A new and large monofenestratan reveals the evolutionary transition to the pterodactyloid pterosaurs.

For over a century, there was a major gap in our understanding of the evolution of the flying Mesozoic reptiles, the pterosaurs, with a major morphological gap between the early forms and the derived pterodactyloids. Recent discoveries have found a cluster of intermediate forms that have the head and neck of the pterodactyloids but the body of the early grade, yet this still leaves fundamental gaps between these intermediates and both earlier and more derived pterosaurs. Here, we describe a new and large Jurassic pterosaur, Skiphosoura bavarica gen.

Prey size and ecological separation in spinosaurid theropods based on heterodonty and rostrum shape.

Members of the dinosaur clade Spinosauridae had numerous traits attributed to feeding in or around water, and their feeding apparatus has often been considered analogous to modern crocodylians. Here we quantify the craniodental morphology of Spinosauridae and compare it to modern Crocodylia. We measured from spinosaurid and crocodylian skeletal material the area of alveoli as a proxy for tooth size to determine size-heterodonty.

Estimation of maximum body size in fossil species: A case study using .

Among extant species, the ability to sample the extremes of body size-one of the most useful predictors of an individual's ecology-is highly unlikely. This improbability is further exaggerated when sampling the already incomplete fossil record. We quantify the likelihood of sampling the uppermost limits of body size in the fossil record using Osborn, 1905 as a model, selected for its comparatively well-understood life history parameters.

Bite and tooth marks on sauropod dinosaurs from the Morrison Formation.

Tooth-marked bones provide important evidence for feeding choices made by extinct carnivorous animals. In the case of the dinosaurs, most bite traces are attributed to the large and robust osteophagous tyrannosaurs, but those of other large carnivores remain underreported. Here we report on an extensive survey of the literature and some fossil collections cataloging a large number of sauropod bones (68) from the Upper Jurassic Morrison Formation of the USA that bear bite traces that can be attributed to theropods.

Allometric wing growth links parental care to pterosaur giantism.

Pterosaurs evolved a broad range of body sizes, from small-bodied early forms with wingspans of mostly 1-2 m to the last-surviving giants with sizes of small airplanes. Since all pterosaurs began life as small hatchlings, giant forms must have attained large adult sizes through new growth strategies, which remain largely unknown. Here we assess wing ontogeny and performance in the giant and the smaller-bodied anurognathids , and .

Evolutionary pressures of aerial insectivory reflected in anurognathid pterosaurs.

Across the evolution of powered flight, the ecological niche of aerial insectivore has been occupied by members of the three volant vertebrate clades-Aves and Chiroptera, and the first known volant vertebrates, pterosaurs. However, morphological and quantitative evidence to support pterosaurs exhibiting this ecology remains scant. Anurognathids are an unusual group of pterosaurs in which the skull exhibits the unique morphology of being mediolaterally expanded, so much so that their skulls may be wider than rostrocaudally long.

New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae.

Spinosaurids are among the most distinctive and yet poorly-known of large-bodied theropod dinosaurs, a situation exacerbated by their mostly fragmentary fossil record and competing views regarding their palaeobiology. Here, we report two new Early Cretaceous spinosaurid specimens from the Wessex Formation (Barremian) of the Isle of Wight. Large-scale phylogenetic analyses using parsimony and Bayesian techniques recover the pair in a new clade within Baryonychinae that also includes the hypodigm of the African spinosaurid Suchomimus.

Rare evidence for 'gnawing-like' behavior in a small-bodied theropod dinosaur.

Mammalian carnivores show a higher degree of prey bone utilization relative to non-avian theropod dinosaurs, with this major ecological difference reflected in the frequency and morphology of tooth marks in modern and Cenozoic assemblages relative to Mesozoic ones. As such, prey bone utilization (i.e.

New data on tail lengths and variation along the caudal series in the non-avialan dinosaurs.

The tails of non-avialan dinosaurs varied considerably in terms of overall length, total number of vertebrae, and gross form and function. A new dataset confirms that there is little or no consistent relationship between tail length and snout-sacrum length. Consequently, attempts to estimate one from the other are likely to be very error-prone.

Volant Fossil Vertebrates: Potential for Bioinspired Flight Technology.

Animal flight is ecologically important and has a long evolutionary history. It has evolved independently in many distantly related clades of animals. Powered flight has evolved only three times in vertebrates, making it evolutionarily rare.

Evidence for the Cretaceous shark feeding on the pterosaur from the Niobrara Formation.

A cervical vertebra of the large, pelagic pterodactyloid pterosaur sp. from the Late Cretaceous Niobrara Formation of Kansas, USA is significant for its association with a tooth from the large lamniform shark, . Though the tooth does not pierce the vertebral periosteum, the intimate association of the fossils-in which the tooth is wedged below the left prezygapophysis-suggests their preservation together was not mere chance, and the specimen is evidence of biting .

Bite marks on the frill of a juvenile from the Late Cretaceous Dinosaur Provincial Park Formation, Alberta, Canada.

Bite marks on bones can provide critical information about interactions between carnivores and animals they consumed (or attempted to) in the fossil record. Data from such interactions is somewhat sparse and is hampered by a lack of records in the scientific literature. Here, we present a rare instance of feeding traces on the frill of a juvenile ceratopsian dinosaur from the late Campanian Dinosaur Park Formation of Alberta.

Fossilized skin reveals coevolution with feathers and metabolism in feathered dinosaurs and early birds.

Feathers are remarkable evolutionary innovations that are associated with complex adaptations of the skin in modern birds. Fossilised feathers in non-avian dinosaurs and basal birds provide insights into feather evolution, but how associated integumentary adaptations evolved is unclear. Here we report the discovery of fossil skin, preserved with remarkable nanoscale fidelity, in three non-avian maniraptoran dinosaurs and a basal bird from the Cretaceous Jehol biota (China).

Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution.

Establishing the origin and function of unusual traits in fossil taxa provides a crucial tool in understanding macroevolutionary patterns over long periods of time. Ceratopsian dinosaurs are known for their exaggerated and often elaborate horns and frills, which vary considerably between species. Many explanations have been proposed for the origin and evolution of these 'ornamental' traits, from predator defence to socio-sexual dominance signalling and, more recently, species recognition.

Palaeontology: Scrapes of Dinosaur Courtship.

Analysis of numerous trace fossils reveals 'nest scrape displays' made by dinosaurs that are analogous to those left by modern birds.

Ontogeny and the fossil record: what, if anything, is an adult dinosaur?

Identification of the ontogenetic status of an extinct organism is complex, and yet this underpins major areas of research, from taxonomy and systematics to ecology and evolution. In the case of the non-avialan dinosaurs, at least some were reproductively mature before they were skeletally mature, and a lack of consensus on how to define an 'adult' animal causes problems for even basic scientific investigations. Here we review the current methods available to determine the age of non-avialan dinosaurs, discuss the definitions of different ontogenetic stages, and summarize the implications of these disparate definitions for dinosaur palaeontology.

Evolution: convergence in dinosaur crests.

The horned, ceratopsid dinosaurs can be easily split into two major groups based on their cranial structures, but now a new discovery shows that at least one genus 'switched sides' and convergently evolved the form of the other clade.

A new mass mortality of juvenile Protoceratops and size-segregated aggregation behaviour in juvenile non-avian dinosaurs.

Background: Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together) or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage). In the latter case, it is generally unknown if these kinds of size-segregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages.

A new basal hadrosauroid dinosaur (Dinosauria: Ornithopoda) with transitional features from the late cretaceous of Henan Province, China.

Background: Southwestern Henan Province in central China contains many down-faulted basins, including the Xixia Basin where the Upper Cretaceous continental sediments are well exposed. The Majiacun Formation is a major dinosaur-bearing stratigraphic unit that occurs in this basin.

Methodology/principal Findings: A new basal hadrosauroid dinosaur, Zhanghenglong yangchengensis gen.

Body size distribution of the dinosaurs.

The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs.

Pedal claw curvature in birds, lizards and mesozoic dinosaurs--complicated categories and compensating for mass-specific and phylogenetic control.

Pedal claw geometry can be used to predict behaviour in extant tetrapods and has frequently been used as an indicator of lifestyle and ecology in Mesozoic birds and other fossil reptiles, sometimes without acknowledgement of the caveat that data from other aspects of morphology and proportions also need to be considered. Variation in styles of measurement (both inner and outer claw curvature angles) has made it difficult to compare results across studies, as have over-simplified ecological categories. We sought to increase sample size in a new analysis devised to test claw geometry against ecological niche.

A new non-pterodactyloid pterosaur from the Late Jurassic of southern Germany.

Background: The 'Solnhofen Limestone' beds of the Southern Franconian Alb, Bavaria, southern Germany, have for centuries yielded important pterosaur specimens, most notably of the genera Pterodactylus and Rhamphorhynchus. Here we describe a new genus of non-pterodactyloid pterosaur based on an extremely well preserved fossil of a young juvenile: Bellubrunnus rothgaengeri (gen. et sp.

The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs.

In extant birds, the hand is permanently abducted towards the ulna, and the wrist joint can bend extensively in this direction to fold the wing when not in use. Anatomically, this asymmetric mobility of the wrist results from the wedge-like shape of one carpal bone, the radiale, and from the well-developed convexity of the trochlea at the proximal end of the carpometacarpus. Among the theropod precursors of birds, a strongly convex trochlea is characteristic of Coelurosauria, a clade including the highly derived Maniraptora in addition to tyrannosaurs and compsognathids.