Amphictene sp.2

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 : 18-20

Amphictene sp.2

Figs 1 & 8 .

Material examined. TIO908 AUTST03 SB290, 1 spec. incomplete with anterior 12 segments, Yellow Sea, 122°15'08.7"E 32°20'05.0"N, 22 m, mud, coll. First Institute of Oceanography , Ministry of Natural and Resources, Science 1, Oct 2007, sta. SB290 .

Description. Preserved specimen pale in colour ( Fig. 8A–B ). Specimen with anterior 12 segments, body length of fragment 6.3 mm including paleae, width 3.8 mm at cephalic regions ( Fig. 8A–B ).

Cephalic veil oval, free from operculum, with 10 smooth cirri on anterior and lateral margins ( Fig. 8A ). Pair of ear-shaped lobes adjacent to both sides of dorsal base of cephalic veil. Buccal tentacles broken and inserted ventrally to cephalic veil ( Fig. 8A ).

Operculum semicircular; dorsal and lateral margin well developed, with 19 cirri or lappets, lateral margin with long cirri and ventral margin with triangular lappets; with 10 pairs of golden paleae, curved dorsally, acute with extended tips; with small median papilla between both rows of paleae ( Fig. 8B ).

Segments 1 and 2 each with pair of tentacular cirri on lateral side of body, with annuli, almost similar in size, second pair inserted more dorsally ( Fig. 8B ). Ventral region distorted ( Fig. 8A ).

Comb-like branchiae distorted present on segments 3–4, 1 st pair larger and inserted more ventrally ( Fig. 8A–C ). Segment 3 with pair of narrow long-leaf shaped dorso-lateral pads ( Fig. 8B–C ). Dorso-lateral pads absent on segment 4. Ventral glandular lobes damaged ( Fig. 8A ).

Notopodia other than those of segment 1 which bear paleae, on segments 5–12, each bearing two kinds of notochaetae ( Fig. 8 F-I). Neuropodia on segments 8–12, 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 two longitudinal rows of major teeth, each with 7–8 teeth ( Fig. 8 D-E).

Scaphe lost. Tube not retained.

Distribution. Southern Yellow Sea ( Fig. 1 ).

Habitat. Muddy sediment in shallow water.

Remarks. The species can be distinguished from the three recorded species from Chinese waters A. jianqingi n. sp. A. alata Zhang, Zhang & Qiu, 2015 and A. japonica ( Nilsson, 1928) , and also from Amphictene sp.1 described above, as the specimen of Amphictene sp.2 has smooth narrow and elongated dorso-lateral pads on segment 3. Amphictene sp.2 also differs from Amphictene sp.1 as its uncini have two longitudinal rows of major teeth on uncinus whereas Amphictene sp.1 has 4–5 longitudinal rows of major teeth on the uncini. Like the case of Amphictene sp.1 , we only have a damaged incomplete specimen, so we are not describing it as a new species until more material becomes available.

Genus Lagis Malmgren, 1866

Type species. Lagis koreni Malmgren, 1866

Type locality. Stavanger , Finnmark, Norway

Diagnosis. Cephalic veil fused to operculum. Anterior rim of cephalic veil with numerous long cirri. Dorsal and lateral margins of operculum smooth, ventral margin with numerous notopodial paleae on each side. Comb-like branchiae present or absent on segments 3–4. Notopodia other than those of segment 1 which bear paleae, on segments 5–19 or 20 (15 or 16 pairs), with capillary notochaetae. Neuropodia, 12 pairs, with transverse row of uncini, on segments 8–19. Uncini with more than two longitudinal rows of major teeth. Scaphe flattened dorsally, with anal flap, and distinctly separate from posterior segments.

Remarks. The genus Lagis can be easily distinguished from all other genera of Pectinariidae as the cephalic veil is connected to the operculum. Day (1955) described the cephalic veil of Lagis pseudokoreni as not attached to the first pair of tentacular cirri, but still placed it in the genus Lagis . Based on the character of there being no connection between cephalic veil and operculum, we propose to transfer four species Lagis abranchiata ( Fauvel, 1932) , Lagis crenulatus Sun & Qiu, 2012 , Lagis plurihamus Choi, Jung & Yoon, 2017 and Lagis pseudokoreni Day, 1955 into the genus Pectinaria . Two species Lagis bocki ( Hessle, 1917) and Lagis neapolitana ( Claparède, 1869) have been recorded from Chinese waters ( Sun et al. 2008; Lin & Zheng 2012), but only Lagis bocki was collected during this Study ( Table 2 & Fig. 9 ).

Figures

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

FIGURE 8. Amphictene sp. 2 Methyl Green stained body (TIO908AUTST03SB290): A. Ventral view of anterior end; B. Dorsal view of anterior end; C. Dorsal view of left tentacular cirrus II to Branchiae II; D–E. Uncini; F–G. Notochaeta 1; H–I. Notochaeta 2. Abbreviations: br, branchiae; bt, buccal tentacles; cv, cephalic veil; dlp, dorso-lateral pad; or, opercular rim; p, paleae; tc, tentacular cirri.

FIGURE 9. Map illustrating the distribution of Lagis bocki (Hessle, 1917) in the coastal waters of China