Nephtys incisa Malmgren, 1865

Kuş, Sevgi, Kurt, Güley & Çinar, Melih Ertan, 2021, Nephtyidae (Annelida: Polychaeta) from the Sea of Marmara and Black Sea, with descriptions of two new species, Zootaxa 5060 (2), pp. 183-214 : 199-202

Nephtys incisa Malmgren, 1865

( Figure 7 )

Nephtys incisa Malmgren 1865: 105 , pl. XII, Fig. 21; McIntosh 1908: 38–39, pl LVII, Figs. 4 , 19, 20; Augener 1913: 203; Pettibone 1963: 198, Figs. 49A, B, 51A; Rainer 1990: 366, Figs. 2A–E ; Rainer 1991: 76, Fig. 3G ; Ravara et al. 2010: 52 , Fig. 20.

Material examined. Sea of Marmara: ESFM-POL/2013-1007 , 06 June 2013, station Y1, 40°01’27’’N, 26°13’24’’E, 10 m, mud with dark detritic material, 1 specimen ; ESFM-POL/2013-1136 , 06 June 2013, station Y1, 40°00’32’’N, 26°13’04’’E, 25 m, mud, 1 specimen ; ESFM-POL/2013-1139 , 07 June 2013, station Y5, 40°20’55’’N, 26°40’38’’E, 25 m, mud, 10 specimens ; ESFM-POL/2013-1143 , 07 June 2013, station Y5, 40°21’21’’N, 26°39’59’’E, 50 m, mud with Amphiura filiformis , 1 specimen ; ESFM-POL/2013-1144 , 07 June 2013, station Y6, 40°26’10’’N, 26°41’51’’E, 10 m, mud, 1 specimens ; ESFM-POL/2013-1149 , 07 June 2013, station Y6, 40°26’03’’N, 26°41’59’’E, 25 m, mud, 10 specimens ; ESFM-POL/2013-1150 , 07 June 2013, station Y8, 40°25’15’’N, 27°03’49’’E, 10 m, mud, 1 specimen ; ESFM-POL/2013-1160 , 07 June 2013, station Y8, 40°25’27’’N, 27°03’34’’E, 25 m, mud with Amphiura filiformis , 3 specimen ; ESFM-POL/2013-1163 , 08 June 2013, station Y9, 40°28’09’’N, 27°11’14’’E, 50 m, sandy mud, 2 specimen ; ESFM-POL/2013-1168 , 08 June 2013, station Y11, 40°36’12’’N, 27°05’20’’E, 10 m, sandy mud, 3 specimen ; ESFM-POL/2013-1170 , 08 June 2013, station Y11, 40°35’55’’N, 27°05’25’’E, 25 m, sandy mud with shell fragments, 10 specimen ; ESFM-POL/2013-1172 , 08 June 2013, station Y11, 40°34’50’’N, 27°05’59’’E, 50 m, mud with Amphiura filiformis , 2 specimen ; ESFM-POL/2013-1178 , station Y12, 40°40’38’’N, 27°16’25’’E, 10 m, fine sand with Spisupa sp. shell fragments, 1 specimens ; ESFM-POL/2013-1179 , 08 June 2013, station Y12, 40°39’44’’N, 27°17’00’’E, 25 m, mud with Amphiura filiformis , 1 specimens ; ESFM-POL/2013- 1188 , 08 June 2013, station Y12, 40°39’44’’N, 27°17’00’’E, 50 m, mud with Amphiura filiformis , 1 specimen ; ESFM-POL/2013-1193 , 10 June 2013, station Y13, 40°45’15’’N, 27°20’49’’E, 50 m, mud, 1 specimen ; ESFM- POL/2013-1196, 08 June 2013, station Y14, 40°24’03’’N, 27°19’23’’E, 10 m, mud with Amphiura filiformis , 17 specimens; ESFM-POL/2013-1199 , 08 June 2013, station Y14, 40°24’22’’N, 27°20’48’’E, 25 m, mud with Amphiura filiformis , 3 specimens ; ESFM-POL/2013-1201 , 08 June 2013, station Y15, 40°19’11’’N, 27°33’51’’E, 10 m, sandy mud, 42 specimens ; ESFM-POL/2013-1204 , 08 June 2013, station Y15, 40°19’47’’N, 27°31’40’’E, 25 m, mud with Amphiura filiformis , 2 specimens ; ESFM-POL/2013-1206 , 09 June 2013, station Y16, 40°18’39’’N, 27°45’43’’E, 25 m, mud with Amphiura filiformis , 8 specimens ; ESFM-POL/2013-1211 , 09 June 2013, station Y16, 40°24’13’’N, 27°39’47’’E, 41 m, mud with Amphiura filiformis , 1 specimen ; ESFM-POL/2013-1214 , 09 June 2013, station Y17, 40°39’09’’N, 27°41’14’’E, 25 m, mud, 1 specimen ; ESFM-POL/2013-1215 , 10 June 2013, station Y18, Y18, 40°54’28’’N, 27°33’24’’E, 25 m, muddy sand with Lithothamnion sp. , 1 specimen ; ESFM- POL/2013-1219, 12 June 2013, station Y20, 40°57’51’’N, 27°55’24’’E, 10 m, sandy mud with shell fragments, 3 specimens; ESFM-POL/2013-1222 , 16 June 2013, station Y25, 40°24’48’’N, 28°20’41’’E, 25 m, sandy mud with shell fragments, 2 specimens ; ESFM-POL/2013-1223 , 16 June 2013, station Y26, 40°22’36’’N, 28°39’41’’E, 25 m, mud with Turitella shell fragments, 4 specimens ; ESFM-POL/2013-1225 , 16 June 2013, station Y27 40°23’30’’N, 29°03’49’’E, 25 m, mud, 2 specimens ; ESFM-POL/2013-1226 , 16 June 2013, Y27, 40°23’30’’N, 29°03’23’’E, 50 m, mud, 1 specimen ; ESFM-POL/2013-1228 , 17 June 2013, station Y28, 40°57’20’’N, 28°07’21’’E, 25 m, sandy mud, 3 specimens ; ESFM-POL/2013-1230 , 17 June 2013, station Y29, 40°32’34’’N, 28°46’53’’E, 25 m, muddy sand with Lithothamnion sp. , 1 specimen ; ESFM-POL/2013-1231 , 14 June 2013, station Y31, 41°01’25’’N, 28°26’23’’E, 25 m, muddy sand with Lithothamnion sp. , 1 specimen ; ESFM-POL/2013-1232 , 19 June 2013, station Y40, 40°41’22’’N, 29°20’58’’E, 25 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2013-1234 , 19 June 2013, station Y40, 40°41’54’’N, 29°20’46’’E, 50 m, mud with shell fragments, 1 specimen ; ESFM-POL/2013- 1235 , 26 June 2013, station Y49, 41°09’15’’N, 29°02’20’’E, 10 m, mud, 1 specimen .

Description. The largest complete specimen 36 mm long, 2.8 mm wide, with 72 chaetigers. Body wider anteriorly and tapering gradually from middle chaetigers 20–25 to posterior end. Colour cream or light brownish in ethanol. When pharynx everted, prostomium subpentagonal ( Fig. 7A ), anterior margin convex, posterior margin “V” shaped; when pharynx not everted, prostomium subrectangular (0.5 mm long, 0.3 mm wide), with slightly convex anterior and “U” shaped posterior margins. Antennae and palps conical and small (0.1 mm), equal in length, palps arising at ventro-lateral margin of prostomium. One pair of eyes visible only in small specimens. Nuchal organs rounded, conspicuous. One pair of dark brown jaws, triangular ( Fig. 7F ), situated on antero-lateral margin of pharynx. Pharynx with 10 bifid terminal papillae, separated by dorsal and ventral gap. 22 rows of 3–4 small subterminal papillae; middorsal papilla conical (0.4 mm), almost four times longer than subterminal papillae (0.07 mm); midventral papilla absent; proximal region of pharynx smooth. Parapodia biramous, interramal space “U” shaped on anterior and middle chaetigers, becoming “V” shaped towards posterior body. Parapodia of chaetiger 1 small, directed dorsally, reaching level of prostomium, with a lamelliform dorsal and conical ventral cirri (0.08 mm long) and well developed acicular lobes. Neuropodial and notopodial postchaetal lamellae well developed from chaetiger 3 and 5, respectively. Pre- and postchaetal lamellae relatively well developed, but not extending beyond acicular lobes; rounded, as long as acicular lobes in anterior chaetigers ( Fig. 7B ), smaller than acicular lobes in middle and posterior chaetigers ( Figs. 7C–E ). Acicular lobes rounded to oblique in anterior chaetigers, conical in middle region and almost acutely pointed in posterior chaetigers. Dorsal cirri leaf-like in anterior chaetigers, conical in middle and posterior regions. Ventral cirri small (0.1 mm) and conical (half the length of dorsal cirri).

Branchiae recurved, cirriform, first appearing on chaetiger 9–10 (rarely on chaetiger 8–11), absent on last 25–30 chaetigers; heavily ciliated on anterior and middle chaetigers, becoming similar in size to dorsal cirri on last 7–8 posterior chaetigers.

Three types of chaetae present in parapodia: capillary chaetae, barred chaetae and spinulated chaetae. Chaetiger 1 with 15–18 capillary chaetae (500 µm) in neuropodia, arranged in a bundle; 8–10 barred and 6–7 spinulated chaetae with very smooth teeth in notopodia. Noto- and neuropodia of subsequent chaetigers with 11–12 barred chaetae (400 µm) on preacicular position ( Fig. 7G ), and up to 20–22 finely spinulated chaetae (1000 µm) with one lateral row of spines on postacicular position ( Fig. 7H ). Barred chaetae thick and long in anterior chaetigers, bar area of chaetae covering almost 1/3 of total chaetae and becoming thinner towards posterior end (bar area 200 µm on chaetiger 20; 100 µm on chaetiger 60; see arrow in Fig. 7G ).

One reddish-brown acicula per ramus; with straight tip on anterior and middle chaetigers, with curved tip in posterior chaetigers.

Pygidium rounded with one digitiform anal cirrus placed dorsally, as long as the last 3–4 chaetigers.

Remarks. The morphology of the Sea of Marmara specimens of Nephtys incisa coincides with those in the original and subsequent descriptions.

Distribution. Only found in the Sea of Marmara in the present study. Previously reported from the Atlantic Ocean ( Rainer 1990; 1991; Ravara et al. 2010; Gillet 2017), Mediterranean Sea ( Laborda 2004; Castelli et al. 2008; Ravara et al. 2010; Çinar et al. 2014; Mikac 2015) and Black Sea ( Kurt-Şahin et al. 2017b).

Habitat. From lower intertidal zone up to 1700 m depths ( Rainer 1990; Laborda 2004; Çinar et al. 2014). This species was found in soft bottoms (sand, sandy mud with shell fragments, etc.) between 10–50 m depths in the present study.

Figures

FIGURE 2. Inermonephtys turcica n. sp., Holotype, ESFM-POL/2000-910.A, Prostomium, dorsal view; B, Palps, ventral view; C, Jaw, lateral view; D. Lyrate chaeta; E, Barred chaeta; F, Spinulated chaeta; G, Parapodium of chaetiger 10, anterior view; H, Parapodium of chaetiger 20, anterior view; I, Parapodium of chaetiger 40, anterior view; J, Parapodium of chaetiger 102, anterior view. Abbreviations: acL, acicular lobe; bp, basal papilla; br, branchia; dc, dorsal cirri; nepsl, neuropodial postchaetal lamella; neupl, neuropodial prechaetal lamella; no, nuchal organ; nopl, notopodial prechaetal lamella; nopsl, notopodial postchaetal lamella; pl, palp; pros, prostomium; vc, ventral ciri. Scale bar: A, B, 1 mm; C, 0.3 mm; D, E, 30 µm; F, 10 µm; G–J, 1 mm.

FIGURE 3. Inermonephtys turcica n. sp., Holotype, ESFM-POL/2000-910.A, Entire body, lateral view; B, Prostomium, dorsal view; C, Palps, ventral view; D, Postacicular spinulated chaetae; E, Postacicular lyrate chaeta; F, Preacicular barred chaetae. Scale bars: A, 3 mm; B, 1 mm; C, 0.09 mm; D, 5 µm; E, F, 10 µm.

FIGURE 4. Inermonephtys turcica n. sp., Holotype, ESFM-POL/2000-910, general view of parapodia; A1, Parapodium of chaetiger 10, anterior view; A2, Parapodium of chaetiger 10, posterior view; B1, Parapodium of chaetiger 20, anterior view; B2. Parapodium of chaetiger 20, posterior view; C1, Parapodium of chaetiger 40, anterior view; C2, Parapodium of chaetiger 40, posterior view; D1, Parapodium of chaetiger 102, anterior view; D2, Parapodium of chaetiger 102, posterior view. Scale bar: 1 mm.

FIGURE 7. Nephtys incisa (ESFM-POL/2013-1196). A, Anterior end with pharynx everted, dorsal view; B, Parapodium of chaetiger 10, anterior view; C, Parapodium of chaetiger 20, anterior view; D, Parapodium of chaetiger 40, anterior view; E, Parapodium of chaetiger 80, anterior view; F, Jaw; G, Barred chaeta; from anterior and posterior parapodia, respectively, Arrow shows bar area of chaeta in anterior parapodia; H, Spinulated chaeta. Scale bars: A, 0.5 mm; B–E, 0.5 mm, F, 0.5 mm; G, 80 µm; H, 150 µm.