Nephtys hombergii Savigny

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 : 195-199

Nephtys hombergii Savigny in Lamarck, 1818

( Figure 6 )

Nephthys hombergii Savigny in Lamarck, 1818: 314; Ehlers 1868: 619, pl. XXIII, Figs. 7 , 42; Saint-Joseph 1894: 3, pl.1, Figs. 1 –13; McIntosh 1908: 17, pl. LXVI Figs. 2–6 ; Heinen 1911: 16, Figs. 3,4; Fauvel 1923: 367, Figs. 143A–D; Tebble 1955: 102; Ravara et al. 2010: 45, Fig. 17.

Material examined. Sea of Marmara: ESFM-POL/2012-499 , 02 October 2012, station K17, 40°48’58’’N, 26°39’37’’E, 0-4 m, Mytilus sp. , 2 specimens ; ESFM-POL/2013-1240 , 06 June 2013, station Y1, 40°01’27’’N, 26°13’24’’E, 10 m, mud with dark detritic material, 1 specimen ; ESFM-POL/2013-1242 , 07 June 2013, station Y5, 40°20’55’’N, 26°40’38’’E, 25 m, mud, 1 specimens ; ESFM-POL/2013-1243 , 07 June 2013, station Y6, 40°26’10’’N, 26°41’51’’E, 10 m, mud, 1 specimens ; ESFM-POL/2013-1246 , 07 June 2013, station Y6, 40°26’03’’N, 26°41’59’’E, 25 m, mud, 1 specimen ; ESFM-POL/2013-1249 , 7 June 2013, station Y8, 40°25’27’’N, 27°03’34’’E, 25 m, mud with Amphiura filiformis , 3 specimens ; ESFM-POL/2013-1250 , 08 June 2013, station Y9, 40°26’25’’N, 27°11’29’’E, 25 m, mud with Amphiura filiformis and shell fragments, 3 specimens ; ESFM-POL/2013-1252 , 08 June 2013, station Y11, 40°36’12’’N, 27°05’20’’E, 10 m, sandy mud, 12 specimens ; ESFM-POL/2013-1255 , 08 June 2013, station Y12, 40°40’38’’N, 27°16’25’’E, 10 m, fine sand with Spisupa sp. shell fragments, 2 specimens ; ESFM- POL/2013-1256, 08 June 2013, station Y12, 40°39’44’’N, 27°17’00’’E, 25 m, mud with Amphiura filiformis , 3 specimens; ESFM-POL/2013-1257 , 09 June 2013, station Y17, 40°39’09’N, 27°41’14’’E, 25 m, mud, 1 specimen ; ESFM-POL/2013-1258 , 10 June 2013, station Y18, 40°54’28’’N, 27°33’24’’E, 25 m, muddy sand with Lithothamnion sp. , 1 specimen ; ESFM-POL/2013-1263 , 12 June 2013, station Y19, 40°57’28’’N, 27°42’16’’E, 50 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2013 1266, 15 June 2013, station Y21, 40°29’54’’N, 27°58’28’’E, 25 m, sandy mud with shell fragments, 3 specimens ; ESFM-POL/2013-1267 , 16 June 2013, station Y22, 40°22’18’’N, 28°00’41’’E, 10 m, sand, 3 specimens ; ESFM-POL/2013-1269 , 16 June 2013, station Y22, 40°23’22’’N, 27°59’46’’E, 50 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2013-1270 , 16 June 2013, station Y23, 40°23’55’’N, 28°09’49’’E, 10 m, sandy mud with shell fragments, 2 specimens ; ESFM-POL/2013-1273 , 16 June 2013, station Y23, 40°24’06’’N, 28°09’57’’E, 25 m, sandy mud with shell fragments, 6 specimens ; ESFM-POL/2013-1274 , 16 June 2013, station Y25, 40°24’280’’N, 28°20’840’’E, 10 m, sandy mud with shell fragments, 1 specimen ; ESFM- POL/2013-1275, 16 June 2013, station Y25, 40°24’48’’N, 28°20’41’’E, 25 m, sandy mud with shell fragments, 2 specimens; ESFM-POL/2013-1277 , 16 June 2013, station Y26, 40°22’06’’N, 28°39’55’’E, 10 m, sandy mud with shell fragments, 3 specimens ; ESFM-POL/2013-1279 , 16 June 2013, station Y27, 40°23’30’’N, 29°03’54’’E, 10 m, mud with shell fragments, 2 specimens ; ESFM-POL/2013-1280 , station Y27, 40°23’30’’N, 29°03’49’’E, 25 m, mud, 8 specimens ; ESFM-POL/2013-1282 , 16 June 2013, station Y28, 17 June 2013, 40°57’20’’N, 28°07’21’’E, 25 m, sandy mud, 25 specimens ; ESFM-POL/2013-1284 , 23 June 2013, station Y33, 40°58’21’’N, 28°45’14’’E, 10 m, mud with shell fragments, 22 specimens ; ESFM-POL/2013-1285 , 22 June 2013, station Y36, 40°57’57’’N, 29°01’14’’E, 10 m, sandy mud, 1 specimen ; ESFM-POL/2013-1287 , 21 June 2013, station Y37, 40°52’22’’N, 29°13’23’’E, sandy mud with shell fragments, 10 m, 11 specimens ; ESFM-POL/2013-1289 , 19 June 2013, station Y39, 40°39’36’’N, 29°09’18’’E, 10 m, sandy mud with dark detritic material, 3 specimens ; ESFM-POL/2013-1290 , 20 June 2013, station Y42, 40°46’37’’N, 29°28’54’’E, 10 m, sand, 1 specimen ; ESFM-POL/2013-1292 , 20 June 2013, station Y43, 40°41’29’’N, 29°35’33’’E, 10 m, sandy mud with shell fragments, 4 specimens ; ESFM-POL/2013- 1293 , 20 June 2013, station Y44, 40°46’28’’N, 29°41’52’’E, 10 m, mud with shell fragments, 2 specimens ; ESFM- POL/2013-1294, 20 June 2013, station Y45, 40°44’33’’N, 29°55’46’’E, 10 m, mud with shell fragments, 1 specimens; ESFM-POL/2013-1297 , 20 June 2013, station Y48, 41°07’36’’N, 29°05’29’’E, 25 m, 1 specimen ; ESFM-POL/2013- 1299 , 26 June 2013, station Y49, 41°09’15’’N, 29°02’20’’E, 10 m, mud, 7 specimens ; ESFM-POL/2013-1301 , 26 June 2013, station Y49, 41°09’08’’N, 29°02’40’’E, 25 m, mud with shell fragments, 9 secimen ; Black Sea: ESFM- POL/2014-635, 12 July 2014, station TRK7, 41°18’40”N, 29°40’10”E, 27 m, mud with shell fragments, 1 specimen; ESFM-POL/2014-636 , 13 July 2014, station TRK10, 41°19’40”N, 30°47’55”E, 21 m, coarse sand with shell fragments, 2 specimens ; ESFM-POL/2014-637 , 14 July 2014, station TRK13, 41°37’20”N, 31°51’3”E, 21 m, coarse sand with phytodetritic material, 3 specimens ; ESFM-POL/2014-638 , 14 July 2014, staion TRK16, 41°43’10”N, 32°4’60”E, 21 m, shell fragments with phytodetritic material, 2 specimens ; ESFM-POL/2014-639 , 14 July 2014, station TRK19, 42°6’47”N, 33°3’35”E, 21 m, shell fragments with phytodetritic material, 4 specimens ; ESFM- POL/2014-640, 15 July 2014, station TRK22, 42°2’34”N, 33°49’33”E, 25 m, mud with shell fragments, 3 specimens; ESFM-POL/2014-641 , 17 July 2014, station TRK34Y, 41°33’40”N, 36°34’19”E, 21 m, mud with phytodetritic material, 1 specimen ; ESFM-POL/2014-642 , 18 July 2014, station TRK44, 41°4’2”N, 38°2’49”E, 52 m, shell fragments with phytodetritic material, 4 specimens ; ESFM-POL/2014-643 , 19 July 2014, station TRK53, 41°0’54”N, 38°27’20”E, mud with phytodetritic material, 52 m, 1 specimen ; ESFM-POL/2015-286 , 02 July 2015, station TRK1, 41°55’34”N, 28°12’27”E, 21 m, shell fragments with fine sand, 3 specimens ; ESFM-POL/2015-287 , 03 July 2015, station TRK10, 41°19’40”N, 30°47’55”E, 20 m, shell fragments with fine sand, 1 specimen ; ESFM-POL/2015- 286 , 04 July 2015, station TRKE1 , 41°23’36”N, 31°38’11”E, 13 m, shell fragments with phytodetritic material, 10 specimens ; ESFM-POL/2015-288 , 04 July 2015, station TRK13, 41°37’20”N, 31°51’3”E, 18 m, shell fragments with fine sand and phytodetritic material, 4 specimens ; ESFM-POL/2015-289 , 05 July 2015, station TRK22, 42°02’34”N, 33°49’33”E, 21 m, shell fragments with detritic material, 2 specimens ; ESFM-POL/2015-290 , 08 July 2015, station TRK34Y, 41°33’40”N, 36°34’19”E, 20 m, mud and fine sand with detritic material, 2 specimens ; ESFM-POL/2015-291 , 11 July 2015, station TRK55, 41°1’45”N, 39°54’15”E, 35 m, shell fragments with detritic material, 2 specimens ; ESFM-POL/2015-292 , 11 July 2015, station TRK61, 41°3’60”N, 40°38’24”E, 65 m, shell fragments with detritic material, 1 specimen ; ESFM-POL/2016-229 , 24 July 2016, station TRK10, 41°19’40”N, 30°47’55”E, 20 m, shell fragments with phytodetritic material, 1 specimen ; ESFM-POL/2016-230 , 26 July 2016, station TRK16, 41°43’10”N, 32°4’60”E, 20 m, mud with phytodetritic material, 1 specimen ; ESFM-POL/2016- 231 , 25 July 2016, station TRK19, 42°6’47”N, 33°3’35”E, 45 m, mud with shell fragments and phytodetritic material, 8 specimens ; ESFM-POL/2016-232 , 27 July 2016, station TRK32, 42°0’57.24”N, 35°9’28.51”E, 60 m, mud with shell fragments, 3 specimens ; ESFM-POL/2016-233 , 27 July 2016, station TRK34Y, 41°19’40”N, 36°32’10”E, 21 m, shell fragments with phytodetritic material, 1 specimen ; ESFM-POL/2016-234 , 27 July 2016, station TRK35, 41°33’40”N, 36°34’19”E, 50 m, mud with phytodetritic material, 1 specimen ; ESFM-POL/2016- 235 , 28 July 2016, station TRK44, 41°2’43”N, 38°3’20”E, 51 m, shell fragments with phytodetritic material, 3 specimens ; ESFM-POL/2016-236 , 31 July 2016, station TRK55, 41°3’60”N, 40°38’24”E, 26 m, shell fragments with phytodetritic material, 5 specimens ; ESFM-POL/2016-237 , 01 August 2016, station TRK61, 41°46’0”N, 41°31’0”E, 69 m, shell fragments with phytodetritic material, 2 specimens ; ESFM-POL/2017-191 , 26 July 2017, station TRK19, 42°6’47”N, 33° 3’35”E, 43 m, mud and shell fragments with phytodetritic material, 1 specimen ; ESFM-POL/2017-192 , 27 July 2017, station TRK22, 42°2’34”N, 33°49’33”E, 27 m, shell fragments with phytodetritic material, 1 specimen ; ESFM-POL/2017-193 , 27 July 2017, station TRK25, 42°16’60”N, 34°56’14”E, 19 m, mud with shell fragments, 1 specimen ; ESFM-POL/2017-194 , 30 July 2017, station TRK34Y, 41°19’40”N, 36°32’10”E, 20 m, mud with phytodetritic material, 2 specimens ; ESFM-POL/2017-195 , 30 July 2017, station TRK35, 41°33’40”N, 36°34’19”E, 51 m, mud with shell fragments, 8 specimens ; ESFM-POL/2017-196 , 31 July 2017, station TRK37, 41°32’60”N, 36°40’40”E, 8 m, shell fragments with phytodetritic material, 1 specimen ; ESFM-POL/2017-197 , 31 July 2017, station TRK44, 41°4’2”N, 38°2’49”E, 48 m, shell fragments with phytodetritic material, 5 specimens ; ESFM-POL/2018-143 , 24 July 2018, station TRK16, 41°43’10”N, 32°4’60”E, 22 m, mud with detritic material, 1specimen ; ESFM-POL/2018-144 , 27 July2018,station TRK32, 42°0’57.24”N, 35°9’28.51”E, 24 m, mud with phytodetritic material, 4 specimens ; ESFM-POL/2018-145 , 28 July 2018, station TRK34Y, 41°19’40”N, 36°32’10”E, 48 m, mud, 6 specimens ; ESFM-POL/2018-146 , 28 July 2018, station TRK35, 41°33’40”N, 36°34’19”E, 20 m, mud with phytodetritic material, 1 specimen ; ESFM-POL/2018-147 , 31 July 2018, station TRK55, 41°3’60”N, 40°38’24”E, 25 m, sand, 1 specimen ; ESFM-POL/2018-148 , 01 August 2018, station TRK61, 41°46’0”N, 41°31’0”E, 45 m, mud with phytodetritic material, 1 specimen ; ESFM-POL/2019-46 , 7 July 2019, station TRKE1 , 41°23’36”N, 31°38’11”E, 14 m, fine sand with shell fragments, 1 specimen ; ESFM-POL/2019- 47 , 08 July 2019, station TRK19, 42°6’47”N, 33°3’35”E, 24 m, mud with shell fragments, 1 specimen ; ESFM- POL/2019-48, 10 July 2019, station TRK32, 42°0’57.24”N, 35°9’28.51”E, 24 m, mud 5 specimens; ESFM- POL/2019-49, 14 July 2019, station TRK44, 41°2’43”N, 38°3’20”E, 48 m, clay and phytodetritic material, 3 specimens; ESFM-POL/2019-50 , 15 July 2019, 41°1’45”N, 39°54’15”E, station TRK 53, 35 m, mud with sand and detritic material, 4 specimens ; ESFM-POL/2019-51 , 16 July 2019, station TRK61, 41°46’0”N, 41°31’0”E, 45 m, mud, 2 specimens .

Description. Largest specimen complete, 65.7 mm long and 3.14 mm wide, with 91 chaetigers. Body wider anteriorly and tapering gradually from middle region to pygidium. Colour cream in ethanol, some large specimens with dark-brownish pigmentation on anterior region (on dorsal side of first 10–15 chaetigers). Prostomium subrectangular (0.43 mm long, 0.54 mm wide), anterior margin slightly convex, posterior margin “U” shaped. Shape of prostomium changes to subpentagonal and posterior margin of prostomium changes to “V” shaped when pharynx everted ( Fig. 6A ). One pair of eyes visible on prostomium of small specimens. One pair of conspicuous nuchal organ situated in postero-lateral margin of prostomium. Antennae conical, smaller (90 µm) than palps. Palps and ventral cirri of chaetiger 1 having similar size (150 µm) and shape (broad base and tapering distally). One pair of dark brown jaws (0.8 mm), triangular, deeply incised at base ( Fig. 6F ), situated on antero-lateral margin of pharynx. Pharynx with 10 bifid terminal papillae (0.3 mm) separated by a dorsal and ventral gap; 22 rows of 3–5 conical subdistal papillae (largest one 0.3 mm), extending over 1/3 length of pharynx. Proximal region smooth. Middorsal papilla long (0.5 mm), slender and conical ( Fig. 6A ), midventral papilla absent.

Parapodia of chaetiger 1 smaller than subsequent ones, directed forward parallel to prostomium, having only a lamelliform dorsal and ventral cirri and well developed acicular lobes. Postchaetal lamellae well developed on neuropodia of chaetiger 3 and on notopodia of chaetiger 4 (same in small and large specimens). Parapodia biramous; interramal space “U” shaped. In anterior region (chaetiger 10) notopodial postchaetal lamellae truncated, longer than acicular lobe. Neuropodial postchaetal lamellae (0.7 mm) rounded, longer than acicular lobes (0.4 mm). Notopodial prechaetal lamellae rounded, neuropodial prechaetal lamella triangular, both almost equal in size to acicular lobe ( Fig. 6B ). In middle region (chaetiger 20–40) notopodial postchaetal lamellae truncated, rounded after chaetiger 25–30, longer than acicular lobe. Neuropodial postchaetal lamellae rounded (1 mm, to base of neuropodia), almost two times longer than acicular lobe (0.5 mm). Noto- and neuropodial prechaetal lamellae unequally bilobed [inner parts much larger than outer ones ( Figs. 6C, D )]. In posterior region (chaetiger 80) notopodial postchaetal lamellae more rounded and almost equal in size to acicular lobe. Neuropodial postchaetal lamellae (0.7 mm) almost two times longer than acicular lobe (0.3 mm) ( Fig. 6E ) but reduced in size on last 10–11 chaetigers. Ventral margin of neuropodial postchaetal lamellae bending up towards dorsal side and enlarging towards tips in middle and posterior parapodia ( Figs. 6D, E ). Prechaetal lamellae of posterior chaetigers similar in shape (bilobed unequally) with those median chaetigers.Acicular lobes rounded on anterior chaetigers and becoming more conical in middle and posterior end. A prominent papilliform outgrowth of acicular lobe first appearing on chaetiger 5 (on chaetigers 3 and 4 in large specimens) and lacking in last 30–35 chaetigers. Dorsal cirri small (0.2 mm), digitiform on anterior chaetigers, becoming conical on middle and posterior chaetigers. Ventral cirri small (0.13 mm), conical.

Branchiae long and cirriform, recurved, first appearing on chaetigers 4–6, continuing to posterior end, absent in last 2–12 parapodia ( Figs. 6B–E ). Papillae-like basal projection first appearing on dorsal surface of second branchiae, becoming larger posteriorly, almost as long as dorsal cirri in posterior chaetigers. Interramal space and branchiae heavily ciliated, especially in anterior chaetigers.

Three types of chaetae present in parapodia: capillary chaetae, spinulated chaetae and barred chaetae. Chaetiger 1 with 7–8 barred and 3–4 spinulated chaetae with very smooth teeth in notopodia, and 17–18 capillary chaetae in neuropodia. Subsequent chaetigers with 15–17 barred chaetae (500 µm) in preacicular position of noto- and neuropodia ( Fig. 6G ) and 20–25 spinulated chaetae (1000 µm) with one lateral row of spines in postacicular position of noto- and neuropodia ( Fig. 6H ).

Acicula reddish-brown, thicker on posterior chaetigers, numbering one per ramus; with a straight tip in anterior parapodia, with a curved tip in posterior parapodia.

Pygidium rounded with one digitiform anal cirrus placed dorsally, as long as the last 5–6 chaetigers.

Remarks. The Black Sea and the Sea of Marmara’s specimens of Nephtys hombergii mostly match the original and subsequent descriptions of the species. However, there are some variation in where the branchiae first appear among populations from different regions. The first appearence of branchiae have been mostly reported on chaetiger 4 or 5: on chaetiger 4 in the specimens from Dinar (French Atlantic coast) ( Saint-Joseph 1894), North Sea ( Heinen 1911) and eastern Australian coast ( Tebble 1955), on chaetiger 5 in the British specimens ( McIntosh 1908), and on chaetigers 4 or 5 (rarely on chaetiger 6) on the specimens from the north Atlantic ( Ravara et al. 2010) and Black Sea ( Dnestrovskaya 2020). Branchiae usually start on chaetiger 5 (rarely on chaetiger 4) in the Black Sea specimens, and on chaetiger 4 or 6 (rarely on chaetiger 5) in the Sea of Marmara specimens.

Distribution. Atlantic Ocean ( Rainer 1991; Ravara et al. 2010; Gil 2011; Gillet 2017); Mediterranean Sea ( Laborda 2004; Castelli et al. 2008; Çinar et al. 2014; Mikac 2015); Black Sea ( Kiseleva 2004; Surugiu 2006; Kurt- Şahin & Çinar 2012; Çinar et al. 2014; Kurt-Şahin et al. 2017a; Dnestrovskaya 2020).

Habitat. Nephtys hombergii occurs in fine sand and mud in shallow and deep waters [557 m ( Rainer 1991); 330 m ( Gil 2011);> 600 m ( Çinar et al. 2014); up to 1000 m ( Laborda 2004)]. In this study, it was found between 0–50 m in the Sea of Marmara and 0–72 m in the Black Sea.

Figures

FIGURE 1. Sampling stations in the Sea of Marmara (a) and the Black Sea (b).

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 5. Micronephthys longicornis (ESFM-POL/2019-41). A, Anterior end, with pharynx everted, dorsal view; B, Jaw; C, Shape of dorsal cirri from anterior to posterior (left to right); D, General view of parapodia (chaetiger 30), anterior view; E, Dentate chaeta of chaetiger 1; F, Lyrate chaeta; G, Barred chaeta; H, Spinulated chaeta. Scale bars: A, D, 0.1 mm; B, 0,1 mm; C, 0.01 mm; E, 40 µm; F, 10 µm; G, 25 µm; H, 35 µm.

FIGURE 6. Nephtys hombergii (ESFM-POL/2014-636). 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; H, Spinulated chaeta. Scale bars:A, 0.5 mm; B–E, 0.5 mm; F, 0.8 mm; G, 60 µm; H, 85 µm.

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.