Search

Both sexes of a new species of sucking louse Hoplopleura janzeni (Phthiraptera: Hoplopleuridae) are described and illustrated from the Central American ichthyomyine swimming mouse Rheomys raptor (Rodentia: Muridae) collected in Costa Rica. The morphology of the new species is compared with that of Hoplopleura exima Johnson, the only other species of sucking louse known to parasitize an ichthyomyine rodent. Hoplopleura janzeni is unique in having posteriorly directed spurs on the first antennal segment, the fore- and midcoxae, and the hind femora of both sexes.

We investigated the swimming abilities of three Costa Rican dry forest rodents (Coues' rice rat. Oryzomys couesi, hispid cotton rat, Sigmodon hispidus, and spiny pocket mouse, Liomys salvini) associated with a large marsh, Laguna Palo Verde, using 90 s swim trials in a plastic container. Swimming ability was evaluated by observing the use of limbs and tail in the water, inclination to the surface, and diving and floating behavior. Rice rats could float, swim and dive, suggesting that they can exploit surface and underwater resources. Cotton rats swam at the water's surface, but were less skilled swimmers than rice rats. Spiny pocket mice tired quickly and had difficulty staying at the water's surface. Results suggest that differential swimming ability is related to the distribution of the three sympatric species within the marsh and adjacent forest habitats.