An aberrant nematode, Baldwinema n. gen. (Nematoda: Panagrolaimomorpha: Panagrolaimidae), from Iran with description of three new species

Abstract

A new genus of Panagrolaimidae, together with three new species, is proposed based on morphological, morphometric and molecular studies. Baldwinema n. gen. is unique in the Tylenchina by a combination of the following characters: having valvular median bulb, no valve in terminal pharyngeal bulb and absence of stylet. It is further characterised by cylindrical body, thin and finely annulated cuticle, lateral field with two lines (forming a single plain band), fused lips, small longitudinal amphidial openings located on lateral lips, lip region without labial probolae, with six inner and six outer labial and four cephalic papillae (as seen using SEM images), stoma aberrant, cheilostom and gymnostom of equal length, cheilostom with thin wall, gymnostom with clear and thick wall, and stegostom beginning with a tubular thin wall and ending with a thicker wall. Baldwinema ilamense n. gen., n. sp., the type, is characterised by its short post-vulval uterine sac of 7.7 (6.0-9.0) μm long, female tail length of 147 (120-175) μm, shape of gubernaculum, and arrangement of male genital papillae; B. ardabilense n. gen., n. sp. by its short post-vulval uterine sac of 11.5 (9.0-15.0) μm, female tail length of 150 (136-169) μm, shape of gubernaculum, and arrangement of male genital papillae; and B. golestanense n. gen., n. sp. by its long post-vulval uterine sac of 16 (13-21) μm, female tail length of 200 (174-220) μm, shape of gubernaculum, and arrangement of male genital papillae. Phylogenetic analyses based on sequences of the small subunit (SSU) ribosomal RNA gene showed that the new genus is nested within the Panagrolaimidae. However, LSU data did not demonstrate monophyly of the Panagrolaimidae.