Streptosyllis baolingi Ding & Westheide 1994
sand patch in dead coral reef, sand flat with ripple marks, fine sand
Body almost transparent, slender, length ca. 2.7mm for 31 chaetigers. Width including parapodia and dorsal cirri 380µm, 180µm without. Greatest width in 4th segment.
Prostomium rounded anteriorly, straight posteriorly. 
Two patches of cilia antero-laterally. 2 pairs of red eyes with lenses and two anterior eyespots; all eyes arranged hexagonally. Antennnae smooth, club-shaped, with short bases. Median antenna ca. 240µm, inserted near middle of prostomium. Lateral ones ca. 90µm, inserted laterally near anterior margin of prostomium. Palps large and swollen, wide base, fused, conical at distal end, cilia at tip, with palpostyles ventrally, ca. 24µm long / 8µm wide, with cilia at tip. Peristomium bears two pairs of tentacular cirri, similar to lateral antennae, on short cirrophores. Dorsal pair slightly longer than ventral pair (90µm-76µm). Dorsal cilia behind dorsal cirri.
Parapodia of chaetigers 2-4 large, truncated distally, all other parapodia more conical and smaller. Dorsal cirri smooth on small cirrophores, similar to lateral
antennae, but in chaetiger 6 articulated and from chaetiger 9 smooth and articulated cirri alternate. Usually three articles per cirrus. Batch of cilia at base of dorsal cirri and below ventral cirri. Ventral cirri digitiform, longer than parapodial lobes.
Aciculae distally truncated, enlarged in chaetigers 2-4.
Dorsal simple chaetae with thick shafts, strongly curved, serrated subdistally.
Compound falcigers with short blades, two of them unidentate, the others bidentate. Shafts bifid.
Remaining parapodia with slender chaetae and aciculae.
Simple dorsal chaeta slightly curved, distally hooded, serrated subdistally.
Two kinds of unidentate compound falcigers, one with long serrated blade, about 7-8 with shorter, finely serrated blades. Shafts bifid. Number of chaetae per parapod decreasing towards posterior end, last segment without chaetae.
Pygidium triangular, with two long lateral anal cirri and one medium appendix.
Pharynx extending from prostomium to chaetiger 9, with 10 papillae, unarmed. Proventriculum about 230µm long with 48 muscular rows.
S. baolingi is most closely related to S. biarticulata, which has enlarged palps visible from dorsal, and enlarged aciculae in chaetigers 2-4. It differs from this species by having small palpostyles and smooth tentacular cirri and no articulated palps. S. baolingi is also similar to S. latipalpa, S. magnapalpa and S. varians, all of these having large, dorsally visible palps. However, S. latipalpa has enlarged aciculae in chaetigers 2-5, S. magnapalpa in chaetigers 2-6 and S. varians in chaetigers 2-20.
