Integrative taxonomy reveals hidden diversity within the concept of a laelapine mite species (Mesostigmata: Laelapidae) associated with sigmodontine rodents (Cricetidae): description of three new species of Laelaps Koch in the Neotropical region

Abstract

Laelapine mites are one of the most common ectoparasites of cricetid rodents. The taxonomical status is unclear of mites reported as Laelaps manguinhosi-like mites, since morphological variation was reported within the species in association with taxonomically and ecologically distinct sigmodontine rodents. We analysed morphological (qualitative and metric variation) and molecular data of four morphotypes of L. manguinhosi-like mites collected from three sigmodontine rodents (Cricetidae) of the tribe Oryzomyini (Holochilus brasiliensis, Nectomys squamipes and Oligoryzomys flavescens) and one of the tribe Akodontini (Scapteromys aquaticus). For better understanding, we defined L. manguinhosi sensu lato as a species concept and limited in a narrower sense L. manguinhosi sensu stricto. The association known from the literature between L. manguinhosi sensu stricto and H. brasiliensis was confirmed and additional information of this mite was provided. Mites associated with the remaining rodent species appear to be new species within L. manguinhosi sensu lato species complex, here described as Laelaps galliarii sp. nov., Laelaps scapteromyos sp. nov., Laelaps odysseos sp. nov., parasitizing O. flavescens, S. aquaticus and N. squamipes, respectively. Morphological analysis showed clear separation between the four studied species, with the majority also supported by molecular data. These results reinforce previous observations that Laelaps species are specific at least to the level of the host genus. Phylogenetic analysis based on 18.S-ITS1-5.8S-ITS2 partial gene markers indicate an earlier host-switch scenario between an akodontine associate (L. scapteromyos sp. nov.) and an oryzomyine associate (L. manguinhosi sensu stricto) followed by cospeciation events. Studied morphotypes of Laelaps were resolved as three separated clades. The basal one included mite species associated exclusively with Murinae (Old World) rodents and the other two are specific to Sigmodontinae (New World). The clade of sigmodontine associates was further divided into a cluster of mites parasitizing semiaquatic rodents and another cluster comprising mites parasitizing scansorial rodents. The obtained topology indicates that both, the phylogeny of rodent hosts and their ecological traits may play an important role in the coevolutionary process of host-mite relationships.