Division of Nematology, Indian Agricultural Research Institute, New Delhi-110012, India.
The type specimens of the nominal species of Caloosia, along with seven other populations (from A.P., Goa, Kerala, Tamil Nadu and West Bengal) were studied, and conventional taxonomic characters used for species identification were evaluated. Morpnometric parameters, ‘b’, ‘V’, spear length, ‘Rst’, ‘Roes’ and ‘VR’ are found to be the most stable out of the twelve characters studied. A positive correlation exists for the length of body and spear, body and tail, vulva and tail, and ratios ‘c’ and ‘V’. Regression equations for the significantly correlated characters are given to project the magnitude of relationship. The reliable morphological characters listed are: head annules, vulval sleeve and sometimes anastamoses of body annules of females; lip region, lateral field and cloacal lips of males. Seven species, C. brevicaudata, C. exilis (=C. indica), C. longicaudata, C. paralongicaudata, C. parlona, ‘C.’ paxi (=C. parapaxi and C. hetrocephala) and C. triannulata are found to be valid. A diagnostic key to the valid species is provided. Closely related genus Hemicaloosia Ray & Das, 1978, is confirmed to form a distinct group. Lastly, the phylogenetic relationships of this group are discussed.
