Lizards and amphisbaenians (Reptilia, Squamata) from the middle Eocene of Mazaterón (Soria, Spain)

The assemblage of lizards and amphisbaenians (Reptilia, Squamata) from the middle Eocene locality of Mazaterón (Spain) is described. Considering the rather limited material available for the study, the assemblage shows a moderate diversity with eight taxa corresponding to five different families. In most cases the scarcity and fragmentary nature of squamate specimens precludes a precise identification, but provides insights on identity of the groups represented. Mazaterón fills the gap between early and late Eocene Iberian localities, showing the persistence of iguanids (possibly Geiseltaliellus), lacertids (possibly Dormaalisaurus), and glyptosaur (tribes glyptosaurini and "melanosaurini") and anguine anguids through most of the Iberian Eocene. It also records the return of amphisbaenians (Blanidae) after their temporary retrieval from Europe during most of the middle Eocene, and the presence of two scincids, one of them possibly corresponding to a new taxon. The information provided by squamates complements what is already known from mammals, crocodylians, and turtles in what is arguably one of the most important vertebrate Paleogene localities of the Iberian Peninsula

First early Eocene lizards from Spain and a study of the compositional changes between late Mesozoic and early Cenozoic Iberian lizard assemblages

Lizard and amphisbaenian fossil material is described for the first time from early Eocene localities in Spain, more specifically from Catalonia (north-eastern Iberian Peninsula). Material is fragmentary and scarce, but diagnostic enough to provide a first approach to the composition of lizard assemblages. The following taxa are recorded: Geiseltaliellus and a second indeterminate pleurodont iguanid; an agamid similar to "Tinosaurus"; an indeterminate gekkotan; a scincoid, possibly scincid lizard; a lacertid similar to Dormaalisaurus; an indeterminate amphisbaenian; a glyptosaurin glyptosaurine (cf. Placosaurus); an indeterminate anguine; and, finally, an indeterminate "necrosaur." The studied localities range from the MP8+9 to the MP10, and thus complement the only previously known lizard locality of the Iberian early Eocene, the Portuguese locality of Silveirinha, which corresponds to the MP7. An analysis of the composition of these new assemblages suggests a great amount of homogeneity through the different levels of the early Eocene, and also between Iberian and contemporaneous assemblages from the rest of Europe. The lack of an Iberian Paleocene record for lizards strengthens the importance of the study of early Eocene assemblages because these are the only ones available for comparison with Cretaceous associations, providing critical information on the changes in composition between Mesozoic and early Cenozoic lizard faunas related to the K/Pg extinction event

A potential record of a procolophonid parareptile from the Triassic of the Iberian Peninsula

Cranial and postcranial remains from the Middle Triassic of the Northeastern part of the Iberian Peninsula are reported and tentatively assigned to Procolophonidae. The finding is the first occurrence of a procolophonid parareptile in the Iberian Peninsula, representing the southernmost record of the group in Europe. The fossilbearing locality is dated as Anisian (Middle Triassic) and includes three tooth-bearing bones, two cranial bone fragments and one interclavicle. The mandible described herein includes nine teeth. No cusps or complete crowns are preserved, but sections of the teeth are available. The three anterior teeth progressively decrease in size from front to back, whereas the teeth from the fourth to the eighth position present the opposite trend. The last tooth (the ninth) is clearly reduced in comparison to the previous ones. A close relationship with Anomoiodon-Kapes is suggested, however, more material is required in order to assess the exact taxonomical determination of the Iberian remains. This finding is expected to shed some light on the geographical distribution of procolophonines

Moradebrichthys vilasecae gen. et sp. nov., a new perleidid (Actinopterygii: Osteichthyes) from the Middle Triassic of Catalonia (NE Iberian Peninsula)

A new actinopterygian, Moradebrichthys vilasecae gen. et sp. nov., from the Middle Triassic (Late Ladinian) of Móra d'Ebre-Camposines (Catalonia, NE Iberian Peninsula) is erected on the basis of several, almost complete, articulated and well-preserved specimens. It is referred to the controversial family Perleididae based on the presence of a combination of features such as paried nasals, presence of rostral, vertical suspensorium, absence of interopercle, lack of coronoid in the mandible, basal and fringing fulcra on fins developed to different extents and an almost symmetrical caudal fin with epaxial fin rays. Comparisons to other well-known taxa usually assigned to the Perleididae family reveals that the new taxon presents many similarities with the genera Perleidus, Peltoperleidus, Aetheodontus and Meridensia, rather than other perleidids. Moreover, additional morphological characters, not shared with any of these genera are: a big half moon shaped infraorbital-2 and one elongate infraorbital-1, a narrow vertical preopercle with a prominent and pointed anterior maxillary process, a dentary covered by horizontally arranged ridges, a very big opercle and a much smaller subopercle, and the high level of lepidotrichia branching in the caudal fin. A comparison of Catalan Middle Triassic actinopterygian assemblages with other ones from Central European basins of coeval age (particularly Italian and Swiss localities) suggest some faunal similarities, being of special interest the potential correlation with the Besano Formation

Lizards and amphisbaenians (Reptilia, Squamata) from the late Eocene of Sossís (Catalonia, Spain)

A new diverse late Eocene lizard and amphisbaenian assemblage from the classical mammal locality of Sossís (Catalonia, Spain) is described. It represents the first Paleogene lizard assemblage from Spain and the first late Eocene lizard locality from the Iberian Peninsula. The family-level composition of the assemblage replicates that of other contemporaneous European localities, with the presence of iguanians, geckos, lacertids, scincids, cordyliforms, amphisbaenians, anguines, and glyptosaurines. Many of these families still occur in Catalonia, but the presence of thermophilic taxa like iguanians and cordyliforms are indicative of warmer conditions during the Eocene. The closest faunal match is with the contemporaneous French localities of the Phosphorites du Quercy. Sossís and other newly recovered Paleogene Spanish squamate assemblages have the potential to contribute to an understanding of patterns of faunal interchange between different Paleogene bioprovinces, complementing existing data on mammals

The Jurassic rise of squamates as supported by lepidosaur disparity and evolutionary rates

The squamates (lizards, snakes, and relatives) today comprise more than 10,000 species, and yet their sister group, the Rhynchocephalia, is represented by a single species today, the tuatara. The explosion in squamate diversity has been tracked back to the Cretaceous Terrestrial Revolution, 100 million years ago (Ma), the time when flowering plants began their takeover of terrestrial ecosystems, associated with diversification of coevolving insects and insect-eating predators such as lizards, birds, and mammals. Squamates arose much earlier, but their long pre-Cretaceous history of some 150 million years (Myr) is documented by sparse fossils. Here, we provide evidence for an initial radiation of squamate morphology in the Middle and Late Jurassic (174-145 Ma), and show that they established their key ecological roles much earlier than had been assumed, and they have not changed them much since

Early Miocene dispersal of the lizard Varanus into Europe : reassessment of vertebral material from Spain

Iberovaranus Hoffstetter, 1969 was erected as a monotypic genus of varanine varanid lizard on the basis of a single trunk vertebra from the Miocene of Spain. Thanks to the study of the holotype, as well as of a still undescribed cervical vertebra from the same locality, we show that the vertebral morphology of Iberovaranus is contained within the known variability of Varanus. Therefore, Iberovaranus Hoffstetter, 1969 is considered a subjective junior synonym of Varanus Merrem, 1820, and the species Iberovaranus catalaunicus Hoffstetter, 1969 should be considered a nomen dubium

New insights on the Permian and Triassic vertebrates from the Iberian Peninsula with emphasis on the Pyrenean and Catalonian basins

Few studies paid attention to the Permian and Triassic vertebrates from the Iberian Peninsula and a reevaluation of these faunas is needed in order to compare them with other European basins. As a first step, we present here the available data from the Catalonian and Pyrenean basins (NE of the Iberian Peninsula), offering new insights on the diversity and temporal distribution of their vertebrate faunas. The two basins have yielded unexpectedly abundant and diverse vertebrate assemblages, including fishes, amphibians and reptiles from continental and marine environments. The revision of classical finds and the analysis of new material provide data towards an understanding of the evolutionary and palaebiogeographical history of the Permian and Triassic vertebrate Iberian faunas. Permian remains mainly correspond to footprints recovered from alluvial deposits; the osteological record is scarce in the Iberian Peninsula. Early Triassic vertebrate localities are unknown. Middle Triassic faunas are abundant and reflect the change from continental environments to a wide diversity of coastal and marine depositional environments. During the Anisian, faunas are represented by footprints and skeletal remains of amphibians (capitosaurs) and terrestrial reptiles (archosauromorphs and procolophonoids). Ichthyofauna, sauropterygians, thalattosaurs and protorosaurians are known through the late Anisian and Ladinian. Finally, Late Triassic localities representing coastal environments have also yielded marine reptiles (sauropterygians) and a diverse ichthyofauna.Se han realizado hasta el momento pocos estudios de los vertebrados del Pérmico y el Triásico de la Península Ibérica y por este motivo, una re-evaluación de estas faunas es necesaria para compararlas con las halladas en otras cuencas europeas. Como primer paso, aquí presentamos la información disponible de las cuencas Catalana y Pirenaica (NE de la Península Ibérica), ofreciendo nuevos puntos de vista sobre la diversidad y distribución temporal de las faunas de vertebrados. Las dos cuencas muestran una inesperada abundancia y diversidad de faunas de vertebrados, incluyendo peces, anfibios y reptiles de ambientes continentales y marinos. La revisión de hallazgos clásicos y el análisis de nuevo material proporcionan nuevos datos para la comprensión de la historia evolutiva y paleobiogeográfica de las faunas de vertebrados durante el Pérmico y el Triásico en la Península Ibérica. Los hallazgos en el Pérmico corresponden mayoritariamente a pisadas encontradas en depósitos aluviales, siendo el registro osteológico muy escaso en la Península Ibérica. Se desconocen localidades de vertebrados del Triásico inferior. Las faunas del Triásico medio son abundantes y reflejan el cambio desde ambientes continentales hasta una amplia diversidad de ambientes deposicionales costeros y marinos. Durante el Anisiense, las faunas están representadas por pisadas y restos esqueléticos de anfibios (capitosaurios) y reptiles terrestres (arcosauriformes y procolofonoideos). De finales del Anisiense y el Ladiniense se conoce ictiofauna, sauropterigios, talattosaurios y protorosaurios. Finalmente, las localidades del Triásico superior están representadas por ambientes costeros conservando reptiles marinos (sauropterigios) y una diversa ictiofauna

First nearly complete skull of Gallotia auaritae (lower-middle Pleistocene, Squamata, Gallotiinae) and a morphological phylogenetic analysis of the genus Gallotia

The Canary Islands are an Atlantic archipelago known for its high number of endemic species. Among the most known endemic vertebrate species are the giant lizards of the genus Gallotia. We describe the cranial osteology of the first almost complete and articulated fossil skull of the taxon Gallotia auaritae, recovered from the lower-middle Pleistocene of the La Palma island. In this work, X-ray computed microtomography images were used to perform an exhaustive phylogenetic analysis where most of the extant and fossil species of the genus Gallotia were included for first time. This analysis recovered a monophyletic Gallotia clade with similar topology to that of molecular analyses. The newly described specimen shares some characters with the group formed by G. bravoana, G. intermedia and G. simonyi, G. auaritae, and its position is compatible with a referral to the latter. Our study adds new important data to the poorly known cranial morphology of G. auaritae, and the phylogenetic analysis reveals an unexpected power of resolution to obtain a morphology-based phylogeny for the genus Gallotia, for inferring the phylogenetic position of extinct species and for helping in the identification of fossil specimens.Fil: Cruzado Caballero, Penélope. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Castillo Ruiz, Carolina. Universidad de La Laguna; EspañaFil: Bolet, Arnau. University of Bristol; Reino Unido. Institut Català de Paleontologia Miquel Crusafont; España. Universitat Autònoma de Barcelona; EspañaFil: Colmenero, Juan Ramón. Universidad de Salamanca; EspañaFil: De la Nuez, Julio. Universidad de La Laguna; EspañaFil: Casillas, Ramón. Universidad de La Laguna; EspañaFil: Llacer, Sergio. Institut Català de Paleontologia Miquel Crusafont; España. Universitat Autònoma de Barcelona; EspañaFil: Bernardini, Federico. Centro di Studi e Ricerche “Enrico Fermi”; Italia. Museo Storico della Fisica. Centro Fermi; ItaliaFil: Fortuny, Josep. Institut Català de Paleontologia Miquel Crusafont; Españ

Integrated multi-stratigraphic study of the Coll de Terrers late Permian-Early Triassic continental succession from the Catalan Pyrenees (NE Iberian Peninsula): A geologic reference record for equatorial Pangaea

The most severe biotic crisis on Earth history occurred during the Permian-Triassic (PT) transition around 252 Ma. Whereas in the marine realm such extinction event is well-constrained, in terrestrial settings it is still poorly known, mainly due to the lack of suitable complete sections. This is utterly the case along the Western Tethys region, located at Pangaea's equator, where terrestrial successions are typically build-up of red beds often characterised by a significant erosive gap at the base of the Triassic strata. Henceforth, documenting potentially complete terrestrial successions along the PT transition becomes fundamental. Here, we document the exceptional Coll de Terrers area from the Catalan Pyrenees (NE Iberian Peninsula), for which a multidisciplinary research is conducted along the PT transition. The red-bed succession, located in a long E-W extended narrow rift system known as Pyrenean Basin, resulted from a continuous sedimentary deposition evolving from meandering (lower Upper Red Unit) to playa-lake/ephemeral lacustrine (upper Upper Red Unit) and again to meandering settings (Buntsandstein facies). Sedimentary continuity is suggested by preliminary cyclostratigraphic analysis that warrants further analysis. Our combined sedimentological, mineralogical and geochemical data infer a humid-semiarid-humid climatic trend across the studied succession. The uppermost Permian strata, deposited under an orbitally controlled monsoonal regime, yields a relatively diverse ichnoassemblage mainly composed of tetrapod footprints and arthropod trace fossils. Such fossils indicate appropriate life conditions and water presence in levels that also display desiccation structures. These levels alternate with barren intervals formed under dry conditions, being thus indicative of strong seasonality. All these features are correlated with those reported elsewhere in Gondwana and Laurasia, and suggest that the Permian-Triassic boundary might be recorded somewhere around the Buntsandstein base. Consequently, Coll de Terrers and the whole Catalan Pyrenees become key regions to investigate in detail the Permian extinction event and the Triassic ecosystems recovery