FURTHER STUDY ON TWO SPECIES OF LOACH FISHES (Cypriniformes: Nemacheilidae: Nemacheilus) BASED ON MORPHOLOGY AND MOLECULAR DATA

Abstract

The identity of two local loaches, Nemacheilus chrysolaimos (Valenciennes, 1846) and N. fasciatus (Valenciennes, 1846), is revealed in this study using morphology and molecular approach based on our collection from six rivers at Biltar, East Java Indonesia. Based on morphology, these two species can be distinguished mainly from the dark bars or dark spots on the lateral body. The meristic data for N. chrysolaimos in this study is DII. 7–8 (dorsal fin), AI. 3–5 (anal fin), PI. 9 (pectoral fin), VI. 6–7 (ventral fin) and C. 17 (caudal fin), meanwhile, for N. fasciatus with D II 7–8 (dorsal fin), AI. 6 (anal fin), PI. 9–10 (pectoral fin), VI. 6–7 (ventral fin) and C. 17 (audal fin). There was a significant difference on the morphometric of N. fasciatus form sampling sites using Kruskal-Wallis Test. The nucleotide base composition sequences consisted of the mean of Thiamine (T) 29.565%, Cytosine (C) 32.023%, Adenine (A)  23.88%, and Guanine (G) 16.244%. Maximum Likelihood (ML) and Neighbour Joining (NJ) analysis was conducted using the Kimura 2 Parameter model to establish two major clades on Nemacheilus spp. and one out-groups clades significantly different from the Nemacheilus spp. These major  clades  were  closely related  to  each  other  at  the  100%  evidence of  bootstrap, which  grouped  as  genus Nemacheilus. The  present  study  on Nemacheilus spp.  from the Blitar  locality  was  able  to  differentiate  COI  sequences between N. fasciatus and N. chrysolaimos. Moreover, N. crysolaimos from references sequence  was inferred as the ancestor to N crysolaimos MZB 26540 and MZB 26539. ABGD analyses at a prior maximal distance of 0.025 also delineated this species into a separate partition.