Charles Whitney Gilmore – The Forgotten “Dinosaur Hunter”

Charles Whitney Gilmore (1874-1945), affectionately known as “Charlie” to his colleagues, was one of the last major figures of America’s “Golden Age” of dinosaur hunting. It is largely due to his efforts that the Department of Paleobiology is now home to one of the premier collections of dinosaurs and other fossil reptiles in the United States. Early in his career Gilmore commenced scientific studies of dinosaurs and many other groups of extinct reptiles, starting with the rich material from the Marsh Collection. His monographs on the skeletal structure of the armored Stegosaurus (1914), the predatory dinosaurs Allosaurus and Ceratosaurus (1920), and the sauropod Apatosaurus (1936) remain essential references for any serious student of dinosaurs. Working at a time when there were few professional vertebrate paleontologists, Gilmore also received invitations from other institutions, including the Carnegie Museum and the American Museum of Natural History, to study and publish on important specimens of dinosaurs and other fossil reptiles from their respective collections. Many important papers, including the first monograph on early Late Cretaceous dinosaurs from Inner Mongolia (China), resulted from these “extramural” research efforts. The collections of fossil reptiles in the Division of Vertebrate Paleontology offer eloquent testimony of Gilmore’s devotion and efforts and will continue to be an unparalleled resource for research and exhibition

Colobops: a juvenile rhynchocephalian reptile (Lepidosauromorpha), not a diminutive archosauromorph with an unusually strong bite

Correctly identifying taxa at the root of major clades or the oldest clade-representatives is critical for meaningful interpretations of evolution. A small, partially crushed skull from the Late Triassic (Norian) of Connecticut, USA, originally described as an indeterminate rhynchocephalian saurian, was recently named Colobops noviportensis and reinterpreted as sister to all remaining Rhynchosauria, one of the earliest and globally distributed groups of herbivorous reptiles. It was also interpreted as having an exceptionally reinforced snout and powerful bite based on an especially large supratemporal fenestra. Here, after a re-analysis of the original scan data, we show that the skull was strongly dorsoventrally compressed post-mortem, with most bones out of life position. The cranial anatomy is consistent with that of other rhynchocephalian lepidosauromorphs, not rhynchosaurs. The ‘reinforced snout' region and the ‘exceptionally enlarged temporal region’ are preservational artefacts and not exceptional among clevosaurid rhynchocephalians. Colobops is thus not a key taxon for understanding diapsid feeding apparatus evolution

Response to Comment on "Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary"

Our recent study on the nature of the ascent of the dinosaurs (1) argued three main points: (i) that a major terrestrial tetrapod mass extinction is concentrated at the palynologically identified Triassic-Jurassic boundary in eastern North America (based on footprints and bones); (ii) that truly large predatory dinosaurs appear immediately after the boundary (based on footprints); and (iii) that both the boundary and the mass extinction level are associated with a modest Ir anomaly and fern spike, plausibly of asteroid or comet impact origin. Although the comment of Thulborn (2) addresses a number of paleontological issues in (1), his only point salient to the conclusions of our paper is his extraordinary claim that very large theropod dinosaurs were already present in the Carnian, some 20 million years or so before the Triassic-Jurassic boundary [in contrast to our assertion in point (ii), above]

New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs

Tyrannosaurids—the familiar group of carnivorous dinosaurs including Tyrannosaurus and Albertosaurus—were the apex predators in continental ecosystems in Asia and North America during the latest Cretaceous (ca. 80–66 million years ago). Their colossal sizes and keen senses are considered key to their evolutionary and ecological success, but little is known about how these features developed as tyrannosaurids evolved from smaller basal tyrannosauroids that first appeared in the fossil record in the Middle Jurassic (ca. 170 million years ago). This is largely because of a frustrating 20+ million-year gap in the mid-Cretaceous fossil record, when tyrannosauroids transitioned from small-bodied hunters to gigantic apex predators but from which no diagnostic specimens are known. We describe the first distinct tyrannosauroid species from this gap, based on a highly derived braincase and a variety of other skeletal elements from the Turonian (ca. 90–92 million years ago) of Uzbekistan. This taxon is phylogenetically intermediate between the oldest basal tyrannosauroids and the latest Cretaceous forms. It had yet to develop the giant size and extensive cranial pneumaticity of T. rex and kin but does possess the highly derived brain and inner ear characteristic of the latest Cretaceous species. Tyrannosauroids apparently developed huge size rapidly during the latest Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses that first evolved at smaller body size

ZooKeys, unlocking Earth's incredible biodiversity and building a sustainable bridge into the public domain: From "print-based" to "web-based" taxonomy, systematics, and natural history.

Publishing taxonomic and systematics studies in the digital era faces major challenges and requires new approaches, many of which are currently stimulating spirited discussions amongst taxonomists and systematists. New amendments to the International Code of Zoological Nomenclature are expected to regulate electronic publishing of new taxa and create a standard form for their registration (ZooBank). Responding to a perceived need, this editorial announces establishment of ZooKeys – a new online and print journal in zoological taxonomy and systematics, which aims to quickly respond and adapt to the newest developments in taxonomic publishing. Open Access is accepted as mandatory for ZooKeys. The rationale for and concept of ZooKeys is discussed in detail

Arctic ice and the ecological rise of the dinosaurs

Abundant lake ice-rafted debris in Late Triassic and earliest Jurassic strata of the Junggar Basin of northwestern China (paleolatitude ~71°N) indicates that freezing winter temperatures typified the forested Arctic, despite a persistence of extremely high levels of atmospheric Pco2 (partial pressure of CO2). Phylogenetic bracket analysis shows that non-avian dinosaurs were primitively insulated, enabling them to access rich deciduous and evergreen Arctic vegetation, even under freezing winter conditions. Transient but intense volcanic winters associated with massive eruptions and lowered light levels led to the end-Triassic mass extinction (201.6 Ma) on land, decimating all medium- to large-sized nondinosaurian, noninsulated continental reptiles. In contrast, insulated dinosaurs were already well adapted to cold temperatures, and not only survived but also underwent a rapid adaptive radiation and ecological expansion in the Jurassic, taking over regions formerly dominated by large noninsulated reptiles

ZooKeys, unlocking Earth’s incredible biodiversity and building a sustainable bridge into the public domain: From “print-based” to “web-based” taxonomy, systematics, and natural history. ZooKeys Editorial Opening Paper

This is the publisher's version, also available electronically from http://zookeys.pensoft.net/articles.php?id=1929.Publishing taxonomic and systematics studies in the digital era faces major challenges and requires new approaches, many of which are currently stimulating spirited discussions amongst taxonomists and systematists. New amendments to the International Code of Zoological Nomenclature are expected to regulate electronic publishing of new taxa and create a standard form for their registration (ZooBank). Responding to a perceived need, this editorial announces establishment of ZooKeys – a new online and print journal in zoological taxonomy and systematics, which aims to quickly respond and adapt to the newest developments in taxonomic publishing. Open Access is accepted as mandatory for ZooKeys. Th e rationale for and concept of ZooKeys is discussed in detail

Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary

Analysis of tetrapod footprints and skeletal material from more than 70 localities in eastern North America shows that large theropod dinosaurs appeared less than 10,000 years after the Triassic-Jurassic boundary and less than 30,000 years after the last Triassic taxa, synchronous with a terrestrial mass extinction. This extraordinary turnover is associated with an iridium anomaly (up to 285 parts per trillion, with an average maximum of 141 parts per trillion) and a fern spore spike, suggesting that a bolide impact was the cause. Eastern North American dinosaurian diversity reached a stable maximum less than 100,000 years after the boundary, marking the establishment of dinosaur-dominated communities that prevailed for the next 135 million years

A new large-bodied oviraptorosaurian theropod dinosaur from the Latest Cretaceous of Western North America

The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs