Characterisation of Stegelletina salinaria Abolafia & Peña-Santiago, 2003 (Rhabditida, Cephalobidae) from Spain and South Africa including the first molecular study of the species

Abstract

Summary Stegelletina salinaria is redescribed from Spain and South Africa. Spanish material was collected in sandy soil from the type locality and a nearby area, while one population collected in compost was examined from South Africa. The species is characterised by its small size (0.27-0.41 mm), lateral field with three incisures, lip region with three pairs of dentate lips bearing four tines each, primary axils bearing a large guarding process, secondary axils lacking guarding processes, nerve ring and secretory-excretory pore at isthmus level, spermatheca and post-vulval uterine sac poorly developed, female tail conoid with rounded hyaline terminus and males unknown. The description, light micrographs and scanning electron microscope images, illustrations and molecular analyses are provided. 18S and 28S rDNA sequence analyses show that the isolates of S. salinaria from Spain and South Africa are closely related to each other and to other species of Stegelletina, while also indicating a close relationship with some species of Nothacrobeles, Scottnema and Stegelleta (28S tree) and Zeldia (18S tree).