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

Abstract

As a consequence of the growth of the Antarctic ice-sheet during the middle Miocene, a global decrease of temperatures and an associated increase in aridity provoked several environmental changes all around the world. Such environmental variations can be detected in the continental record of the mammalian prey community structure using a synecological approach. Because of the good quality of its faunas, the rich Aragonian vertebrate fossil record from the Madrid Basin (Spain) appears as a good candidate to explore these environmental changes. In order to analyse the climatic evolution of the Iberian Peninsula associated to the Global Cooling Event, two classic palaeosynecological methodologies (cenograms and body size diversity), based on body-size community structure, were applied to 6 fossil sites from the Madrid Basin, ranging over 2 million years (15.5 -13.5 Ma). To establish a comparative framework, we used the ecological faunal data from 100 modern localities uniformly distributed all around the world. Our palaeoenvironmental inference is based on multivariate discriminant analysis of the dataset containing both modern and fossil mammals. Finally, we can conclude that the Aragonian mammalian assemblage from the Madrid Basin showed a predominance of semiarid environments with pulses of higher aridity in biozones Dc, E and F associated with the Global Cooling Event of the middle Miocene.

Heterogeneidad lateral en las muestras de roedores del tramo T1 del Mioceno Medio de Somosaguas (Pozuelo de Alarcón, Madrid)

“…Por tanto, teniendo en cuenta la reducida cantidad de sedimento necesaria para el muestreo faunístico de este tramo, podría darse una cierta mezcla temporal (no significativa sensu Kowalewski, 1996) diferencial entre la muestra recogida en Somosaguas-Sur y la Cata-3, que se relacionaría con potenciales diferencias en la distribución lateral de distintos abanicos sucesivos, afectando de manera diferenciada a cada punto de muestreo. Además, el Aragoniense Medio es una época de marcada estacionalidad con precipitaciones escasas y probablemente impredecibles, lo que pudo dar lugar a sequías de duración variable (Domingo et al, 2009;García Yelo et al, 2014;Martín, 2015). La escasez de agua puede llegar a ser el factor limitante con mayor efecto sobre la dinámica poblacional de las comunidades de roedores (Morgan Ernest et al, 2000;Stapp, 2010;Heisler et al, 2014;Shenbrot, 2014).…”

Mortalidad excepcional en los cricétidos (Rodentia) del Mioceno medio de Somosaguas (Pozuelo de Alarcón, Madrid)

“…Los análisis paleoambientales sugieren que durante el Mioceno en Somosaguas se extendía una sabana tropical o subtropical rodeando un lago temporal, en un contexto paleoclimático global cada vez más fresco y árido como consecuencia del restablecimiento de la capa de hielo de la Antártida Hernández Fernández et al, 2006;Carrasco et al, 2008;Domingo et al, 2009;Perales et al, 2009;García Yelo et al, 2014;Fesharaki et al, 2015).…”

“…Este patrón ha sido asociado a eventos de aridez extrema en un marco macroclimático tropical semiárido (Hernández Fernández et al, 2006;Domingo, L. et al, 2012;García Yelo et al, 2014;Domingo et al, 2017). Estas condiciones paleoclimáticas fueron inferidas a partir de análisis faunísticos (Hernández Fernández et al, 2003Perales et al, 2009), así como distintos análisis geológicos del yacimiento, tanto sedimentológicos y mineralógicos (Carrasco et al, 2008;Fesharaki et al, 2015) como geoquímicos (Domingo et al, 2009).…”

Plio-Pleistocene climatic change had a major impact on the assembly and disassembly processes of Iberian rodent communities

“…An understanding of ecological disassembly at an evolutionary scale may have important implications for conservation, because of the potential effects arising from the current anthropogenic global warming. In fact, based on the idea that faunal communities and metacommunities are non-random sets of species (Wilson 1999) and that palaeosynecological characterisation of past assemblages (Nieto and Rodríguez 2003;Costeur et al 2013;García Yelo et al 2014) enable the understanding of the processes involved in the development of their changing patterns through time, the fossil record has provided solid evidence of the link between abiotic factors, such as climate change, tectonics, etc., and biotic responses, such as speciation, extinction, dispersals, replacement, etc. (Vrba 1985;Barnosky 2001;van Dam et al 2006;Benton 2009).…”