A New Species of Free-Living Nematodes (Desmodorida, Desmodoridae) in the Romanian Black Sea Waters

The paper reports the record of Pseudochromadora gomoi sp.n. in circalittoral habitats (at depths of 47-59 m) of the Romanian Black Sea waters. The species is characterized by a unispiral amphidial fovea, the presence of lateral alae stretching from the posterior end of the cardia to the level of the cloacal opening, but also shows unique features found in other Desmodorida genera (i.e., the presence of a precloacal ventral ala in males similar to several Desmodora or Echinodesmodora species and eight subcephalic setae on the head capsule). The presence of a constrictor cuticle ring and orange elongated ducts in the anterior body part as in Pseudodesmodora lacrima, Leduc and Wharton, 2010, were also noted. The morphometric measurements of our species differ from most of the Pseudochromadora species reported in specialty literature. We extracted and counted all desmodorid individuals from 9 meiobenthic samples collected in June 2020, and performed a detailed morphological analysis of 12 individuals (5 females and 7 males) belonging to our species, also highlighting the dissimilarities with the related desmodorid species.