Sphaerodoropsis Hartman and Fauchald, 1971
Sphaerodoropsis sp. 4
Voucher specimen. SEA LION: stations 3MFB and 6MFC.
Diagnosis. Small sized species; voucher specimen short and maggot-like, tapering anteriorly and posteriorly; 4.5mm long, 0.8mm wide for about 22 chaetigers. Six sessile and distally rounded, globular macrotubercles in each of the two transverse rows per chaetiger; macrotubercles in a zig-zag pattern on dorsum, not tightly packed (dorsum easily visible); the lateralmost macrotubercles often smaller than others; surface of all macrotubercles evenly covered by many small papillae. Dorsum covered by one to very few small papillae located in spaces between macrotubercles. Uniramous parapodia short, cylindrical with one small papilla observed on parapodium (dorsal side); ventral cirri short, digiform; chaetae compound, unidentate falcigers, about 8 per fascicle. Venter sparsely covered with small papillae forming 2 regular rows, each with 4-5 papillae in each row.
Remarks. Falkland Islands specimens belong to group of Spaherodoropsis with more than 4 rows of macrotubercles (Borowski, 1994). Several species with similar number and arrangement of macrotubercle are known, including those known from the region. Important characters that differentiate between species, related to number and patterns formed by papillae on ventrum and parapodia (see Moreira et al., 2004 for details). This species is very similar to Sphaerodoropsis sp. 1 also recorded from Falkland Islands in its number and arrangement of macrotubercles, but the presence of multiple papillae on surface of macrotubercles differentiates Sphaerodoropsis sp. 4. This feature is not commonly reported in Sphaerodoridae. For now, we assign this specimen to morphospecies Sphaerodoropsis sp. 4.
