Chaetopterus qiani, Sun, 2014

Sun, Yanan, 2014, A new species of Chaetopterus (Annelida, Chaetopteridae) from Hong Kong, Memoirs of Museum Victoria 71, pp. 303-309 : 304-305

Chaetopterus qiani sp. nov.

Zoobank LSID. http://zoobank.org/ urn:lsid:zoobank.org:act:

DB2F51FF-35F1-4676-890C-F4A4B83FCB68

Figures 1A–G, 2A–H

Material examined. 18 specimens. All type specimens were collected from the fish farm in Port Shelter, Hong Kong (22º20'37.15”N 114º16'58.70”E) on 19 Mar 1998. Holotype: MBM179979 , 1 complete specimen in tube with eggs in the parapodia of region C. Paratypes: MBM79980–79986 , AM W46121 – W46129 and AM W46131 (table 1) .

Diagnosis. 9 chaetigers in region A; modified chaetae of A4 light brown, 10–12 in number; wide neuropodia in A9; large wing-shaped notopodia in B1; long club-shaped notopodia and short conical dorsal cirrus in the dorsal lobe of neuropodia in region C; uncini with 7–9 teeth on lateral lobe of C1, and 10– 13 teeth on ventral lobe of C1.

Description. Holotype complete with tube (fig. 1A–C), total length 24.3 mm: 5.4 mm in region A, 11.7 mm in region B, and 7.2 mm in region C. Widest part of region A 4 mm.

Region A with 9 chaetigers. Prostomium small, with anterior border rounded, entire. Peristomium extended, completely covering prostomium; wide-horseshoe shaped in anterior view. Two grooved palps extending beyond peristomium, length 3.6 mm (fig. 1A). A pair of eyes present, located at the base of palps. Middorsal ciliated groove extending through region A (fig. 1A). Ventral surface with a long, slender ventral shield (plastron) (fig. 1B): length 4.2 mm, width 2 mm. First 8 chaetigers uniramous, with long, triangular notopodia. Notopodia of A6 longest (figs 1D, 2A). Ninth chaetiger biramous, with long notopodium and stubby neuropodial lobe. Each notopodium with 2–3 rows of light-yellow lanceolate chaetae; dorsal chaetae longer and more slender than lateral ones (fig. 2B, D–E). Notopodia of A4 with 10 modified chaetae. Modified chaetae light brown and club-shaped, with knob-like expanded tip, and arranged in 3 or 4 rows with 2–4 chaetae per row (figs 1E, 2B–C). Neuropodia of A9 with a row of uncini; uncini bluntly D-shaped, with 6–7 teeth in a single row (fig. 2F).

Region B with 5 chaetigers. Digestive gland green in fresh material; colour lost in ethanol-preserved specimens. Parapodia biramous. B1 with enormously enlarged, distally tapering, aliform notopodia extending to A1 (fig. 1A). B2 with elongate parapodium modified as large cupule. B3–B5 fused middorsally, forming enlarged fans. All notopodia of region B without chaetae or uncini. Neuropodia of B1 and B2 with upper and lower uncini lobe, B3–B5 with lower uncini lobe only. Uncini in a single row, similar in shape with uncini in region A; with 5–6 teeth in upper and lower lobe of B1 and B2 (fig. 2G), and 9–10 teeth in B3–B5.

Region C with 14 chaetigers. Parapodia all biramous. Notopodia long, club-shaped with slightly swollen tip (fig. 1A, B). Neuropodia bilobed; lateral lobe with papillary cirrus on lateral side only; ventral neuropodial lobe without cirrus (fig. 1F). Eggs present in neuropodia of holotype (fig. 1G). Uncini of region C similar to those of region A in shape, with 6–7 teeth in lateral neuropodial lobe of C1, and 10–13 teeth in ventral neuropodial lobe of C1 (fig. 2H). Other uncini of region C with 7–9 teeth.

Variation. Several morphological parameters show variations among the type specimens (table 1). The body length varies from 11.6–35.6 mm and the width from 2.4–4.5 mm. The number of modified chaetae in A4 ranges from 8–16. The first notopodia in region B extends to chaetiger A 1 in 7 specimens, to A 2 in 3 specimens and to A 4 in 5 specimens. The number of chaetigers in region C varies from 10–16. Of the type specimens, 5 are females with observable eggs under the body wall, but sex is indeterminable in other type specimens.

Type location and distribution. Currently only known from Port Shelter, Hong Kong .

Etymology. This species is named in honour of Professor Pei- Yuan Qian to recognise his support for polychaete research.