The eusuchian crocodylomorph Allodaposuchus subjuniperus sp. nov., a new species from the latest Cretaceous (upper Maastrichtian) of Spain
ABSTRACT 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.
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ABSTRACT: We present a detailed morphological description of the type-locality cranial material of Theriosuchus sympiestodon Martin, Rabi, and Csiki, 2010 from the Maastrichtian Densus -Ciula Formation of the Hat xeg Basin, Romania together with new material of isolated cranial elements and teeth from various sites of the same general area. The recognition of several individuals of distinct sizes allows for an assessment of ontogenetic variation in this taxon. New material, consisting of isolated teeth and an incomplete maxilla with in situ teeth, coming from various late Campanian/ early Maastrichtian sites in southern France is referable to ?Theriosuchus sp. and hints to a rare but widespread distribution of Theriosuchus in the Late Cretaceous European archipelago. INTRODUCTIONJournal of Paleontology 05/2014; · 1.10 Impact Factor
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ABSTRACT: The controversial European genus Allodaposuchus is currently composed of two species (A. precedens, A. subjuniperus) and it has been traditionally considered a basal eusuchian clade of crocodylomorphs. In the present work, the new species A. palustris is erected on the base of cranial and postcranial remains from the lower Maastrichtian of the southern Pyrenees. Phylogenetic analyses here including both cranial and postcranial data support the hypothesis that Allodaposuchus is included within Crocodylia. The studied specimen suggests little change in postcranial skeleton along the evolutionary history of crocodylians, except for some bone elements such as the axis, the first caudal vertebra and the ilium. The specimen was found in an organic mudstone corresponding to a coastal wetland environment. Thus, A. palustris from Fumanya is the first Allodaposuchus reported in lacustrine-palustrine settings that expand the ecological range for this genus. The S-DIVA palaeobiogeographic reconstruction of ancestral area suggests that early members of Crocodylia rapidly widespread for the Northern Hemisphere landmasses no later than the Campanian, leading the apparition of endemic groups. In that way “Allodaposuchia” represents an endemic European clade probably originated in the Ibero-Armorican domain in the late Campanian and dispersed by the Southern European archipelago prior to the early Maastrichtian.PLoS ONE 12/2014; 9(12):e115837. · 3.53 Impact Factor
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ABSTRACT: The phylogenetic position of the Indian gharial (Gavialis gangeticus) is disputed - morphological characters place Gavialis as the sister to all other extant crocodylians, whereas molecular and combined analyses find Gavialis and the false gharial (Tomistoma schlegelii) to be sister taxa. Geometric morphometric techniques have only begun to be applied to this issue, but most of these studies have focused on the exterior of the skull. The braincase has provided useful phylogenetic information for basal crurotarsans, but has not been explored for the crown group. The Eustachian system is thought to vary phylogenetically in Crocodylia, but has not been analytically tested. To determine if gross morphology of the crocodylian braincase proves informative to the relationships of Gavialis and Tomistoma, we used two- and three-dimensional geometric morphometric approaches. Internal braincase images were obtained using high-resolution computerized tomography scans. A principal components analysis identified that the first component axis was primarily associated with size and did not show groupings that divide the specimens by phylogenetic affinity. Sliding semi-landmarks and a relative warp analysis indicate that a unique Eustachian morphology separates Gavialis from other extant members of Crocodylia. Ontogenetic expansion of the braincase results in a more dorsoventrally elongate median Eustachian canal. Changes in the shape of the Eustachian system do provide phylogenetic distinctions between major crocodylian clades. Each morphometric dataset, consisting of continuous morphological characters, was added independently to a combined cladistic analysis of discrete morphological and molecular characters. The braincase data alone produced a clade that included crocodylids and Gavialis, whereas the Eustachian data resulted in Gavialis being considered a basally divergent lineage. When each morphometric dataset was used in a combined analysis with discrete morphological and molecular characters, it generated a tree that matched the topology of the molecular phylogeny of Crocodylia.PLoS ONE 09/2014; 9(9):e105793. · 3.53 Impact Factor