Gema Alcalde

The National Museum of Natural Sciences · Paleontology

Elisabeth S. Vrba’s resource-use hypothesis suggests that speciation in biomes subjected to successive expansion-contraction-fragmentation during periods of climatic change generates high frequency of species restricted to a single biome (stenobiomic species). We compiled biome occupation for all terrestrial mammals and, using Monte Carlo simulatio...

Corral de Lobato, a karstic site in the area of Molina de Aragón has been studied in a preliminary way. Even though there are not many Neogene karstic sites in the Iberian Chain, they occur in four clusters, with ages ranging from latest middle Miocene (MN7/8) to early Pleistocene (MN17). Correlations between these clusters and the reference strati...

Debris-flow hosted assemblages dominated by mammalian remains are very scarce in the fossil record and few examples are reported. Herein we present a detailed taphonomic study of Somosaguas-North (Madrid Basin, Spain), a Middle Miocene mammalian-dominated site embedded in debris-flow deposits, in order to increase our knowledge of themode of format...

The increasing availability of published evolutionary trees and phylogenetic methods has changed the way we tackle the study of evolution. In this sense, ruminants have become one paradigmatic object of study due to their ecological variety and well-known evolutionary history. The last decades of ruminant research have benefited from diverse phylog...

Villafranchian faunas were widely spread throughout the European continent during the Plio-Pleistocene. Ungulates, and particularly ruminants, are very well represented in most of the localities of this period. The fossil site of Tegelen (Province of Limburg, the Netherlands) is a classical Villafranchian locality where cervids are especially abund...

In the present study we analyze the microwear of the species included in the lineage Armantomys aragonensis-A. tricristatus of two samples from two middle Miocene localities from the Madrid Basin (El Cañaveral and Casa Montero). The methodological part of the study compares light stereomicroscope photographs from resin casts and Environmental Scann...

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 synecologi...

Integration between phylogenetic systematics and paleontological data has proved to be an effective method for identifying periods that lack fossil evidence in the evolutionary history of clades. In this study we aim to analyze whether there is any correlation between various ecomorphological variables and the duration of these underrepresented por...

Integration between phylogenetic systematics and paleontological data has proved to be an effective method for identifying periods that lack fossil evidence in the evolutionary history of clades. In this study we aim to analyze whether there is any correlation between various ecomorphological variables and the duration of these underrepresented por...

This work offers a tentative interpretation of the possible coat colour pattern of the Miocene bovid genus Tethytragus. The method used includes a maximum likelihood reconstruction analysis of data collected from all the 55 species of extant ruminants pertaining to the monophyletic group including the subfamilies Aepycerotinae, Alcelaphinae, Hippot...

The Cerro de los Batallones (Los Batallones Butte) is located in the central-northern area of the Madrid Basin, central Spain. Nine vertebrates localities containing a large variety of mammals of Upper Vallesian Age (Late Miocene) have been found associated with the sediments forming the butte. From bottom to top, these sediments consist of magnesi...