Himasthla limnodromi n. sp. (Digenea: Echinostomatidae) from the Short-Billed Dowitcher, Limnodromus griseus (Aves: Scolopacidae)

Abstract

Himasthla limnodromi n. sp. is described from short-billed dowitchers, Limnodromus griseus, from the Araya Peninsula, Venezuela, and Delaware Bay, U.S.A. Himasthla limnodromi was not found in dowitchers on the breeding grounds or on the fall staging grounds in the Bay of Fundy but reappeared in dowitchers on the wintering grounds in the fall. This suggests that H. limnodromi is acquired by the birds on arrival on the wintering grounds and then gradually disappears during the birds' northward migration in the spring. The new species has a reniform collar armed with 31 spines, with 23 in a single uninterrupted row, and 4 corner spines in overlapping pairs at each end. The cirrus sac is up to 10 times longer than the length of the acetabulum and contains a long, smooth cirrus. The vitellaria always commence posterior to the posterior end of the cirrus sac in mature specimens. The testes are found in the posterior eighth of the long, filamentous body. Himasthla limnodromi n. sp. most closely resembles Himasthla alincia, but H. limnodromi is larger in size and has an unspined cirrus and smaller eggs.