Catherine A Forster

Catherine A Forster
George Washington University | GW · Department of Biological Sciences

PhD

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88
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Introduction
Skills and Expertise

Publications

Publications (88)
Article
Full-text available
The dental system of ceratopsids is among the most specialized structure in Dinosauria by the presence of tooth batteries and high-angled wear surfaces. However, the origin of this unique dental system is poorly understood due to a lack of relative knowledge in early-diverging ceratopsians. Here we study the dental system of three earliest-divergin...
Preprint
The dental system of ceratopsids is among the most specialized structure in Dinosauria, and includes high angled wear surfaces, split tooth roots, and multiple teeth in each tooth family. However, the early evolution of this unique dental system is generally poorly understood due to a lack of knowledge of the dental morphology and development in ea...
Article
Ceratopsia includes some of the best-known ornithischian dinosaurs. Many species are erected based on cranial elements alone, and the postcranial skeletons are either missing or undescribed in many taxa. Here we provide the first detailed postcranial description of Yinlong downsi based on the holotype and eight other well-preserved skeletons. Yinlo...
Article
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Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of Psittacosaurus, is still controversial and unclear. Here, we report a second basal ceratopsian, Hualianceratops wucaiwanensis gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Jungg...
Article
Full-text available
Yinlong downsi, from the Upper Jurassic Shishugou Formation, Xinjiang, northwestern China, is the oldest known ceratopsian dinosaur. Here we provide a detailed description of the skull and mandible based on the holotype, three partial skulls, and disarticulated materials from several other specimens. Yinlong can be diagnosed by six autapomorphies:...
Poster
Fossil vertebrates from the Gokwe Formation (Fm) of central Zimbabwe have been known for over 50 years, yet remain poorly understood due in part to their poor preservation and the uncertainty surrounding their age, previously constrained to Upper Jurassic-Cretaceous. Collections from the Gokwe Fm include a diverse array of vertebrate fossils that b...
Article
Full-text available
We describe the anatomy of a new coelurosaurian theropod Aorun zhaoi gen. et sp. nov., from the Middle–Late Jurassic of Xinjiang, China. Histological analysis of the holotype and only known specimen shows that the new taxon is represented by the skeleton of a juvenile individual aged no more than one year. A phylogenetic analysis of theropod relati...
Article
Full-text available
Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semic...
Data
Specimens and measurements used in this study. All Skull length and Body length values and all Body mass values except for the four taxa listed in Table S2 are taken from the listed references. (DOCX)
Data
Femur measurements used to calculate body mass estimates in four specimens without reliable literature values. Diameter and length for Masiakasaurus knopfleri are composite values from the six specimens listed in Carano et al. (2002, J Vert Paleo 22:510-534) with femur lengths greater than 170 mm (8). (DOCX)
Article
Full-text available
We performed additional preparation on the holotype skeleton of Nqwebasaurus thwazi and discovered new skeletal material. We describe this material, which includes a maxilla with small, conical, unserrated teeth and bones of the braincase, as well as parts of the holotype postcranial anatomy that were previously poorly documented. We incorporate th...
Article
Full-text available
Chasmosaurus irvinensis (sp. nov.) is distinguished from other species of this genus by the possession of a broad snout, absence of a brow horn (the position of which is occupied by a pit or rugosities suggestive of bone resorption), broadly rounded and open jugal notch, subrectangular squamosal, straight posterior parietal bar bearing 10 epoccipit...
Article
Full-text available
We describe a new coelurosaurian theropod, Zuolong salleei, gen. et sp. nov., from exposures of the upper part of the Shishugou Formation at the Wucaiwan locality, Xinjiang Autonomous Region, People's Republic of China. Zuolong has a large, inclined quadrate foramen that extends onto the medial surface of the quadratojugal, an unusually large fovea...
Data
Extended results of phylogenetic analysis, consisting of: 1) character taxa; and 2) taxon-character matrix. (0.09 MB DOC)
Data
Phylogenetic relationships of Utahceratops gettyi and Kosmoceratops richardsoni within Ceratopsidae. Strict consensus of 3 most parsimonious trees (tree length = 263; CI = 0.6692; CI excluding uninformative characters = 0.6602; HI = 0.3308; HI excluding uninformative characters = 0.3398; RI = 0.7904; RC = 0.5289). Bootstrap values greater than 50%...
Article
Full-text available
Background: During much of the Late Cretaceous, a shallow, epeiric sea divided North America into eastern and western landmasses. The western landmass, known as Laramidia, although diminutive in size, witnessed a major evolutionary radiation of dinosaurs. Other than hadrosaurs (duck-billed dinosaurs), the most common dinosaurs were ceratopsids (la...
Article
Full-text available
The fossil record of Jurassic theropod dinosaurs closely related to birds remains poor. A new theropod from the earliest Late Jurassic of western China represents the earliest diverging member of the enigmatic theropod group Alvarezsauroidea and confirms that this group is a basal member of Maniraptora, the clade containing birds and their closest...
Article
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Two lower jaws from the upper part (early Maastrichtian) of the late Cretaceous Maevarano Formation in the Mahajanga Basin, northwestern Madagascar, are identified as belonging to side-necked turtles (Pleurodira). A nearly complete lower jaw is identified as cf. Erymnochelys because of its close resemblance to the living Malagasy Erymnochelys madag...
Article
Full-text available
Theropods have traditionally been assumed to have lost manual digits from the lateral side inward, which differs from the bilateral reduction pattern seen in other tetrapod groups. This unusual reduction pattern is clearly present in basal theropods, and has also been inferred in non-avian tetanurans based on identification of their three digits as...
Article
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We report the occurrence of a furcula (fused clavicles) in both species of the Early Jurassic coelophysid theropod dinosaur Syntarsus (Coelophysidae sensu Holtz, 1994; Coelo-physis and Syntarsus and all descendants of their most recent common ancestor). The furcula is a median pectoral element formed by ontogenetic fusion of the left and right clav...
Article
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Rapetosaurus krausei (Sauropoda: Titanosauria) from the Upper Cretaceous Maevarano Formation of Madagascar is the best-preserved and most complete titanosaur yet described. The skull of Rapetosaurus is particularly significant because most titanosaurs are diagnosed solely on the basis of fragmentary postcranial material, and knowledge of the titano...
Article
Full-text available
The origin of Madagascar’s highly endemic vertebrate fauna remains one of the great unsolved mysteries of natural history. From what landmasses did the basal stocks of this unique and imbalanced fauna come? When and how did the ancestral populations arrive on the island? How rapidly did they diversify, and why? The most direct means of addressing t...
Article
Full-text available
Although the Ceratopsia and Pachycephalosauria, two major ornithischian groups, are united as the Marginocephalia, few synapomorphies have been identified due to their highly specialized body-plans. Several studies have linked the Heterodontosauridae with either the Ceratopsia or Marginocephalia, but evidence for these relationships is weak, leadin...
Article
Full-text available
The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest kn...
Chapter
This chapter focuses on the ceraptopsids, a monophyletic group of large-bodied (4–8 m long), quadrupedal, and herbivorous dinosaurs. Ceraptosids have elaborate horns and frills and complex dental batteries. Fossil remains have been confirmed only in the United States, Canada, and Mexico. Ceratopsidae consists of two well-defined clades: Centrosauri...
Article
Full-text available
The skull of living crocodylians is highly solidified and the jaw closing muscles are enlarged, allowing for prey capture by prolonged crushing between the jaws. Living species are all semi-aquatic, with sprawling limbs and a broad body that moves mainly from side-to-side; however, fossils indicate that they evolved from terrestrial forms. The most...
Chapter
More is known about hadrosaurids than about virtually any other group of dinosaurs. Remains are often abundant and range from fully articulated skeletons (sometimes complete with sclerotic rings, stapes, hyoids, and ossified tendons) to disartic-ulated and isolated material. In addition, remains of eggs, embryos , hatchlings (perinates), and juveni...
Article
Full-text available
Rapetosaurus krausei (Sauropoda: Titanosauria) from the Upper Cretaceous Maevarano Formation of Madagascar is the best-preserved and most complete titanosaur yet described. The skull of Rapetosaurus is particularly significant because most titanosaurs are diagnosed solely on the basis of fragmentary postcranial material, and knowledge of the titano...
Chapter
Plate tectonic processes have shaped the surface of the Earth and its environments since its formation and have profoundly influenced the lives of the organisms that have existed upon it. The physical rift of a once contiguous landmass can divide populations of species, allowing each to evolve along a separate pathway, while simultaneously joining...
Article
Full-text available
We describe the osteology of the new small theropod dinosaur Masiakasaurus knopfleri, from the Late Cretaceous Maevarano Formation of northwestern Madagascar. Approximately 40% of the skeleton is known, including parts of the jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws of Masiakasaurus are remarkably derived, bearing a hete...
Article
Full-text available
We describe the osteology of the new small theropod dinosaur Masiakasaurus knopfleri, from the Late Cretaceous Maevarano Formation of northwestern Madagascar. Approximately 40% of the skeleton is known, including parts of the jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws of Masiakasaurus are remarkably derived, bearing a hete...
Article
Full-text available
We describe the osteology of the new small theropod dinosaur Masiakasaurus knopfleri, from the Late Cretaceous Maevarano Formation of northwestern Madagascar. Approximately 40% of the skeleton is known, including parts of the jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws of Masiakasaurus are remarkably derived, bearing a hete...
Article
Full-text available
The enigmatic concretionary exposures that typify the Chahares Formation (Ladinian, northwestern Argentina) long have defied precise paleoenvironmental characterization. Recent work indicates that the formation accumulated in an alluvial-to-lacustrine setting within an active rift basin that received sedimentary detritus from surrounding highlands,...
Article
Full-text available
The Titanosauria, the last surviving group of the giant sauropod dinosaurs, attained a near-global distribution by the close of the Cretaceous period (65 Myr ago). With the exception of a few new discoveries in Argentina, most titanosaurs are known only from fragmentary postcranial skeletons and rare, isolated skull elements. Here we describe the m...
Article
Full-text available
Here we report the discovery of a small-bodied (approximately 1.8 m) predatory dinosaur from the Late Cretaceous (Maastrichtian) of Madagascar. Masiakasaurus knopfleri, gen. et sp. nov., represented by several skull elements and much of the postcranial skeleton, is unique in being the only known theropod with a highly procumbent and distinctly hete...
Article
Chasmosaurus irvinensis (sp. nov.) is distinguished from other species of this genus by the possession of a broad snout, absence of a brow horn (the position of which is occupied by a pit or rugosities suggestive of bone resorption), broadly rounded and open jugal notch, subrectangular squamosal, straight posterior parietal bar bearing 10 epoccipit...
Article
Full-text available
We report the well preserved skeleton of a small theropod dinosaur, Nqwebasaurus thwazi, gen. et sp. nov., from the Lower Cretaceous Kirkwood Formation of South Africa. Nqwebasaurus has an elongate three-digit manus with a partially opposable first digit, a long and slender pes with a highly reduced metatarsal IV, and preserves gastroliths (stomach...
Article
Gondwanan dinosaurs, though less well-known than their Laurasian counterparts, are being discovered and described at an ever accelerating pace. Dinosaurs are known from every major Gondwanan landmass, including South America, Africa, Antarctica, Australia, India, Madagascar and New Zealand. Much of the Gondwana dinosaur literature includes speculat...
Article
Full-text available
Immunohistochemical studies, supported by additional lines of evidence, suggest that original proteinaceous components of keratin claw sheath material may be preserved in the pedal ungual phalanx associated with the primitive bird, Rahonavis ostromi, from the Late Cretaceous of Madagascar. This conclusion is based upon immunohistochemical analyses,...
Article
A rich, newly discovered assemblage of exquisitely preserved vertebrate fossils from the Late Cretaceous of Madagascar provides an unparalleled opportunity to investigate the paleobiogeography of Gondwanan landmasses. Most current plate tectonic models depict widespread fragmentation of Gondwana prior to the Late Cretaceous. The discovery of mammal...
Article
Full-text available
In 1896 Charles Depéret described a fauna of dinosaurs from the Upper Cretaceous (?Campanian) Maevarano Formation from the Mahajanga Basin of northwest Madagascar. Among the dinosaurs was a titanosaurid sauropod that he named Titanosaurus madagascariensis. He attributed to the titanosaurid a large, thick circular osteoderm. His referral of an osteo...
Article
Full-text available
Recent discoveries of fossil vertebrates from the Late Cretaceous of Madagascar include several specimens of a large theropod dinosaur. One specimen includes a nearly complete and exquisitely preserved skull with thickened pneumatic nasals, a median frontal horn, and a dorsal projection on the parietals. The new materials are assigned to the enigma...
Article
Genus Correction The name Rahona, which we recently proposed as a genus name for a basal avian from the Late Cretaceous of Madagascar (Reports, 20 Mar., p. 1915), is already occupied by the lymantriid lepidopteran Rahona Griveaud, (1). We therefore propose the replacement name Rahonavis for this genus, whose type species is Rahonavis ostromi.
Article
Full-text available
A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous of Madagascar. This specimen, although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral arti...
Conference Paper
Gross analyses of two Late Cretaceous specimens, a primitive bird from Madagascar and a mononykosaur from the Gobi desert, indicated preservation of keratinous structures, thus documenting the oldest occurrence of keratin in the fossil record. Fibrous material adhering to an ungual of the Madagascar bird was subjected to multiple analyses; results...
Conference Paper
Full-text available
Our knowledge of Mesozoic birds from Gondwana has been derived almost entirely from South America, Australia, and the Antarctic Peninsula. Several representing at least three distinct taxa of birds, were recently recovered from the Campanian Maevarano Fm., Mahajanga Basin, northwestern Madagascar. This avifauna provides the first pre Late-Holocene...
Article
Full-text available
WE report the discovery of two exquisitely preserved specimens of a new, very primitive bird from the Late Cretaceous period of Madagascar. The new taxon, Vorona berivotrensis, is provisionally placed phylogenetically in an unresolved trichotomy with Enantiornithes and a clade consisting of Patagopteryx and Ornithurae. These specimens are the first...
Article
Sixteen species of Triceratops have been proposed since the genus was erected by O. C. Marsh in 1889. Five of these species are here considered technically invalid and a sixth is reassigned to Diceratops. Based on both cladistic analysis and morphometric shape analysis, all available skulls of the ten remaining “species” of Triceratops are placed i...
Article
Well preserved skulls of Triceratops are extremely abundant in Maastrictian rocks from western North America. Although ossification obscures sutural and structural details in many skulls, others reveal much previously undescribed morphology. The circumnarial area includes enlarged nares and a complex narial fossa. A nasal horn of varying size, augm...