Morphological and molecular characterization of Acrobeloides saeedi Siddiqi, de Ley and Khan, 1992 (Rhabditida, Cephalobidae) from India and comments on its status

Abstract

Two cultured populations of Acrobeloides saeedi are described from India. Morphologically and morphometrically this material agrees with other species of the Maximus-group (A. bodenheimeri, A. longiuterus, and A. maximus), especially with A. longiuterus. However, molecular studies based on 18 S, 28 S and ITS rDNA confirmed the Indian material is well differentiated from all of these species. According to this, A. saeedi is considered a valid taxon distinguished mainly from A. bodenheimeri by having dextral female reproductive system (vs sinistral), from A. longiuterus by having larger females (1.03-1.57 vs 0.57-0.88 mm) and from A. maximus by having seta-like labial processes (vs absent) and males as frequent as females (vs males very infrequent). Molecular and phylogenetic studies revealed the present specimens to be conspecific to undescribed Acrobeloides sp. population from Iran, and hence, both regarded to be conspecific to each other. In addition, other similar species are revised: Acrobeloides ishraqi is considered new junior synonym of A. saeedi, Acrobeloides mushtaqi is considered new junior synonym of A. bodenheimeri, while Acrobeloides gossypia is also considered junior synonym of A. saeedi.