Shell morphometry and fecundity of the exotic snail Planorbarius corneus (Linnaeus, 1758) (Gastropoda: Planorbidae) in Kolkata, India.
An assessment of the shell morphology and the fecundity of the 'great ramshorn snail', Planorbarius corneus (Linnaeus, 1758) (Gastropoda: Planorbidae) obtained from pet market in Kolkata, India was carried out. Using various dimensions of the shell, including shell diameter, and body weight of the living specimens (n=204) and shell weight for dead specimens (n=306), the correlations and regression equations were framed to portray the shell shape of P. corneus. A relationship between fecundity with the shell diameter was also deduced to highlight the reproductive potential of P. corneus. In the living specimens, the shell diameter (x) and the body weight (y) fitted with a power regression y=0.396x2.74, R2=0.987. Similar observation was made for the dead specimens, where the shell diameter (x) and the shell weight (y) were related as: y=0.067x2.99, R2=0.973. All the dimensions of the shell were highly correlated (P < 0.0001) and could be related through regression equations. A positive correlation was observed between fecundity and shell diameter but with a low fit to a linear regression equation, indicating sufficient variability in the fecundity for a particular size of P. corneus. In continuation with these observations, further studies on P. corneus are required to deduce its possible effects as an invasive freshwater species in Indian context.