Taxonomic Studies on the Talitridae (Crustacea: Amphipoda) of Taiwan. V. The Genus Brevitalitrus Bousfield, 1971

Abstract

The terrestrial amphipod genus Brevitalitrus Bousfield, 1971 (Talitridae) is represented by seven previously described species. In this study, two species of the genus are reported for the first time from Taiwan: B. hortulanus (Calman, 1912) collected from the terrestrial habitat of Green Island (=Lu Tao) and B. kumanoi sp. nov. from the coastal areas of Nan Bay of the mainland and Lanyu Island. Among its congeners, this latter species is most similar to B. nesius (Barnard, 1960) and B. toli (Barnard, 1960) in lacking marginal spines on the outer rami of uropods 1 and 2 and in having the propodus of pereopod 6 subequal in length to the basis. It differs from B. nesius in having the posterodistal lobe of the basis of pereopod 7 hardly incised at junction, the posterior margin of epimeral plate 3 gently convex, and the distolateral spine of uropod 1 simple, and from B. toli by the distally narrowing basis of pereopod 7, the rami of pleopod 2 that are shorter than the pe-duncle, and the tri-articulate rami of pleopod 3. Brevitalitrus kumanoi sp. nov. also differs from B. hortulanus in having the peduncle of pleopod 3 subequal in width to those of pleopods 1 and 2 and the outer rami of uropods 1 and 2 without marginal spines. Special attention is paid to the armature of the dactyli of pereopods 3-7 and the sub-categories of the cuspi-dactylate state. The terms uni-cuspidactylate and bi-cuspidactylate are proposed to better express the relationship of species in the genus. An identification key to all known species of the family Talitridae from Taiwan is provided.