Faunal change over three decades to reveal Rotundocollarette capoori n. gen., n.sp., a unique anisakid from Johnius dussumieri at the Central west coast of India at Goa

Abstract A unique anisakid roundworm, Rotundocollarette capoori n. gen., n.sp. infesting Johnius dussumieri from the Central West coast of India at Goa has been described. The worms are typically characterized by a cephalic collarette, a muscular collarette in post-caudal zone, intestinal caecum and a ventricular appendix. 3 pores, a part of cephalic infrastructure– a dorsal oral aperture, a dorso-laterally placed genital pore, and a sub-ventral excretory pore at the junction of the bases of the 2 ventro-lateral lips were typically unique as revealed by SEM studies. A pair of large squarish teeth flanked each of these three pores in the cephalic region, with 3-5 denticles in the median group, at the junction of the two arms of V-shaped structure, that joined 26-29 denticles on each arm of this V-shaped formation running parallel and crossed past dentigerous ridges on each lip. In addition a set of 49-50 medially organized denticles occupying the dorsal arm of V- shaped formation, in the medial space, were a conspicuous configuration, besides 40 minute triangular denticles at the junction of sub-ventral lips. A spined mucron at the tip of tail. The key provided by Moravec and Justine (2020) to segregate Porrocaecum -like nematode genera ( Porrocaecum , Pseudoterranova , Pulchrascaris , Euterranova , and Neoterranova ) has been revised to include the newly proposed genus, Rotundocollarette capoori n. gen., n.sp.