Four new species of Parabathynellidae (Bathynellacea, Syncarida) from the interstitial environment of the Mekong River

Abstract

ABSTRACT This paper describes and illustrates four new species of the parabathynellid genus Mekongbathynella Nam and Cho, 2014 (M. kampucheana sp. n., M. pienensis sp. n., M. jayavarmani sp. n. and M. jayavarthoni sp. n.) collected from the interstitial habitat of the Cambodian Mekong, thereby increasing the number of the known species of the genus to six. The species are clearly distinguished from each other in their general habitus and in the morphology of labrum, mandible, maxillule, male thoracopod VIII and anal operculum. The combination of these characteristics allows us to group the six species into two lineages; one lineage includes M. sesanensis Nam and Cho, 2014, M. kampucheana, M. pienensis (the lineage I), while the other one consists of M. kryi Nam and Cho, 2014, M. jayavarmani and M. jayavarthoni (the lineage II). Moreover, each species in a lineage occurs in sympatry with a species from the other lineage: M. sesanensis (lineage I) and M. kryi (lineage II), M. kampucheana (lineage I), and M. jayavarmani (lineage II) and M. pienensis (lineage I) and M. jayavarthoni (lineage II). The three areas where the species occur are placed in distinctive reaches and/or tributary of the Mekong displaying different hydrological conditions. urn:lsid:zoobank.org:pub:6C143F95-86D3-446E-9FE4-AE6B018F3128