Abstract:
Taxonomic status of endemic members of the Sri Lankan snakeheads from family
Channidae i.e. Channa orientalis complex and Channa ara/marulius complex are
still plagued with taxonomical ambiguities and complexities. The objectives of this
study were to understand and resolve such issues of these two groups of species
based on molecular genetics, morphological characters and biogeographical
modelling. A field survey was carried out to record their distribution pattern while
fin clip samples were collected for molecular genetic study. C. orientalis complex
has been recorded from Mahawali and southwest icthiological zones while C.
ara/marulius complex was recorded from southwest, Mahaweli and dry
ichthyological zones of Sri Lanka. Genetic diversity of these two groups were
assessed using the mitochondrial COX1 gene. Our findings confirmed the existence
of two cryptic lineages within C. orientalis complex (with >8% genetic divergence),
while these two populations could not be distinguished based on the currently known
morphological characters. Further, the study revealed taxonomical and molecular
genetics ambiguity within the C. ara/marulius complex suggesting the need for
further studies. Among the studied linages of C. orientalis, one population is
restricted to Mahawali and Kelani basins including coastal flood plain penetration to
lower reaches of Kalu and Benthara catchments. The other lineage is distributed in
Nilwala, Gin and upper reaches of the Kalu river catchment, without overlapping the
previous population. Current taxonomy on C. ara/marulius complex has elsewhere
suggested to be consisting of three distinct, but puzzling lineages based only on a
few morphological characters and COX1 barcoding gene region. However, our
findings revealed that morphologically intermediate characters specially in the
contact zone of C. marulius and C. cfara, proposing a genetically and
morphologically highly diverse single species than two or three separate species. To
resolve the taxonomic puzzles related to these two groups ,we proposed to assess the
molecular genetics of species by using additional genetic markers such as NT2 and
16s rRNA and also to examine extended morphometric characters.
