Redescription of Trichuris laevitestis (Nematoda: Trichuridae) from Akodon azarae and Scapteromys aquaticus (Sigmodontinae: Cricetidae) in Buenos Aires Province, Argentina.

Trichuris spp. have a cosmopolitan distribution; the species are typically identified by features related to the reproductive system. Trichuris laevitestis was described on the basis of specimens collected from rodents captured in Punta Lara, Buenos Aires Province, Argentina. Here, T. laevitestis is redescribed considering new and relevant morphological features of diagnostic importance such as arrangement of spines on the spicular sheath, spicule length, length and shape of proximal cloacal tube, paracloacal papillae, features of the vulva, and ratios between different features. Akodon azarae and Scapteromys aquaticus specimens captured in the Rio de la Plata and Paraná Guazú River, and at Cerro de la Gloria, Buenos Aires Province, Argentina, were examined. The bacillary band of T. laevitestis is described, and several morphological details of this species are illustrated and recorded by scanning electron microscopy for the first time. The redescription of T. laevitestis confirms its identity as a valid species. In addition, the present study extends the geographical distribution of the species.