Description of Capillaria forresteri sp.n. (Nematoda: Trichuridae) from the rice rat Oryzomys palustris in Florida, with notes on its ecology and seasonal variation

Abstract

Capillaria forresteri sp.n. is described from the fundic stomach of the rice rat Oryzomys palustris in Florida. It can be differentiated from related mammalian Capillaria spp. with lateral caudal alae in males by a combination of the following characters: location in the host, short (40–55 μm) lateral alae distinctly separated from caudal alae, and spicule length (380–426 μm). Prevalences were not different between male and female rats, but subadult and adult rats were more commonly infected than juveniles. Rice rats from freshwater marshes had a much higher prevalence than those from salt water marshes. Over a 2-year-period, both prevalence and intensity showed spring–summer peaks and sharp declines in autumn. Other species of mammals trapped in the same marshes were not infected with C. forresteri. The possibility of a paratenic or intermediate host in the life cycle is suggested.