Steinernema keralense n. sp., a new entomopathogenic nematode (Nematoda: Steinernematidae) from India.

Abstract

In this study, morphological and molecular features were used to identify a new Steinernema sp. from Kerala, India. Morphological and molecular features provide evidence for placing the new species into the longicaudum clade. The new species is characterized by the following morphological features: infective juveniles with a body length of 1067 μm (914-1268 μm); a distance from the anterior end to excretory pore of 82 μm (73-92 μm); a distance from anterior end to nerve ring of 105 μm (91-118 μm). The distinguishing feature of the infective juveniles of S. keralense n. sp. is the presence of seven ridges in the mid-body region, while all other species classified within the logicaudum clade to date are characterized by eight ridges. The first-generation males are characterised by 25 genital papillae, very short spicules, with a length of 68 μm (60-72 μm), and the SW% ratio is 136 (114-169). The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that S. keralense n. sp. is closely related to species within the longicaudum clade.