Canaania obesa (Platyhelminthes: Dicrocoeliidae): redescription and new hosts records

ABSTRACT

The digenetic trematode Canaania obesa Travassos, 1944 (Dicrocoeliidae) was described as a parasite of the bile ducts of the rodent Akodon cursor Winge, 1887 (Cricetidae) collected in Santa Teresa, state of Espírito Santo, Brazil. In the present study, we report the occurrence of C. obesa infecting three additional sigmodontinae rodent species Akodon montensis Thomas, 1913; Oligoryzomys nigripes Olfers, 1818 and Nectomys squamipes Brants, 1827, from three municipalities situated at Serra dos Órgãos, Rio de Janeiro, Brazil. Scanning electron microscopy showed that this helminth has a leaf-like shape with conical extremities and the ventral mid body protrudes at the acetabulum level. The microtopography of the tegument shows a heterogeneous surface with smooth or wrinkled areas and several randomly distributed papillae. The cirrus is located just posterior to the oral sucker and is covered by smooth tegument without spines or papillae. The excretory pore is subterminal. The eggs are elliptic and operculate at one of the extremities. The present study adds new taxonomic characters to C. obesa. The municipalities of Nova Friburgo, Teresópolis and Sumidouro are new geographical areas of distribution, and A. montensis, O. nigripes and N. squamipes are new host records for C. obesa.