Two new species of Stenosoma (Isopoda, Idoteidae) from the Sea of Marmara

Abstract

Two new species of isopod crustaceans belonging to the genusStenosomaLeach, 1814 (Valvifera, Idoteidae) are described, illustrated, and compared with the other known species of the genus. The new species can be distinguished both from each other and from all their congeners by having a maxilliped with two coupling hooks; length of the appendix masculina on pleopod II; and an antennal flagellum with 12 articles inStenosoma aasenisp. nov.; and by having a pair of distinctive lateral spinous tubercles on pereonites I-II; and a pereon with a part of a mid-dorsal carina on the posterior half of each of the pereonites inStenosoma inonueisp. nov.; the two new species also differ in the morphology of mouthparts, pleotelson, and pereopods. Both new species were collected from seagrass meadows, colonized predominantly byZostera(Zostera)marinaLinnaeus, 1753 andPosidonia oceanica(Linnaeus) Delile, 1813, in the Sea of Marmara, Turkey. An up-to-date morphological identification key to species level for to genusStenosomais also provided.