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Abstract

REVISION OF THE TAXONOMIC STATUS OF LYSIDICE AND NEMATONEREIS (POLYCHAETA, EUNICIDAE) IN THE WESTERN CARIBBEAN SEA WITH OBSERVATION OF REPRODUCTIVE FEATURES AND HABITAT PREFERENCE OF DIFFERENT SPECIES.

L.F. Carrera Parra¹, Kristian Fauchald² and Maria C. Gambi^3
1ECOSUR
²National Museum of Natural History
³Stazione Zoologica Anton Dohrn
Bio

Although the Eunicidae (Polychaeta) of the Western Caribbean Sea appear to be well studied, the taxonomic status of Lysidice and Nematonereis has yet to be evaluated. A first attempt to revise the taxonomy of these two genera is here presented, based on material collected at Carrie Bow Cay, as well as at other sites along the Yucatan Peninsula, representing a variety of habitat types (dead rubble corals, sponges, coralline sands, Thalassia testudinum meadows) and depths (0.5-20 m). The new specimens were also compared with literature description and records, as well as with Museum’ specimens for the re-description of the type species of the genus, Lysidice ninetta Audouin & Milne Edwards, which has been confused with, and synonymized in the past, with many Caribbean morphotypes of Lysidice. A preliminary analysis reveal that at least 3 species of Lysidice new to science occur in our material, two of them, Lysidice sp. c (yellow aciculae and sub-acicular hooks), and Lysidice sp. b (all black aciculae and sub-acicular hooks in transition from black to yellow) are preferentially associated with dead rubble corals, while Lysidice sp. a appeared to be strictly associated with Thalassia testudinum meadows, as a borer in the seagrass sheaths. Only a single specimen of Lysidice was found inside a sponge. The single species of Nematonereis recorded was associated with both coralline sands and Thalassia sheaths. Several specimens of Lysidice sp. c and Lysidice sp. a were mature demonstrated by the presence of a schizogamic-epitokous transformation with nearly 2/3 of the body swollen and full of gametes, and with eyes extraordinarily enlarged. The mature sperm of Lysidice sp. c has a typical “ect-aquasperm” structure. The reproductive features and sperm ultrastructure are consistent with those observed in the Mediterranean Sea members of the genus. These first results point out that Lysidice display a complex and diversified taxonomy in the Western Caribbean, supported by a clear habitat selection among different species.