A5007033677- Paleontology and Evolutionary Biology
- Evolution and Paleontology Studies
- Ichthyology and Marine Biology
- Amphibian and Reptile Biology
- Paleontology and Stratigraphy of Fossils
- Pleistocene-Era Hominins and Archaeology
- Morphological variations and asymmetry
- Geology and Paleoclimatology Research
- Wildlife Ecology and Conservation
- Fossil Insects in Amber
- Ecology and biodiversity studies
- Spider Taxonomy and Behavior Studies
- Sports Performance and Training
- History of Science and Natural History
- Coleoptera Taxonomy and Distribution
- Advanced Fluorescence Microscopy Techniques
- Plant Diversity and Evolution
- Veterinary Equine Medical Research
- Landslides and related hazards
- Primate Behavior and Ecology
- Marine Ecology and Invasive Species
- Bat Biology and Ecology Studies
- Fish Ecology and Management Studies
- Biochemical and biochemical processes
- Scarabaeidae Beetle Taxonomy and Biogeography
George Washington University
2009-2023
Stony Brook University
1996-2009
State University of New York
1996-2006
New York Institute of Technology
1998
York University
1998
Ohio University
1998
University of Pennsylvania
1990-1998
University of Antananarivo
1998
American Museum of Natural History
1998
University of Chicago
1992-1996
Recent discoveries of fossil vertebrates from the Late Cretaceous Madagascar include several specimens a large theropod dinosaur. One specimen includes nearly complete and exquisitely preserved skull with thickened pneumatic nasals, median frontal horn, dorsal projection on parietals. The new materials are assigned to enigmatic group Abelisauridae basis number unique features. Fossil remains attributable abelisaurids restricted three Gondwanan landmasses: South America, Madagascar, Indian...
A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous Madagascar. This specimen, although exhibiting avian features such as reversed hallux and ulnar papillae, retains characteristics that indicate theropod ancestry, including pubic foot hyposphene-hypantra vertebral articulations. robust, hyperextendible second digit on hind terminates in sicklelike claw, unique characteristic groups Troodontidae Dromaeosauridae. phylogenetic...
(40)Ar/(39)Ar dating of sanidine from a bentonite interbedded in the Ischigualasto Formation northwestern Argentina yielded plateau age 227.8 +/- 0.3 million years ago. This middle Carnian is direct calibration tetrapod assemblage, which includes some best known early dinosaurs. shifts last appearances taxa back into Carnian, diminishing magnitude proposed late extinction event. By 228 ago, major dinosaurian lineages were established, and theropods already important constituents carnivorous...
ABSTRACT We describe the osteology of new small theropod dinosaur Masiakasaurus knopfleri, from Late Cretaceous Maevarano Formation northwestern Madagascar. Approximately 40% skeleton is known, including parts jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws are remarkably derived, bearing a heterodont, procumbent dentition that unknown elsewhere among dinosaurs. vertebrae similar to those abelisauroids in reduction neural spine, lack pleurocoelous fossae on centrum,...
Background During much of the Late Cretaceous, a shallow, epeiric sea divided North America into eastern and western landmasses. The landmass, known as Laramidia, although diminutive in size, witnessed major evolutionary radiation dinosaurs. Other than hadrosaurs (duck-billed dinosaurs), most common dinosaurs were ceratopsids (large-bodied horned currently only from Laramidia Asia. Remarkably, previous studies have postulated occurrence latitudinally arrayed dinosaur “provinces,” or...
The fossil record of Jurassic theropod dinosaurs closely related to birds remains poor. A new from the earliest Late western China represents diverging member enigmatic group Alvarezsauroidea and confirms that this is a basal Maniraptora, clade containing their closest relatives. It extends by 63 million years provides evidence for maniraptorans earlier in than Archaeopteryx. taxon extreme morphological convergence between derived alvarezsauroids illuminates incipient stages highly modified...
Although the Ceratopsia and Pachycephalosauria, two major ornithischian groups, are united as Marginocephalia, few synapomorphies have been identified due to their highly specialized body-plans. Several studies linked Heterodontosauridae with either or but evidence for these relationships is weak, leading most recent consider basal member of another radiation, Ornithopoda. Here, we report on a new ceratopsian dinosaur, Yinlong downsi gen. et. sp. nov., from Late Jurassic upper part Shishugou...
ABSTRACT Tenontosaurus tilletti is a moderate-sized ornithopod dinosaur from the Lower Cretaceous (Aptian–Albian) Cloverly Formation in Montana and Wyoming. remains are abundant. The vertebral count 12-16-5-60+, extremely long tail comprising approximately twothirds length of animal. Ossified epaxial tendons arranged bundles to each side neural spines dorsal, sacral, caudal vertebrae. hypaxial run longitudinally across centra chevrons. forelimb relatively long, humerus dominated by strong...
Abstract Rapetosaurus krausei (Sauropoda: Titanosauria) from the Upper Cretaceous Maevarano Formation of Madagascar is best-preserved and most complete titanosaur yet described. The skull particularly significant because titanosaurs are diagnosed solely on basis fragmentary postcranial material, knowledge has remained incomplete. Material referred to includes type an adult that preserves basicranium, rostrum, mandible, palate. A second, juvenile braincase cranial vault, as well some palate...
Jonah N. Choiniereabg*, James M. Clarkb, Catherine A. Forsterb, Mark Norella, David Eberthd, Gregory Ericksone, Hongjun Chuc & Xing Xufa Division of Paleontology and Richard Gilder Graduate School, American Museum Natural History, New York, USAb Department Biological Sciences, George Washington University, Washington, USA, DCc Bureau Forestry, Altai, PR Chinad Sedimentary Geology Palaeoecology Research, Royal Tyrell Museum, Canada, Albertae Science, Florida State Tallahassee, USAf Key...
Other| October 01, 2001 Paleoenvironment and Taphonomy of the Chañares Formation Tetrapod Assemblage (Middle Triassic), Northwestern Argentina: Spectacular Preservation in Volcanogenic Concretions RAYMOND R. ROGERS; ROGERS 1Department Geology, Macalester College, St. Paul, MN 55105 Search for other works by this author on: GSW Google Scholar ANDREA B. ARCUCCI; ARCUCCI 2Museo de Paleontologia, Instituto Anthropologia, Universidad Nacional La Rioja, Avenida Ortiz Ocampo 1700, 5300 Argentina...
Ceratopsia includes some of the best-known ornithischian dinosaurs. Many species are erected based on cranial elements alone, and postcranial skeletons either missing or undescribed in many taxa. Here we provide first detailed description Yinlong downsi holotype eight other well-preserved skeletons. from early Late Jurassic Shishugou Formation Wucaiwan area, Xinjiang, China, represents one most basal ceratopsians. The study skeleton reveals feature unique to it among ceratopsians: a...
ABSTRACT We describe a new coelurosaurian theropod, Zuolong salleei, gen. et sp. nov., from exposures of the upper part Shishugou Formation at Wucaiwan locality, Xinjiang Autonomous Region, People's Republic China. has large, inclined quadrate foramen that extends onto medial surface quadratojugal, an unusually large fovea capitis on femoral head, and apomorphically distal condyle metatarsal III with medially projecting flange extensor surface. Radiometric dating constrains age specimen to...
Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature body mass. However, this method fails discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range relative head sizes, we use dinosaurs test the hypothesis that ducts scale more closely with size. Comparing area enclosed each canal estimated mass and two different measures size, skull length mass, reveals significant...
ABSTRACT We report the well preserved skeleton of a small theropod dinosaur, Nqwebasaurus thwazi, gen. et sp. nov., from Lower Cretaceous Kirkwood Formation South Africa. has an elongate three-digit manus with partially opposable first digit, long and slender pes highly reduced metatarsal IV, preserves gastroliths (stomach stones) in its abdominal region. As basal coelurosaurian, pushes back Gondwanan record this derived group tetanuran theropods approximately 50 million years. This confirms...