Pectinaria torquata Zhang & Qiu, 2017

Zhang, Jinghuai, Hutchings, Pat & Qiu, Jian-Wen, 2022, Pectinariidae (Annelida, Polychaeta) from the coastal waters of China, with description of new species and new records, Zootaxa 5151 (1), pp. 1-74 : 33-34

Pectinaria torquata Zhang & Qiu, 2017

Figs 17–18 ; Figs 1–3 in Zhang et al. (2017)

Material examined. Holotype: MBM240082 , complete, Daya Bay, northern South China Sea , Guangdong Province, 114°42.98'E, 22°45.17'N, 9.0 m, muddy sand, Aug 2015 . Paratypes: MBM240083 , 1 spec. complete, Daya Bay, northern South China Sea , Guangdong Province, 114°33.22'E, 22°35.50'N, 11.0 m, muddy sand, Jun 2015 . MBM240084 , 1 spec. incomplete (17 anterior segments), Beibu Gulf, South China Sea , 108°34.46'E, 21°39.42'N, 9.7 m, muddy sand, Aug 2015 .

Non type material examined. SCSMBC030931, 1 spec. complete, Daya Bay, northern South China Sea , Guangdong Province, 114°43'15.6"E 22°42'25.2"N, 9 m, mud, coll. J. Zhang, Y. Gao & K. Chen, Jun 2015 , sta. D11. SCSMBC030933 (tissue sample sequenced), 1 spec. complete, Daya Bay, northern South China Sea , Guangdong Province, 114°35'50.0"E 22°38'01.0"N, 9 m, mud, coll. J. Zhang & X. Lyu, Aug 2020 , sta. SZ29. SCSMBC030932, 1 spec. complete, Beibu Gulf, South China Sea , 108°34'27.6"E 21°39'25.2"N, intertidal, mud, coll. G. Liu, Sep 2018 .

Description. Based on all specimens examined. Preserved specimens pale or reddish in colour, conical in shape ( Fig. 18A–B ). Body length 17.0–53.0 mm including paleae and scaphe, width 4.7–9.0 mm at cephalic regions.

Cephalic veil semicircular, free from operculum, with 26–32 smooth cirri on anterior and lateral margins ( Fig. 18C–D ). Pair of ear-shaped lobes adjacent to both sides of dorsal base of cephalic veil. Buccal tentacles with deep median longitudinal grooves, arising posterior to cephalic veil from buccal cavity, extending over margin of cephalic veil ( Fig. 18C–D ).

Operculum semicircular; dorsal and lateral margins well developed, smooth; ventral margin (opercular ridge) with 11–12 pairs of acute and golden paleae, curved dorsally, with extended tips ( Fig. 18C, E ).

Segments 1–2 with pair of tentacular cirri respectively, annulate, tapering to tip ( Fig. 18C–E ). Segment 2 with complete and smooth dorsal lobe ( Fig. 18C, E ). Segments 3–4 with pair of lateral comb-like branchiae respectively, with dorso-lateral pad adjacent to branchia ( Fig. 18C–D ). Distinct ventral glandular lobes present on segments 3–6 ( Fig. 18D ). Segment 4 with pair of lateral humps near branchiae ( Fig. 18D ). Segment 20 with a complete dorsal lobe ( Fig. 18G, F ).

Notopodia other than those of segment 1 which bear paleae, on segments 5–20 (16 pairs), each bearing two types of capillaries. Neuropodia, 13 pairs on segments 8–20, each with raised torus with a transverse row of uncini; each uncinus with U-shaped anterior peg embedded into torus, several rows of minor teeth, two longitudinal rows of major teeth, each with about seven teeth.

Scaphe distinctly separated from segment 21 ( Fig. 18G–H ). Scaphe longer than broad, arched ventrally and flattened dorsally with crenulated lateral margin. Anal flap tongue-shaped with tip, with crenulated margin ( Fig. 18H–I ). Scaphal hooks 4–7 pairs, short, barely visible, with a curved blunt tip ( Fig. 18G ).

Distribution. Northern South China Sea ( Fig. 17 ).

Habitat. Collected in mud of intertidal area and shallow water.

Remarks. The species can be easily separated from all other recorded species of pectinariids from China waters as Pectinaria torquata has a complete dorsal lobe on segment 2. Three complete specimens collected from close to the type locality in the northern South China Sea were examined and fit the original type description ( Zhang & Qiu 2017). A specimen was used for molecular studies, with partial sequences of five genes (COI, 16S rDNA, 18S rDNA, 28S rDNA and H3) being obtained. Bayesian phylogenetic tree confirm that P. torquata is a valid species and forms a clade with two other species P. lizhei n. sp. and P. dayaensis n. sp. from Chinese waters ( Fig. 41 ).

Figures

FIGURE 1. Map illustrating the distribution of species of Amphictene in the coastal waters of China

FIGURE 2. Amphictene alata Zhang, Zhang & Qiu, 2015 Methyl Green stained body (SCSMBC030866): A. Dorso-lateral view of distorted entire body; B. Ventral view of distorted entire body; C. Dorsal view of anterior end; D. Lateral view of anterior end; E. Ventral view of posterior end; F. Lateral view of posterior end; G. Ventral view of posterior end; H. Dorsal view of posterior end; I. Scaphal hooks. Abbreviations: af, anal flap; br, branchiae; bt, buccal tentacles; cv, cephalic veil; dlp, dorsolateral pads; dls, dorsal lobe of scaphe; nep, neuropodium; noc, notopodial chaetae; op, operculum; or, opercular rim; p, paleae; s, segment; sc, scaphe; sh, scaphal hooks; tc, tentacular cirri; vl, ventral lappet.

FIGURE 3. Relationship between body width and body length, number of pairs of paleae, number of cirri on cephalic veil, number of pairs of scaphal hooks, number of cirri on opercular rim, for Amphictene alata Zhang, Zhang & Qiu, 2015.

FIGURE 17. Map illustrating the distribution of Pectinaria torquata Zhang & Qiu, 2017, P. dayaensis n. sp., P. lizhei n. sp. and P. xiukaii n. sp. in the coastal waters of China

FIGURE 18. Pectinaria torquata Zhang & Qiu, 2017 Methyl Green stained body (SCSMBC030933): A. Ventral view of entire body; B. Lateral view of entire body; C. Lateral view of anterior end; D. Ventral view of anterior end; E. Dorso-lateral view of anterior end; F. Lateral view of posterior end; G. Dorsal view of posterior end; H. Ventral view of posterior end; I. Anal flap. Abbreviations: af, anal flap; br, branchiae; bt, buccal tentacles; cv, cephalic veil; dl, dorsal lobe; dlp, dorso-lateral pad; lh, lateral hump; nep, neuropodium; op, operculum; or, opercular rim; p, paleae; s, segment; sc, scaphe; sh, scaphal hooks; tc, tentacular cirri; vl, ventral lappet.

FIGURE 41. Bayesian phylogenetic tree of the family Pectinariidae based on multigene sequences (COI, 16S rDNA, 18S rDNA, 28S rDNA and H3), including 13 species of pectinariids and two outgroups (one of the family Trichobranchidae, another of the family Arenicolidae). Numbers above nodes are posterior probabilities.