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Abstract

han proporcionado numerosos restos pertenecientes a 23 especies de mamíferos datados en la zona local E (MN5, Aragoniense Medio). En este trabajo se presentan nuevas aportaciones a su estudio, que han permitido descubrir una especie de rinoceronte no citada anteriormente en la cuenca de Madrid (Prosantorhinus douvillei) y la definición de una especie nueva de hámster (Cricetodon soriae nov. sp.). La sucesión muestra varios episodios de coladas de tipo debris-flow con transporte de huesos, rocas y arcosas discordantes por debajo y por encima de un relleno lacustre. Los depósitos contienen una secuencia de alteración de micas con arcillas de neoformación progresivamente más evolucionadas y vetas de caliche hacia techo, indicando aridez creciente. La riqueza del conjunto de macro y microvertebrados de los yacimientos de Somosaguas permite relacionarlo con el de otros yacimientos de edad similar, resultando en un patrón biogeográfico de transición paleártico-paleotropical. Esto coincide con los datos paleoclimáticos aportados por la fauna de mamíferos, que indican la existencia de condiciones tropicales con estacionalidad hídrica muy marcada. Se infiere la existencia en el área de un mosaico de ambientes dentro de un bioma de sabana, combinando áreas abiertas y bosquetes asociados al medio lacustre. El análisis isotópico indica un progresivo enfriamiento y aridez, que se correlaciona con los cambios climáticos inferidos a escala global en este período, hace unos 14 millones de años.Palabras clave: Aragoniense, Cricetodon soriae nov. sp., España, Geoquímica isotópica, Mammalia, Mineralogía, Paleobiogeografía, Paleoclimatología, Paleoecología, Estratigrafía, Paleontología Sistemática, Vertebrata. ABSTRACTThe Middle Miocene vertebrate fossil sites from the Somosaguas Campus of the Complutensian University of Madrid (Pozuelo de Alarcón) have provided many fossils from 23 mammal species, dated in local zone E (MN5, Middle Aragonian). In this work we show new research results which allow recognizing a new species of rhinoceros for the Madrid Basin (Prosantorhinus douvillei) and defining a new species of hamster (Cricetodon soriae nov. sp.). The succession shows several episodes of debris-flow deposits transporting bones, pebbles and arkosic sands, discordant below and above lacustrine sediments. The deposits content an alteration sequence of micas, with neomorphic clays progressively more

Composition of clastic sediments in the Somosaguas area (middle Miocene, Madrid Basin): insights into provenance and palaeoclimate

“…Finally, the indices and parameters used in this study (Tables 3, 4 and 5) serve to identify differences between the six samples collected from the unit T3 (N-4.1 to N-4.6), confirming the variations observed by Fesharaki (2005), Élez (2005) and Hernández Fernández et al (2006) between the different T3 levels. Such differences could point to a multi-episodic process, with sediments deposited by different pulses.…”

“…These climate perturbations coincide in time with the formation of the Somosaguas palaeontological site (Domingo et al, 2009(Domingo et al, , 2012aGarcía Yelo et al, 2014;see Fesharaki et al, 2012 for a complete bibliographic references list about this palaeontological site). Previous palaeoclimatic and palaeoenvironmental inferences based on the abundance and variety of fauna and its characteristics, together with sedimentological, mineralogical and isotope data obtained for the Somosaguas site, have assigned this site to a period of worldwide climate changes (López Martínez et al, 2000;Hernández Fernández et al, 2006;Fesharaki et al, 2007;Carrasco et al, 2008;Domingo et al, 2009;Perales et al, 2009;García Yelo et al, 2014). This available data make it an ideal location to extend palaeoclimate studies to other scientific fields such as light mineral petrology.…”

“…Further, these palaeontological sites offer considerable palaeoenvironmental and palaeoclimate information on this particular time period, especially for the Miocene (Van der Meulen and Daams, 1992; Calvo et al, 1993;Hernández Fernández et al, 2006). The Middle Miocene experienced remarkable climate changes with evidence suggesting a sharp drop in temperatures and an increase in aridity after the Miocene Climatic Optimum, a warm and humid period between 17 and 14 Ma (Zachos et al, 2001;Böhme, 2003).…”

Palaeoenvironmental analysis of the Aragonian (middle Miocene) mammalian faunas from the Madrid Basin based on body-size structure

“…The second one (between Arroyo del Olivar-Puente de ValArroyo del Olivar-Puente de Val--Puente de ValPuente de Vallecas and Somosaguas) coincided with the middle Miocene Global Cooling Event and reflects more arid conditions. The relative humidity curves given by Meulen and Daams (1992) and Hernández Fernández et al (2006b), based in changes in the structure of rodent faunas, depict aridity peaks that match in time with the climatic change towards more open and arid environments detected in the present study (Fig. 2).…”

“…These localities are: Estación Imperial; Paseo de las Acacias; Arroyo del Olivar-Puente de Vallecas; Somosaguas; Paracuellos 5 and Paracuellos 3. The faunal list of the six localities, together with the body size for fossil species were obtained from Peláez-Campomanes et al (2003), Hernández Fernández et al (2006b, Perales et al (2009) In body size spectra, every prey mammal from a particular community is assigned to one of the body size categories defined in table 1 (Andrews et al, 1979;Hernández Fernández et al, 2006a). Once each species of the prey community was classified in one of the body size categories and the final sum for each category converted to a percentage, the body size spectrum of the community was obtained.…”