Redescription of Huridostomum formionis Mamaev, 1970 (Digenea: Monorchiidae) from the black pomfret, Apolectus niger (Carangidae), from the coast of Visakhapatnam, Bay of Bengal with a discussion on related genera and the proposal of Pseudametrodaptes n. gen.

Abstract

The monorchiid trematode Huridostomum formionis Mamaev, 1970 originally described from the black pomfret, Apolectus niger, from the Gulf of Tonkin by Mamaev (1970) is redescribed based on material collected from the same host from the Visakhapatnam coast, Bay of Bengal. The redescription provides additional information on the arrangement of the enlarged spines on the anterodorsal region of the oral sucker, the structure of the terminal genitalia and the course of uterus. The most significant features typical for the genus are considered to be the combination of morphological features including the presence of enlarged spines along the anterodorsal margin of the oral sucker, a very long elliptical cirrus sac, a unipartite terminal organ with the metraterm joining it distally, and extensive uterine coils. The genus Huridostomum is included in the subfamily Monorchiinae, its relationship with other monorchiid genera possessing spines anterodorsal to the oral sucker is discussed, and the validity of some of these genera is examined. Neopisthomonorchis Varma, 1982 is synonymized with Ametrodaptes Bravo-Hollis, 1956 and the new combination Ametrodaptes pristopomatis (Varma, 1982) n. comb. is suggested. Pseudametrodaptes n. gen. is erected to include the Indian species of the genus Ametrodaptes characterized by the absence of spines in the genital atrium and the presence of a unipartite terminal organ with the metraterm joining its distal end. The following new combinations are suggested: Pseudametrodaptes secundus (Madhavi, 1977) n. comb., Pseudametrodaptes bravoae (Ahmad, 1985) n. comb., Pseudametrodaptes caballeroi (Ahmad, 1985) n. comb. and Pseudametrodaptes fischthali (Ahmad & Dhar, 1987) n. comb.