Chlebovitch, 1962 : 171 Revision of Autolytinae (Syllidae: Polychaeta). Nygren, Arne Zootaxa 2004 680 1 314 20dfea26-70c7-4243-abb1-6b6eab573236 Chlebovitch, 1962 Chlebovitch 1962 [264,764,1524,1550] Polychaeta Syllidae Autolytus Animalia Phyllodocida 111 112 Annelida species rostripalpus     Autolytus rostripalpus  Chlebovitch, 1962: 171–173, fig. 3.   Material examined.  Russia: holotype, ZIL4572, 4 paratypes ZIL4570, Onekotan Island, Bay of Nemo, 24 Aug 1955.   Description. Length 6–6.5 mmfor 6+(27–29)+(0–10) chaetigers, width c. 0.5 mmin region a excluding parapodial lobes, width c. 0.9 mmin region b including parapodial lobes. Preserved specimens yellowish, no colour markings; eyes red. Ciliation not possible to assess. Prostomium rounded rectangular, slightly concave anteriorly; ventrally with 2 lateral triangular processes (Fig. 53B). Eyes large, 2 pairs, with lenses; eyes situated on ventral and dorsal side of prostomium (Fig. 53A, B), ventral pair larger. Palps absent. Nuchal epaulettes as small ridges just posterior to prostomium (Fig. 53A). Median antenna reaching chaetiger 8–9 (n=3), inserted on posterior part of prostomium (Fig. 53A). Lateral bifid antennae, inserted on anterior margin of prostomium, 2 times as long as prostomial width; basal part 1/2 of total length, outer ventral rami slightly longer than inner dorsal rami (Fig. 53A). Basal part and inner dorsal rami on lateral antennae segmented (Fig. 53A) with abundant cilia. Pair of frontal processes, inserted anterolaterally to dorsal pair of eyes, equal in length to 1/2 prostomial width (Fig. 53A, B). Tentacular cirri 2 pairs (Fig. 53B), dorsal pair equal in length to prostomial width, ventral pair 1/3 as long as dorsal. First pair of dorsal cirri, equal in length to median antenna; achaetous knobs present (Fig. 53B). Second dorsal cirri situated above first chaetigerous lobes. Cirri in region a, reciprocally equal, measuring 1/2 of body width; cirri in region b and c slightly shorter than cirri in region a, diminishing posteriorly without any alternation in length. Median ceratophore, and cirrophores on first dorsal cirri, present; cirrophores otherwise absent. Cirri in region a, and anterior part of region b fusiform (Fig. 53A), more posterior gradually more cylindrical, other appendages cylindrical. Parapodia in region a, and c with rounded conical neuropodial lobes, of medium size; parapodia in region b flattened, with additional notopodial lobes, rectangular in outline. Notopodial lobes with single posteroventral papilla (Fig. 53C). Single neuropodial acicula in all chaetigers; 3–4 anterodorsal, and 3 thick and 3–4 thin posteroventral notopodial aciculae in region b. Neuropodial chaetal fascicle with 4–8 compounds in all chaetigers. Compound chaetae with large distal tooth (Fig. 53D); serration present. Single thin bayonet chaetae (Fig. 53E), subdistally denticulated, beginning between chaetiger 14–17. Notopodial chaetal fascicle with 15–20 swimming chaetae. Anal cirri equal in length to posterior dorsal cirri.   Distribution. North West Pacific, only known from typelocality.   Remarks.  Autolytus rostripalpuslike  A. obliquatushas a combination of 6 chaetigers in region a, achaetous knobs, large distal tooth in compound chaetae, and a thin bayonet chaetae.  Autolytus rostripalpusis distinct from  A. obliquatusin possessing triangular processes on ventral side of prostomium, and posteroventral notopodial papillae. Like for  A. obliquatusit is difficult to know generic placement, but close affinity with  Proceraeais likely; it is considered as incertae sediswithin Procerini. In the original description Chlebovitch states that  A. rostripalpusis unique in having both 3 and 6 chaetigers in region a, and the paratypesare a mixture of 4 specimensof  A. rostripalpus, and 9 specimensof another taxon with 3 chaetigers in region a. The latter typelack achaetous knobs, the triangular ventral processes, and the notopodial papilla; further, the distal tooth in compound chaetae is small.