Taxonomic Review and Ultrastructural Analysis of the Commensal Amphipod genus Paraleucothoe (Crustacea: Amphipoda)

A re-examination of the genera Leucothoe and Paraleucothoe through a literature review was performed. Specimens of a suspected invasive amphipod initially identified as Paraleucothoe flindersi collected from a host sponge Mycale sp. Gray, 1867, in Hawaiian coastal waters by D.G. Muir (Bishop Museum, Honolulu, Hawai’i) (Muir, 1997) were also examined for the purpose of their proper identification and to determine whether they are native or invasive to Hawai’i. Published research suggests that, L. novaehollandiae Haswell, 1880, L. brevidigitata Miers, 1884, and P. flindersi (Stebbing, 1888) appear to be the same species, although their exact taxonomic placement remains uncertain. Careful reexamination revealed each to be distinct, all differing from the Hawaiian species examined here. Detailed examination using both light and scanning electron microscopy and comparison with P. flindersi P. spinicarpus (Abildgaard, 1789), P. commensalis (Haswell, 1879 a), L. novaehollandiae, L. brevidigitata, and L. lihue Barnard, 1970, determined that the Hawaiian specimens represent a new undescribed species of Leucothoe