Manuel Hernández Fernández

A complete estimate of the phylogenetic relationships in Ruminantia: a dated species-level supertree of the extant ruminants

This paper presents the first complete estimate of the phylogenetic relationships among all 197 species of extant and recently extinct ruminants combining morphological, ethological and molecular information. The composite tree is derived by applying matrix representation using parsimony analysis to 164 previous partial estimates, and is remarkably well resolved, containing 159 nodes (>80% of the potential nodes in the completely resolved phylogeny). Bremer decay index has been used to indicate the degree of certainty associated with each clade. The ages of over 80 % of the clades in the tree have been estimated from information in the literature. The supertree for Ruminantia illustrates which areas of ruminant phylogeny are still only roughly known because of taxa with controversial relationships (e.g. Odocoileini, Antilopinae) or not studied in great detail (e.g. Muntiacus). It supports the monophyly of the ruminant families and Pecora. According to this analysis Antilocapridae and Giraffidae constitute the superfamily Giraffoidea, which is the sister group of a clade clustering Bovoidea and Cervoidea. The position of several taxa whose systematic positions have remained controversial in the past (Saiga, Pelea, Aepycerus, Pantholops, Ammotragus, Pseudois) is unambiguously established. Nevertheless, the position of Neotragus and Oreotragus within the original radiation of the non‐bovine bovids remains unresolved in the present analysis. It also shows that six successive rapid cladogenesis events occurred within the infraorder Pecora during the Oligocene to middle Pliocene, which coincided with periods of global climatic change. Finally, the presented supertree will be a useful framework for comparative and evolutionary biologists interested in studies involving the ruminants.

Macroevolutionary processes and biomic specialization: testing the resource-use hypothesis

The resource-use hypothesis predicts that generalist species have lower speciation and extinction rates than specialists. In this work we test several subsidiary predictions of the resource-use hypothesis using the biomic specialization index (BSI) for each African large mammal species, which is based on its geographical range within different climate zones. This index can be used globally allowing intercontinental and intertaxa comparisons. Our results are consistent with the axioms of the resource-use hypothesis theory, which predicts (1) a high frequency of stenobiomic species, (2) carnivores are more eurybiomic than herbivore clades (particularly, Artiodactyla and Primates), (3) the higher incidence of these biomic specialists in the tropical rainforest and desert biomes, and (4) the fact that certain combinations of inhabited biomes occur more frequently among species than do others. We also found that the tropical deciduous woodland is an important source of new species, and that there is a macroevolutionary segregation between extreme eurybiomic species (inhabitants of five or more biomes) and ‘semi-eurybiomic’ species (inhabitants of 2–5 biomes). These results can also be explained within the premises of the resource-use hypothesis. Finally, we discuss the relevance of our results to the understanding of the latitudinal gradient in species richness.