Podocoryna tenuis (Hydrozoa) in temperate waters of the southwestern Atlantic: additional data on life cycle stages support its synonym with Podocoryna humilis

GENZANO, GABRIEL N.; MIRANDA, THAÍS P.; VÁZQUEZ, NURIA; JAÑEZ, JULIETA; MARQUES, ANTONIO C.

Marine and Fishery Sciences (MAFIS)

Instituto Nacional de Investigación y Desarrollo Pesquero

Año: 2023 vol. 37

Two species of Hydractiniidae (Hydrozoa) with metagenetic life cycle have beenrecorded for the temperate region of the southwestern Atlantic Ocean: the medusa stage of Podoco-ryna tenuisand the polyp stage of P. humilis. Both the adult medusa of P. humilisand the polyp stageof P. tenuis are unknown, but it is possible that they are different stages of the same species, ahypothesis still to be tested. Colonies of P. humilisgrowing on the southern king crab Lithodes san-tolla collected at the Atlantic Patagonian coast, and two small medusae released from these hydroidcolonies were analyzed. Medusa of P. humiliswere kept alive for 3 days and they were morpholog-ically compared with the medusae of P. tenuis sorted out from ~2,500 plankton samples along theAtlantic Patagonian coast. The study of these specimens allowed reassessing the taxonomic statusof P. humilis and P. tenuis from the southwestern Atlantic Ocean. Polyp and young medusa stagesof P. humilis were described, and additional information was recovered to better describe themedusa stage of P. tenuis. New morphologic and biogeographic evidences in order to propose thesynonymy betweenP. tenuis and P. humilis were discussed.