Victor Surugiu

Taxonomic contribution to the genus Sphaerosyllis (Annelida: Syllidae: Exogoninae) in the Black Sea

During a study of fauna associated with a shallow-water Zostera (Zosterella) noltei bed from the southern part of the Romanian Black Sea coast, among the identified material collected in 2015, a syllid polychaete belonging to the subfamily Exogoninae, Sphaerosyllis taylori Perkins, 1981, represents a new record for the Black Sea. Re-examination of available specimens previously identified as Sphaerosyllis bulbosa Southern, 1914 revealed that they belong to an unknown species, described herein as Sphaerosyllis pontica sp. nov. The new species is characterized by the median antenna inserted more posteriorly than the lateral antennae, dorsal cirri with bulbous bases and very short tips, shorter than the parapodial lobes, dorsal cirri absent on chaetiger 2, parapodial glands with fibrillar material from chaetiger 4 onwards, compound chaetae with short blades and smooth shafts, anterior parapodia with two aciculae each, one straight and one with bent tip. Descriptions of both species are provided together with a key to all Sphaerosyllis species known from the Black Sea.

Fine‐scale population genetics analysis of Platynereis dumerilii (Polychaeta, Nereididae) in the Black Sea: How Do Local Marine Currents Drive Geographical Differentiation?

In this study we analyzed at a submeso-geographic scale (2 km) the genetic diversity of two sub-populations of Platynereis dumerilii and correlated this with the physical characteristics of the marine currents along the western Black Sea coast. For this purpose, we developed a set of 13 new polymorphic microsatellite markers and used them to assess the genetic differentiation, as well as the bi-directional migration rates between the studied sub-populations. We also computed the Peclet number (Pe) as an indicator of the relative effect of advection and eddy diffusion on larval dispersion for the specific conditions of the Black Sea study area. The results indicated no genetic structure in P. dumerilii sub-populations which indicates that the longitudinal alongshore currents dominate in the population structuring of this species. This finding is important, because with the average current speeds of 5 cm/sec on the Black Sea coast during May-August we might have expected a certain population structuring to occur. In accordance with the periodical change of direction of the longitudinal current (either form North to South, or form South to North) the gene flow was found to be bi-directional, with the same intensity.