A new Neocalceostomatid (Monogenoidea) from the gills of the blackfin sea catfish, Arius jella (Siluriformes: Ariidae), in the Bay of Bengal, India

Thysanotohaptor n. gen. (Neocalceostomatidae) is proposed to accommodate Thysanotohaptor rex n. sp. collected from the gills of the blackfin sea catfish Arius jella Day (Siluriformes: Ariidae) from off the coast of Visakhapatnam, Bay of Bengal, Andhra Pradesh, India. Thysanotohaptor is differentiated from the other known neocalceostomatid genera by its species having multiple postgermarial testes (single testis in species of Neocalceostoma and Neocalceostomoides ), lacking a transverse bar associated with the ventral anchor pair (present in species of Neocalceostoma ), and possessing a disc-shaped haptor with a pleated marginal frill (frill absent in Neocalceostomoides spp.; Neocalceostoma spp. with delicate marginal membranes). The Neocalceostomatidae is considered valid within the Order Dactylogyridea based on its members having a haptor armed with 10 marginal and 4 ventral hooks and a germarium having a distal loop prior to uniting with the ootype; the family is not assigned to a suborder of Dactylogyridea because of uncertainty in part about the way in which the distribution of haptoral hooks evolved within the taxon.