Amphictene sp.1

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 : 17-18

Amphictene sp.1

Figs 1 & 7 .

Material examined. SCSMBC030872, 1 spec. incomplete with anterior 15 segments, Yellow Sea, 122°20'43.8"E 33°01'00.1"N, 20 m, mud, coll. P. Ni, X Zhong, B. Chou & L. He, Sep 2017, sta. H31. Preserved specimen stained with Rose Bengal.

Description. Preserved specimen width progressively becoming narrower posteriorly ( Fig. 7A–B ). Specimen incomplete with anterior 15 segments, body length 6.5 mm including paleae and scaphe, width 0.8 mm at cephalic regions ( Fig. 7A–B ).

Cephalic veil oval, free from operculum, with 10 smooth cirri on anterior and lateral margins ( Fig. 7C–D ). Pair of ear-shaped lobes adjacent to both sides of dorsal base of cephalic veil. Prostomial buccal tentacles short with deep medial grooves and inserted ventrally to cephalic veil ( Fig. 7C–D ).

Operculum semicircular; dorsal and lateral margins well developed, with two pairs of lateral long cirri and 12 ventral triangular lappets; with 11 pairs of golden paleae, curved dorsally, acute with extended tips; with small median papilla between both rows of paleae ( Fig. 7E ).

Segments 1 and 2 each with pair of tentacular cirri on lateral sides of body, with annuli, second pair larger and inserted more dorsally ( Fig. 7C, E ). Pair of small ventral lappets present ventrally to tentacular cirri, near cephalic veil, on segment 1. Segment 2 with pair of lateral lobes and mid ventral lobes on ventral margin ( Fig. 7C–D ).

Comb-like branchiae present on segments 3–4, 1 st pair larger and inserted more ventrally ( Fig. 7C–E ). Segment 3 with pair of small dorso-lateral pads ( Fig. 7C, E ). Dorso-lateral pads absent on segment 4 ( Fig. 7C, E ). Ventral glandular lobes present on segments 3–6 ( Fig. 7C–D ).

Notopodia other than those of segment 1 which bear paleae, on segments 5–15, each bearing two kinds of notochaetae. Neuropodia on segments 8–15, 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, and four longitudinal rows of major teeth, each with 6–8 teeth ( Fig. 7F ).

Scaphe lost. Tube not retained.

Distribution. Southern Yellow Sea ( Fig. 1 ).

Habitat. Muddy sediment in shallow water.

Remarks. The species can be distinguished from other species A. jianqingi n. sp. A. alata Zhang, Zhang & Qiu, 2015 and A. japonica ( Nilsson, 1928) from Chinese waters for specimen of Amphictene sp.1 has 4–5 longitudinal rows of major teeth on uncinus. As we only have a damaged incomplete specimen, we can only identify the animal to genus level and characterize the taxon by the cirri or lappets on the dorsal and lateral margins of the operculum, with the formal description requiring more material to be collected.

Figures

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

FIGURE 7. Amphictene sp.1 Methyl Green stained body with Rose Bengal (SCSMBC030872): A. Lateral view of incomplete body; B. Dorsal view of incomplete body; C. Close up of lateral view of anterior end; D. Ventral view of anterior end; E. Close up of dorsal view of anterior end; F. Uncini on segment 9. Abbreviations: br, branchiae; bt, buccal tentacles; cv, cephalic veil; dlp, dorso-lateral pad; op, operculum; or, opercular rim; p, paleae; s, segment; tc, tentacular cirri; vl, ventral lappet.