Abstract
Namalycastis glasbyi Fernando & Rajasekaran, 2007 was originally described from the creek-lined coast north of Mumbai in western India. However, the original description includes some oddities that make species recognition problematic and may confuse future taxonomic evaluations of the genus. Moreover, the type material of the species has been lost and, therefore, this species is herein redescribed, a neotype is assigned, and the distinguishing morphological features are clearly illustrated. The species shares some features with two other Indian species: Namalycastis indica Southern, 1921 and the N. abiuma Müller in Grube, 1871 species group. However, N. glasbyi differs from N. indica in having comparatively smaller antennae, shorter posterior dorsal cirri, a higher count of notochaetae (maximum of three) in the mid and anterior body, and finely serrated blades in sub- and supra-neuroacicular falcigers in the anterior and mid-body. Further, sub-neuroacicular spinigers have finely serrated blades in all parapodia in N. glasbyi, as opposed to the coarsely serrated spinigers from antero-mid body parapodia of N. indica. Moreover, N. glasbyi differs from the N. abiuma species group in lacking coarsely serrated sub-neuroacicular spinigers in the parapodia of mid and posterior parts of the body and in possessing a tripartite pygidium. In addition to these morphological differences, the mitochondrial COI sequence (DNA barcode) of the neotype of Namalycastis glasbyi clearly distinguishes it from other Indian species.