N. leithii is intermediate between
N. gangetica and
N. hurum. It is like the former in the width of the interorbital space, the comparatively short mandibular symphysis, and the markings of the head. It is like the latter in the longer and more pointed snout, the absence of a strong ridge on the inner alveolar surface of the mandible, and in the presence, in the young, of four or more dorsal ocelli, which are, however, smaller than in
N. hurum. Adults may attain a straight
carapace length of . ==Diet==