This paper describes the skull of the eusuchian Allodaposuchus subjuniperus sp. nov. This new skull was recovered between the villages of Beranuy and Serraduy del Pon (Huesca, Spain). Stratigraphically, it was located in a level of coarse-grained sandstones in the middle-upper part of the lower red unit (Conque´s Formation) of the Tremp Group, in the uppermost Maastrichtian close to the Cretaceous–Paleogene boundary. Until now Allodaposuchus was a monospecific genus. Phylogenetic analysis places the new taxon as a basal member of Eusuchia forming a clade with the other European Allodaposuchus remains and as a sister clade to the endemic European members of Hylaeochampsidae. Furthermore, Allodaposuchus and Hylaeochampsidae are within the stem of Crocodylia, being key taxa to understanding the origin of Crocodylia. The new taxon is the latest record of Allodaposuchus from Europe, and it presents significant enough morphological differences from Allodaposuchus precedens to establish a new species. The morphological variations in the material included in Allodaposuchus, the wide range of age and the geographical separation among the remains from Romania, France and Spain indicate that Allodaposuchus is not a monospecific genus as traditionally established.
"The external ear of the genus Allodaposuchus is distinguished by a broad cranioquadrate passage, a feature shared with the basal Eusuchian Hylaeochampsa (Buscalioni et al., 2001; Delfino et al., 2008; Blanco et al., 2014; Puértolas-Pascual, Canudo & Moreno-Azanza, 2014). "
[Show abstract][Hide abstract] ABSTRACT: Background. The Late Cretaceous is a keystone period to understand the origin and early radiation of Crocodylia, the group containing all extant lineages of crocodilians. Among the taxa described from the latest Cretaceous of Europe, the genus Allodaposuchus is one of the most common but also one of the most controversial. However, because of its fragmentary record, several issues regarding its phylogenetic emplacement and its ecology remain unsolved or unknown. The discovery of a single specimen attributed to Allodaposuchus, represented by both cranial and postcranial remains, from the Casa Fabà site (Tremp Basin, NE Spain) in the lower red unit of the Tremp Fm. (early Maastrichtian, Late Cretaceous) offers a unique opportunity to deepen in the phylogenetic relationships of the group and its ecological features.
Methods. The specimen is described in detail, and CT scan of the skull is performed in order to study the endocranial morphology as well as paratympanic sinuses configuration. In addition, myological and phylogenetic analyses are also carried out on the specimen for to shed light in ecological and phylogenetic issues, respectively.
Results. The specimen described herein represents a new species, Allodaposuchus hulki sp. nov., closely related to the Romanian A. precedens. The CT scan of the skull revealed an unexpected paratympanic sinuses configuration. Allosaposuchus hulki exhibits an “anterodorsal tympanic sinus” not observed in any other extant or extinct crocodilian. The caudal tympanic recesses are extremely enlarged, and the expanded quadratic sinus seems to be connected to the middle-ear channel. Phylogenetic analyses confirm the emplacement of the informal taxonomic group ‘Allodaposuchia’ at the base of Crocodylia, being considered the sister group of Borealosuchus and Planocraniidae.
Discussion. Although this is a preliminary hypothesis, the unique paratympanic configuration displayed by A. hulki suggests that it could possess a high-specialized auditory system. Further, the large cranial cavities could help to reduce the weight of the cranium. Concerning the postcranial skeleton, Allodaposuchus hulki shows massive and robust vertebrae and forelimb bones, suggesting it could have a bulky body. The myological study performed on the anterior limb elements supports this interpretation. In addition, several bone and muscular features seem to point at a semi-erected position of the forelimbs during terrestrial locomotion. Taking all the above results into consideration, it seems plausible to suggest that A. hulki could conduct large incursions out of the water and have a semi-terrestrial lifestyle.
"The LRG unit has fossil remains of marine organisms such as planktonic foraminifera deposited after being transported landwards from the outer/inner shelf, as well as freshwater organisms such as ostracods and charophytes. Continental vertebrates include lizards, lissamphibians, dinosaurs, crocodylomorphs, chelonians and pterosaurs (Casanovas et al., 1987; Vila et al., 2012; Marmi et al., 2012; Pu ertolas-Pascual et al., 2014; Díez-Canseco et al., 2014; Dalla Vecchia et al., 2014; Blanco et al., 2015a). Fossils of vascular plants are also present in the LRG (Marmi et al., 2015). "
[Show abstract][Hide abstract] ABSTRACT: In the present paper, the fossil record of the archosaurs (dinosaurs, crocodylomorphs and pterosaurs) of the southern Pyrenees before the Cretaceous–Palaeogene (K–Pg) transition is revised. On the basis of this fossil record, a well-dated succession of dinosaurs and other archosaurs is established within polarity magnetochrons C30 and C29r. Almost 150 sites with dinosaur remains have been identified, containing hadrosauroid ornithopods, titanosaur sauropods and theropods, as well as egg sites and tracks. Fossil remains of dinosaurs and other archosaurs are abundant in C29r, disappearing abruptly near the top of the “Lower Red Garumnian” unit of the Tremp Formation. Thus this should be located very close to, or coinciding with the K–Pg boundary. These data suggest that the disappearance of the dinosaurs and other archosaurs was geologically abrupt in the southern Pyrenees, but to date there is no incontrovertible evidence of the presence of the impact level that marks the Cretaceous–Palaeogene boundary. Interestingly, what is highlighted in the southern Pyrenees is that the vertebrate-rich upper Maastrichtian continental sites were replaced by similar sedimentological facies characterized by the virtual absence not only of dinosaurs but also of any vertebrate remain throughout the lower Palaeocene. This could mean that the Danian terrestrial ecosystems of the southern Pyrenees took longer than other areas of the world to recover their biodiversity after the K−Pg extinction event.
Cretaceous Research 07/2015; DOI:10.1016/j.cretres.2015.06.013 · 1.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Upper Cretaceous outcrops of the Pyrenees yield one of the most extensive and continuous records of paleoological remains anywhere in the world. Most of eggs and eggshells have been referred to the oofamily Megaloolithidae. In this study, we present a revision of eggshell fragments from the Blasi 2 locality, lattermost Maastrichtian in age, previously assigned to aff. Megaloolithidae. The presence of a blocky extinction pattern and basal knobs supports a crocodilian affinity of these materials. We classify them as Krokolithidae indet. Three structural layers can be recognised in the Blasi 2 eggshells, a feature that is shared with other recent eggshells (e.g. Crocodylus porosus and Crocodylus niloticus) and fossil crocodylomorph eggshells (Krokolitheswilsoni), which were previously described as single layered. The new proposed affinity of the Blasi 2 eggshells reduces the Megaloolithidae oodiversity of the last few million years of the Cretaceous in the Pyrenees to only two valid ootaxa, Megaloolithusmamillare and Megaloolithusbaghensis. The lack of more complete material precludes the erection of new ootaxa based on the Blasi 2 material.
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