by a relatively short preacetabular process of the ilium compared with its postacetabular process, and relatively high ratio of the ilium height (above the center of the acetabulum) to its length, the ventral margins of the preacetabular and postacetabular processes are much higher than the dorsal margin of the acetabulum, however. "Shixinggia" shows a special character of large openings present on the anterior mesial surface of the trochanteric ridge in the femur, and the proximal end of the tibia, those openings are not reported in any known oviraptorosaurs. This is the second new genus of oviraptorosaurs from southern China in addition to "Heyuannia huangi", which was reported in 2003.