Manus track preservation bias as a key factor for assessing trackmaker identity and quadrupedalism in basal ornithopods.

BACKGROUND: The Las Cerradicas site (Tithonian-Berriasian), Teruel, Spain, preserves at least seventeen dinosaur trackways, some of them formerly attributed to quadrupedal ornithopods, sauropods and theropods. The exposure of new track evidence allows a more detailed interpretation of the controversial tridactyl trackways as well as the modes of locomotion and taxonomic affinities of the trackmakers. METHODOLOGY/PRINCIPAL FINDINGS: Detailed stratigraphic analysis reveals four different levels where footprints have been preserved in different modes. Within the tridactyl trackways, manus tracks are mainly present in a specific horizon relative to surface tracks. The presence of manus tracks is interpreted as evidence of an ornithopod trackmaker. Cross-sections produced from photogrammetric digital models show different depths of the pes and manus, suggesting covariance in loading between the forelimbs and the hindlimbs. CONCLUSIONS/SIGNIFICANCE: Several features (digital pads, length/width ratio, claw marks) of some ornithopod pes tracks from Las Cerradicas are reminiscent of theropod pedal morphology. This morphological convergence, combined with the shallow nature of the manus tracks, which reduces preservation potential, opens a new window into the interpretation of these tridactyl tracks. Thus, trackmaker assignations during the Jurassic-Cretaceous interval of purported theropod trackways may potentially represent ornithopods. Moreover, the Las Cerradicas trackways are further evidence for quadrupedalism among some basal small- to medium-sized ornithopods from this time interval

NEW ABELISAURID MATERIAL FROM THE UPPER CRETACEOUS (CENOMANIAN) OF MOROCCO

Fragmentary cranial bones of dinosaur origin have been recently recovered from the Kem Kem beds (Upper Cretaceous, Cenomanian) of Morocco. They include two incompletely preserved maxillary bones evidencing diagnostic features of abelisaurid theropods. These new finds provide further evidence of Abelisauridae in the Late Cretaceous of Morocco.

NEW ABELISAURID MATERIAL FROM THE UPPER CRETACEOUS (CENOMANIAN) OF MOROCCO

Fragmentary cranial bones of dinosaur origin have been recently recovered from the Kem Kem beds (Upper Cretaceous, Cenomanian) of Morocco. They include two incompletely preserved maxillary bones evidencing diagnostic features of abelisaurid theropods. These new finds provide further evidence of Abelisauridae in the Late Cretaceous of Morocco.

NEW ABELISAURID MATERIAL FROM THE UPPER CRETACEOUS (CENOMANIAN) OF MOROCCO

Fragmentary cranial bones of dinosaur origin have been recently recovered from the Kem Kem beds (Upper Cretaceous, Cenomanian) of Morocco. They include two incompletely preserved maxillary bones evidencing diagnostic features of abelisaurid theropods. These new finds provide further evidence of Abelisauridae in the Late Cretaceous of Morocco

A salamandrid from the middle Pleistocene of northern Latium (Fosso di San Martino, Rome, Italy)

An almost complete salamandrid specimen has recently been discovered from diatomite deposits in the Sabatini Volcanic District, at the Fosso di San Martino locality, about 45 km north of Rome (Rignano Flamino, Latium, central Italy). The age of the fossil- bearing level is constrained between 488±2 and 457±4 ka based on the presence of well-dated volcanic ash layers at the top and at the bed of the diatomite level where the specimen was embedded. The fossil record of Caudata from the Pleistocene of central Italy is scarce, and this new find adds important data on the presence of the taxon in this area. The specimen, although comprised of a fairly complete and articulated skeleton, shows a sub-optimal preservation of single bony elements, to such an extent that a definite taxonomic assignment is not feasible. Moreover, it probably represents a juvenile individual in somatic terms at the time of the death. The specimen is tentatively referred to Triturus sp

A new purported ankylosaur trackway in the Lower Cretaceous (lower Aptian) shallow-marine carbonate deposits of Puglia, southern Italy

The Apulian marine carbonate Platform, an unusual environment for terrestrial animals, has revealed a diverse ichnological record, especially for dinosaurs. Members of most higher taxa are present, including sauropods, theropods, ankylosaurs and ornithopods. Recently, a small outcrop of Aptian age referred to the Calcare di Bari near Bisceglie (Bari) has yielded a new quadrupedal trackway that we attribute to Ankylosauria. This new find enhances the record of Cretaceous ankylosaur footprints from the Apulian carbonate Platform, previously known from another site near Bisceglie (early Aptian), from Borgo Celano (late Hauterivian-early Barremian), and from Altamura (late Coniacian-early Santonian). (C) 2010 Elsevier Ltd. All rights reserved