Abstract:
Puntius dorsalis (Teleosteii: Cyprinidae) is widely distributed in Sri Lanka and adjacent
countries. No previous information exists on its intraspecific geographic variation and
whether the Sri Lankan species is similar or different from Indian P. dorsalis. The
present study aimed to describe the morphometric characters of P. dorsalis in Sri Lanka,
and to carry out a comparative analysis with some Indian specimens. Fish specimens (n=
5-30) from 10 selected streams or tanks with hydrological connection to different major
river systems in Sri Lanka were collected (Kalu river, Nilwala river, Walawe river,
Menik river, Kirindi oya, Mahaweli river, Malwathu oya, and Kelani river) and museum
specimens (n=5) of one Indian location (Tamilnadu) was also included. Data of*20
morphometric characters of individual fish using pre-decided landmark points were
obtained, and all characters were standardized to remove size effect prior to data
analysis. Caudal Peduncle Length (CPL) and Pre Orbital Length (PrOL) of P. dorsalis
were significantly different between males and females (t-test, p<0.05, n=30, Nilwala
River), thus further data analysis for population comparison was done excluding CPL
and PrOL. Univariate ANOVA revealed significant heterogeneity in nine shape
characters among eleven samples, but no population specific characters were found. In
the discriminant function analysis (DFA) using significant characters for eleven
populations, Eye Diameter was identified as having the greatest power to discriminate
populations. In principal component analysis (PCA) plot, separation of two groups of
populations was possible, where CV1 and CV2 explained 61.0% of the total variation in
data. In the cluster analysis, Indian sample clustered with Nilwala river, Nuwara wewa,
Menik River, Minneriya, Kalu river, Kirindi oya and Walawe river populations (clade 1)
whereas Kelani and Mahaweli river populations made another clade. The results
concluded that Indian specimens shared the characters of the first Sri Lankan clade, so
that Sri Lankan specimens belonged to the same species Puntius dorsalis that was
described from India. However, significant intraspecific heterogeneity is evident so that
measures should be taken to conserve any genetic diversity present among them.
