Laonice (Sarsiana) sinica Sikorski & Wu, 1998

Sikorski, Andrey, Pavlova, Lyudmila, Martin, Daniel & Gil, João, 2023, New sublittoral species of Laonice (Annelida: Spionidae) from southern Asian coasts, Zootaxa 5277 (3), pp. 490-508 : 501-502

Laonice (Sarsiana) sinica Sikorski & Wu, 1998

Laonice sinica Sikorski & Wu 1998: 1243–1247 , Figs 1–3 , Tabs 1–3 [in Russian].

Material examined. Translated and adapted from Sikorski & Wu (1998).

Holotype. ZISP 1 /10363, Kiao Chou Bay , Qingdao, China, st. 43, 17–37 m, silt with shells, 20 June 1957.

Paratypes. ZISP 9 /10369, 1 specimen, Chefoo Bay , Yantai, China, st. 52, 10 m, silt, 03 July 1957 . Kiao Chou Bay , Qingdao, China, 5–37 m, silt with shells : ZISP 1 /10361 and 12/10372, 2 specimens, st. 3, 37 m, 03 June 1957 ; ZISP 13 /10373, 1 specimen, st. 18, 17 m, silt, 07 June 1957 ; ZISP 5 /10365, 8 specimens , ZMUM 1789 , 2 specimens, st. 20, 08 June 1957 ; ZISP 7 /10367, 1 specimen, st. 23, 08 June 1957 ; ZISP 15 /10375, 1 specimen, st. 24, 17 m, silt, 08 June 1957 ; ZISP 4 /10364, 2 specimens, st. 41, 5 m, 20 June 1957 ; ZISP 6 /10366, 1 specimen, st. 42, 27 m, 20 June 1957 ; ZISP 2 /50406, 5 specimens , ZMUM 1788 , 1 specimen, st. 43, 25 m, 20 June 1957 . Bohai Sea , China, 10–32 m, silt : ZISP 16 /10376, 1 specimen, st. 110, 18 July 1957 ; ZISP 8 /10368, 5 specimens, st. 206, 14–26 m, silt, 13 July 1957 ; ZISP 10 /10370, 2 specimens, st. 209, 23 September 1957 . ZISP 14 /10374, 1 specimen, Bohai Strait, China , R / V “ Venus ”, st. 5, 05 July 1958 . ZISP 11 /10371, 4 specimens, Yellow Sea, off China , R / V “ Venus ”, st. 201, 20–60 m, sandy silt with stones and broken shells, 27 July 1957 .

Description of Chinese specimens (translation of the original description). Up to 77 mm long and 1.3 mm wide for 144 chaetigers (re-examination of type material showed size-related data being slightly different from original description); largest incomplete specimen 1.4 mm wide.

Prostomium T-shaped with rounded anterior margin, not fused with peristomium at antero-lateral angles. Nuchal organs reaching chaetiger 8–11, as U-shaped ciliary bands on sides of caruncle. Palps reaching chaetiger 19. Short erect occipital antenna. Large bright bean-shaped eyespots in front of occipital antenna, sometimes with additional small pale spots in front.

Branchiae from chaetiger 2, short, very gradually lengthening from 1.5 times shorter on chaetiger 2 to nearly as long as notopodial postchaetal lamellae at chaetiger 7–8. Last pair of branchiae on chaetiger 26–42.

Notopodial postchaetal lamellae leaf-like, narrowing into sharply acute tips in all branchiate chaetigers, losing acute tips to become round on first 3–4 post-branchial chaetigers, becoming small rounded dorso-laterally shifted protrusions on posterior chaetigers, and finally becoming lanceolate on posteriormost chaetigers. Neuropodial postchaetal lamellae triangular, with acute upper tips becoming round on posterior post-branchial chaetigers.

Dorsal transverse crests first appearing on last 4–6 branchial chaetigers, then continuing up to chaetiger 25; first 2–3 as large oval (tongue-shaped) mid-dorsal membranes non-connecting with notopodial postchaetal lamellae; of equal height without any mid elevation from mid postbranchiate region to reach maximum size on last 1–2 branchial chaetigers.

Lateral inter-neuropodial pouches from chaetiger 5–9, sometimes larger than parapodia in most posterior chaetigers; usually not visible on posteriormost 12–17 chaetigers.

Capillaries of anterior chaetigers arranged in two vertical rows. Neuropodial hooks from chaetiger 27–41, up to 7–13 per fascicle, bidentate in lateral view, tridentate in frontal view, with one pair of small apical teeth very close to each other, side by side above main fang. Notopodial hooks absent. Sabre chaetae from chaetiger 20–36, at first two per fascicle (one in juveniles less than 0.5 mm wide), only one after 6–12 chaetigers.

Pygidium with one pair of closely set ventral lobes resembling small tubercles, and up to six bilaterally symmetrical pairs of thin threadlike dorsal anal cirri around anus.

Yellow-brown in vivo, non-pigmented when preserved.

Methyl Green staining. Lacking a distinct pattern.

Biology. Sexually mature females having oocytes 0.13–0.15 mm in diameter found on the 3rd and 20th of June of 1957 at Kiao Chou Bay (Yellow Sea). Mature specimens (with oocytes and sperm) found on the 26–27th of July 1957 at the Yellow Sea, and on the 17th of August 1957 at the Bohai Sea.

Type locality. Kiao Chou (= Jiaozhou) Bay (Yellow Sea), 17–37 m depth.

Distribution. Laonice (S.) sinica is known from the Yellow and Bohai seas (Pacific Ocean), where it can be dominant in sublittoral communities ( Fig. 6 ).

Remarks. The original description of Laonice sinica was published only in Russian by Sikorski & Wu (1998). Here we are presenting the first English translation. The comparison with the specimens collected in the Gulf of Siam can be found in the Remarks for Laonice (Sarsiana) cf. sinica .

Figures

FIGURE 1. Laonice persica sp. nov. A: anterior region (10 chaetigers), dorsal view. B: end of branchiate region (chaetigers 31–35), dorsal view. C–F: parapodia of chaetigers 7, 20, 32 and 46, frontal view. G: staining pattern with Methyl Green, anterior region (10 chaetigers), dorsal view. H: neuropodial hooded hook, lateral view. Scale, mm: A–F, 1; G, 1.4; H, 0.05. Material: A–B, G, paratype, Persian Gulf, st. 8 (MNCN16.01/19126); C–F, H, holotype, Persian Gulf, st. 19 (MNCN16.01/19125).

FIGURE 2. Laonice siamica sp. nov. A: anterior region (9 chaetigers), dorsal view. B: end of branchiate region (chaetigers 46–53), dorsal view. C: staining pattern with Methyl Green, anterior region (9 chaetigers), dorsal view. D: pygidium, rear view. E–G: parapodia of chaetigers 3, 25 and 49 (chaetiger anterior to last branchiate chaetiger), frontal view. H: neuropodial hooded hook, chaetiger 49, lateral view. I: neuropodial hooded hook, chaetiger 49, frontal view (scheme). Scale, mm:A–B, 1; C–D, 0.7; E–G, 0.5; H–I, 0.05. Material: holotype, Gulf of Siam, st. 5 (MNCN16.01/19128).

FIGURE 3. Laonice apicelamella sp. nov. A: anterior region (12 chaetigers), dorsal view. B: end of branchiate region (chaetigers 44–48), dorsal view. C: anterior region (7 chaetigers), lateral view. D: staining pattern with Methyl Green, anterior region (12 chaetigers), dorsal view. E–H: parapodia of chaetigers 4, 13, 29? (last branchiate chaetiger) and 19 before pygidium, frontal view. I: neuropodial hooded hook, chaetiger 19 before pygidium, lateral view. J: neuropodial hooded hook, chaetiger 19 before pygidium, frontal view (scheme). K, notopodial hooded hook, chaetiger 19 before pygidium, lateral view. L: notopodial hooded hook, chaetiger 19 before pygidium, frontal view (scheme). Scale, mm: A–C, 1; D, 1.4; E–H, 2.1; I–L, 0.05. Material: A–C, E–G, paratype, Andaman Sea, st. E7 (MNCN16.01/19130); D, paratype, Gulf of Siam, st. 8 (MNCN16.01/19132); H–L, paratype, Gulf of Siam, st. 1 (MNCN16.01/19134).

FIGURE 6. Location of the different species of Laonice discussed in the study: Persian Gulf (dot), Andaman Sea (square), Gulf of Siam (star), and Yellow Sea (triangle).