Proctocaecum gairhei n. sp. (Digenea : Cryptogonimidae : Acanthostominae) from Gavialis gangeticus (Gmelin) in Nepal and a revised cladogram of Proctocaecum Baugh, 1957

Abstract

Proctocaecum gairhei n. sp. is described from the gharial Gavialis gangeticus (Gmelin) in Nepal. The new taxon can be distinguished from all other species of Proctocaecum Baugh, 1957 by the combination of the following morphological characters: a single row of 23 cephalic spines, lateral anal pores opening at uneven levels, a forebody accounting for 16% of the total body length (TBL), an oral to ventral sucker width ratio of 1:0.7, an oral sucker to pharynx width ratio of 1:0.6 and uterine loops that occupy 59–67% of the TBL. While sharing some morphological characteristics with Acanthostomum slusarskii Kalyankar, 1977 from Crocodylus palustris (Lesson) in India, P. gairhei n. sp. is distinguished from the latter by possessing the solid muscular gonotyl diagnostic for Proctocaecum, by the number of cephalic spines, position of the anal pores and egg size. The existing cladogram for Proctocaecum was expanded using the character information of P. gairhei n. sp. The host range of Proctocaecum is now known to include all three families of the order Crocodylia.