3. Pesquisa biológica aplicada ao manejo – Temas
Fernanda Martins-Hatano & Donald Gettinger
SPECIES OF LAELAPINE MITES ASSOCIATED WITH A SPECIES-COMPLEX OF TERRESTRIAL RODENTS COMMONLY KNOWN AS ORYZOMYS CAPITO
Recently, a comprehensive specimen-based taxonomic revision of the large complex of terrestrial oryzomyine rodents formerly classified as Oryzomys capito clearly divided these taxa, using morphological, distributional, and chromosomal evidence. Then, in 2006, these results were advanced by the establishment of two separate genera of these morphogically related groups: Hylaeamys Weksler (including the amazonian species megacephalus and yunganus) and Euryoryzomys Weksler (including nitidus, russatus, and the amazonian species macconnelli and emmonsae). Using ectoparasites collected from the same museum specimens used in the mammal studies, we identified laelapine mites (Acari: Laelapidae). The assemblage of mites associated with three species of rodents of the genus Hylaeamys Weksler, (H. nitidus, H. russatus, and H. macconnelli) was identical, composed of four mite species. However, the assemblage of mites associated with the host genus Euryoryzomys Weksler (E. megacephalus) was different, with only one species, Gigantolaelaps oudemansi, in common (see Table). Also, a morphometric analysis of mite exemplars drawn from populations of the one shared mite species (G. oudemansi) produced two distinct morphological groups, supporting the present mammalogical concept of the group (see Figure). Preliminary analysis of the laelapid fauna associated with terrestrial oryzomyine rodent species in the Floresta Nacional de Carajás, Pará, strongly predicts the presence of both host genera, and (at least two rodent species) in sympatry Using the species composition of the laelapid guild, we found one rodent species infested with the four laelapine species typically associated with the host genus Hylaeamys, and another rodent with the laelapids typically associated with host genus Euryoryzomys. So, both and examination of the species composition of the mite assemblages, and a morphological comparison of the one shared mite species produce the same relationship, and strongly support the decisions of mammalogists using modern systematic methods. Because the host mammals are presumed to be closely related phylogenetically, this appears to be a cospeciated mite fauna, with some sorting events thrown in to make it more interesting. Within the rodent genus Hylaeamys, some of the mites have either missed the boat, so to speak, or have gone extinct after the hosts diverged in evolutionary time.