Species-level differentiation of two cryptic species pairs of wild cavies, genera Cavia and Galea, with a discussion of the relationship between social systems and phylogeny in the Caviinae

Trillmich F, Kraus C, Kunkele J, et al. Species-level differentiation of two cryptic species pairs of wild cavies, genera Cavia and Galea, with a discussion of the relationship between social systems and phylogeny in the Caviinae. CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE. 2004;82(3):516-524.Two little-known species of guinea-pig from the genera Cavia and Galea (Cavia magna Ximenez, 1980 and Galea sp. nov.) have recently been studied in more detail with respect to their behavior, social structure, and mating system. To determine the specific distinctness of these little-known species from Cavia aperea Erxleben, 1777 and Galea musteloides Meyen, 1832, crossbreeding between species was tried and it demonstrated that the two Cavia species will rarely cross in captivity to produce hybrids of much reduced fertility, whereas the Galea species could not be crossed. To analyze the phylogenetic position of C. magna and Galea sp. nov., we present an analysis based on major parts of the 12S (778 base pair) and 16S genes of mitochondrial RNA (1435 base pair) in conjunction with corresponding data on all other genera of the Caviinae. We also determined the relationship between C. magna and the sympatric wild guinea-pig (C. aperea) and its domestic form (Cavia aperea f. porcellus (Linnaeus, 1758)). Phylogenetic and distance analysis of all genera of cavies (Cavia (two species), Galea (two species), Kerodon, Microcavia) showed the close relationship of C. magna with C. aperea and the latter's particularly low genetic distance to C. aperea f. porcellus. Galea sp. nov. differed markedly from G. musteloides. Of the three genera, Galea appears most distinct. The genus Kerodon clustered with the genus Hydrochaeris, supporting the previous conclusion by Rowe and Honeycutt (2002. Mol. Biol. Evol. 19: 263-277) regarding the placement of the genus Hydrochaeris within the Caviidae. Recently published data on the social systems of the above-mentioned cavy species, however, show their great inter- and intraspecific social flexibility and contradict the interpretation of the same authors about a simple relationship between phylogeny and social systems in the Caviidae