Borja Sanchiz

Early Cretaceous Lower Vertebrates from Galve (Teruel), Spain

ABSTRACT The Early Cretaceous (Barremian–Aptian) lower vertebrate fauna from Galve, Spain, includes two hybodontid sharks, Hybodus parvidens and Lonchidion microselachos n. sp., as well as fragmentary remains of characteristic Mesozoic bony fishes. The salamander AIbanerpeton cf. megacephalus (Prosirenidae) is most similar to Jurassic Portuguese specimens of this species. Galverpeton ibericum n. gen. et sp. (family incertae sedis) was probably a slim-bodied animal; it resembles the ambystomatoid–plethodontoid salamanders and is the earliest record of the more derived salamander groups. The first disarticulated specimens of the Upper Jurassic or Lower Cretaceous discoglossid frog Eodiscoglossus santonjae permit refinement of the diagnosis of this primitive frog. A variety of small reptiles is also present, including lizards, crocodilians and dinosaurs; the latter are notable in being represented by teeth of very small (young?) animals. The Galve assemblage includes primarily freshwater forms, and, based on...

New discoglossid and palaeobatrachid frogs from the Late Cretaceous of Wyoming and Montana, and a review of other frogs from the Lance and Hell Creek formations

ABSTRACT A review of North American Late Cretaceous frogs demonstrates that Paradiscoglossus americanus n. gen. et sp. (Discoglossidae) and Palaeobatrachus occidentalis n. sp. (Palaeobatrachidae) definitively establish the presence of these families in the Late Cretaceous of North America (Lance Formation, Wyoming). P. occidentalis is also represented in the Late Cretaceous Hell Creek Formation in Montana. Interrelationships of palaeobatrachids are briefly discussed. A critical review of Scotiophryne pustulosa, earlier referred to the bombinid line within the Discoglossidae, establishes that there is a weak but definite case for maintaining this taxon in the Discoglossidae. Material that has been questionably referred to the pelobatid frog Eopelobates may be referred to the genus with some confidence. Familial relationships of Theatonius lancensis remain obscure. The presence of discoglossids and palaeobatrachids in North America during the Cretaceous strengthens the hypothesis of Estes and Reig (1973) th...

Une faune très diversifiée du Pléistocène inférieur de la Sierra de Quibas (province de Murcia, Espagne)

The Quaternary karstic site of Sierra de Quibas (Abanilla, province of Murcia, Spain) has provided a wide faunal list with more than 60 species. The assemblage of the taxa Arvicola deucalion, Castillomys rivas rivas, Eliomys intermedius, Equus altidens, Capra sp. aff. C. alba and cf. Praeovibos allows the correlation with other Spanish Lower Pleistocene sites in the Betic Cordillera, as Plines 1, Orce 3 and Venta Micena. Therefore Quibas can be located between 1.3 and 1.0 Ma. The palaeoenvironmental features of the area around the karstic cavity and the palaeoclimatic regime are inferred.

Middle Miocene remains of Alytes (Anura, Alytidae) as an example of the unrecognized value of fossil fragments for evolutionary morphology studies

ABSTRACT. Fragmentary anuran remains (an ilium and radioulna) from the middle Miocene of Moratilla 2 (Teruel Province, Spain) are identified, using qualitative characters and geometric morphometrics, as belonging to a new unnamed species of midwife toad, of the extant anuran genus Alytes (Alytidae). The Moratilla 2 fossils of Alytes are dated to ca. 16–17 Ma, prior to the early splits that resulted in the current Alytes diversification. Our biometric study of the fossil radioulnar fragment, an element usually considered uninformative, has revealed convergent adaptive trends in forearm locomotor performance within the genus. This finding would have remained hidden otherwise, because neither molecular approaches nor the comparative osteology of living forms would have detected it. A model for the evolutionary history of midwife toads is proposed, as a case example of how molecular phylogeographic results can be combined with morphological and paleontological studies at the genus level. Historical models of morphological adaptation at low taxonomic and anatomical levels now seem feasible using quantitative reconstructions of fossil fragments. In the future, these models can be compared with independently derived data based on environmental history.

A review of the palaeoclimatic inference potential of Iberian Quaternary fossil batrachians

Ecological suitability analysis aims to model the potential or probable distribution of species using environmental variables and available species occurrence information as predictors. Most of the European fossil Quaternary amphibians belong to extant species, and being physiologically ectothermic animals, their current ecological niches could become a reliable inference tool to infer past environmental conditions. However, this expectation has never been properly verified. The validity and accuracy of palaeoclimatic inferences based on batrachian species ranges is tested on the Iberian Peninsula, using both palaeofaunistic and Recent distribution data, and an updated database of georeferenced species occurrences is provided. The difficulties of using current geographic information to represent the full spectrum of environmental conditions at which a species occurs are critically examined. A palaeofaunistic review of the role played by historical factors as dispersal limitations for present amphibian species ranges is presented using the available phylogeographical scenarios. Virtual hypothetical taxa can be devised by considering the distributions of several species together and relating their known joint presences with the environmental conditions in these locations. Species distribution models based on these virtual taxa provide the best advisable inferential procedure. For direct raw inferences of the mutual climatic range method, contrary to expectations, the combined taxa sets do not increase their accuracy with the number of species included. This preliminary review shows that Iberian amphibian palaeoclimatic inferences are both valid and reliable enough, a sufficient approximation to complement other techniques. The precision, however, is quite variable among taxa, reflecting the effect of non-climatic distributional constraints.

Geology and paleontology of Tresjuncos (Cuenca, Spain), a new diatomaceous deposit with Konservat-Lagerstätte characteristics from the European late Miocene

PurposeA new Iberian Konservat-Lagerstätte discovered in Tresjuncos (Cuenca, Spain) is described and interpreted based on geological and paleontological information.MethodsThe samples were studied using conventional mineralogical (powder X-ray diffraction), petrographic (optical and scanning electron microscopy) and geochemical (X-ray energy-dispersive spectrometry) techniques.ResultsBased upon geological context, stratigraphy, lithology, sedimentology and origin of the rocks, we describe and interpret the new fossil site as originated in a lacustrine environment. The micromammals found in the Tresjuncos 1 outcrop suggest that the main site is Turolian in age (uppermost Miocene), continental chronological unit MN13. The fossils are preserved in laminates comprising rhythmic, millimeterscale alternations of diatomites and calcareous diatomites. An analysis of the lake paleobiota includes amphibians, crustaceans, insects, plants, and diatoms. The diatoms are dominated by Cyclotella iris. The whole assemblage is indicative of a planktic community developed in somewhat alkaline waters. An extremely well preserved premetamorphic Pelobates (Pelobatidae) tadpole was discovered; it is remarkable because of its gigantic size. Its digestive tract predominantly contains the rare diatom Navicula halionata var directa, likely associated with the shore vegetation in which it presumably lived and fed. The arthropods form a typical lacustrine aquatic assemblage, lacking fish. This assemblage is made up of small filtering crustaceans and of both predator and non-predator insects of diverse sizes.ConclusionsThe available evidence on Tresjuncos shows the extraordinary potential for paleontological information that can be expected from this new Konservat-Lagerstätte, which constitutes a significant finding that improves our understanding of continental late Miocene Mediterranean environments.ResumenPropósitoSe describe e interpreta un nuevo Konservat-Lagerstätte Ibérico descubierto en Tresjuncos (Cuenca, España) a partir de información geológica y paleontológica.MétodosLas muestras se han estudiado utilizando metodologías convencionales mineralógicas (difracción de rayos X) petrográficas (microscopía óptica y electrónica) y geoquímicas (Espectrometría de energía dispersiva de rayos X).ResultadosBasados en el contexto geológico, estratigrafía, litología, sedimentología y origen de las rocas, describimos e interpretamos la nueva localidad fósil como originada en un ambiente lacustre. Los micromammíferos encontrados en el afloramiento de Tresjuncos 1 sugieren una edad Turoliense (Mioceno superior), unidad cronológica continental MN13. Los fósiles se conservan en laminaciones que comprenden alternancias rítmicas a escala milimétrica de diatomitas y diatomitas calcáreas. Un análisis de la paleobiota del lago incluye anfibios, crustáceos, insectos, plantas y diatomeas. Las diatomeas están dominadas por Cyclotella iris. Todo el conjunto es indicativo de una comunidad planctónica desarrollada en aguas algo alcalinas. Se descubrió un renacuajo de Pelobates (Pelobatidae) pre-metamorfosis muy bien conservado; remarcable debido a su enorme tamaño. Su tracto digestivo contiene predominantemente la rara diatomea Navicula halionata var directa, probablemente asociada con la vegetación de la orilla en la que presumiblemente vivía y se alimentaba. Los artrópodos forman una típica agrupación acuática lacustre, carente de peces. Este conjunto se compone de pequeños crustáceos filtrantes y de insectos predadores y no predadores de diversos tamaños.ConclusionesLa evidencia disponible sobre Tresjuncos muestra el extraordinario potencial de información paleontológica que se puede esperar de esta nueva Konservat-Lagerstätte, que constituye un hallazgo significativo que mejora nuestra comprensión de los ambientes mediterráneos del Mioceno continental.

On Building Knowledge: Comments on “Qualifying Consequences”

This essay summarizes the authors’ methodological approach to historical research, which is based on methods employed in evolutionary biology. Emphasis is placed on the initial research questions and hypotheses, selection of operational units, and variables to be used. The numerical results obtained, though restricted pieces of information, may be combined with other similar ones to generate predictive models. Comparisons are made between this methodology and classic holistic narrative ones.

Consequences of the Spanish Civil War for Entomology: A Quantitative Example of Abrupt Alteration in Scientific Research Dynamics

The effects of the Spanish Civil War (1936–1939) on entomology are evaluated quantitatively using publication-related data. The authors tested the hypothesis that all research results are equally affected by a period of severe disruption. This hypothesis is rejected, and they quantified the degree to which different research outputs were affected. The recovery of scientific production was fast; there was no major destruction of infrastructure. Exiles were not an important factor, and half of the entomologists were active both immediately before and just after the war. Important differences are found in the postwar period in relation to the international situation influencing Spain and the new organization of the state. A decrease is detected in publication in foreign journals, and there was less use of foreign languages. There was a growing importance of publications and scientists associated with the public sector. Conversely, there was a clear decline in research outside the public sector, and local learned societies recovered much more slowly than governmental institutions, which explains, for instance, the near-disappearance of publications in Catalan until the late 1950s. The study indicates that an abrupt social alteration will have a relatively minor impact on scientific production as long as there is a base of continuity of human and material resources and continuous government financial support.