New insights into Diplogastrellus Paramonov, 1952 (Nematoda: Rhabditida: Diplogastroidea) with three novel and three known species from India

Diplogastrellus longipharyngis sp. nov. is characterised by a short tubular stoma; a medium-sized ventrally directed dorsal tooth; an ovoid median bulb and a long isthmus; heavily cuticularized almost straight spicules; a keel-like triangular gubernaculum proximally notched, a caudal margin interrupted and nine pairs of genital papillae. Diplogastrellus robustus sp. nov. is characterised by a medium-sized dorsal tooth with a ventrally directed apex; an ovoid median bulb; a mono-prodelphic or amphidelphic reproductive system; robust spicules, with a blunt distal tip; a boat-shaped gubernaculum with a prominent distal sleeve and nine pairs of genital papillae.

Three known species, viz., D. gracilis, D. graciloides and D. monhysteroides are redescribed/illustrated with emended diagnosis and SEM details. The comparative analysis of morphometrics and morphological traits as well as cladogram based on morphological characters are provided besides their biogeographic distribution.