Morpho-molecular characterisation of two new and two previously reported species of(Acanthogyrus: Quadrigyridae) from freshwater fishes in India.

Abstract

Of the total 47 species in the subgenus43 have been reported from the freshwater fishes of Asia. Amin. (2017) provided a key to the 23 species of the genusreported from the Indian subcontinent. The present study reports two new species:n. sp. andn. sp. fromHamilton andHamilton, respectively, and two previously described species:Gupta and Jain, 1980 andKhan and Bilqees, 1990 fromHamilton andHamilton, respectively.n. sp. comprises 3 circles of 6 proboscis hooks each. Trunk spines inn. sp are divided into two groups: anterior and posterior separated by unarmed region, which has not been previously reported in the subgenus. Anterior spines are present in 7-8 and 7-10 circles in females and males, respectively, whereas posterior spines are in 23-28 and 31-38 circles in males and females, respectively.n. sp. comprises 3 circles of 6-8 hooks each and a single set of trunk spines is present inn. sp., comprising 35-42 and 25-45 circles in males and females, respectively. All four species were also characterised based on the 18S, 28S, and ITS1-5.8S-ITS2 rRNA molecular markers. The Bayesian inference tree generated based on these markers showed distinct identities of all the species, with a significant molecular divergence, ranging from 3.2 to 53.6%.