Dorvillea similis ( Crossland, 1924 )

Çinar, Melih Ertan, 2009, Alien polychaete species (Annelida: Polychaeta) on the southern coast of Turkey (Levantine Sea, eastern Mediterranean), with 13 new records for the Mediterranean Sea, Journal of Natural History 43 (37 - 38), pp. 2283-2328 : 2301-2304

Dorvillea similis ( Crossland, 1924)

( Figure 6 )

Staurocephalus (Dorvillea) similis Crossland 1924: 100–106 , figs 119–126.

Dorvillea similis ; Imajima 1992: 143–146, figs 9a–t, 10a–j.

Material examined

ESFM-POL/2005-168 , 10 September 2005, I skenderun Bay, D21, 36°20′43″ N, 35°48′08″ E, 25 m, muddy sand, 2 specimens ; ESFM-POL/05-585 , 11 September 2005, K4, 0.5 m, ropes, 3 specimens ; ESFM-POL/05-408 , 12 September 2005, K 1, 1 m, rocks, 4 specimens ; ESFM-POL/05-352 , 12 September 2005, K5, 0.3– 1 m, rocks, 21 specimens ; ESFM-POL/2005-406 , 13 September 2005, K6, 0.1 m, Cystoseira sp. , 3 specimens ; ESFM-POL/05-363 , 13 September 2005, K6, 1– 3 m, rocks, 14 specimens ; ESFM-POL/05-625 , 14 September 2005, K9, 0.1– 3 m, port’s piling, 3 specimens ESFM-POL/05-472 , 14 September 2005, K8, 1– 3 m, rocks, 1 specimen ; ESFM-POL/ 05-530 , 15 September 2005, K10, 0–1 m, rocks ; ESFM-POL/2005-448 , 15 September 2005, K10, 0.5 m, J. rubens , 3 specimens ; ESFM-POL/2005-557 , 18 September 2005, K15, 0.2– 3 m, rocks, 2 specimens ; ESFM-POL/2005-803 , 19 September 2005, K17, 0.1– 3 m, rocks, 25 specimens ; ESFM-POL/2005-1261 , 19 September 2005, K 17, 2 m, Sarcotragus sp. , 4 specimens ; ESFM-POL/2005-1198 , 19 September 2005, K19, 0.1 m, Brachidontes pharaonis , 1 specimen ; ESFM-POL/2005-691 , 19 September 2005, K19, 0.1– 5 m, rocks, 68 specimens ; ESFM-POL/2005-1244 , 19 September 2005, K19, 0.1 m, Co. mediterranea , 68 specimens ; ESFM-POL/2005-1305 , 19 September 2005, K 19, 4 m, Halophila stipulacea , 5 specimens ; ESFM-POL/2005-776 , 20 September 2005, K22, 0.1– 5 m, rocks, 7 specimens ; ESFM-POL/2005-1177 , 21 September 2005, K 24, 5 m, sand, 1 specimen ; ESFM-POL/2005-1376 , 21 September 2005, K24, 0.5 m, Sphacelaria cirrosa , 12 specimens ; ESFM-POL/2005-590 , 21 September 2005, K24, 0.1– 5 m, rocks, 41 specimens ; ESFM-POL/2005-1195 , 21 September 2005, K24, 0.5 m, J. rubens , 2 specimens ; ESFM-POL/2005-1209 , 21 September 2005, K24, 0.5 m, Co. mediterranea , 9 specimens ; ESFM-POL/2005-1224 , 22 September 2005, K28, 0.1 m, sand, 1 specimen ; ESFM-POL/2005-637 , 22 September 2005, K26, 0.1– 3 m, rocks, 4 specimens ; ESFM-POL/2005-1283 , 22 September 2005, K27, 0.4 m, H. scoparia , 2 specimens ; ESFM-POL/2005-1341 , 22 September 2005, K 27, 2 m, Sarcotragus sp. , 1 specimen ; ESFM-POL/2005-1151 , 22 September 2005, K27, 0.1– 5 m, rocks, 1 specimen ; ESFM-POL/2005-970 , 22 September 2005, K27, 0.4 m, J. rubens , 1 specimen ; ESFM-POL/2005-2491 , 24 September 2005, K 30, 2 m, P. oceanica , 25 specimens ; ESFM-POL/2005-2326 , 24 September 2005, K30, 0.1 m, H. scoparia , 17 specimens ; ESFM-POL/2005-2770 , 25 September 2005, K 32, 2 m, rocks, 4 specimens ; ESFM- POL/2005-2655, 25 September 2005, K33, 0.1 m, Co. mediterranea , 3 specimens; ESFM-POL/2005-2469 , 29 September 2005, K37, 0.2 m, Brachidontes pharaonis , 17 specimens ; ESFM-POL/2005-2341 , 28 September 2005, K36, 0.3 m, Cy. elegans , 92 specimens ; ESFM-POL/2005-2659 , 3 October 2005, K44, 0.1 m, Co. mediterranea , 111 specimens ; ESFM-POL/2005-2537 , 3 October 2005, K 45, 9 m, P. oceanica , 2 specimens ; ESFM-POL/2005-2213 , 3 October 2005, K44, 0.1 m, J. rubens , 110 specimens ; ESFM-POL/2005-2742 , 3 October 2005, K45, 0.1– 3 m, rocks, 7 specimens ; ESFM-POL/2005-2255 , 3 October 2005, K45, 0.2 m, Amphiroa rigida , 17 specimens ; ESFM-POL/2005-2300 , 4 October 2005, K48, 0.2 m, H. scoparia , 8 specimens ; ESFM-POL/2005-1525 , 5 October 2005, K 50, 5 m, muddy sand, 2 specimens ; ESFM-POL/2005-2539 , 5 October 2005, K 50, 6m, P. oceanica , 3 specimens ; ESFM- POL/2005-2288, 5 October 2005, K50, 0.1 m, Cytoseira crinita , 140 specimens; ESFM-POL/2005-2183 , 5 October 2005, K50, 0.1 m, J. rubens , 27 specimens ; ESFM- POL/2005-2436, 7 October 2005, K 53, 3 m, Sarcotragus sp. , 3 specimens; ESFM- POL/2005-2273, 7 October 2005, K53, 0.1 m, Cy. elegans , 17 specimens; ESFM-POL/ 2005-2374 , 7 October 2005, K 53, 3 m, Z. marina, 4 specimens .

Description

Largest specimen complete, 4.5 mm long, 0.4 mm wide (chaetiger 4), with 43 chaetigers. Ventral surface flattened, dorsal surface slightly domed; body pale brownish, with no colour markings ( Figure 6A ). Prostomium somewhat rounded, slightly longer than wide; with two reddish eyes, large, in open trapezoidal arrangement; anterior and posterior pairs almost similar in size ( Figure 6A ). Two antennae emerging just posterolateral sides of anterior eyes, with seven joints. Palps stout, with palpostyles, shorter than antennae. Peristomium large, two or three times larger than anterior segments. Each segment with two ciliary bands. Chaetiger 1 without notopodia, without dorsal cirri, with thick ventral cirri. Subsequent chaetigers with slender dorsal cirri, extending slightly beyond parapodial lobes; with internal acicula; cirrophores large, subrectangular, almost three times longer than cirrostyles; cirrostyles subtriangular. Neuropodia of chaetiger 1 with rudimentary subtriangular pre- and postchaetal lobes. Neuropodia of anterior chaetigers well developed, with bifid prechaetal lobe and distally pointed postchaetal lobe. Posterior neuropodia becoming slender, with pointed pre- and postchaetal lobes. Supra-acicular neurochaetae with two types; one placed most superiorly, numbering two per fascicle, simple, slen- der, serrate with bidentate tip ( Figure 6B ); other numbering two or three per fascicle, simple, cultriform, serrated subdistally, with bidentate tip ( Figure 6D ); furcate chaeta absent. Subacicular part of parapodia with 10 falcigers; blades strongly bidentate, 20–12.5 µm long, with thin spines along cutting edge, with thin hoods; shafts densely serrated ( Figure 6C ). Notopodial aciculum slender, neuropodial aciculum simple, stout. Posterior parapodia with one cultriform chaeta and eight falcigers; blades strongly bidentate, 22.5–10 µm long. Dorsal cirri becoming shorted in posterior parapodia, as long as parapodial lobes. Pygidium with two pairs of anal cirri; dorsal anal cirri almost four times longer than ventral ones, wrinkled. Ventral anal cirri digitiform. Anus placed dorsally. Maxillary has symmetrical, fused- to oval-shaped base, serrate along anterior margins. Maxillae with 24 free denticles in superior row, 32 free denticles in inferior row. Each basal plate of superior row with nine teeth. Anterior free denticles prolonged, distally curved, with main fang, one lateral, three medial teeth. Middle free denticles with strongly curved main fang, one lateral, two medial teeth ( Figure 6G ). Posterior free denticles short, with large main fang, one lateral, three medial teeth ( Figure 6E ). Each basal plate of inferior row with seven teeth. Middle free denticles with main fang, two lateral teeth, three medial teeth ( Figure 6F ). Anterior free denticles strongly prolonged, with main fang, two lateral, four medial teeth. Mandibles symmetrical, fused medially, each with four to six small free denticles anteriorly, 10 small teeth on inner margin ( Figure 6H ).

Reproduction

Oocytes were found in the coelomic cavity of a specimen at K15 ( ESFM-POL /2005- 557): large, almost ovoid, having a maximum diameter of 190 µm (mean 163.4 ± 3.7 µm, n = 25).

Distribution

Dorvillea similis was previously reported from the Suez Canal, Indian Ocean and Pacific Ocean ( Imajima 1992). This species is being newly reported from the Mediterranean Sea. It seems to have been well established along the Levantine coast of Turkey, as it is almost present in all shallow-water habitats sampled. As this species was originally described from the Suez Canal by Crossland (1924), it is most probably a Lessepsian migrant. However, its occurrence on the other coasts of the Levantine Sea (i.e. Egypt, Israel, Lebanon, Cyprus) should be checked.

Figures

Figure 6. Dorvillea similis: (A) whole body, dorsal view (ESFM-POL/2005-691), (B) unidentate simple chaetae on chaetiger 5, (C) falciger on chaetiger 5, (D) bidentate simple chaetae on chaetiger 5, (E) posterior free denticle of superior row, (F) middle free denticles of superior row, (G) middle free denticle of inferior row, (H) mandible, dorsal view. Scale bars: (A) 0.4 mm, (B) 22 µm, (C) 19 µm, (D) 15 µm, (E) 9 µm, (F) 18 µm, (G) 16 µm, (H) 92 µm.