Neanthes succinea ( Leuckart, 1847 )

Sato, Masanori, 2013, Resurrection of the genus Nectoneanthes Imajima, 1972 (Nereididae: Polychaeta), with redescription of Nectoneanthes oxypoda (Marenzeller, 1879) and description of a new species, comparing them to Neanthes succinea (Leuckart, 1847), Journal of Natural History (J. Nat. Hist.) 47 (1 - 2), pp. 1-50 : 35-43

Neanthes succinea ( Leuckart, 1847)

(Japanese name: Ashinaga-gokai) (Korean name: Du-jul-bak-i-charm-gaet-ji-reong-i)

( Figures 3 D–F, 4B, 15–17)

Nereis succinea Leuckart, 1847: 154–156 , pl. 2, figs. 9, 11.

Nereis (Neanthes) succinea: Pettibone, 1963: 165–170 , figs. 44a–e, 45a–d; Day, 1953: 425, 1957: 78, 1967: 321, figs. 14.9a–e; Hartmann-Schröder, 1996: 207–209, fig. 90.

Neanthes succinea: Imajima, 1972: 108–110 , figs. 32 a–k; Nunomura et al., 1975: 89; Wilson, 1984: 218–221, fig. 4 (in part, specimens from Victoria in Australia); Wu et al., 1985: 156–159, fig. 88; Wilson, 1988: 5–7 (in part); Yang and Sun, 1988: 37–38, figs. 7F–I; Yamanishi, 1988: 9; Ben-Eliahu, 1991: 322; Ueda et al., 1992: 62; Uchida, 1992: 328; Kimura et al., 1993: 169; Hiraoka, 1994: 257; Imajima, 1996: 142, fig. 114; Khlebovich, 1996: 103–104, pl. XIV; Hong et al., 1997: 885; Nishi et al., 1998: 199; de León-González and Solís-Weiss, 2000: 556; Fujioka and Kimura, 2000: 34, figs. 2–3a, b; Hori et al., 2000: 48; Uchida, 2000: 282, fig. 20–4A; Lee et al., 2003: 192–197; Otani et al., 2004: 43; Nishi, 2005: 27; Iwamatsu et al., 2007: 685; Nishi and Tanaka, 2007: 102, 104, figs. 3I, J; Seo et al., 2007: 215; Yamanishi and Sato, 2007: 189.

Alitta succinea: Bakken and Wilson, 2005: 516–517 (in part).

Type material

Three syntypes of Nereis succinea , collected from Helgoland, German North Sea , sampling date unknown. One of them designated as lectotype ( ZMH P-25975) ( Figure 15A ). The others designated as paralectotype ( ZMH P-25976) .

Other material examined

Atokes. Japan: Intertidal flats at Fujimae-higata (35 ◦ 07 ′ 45 ′′ N, 136 ◦ 07 ′ 02 ′′ E), Nagoya , Aichi Prefecture, 25 April 1997, coll. M. Sato et al., 3 (BW, 3.0 mm; NSMT Pol 11415) . Concrete walls covered with sessile organisms including an exotic mytilid bivalve Xenostrobus securis at Tokai-bashi Bridge (35 ◦ 07 ′ 01 ′′ N, 136 ◦ 07 ′ 38 ′′ E), Nakagawa Canal , Nagoya , Aichi Prefecture, 20 May 1997, coll. Y. Sakakibara, 1 (BW, 1.7 mm; MS); 23 April 1985, coll. Y. Sakakibara, 1 (BW, 1.5 mm; MS); 10 September 2007, coll. Y. Sakakibara, 1 (BW, 3.0 mm; MS) . Minato-shin-bashi Bridge (35 ◦ 07 ′ 53 ′′ N, 136 ◦ 07 ′ 28 ′′ E), Horikawa River, Nagoya , Aichi Prefecture, 16 August 1989, coll. Y. Sakakibara, 9 (BW, 1.5–2.5 mm; MS); 20 May 1997, coll. Y. Sakakibara, 10 (BW, 2.0– 3.5 mm; MS); 15 June 1999, coll. Y. Sakakibara, 11 (BW, 0.6–3.5 mm; MS); 11 September 2007, coll. Y. Sakakibara, 10 (BW, 0.9–3.5 mm; MS) . Intertidal flats at Dotoku-bashi Bridge (35 ◦ 07 ′ 48.46 ′′ N, 136 ◦ 07 ′ 55.43 ′′ E), Yamazaki-gawa River , Nagoya , Aichi Prefecture, 1987, coll. Y. Sakakibara, 9 (BW, 1.7–4.0 mm; MS); 20 May 1997, coll. Y. Sakakibara, 9 (BW, 1.9–2.5 mm; MS); 15 June 1999, coll. Y. Sakakibara, 7 (BW, 1.5–2.5 mm; MS); 10 September 2007, coll. Y. Sakakibara, 6 (BW, 1.5–3.0 mm; MS); 13 March 2010, coll. R. Nishizawa, 18 (BW, 1.2–3.5 mm; MS) . Intertidal flats in Tenpaku-gawa River (35 ◦ 07 ′ 09 ′′ N, 136 ◦ 07 ′ 33 ′′ E), Nagoya , Aichi Prefecture, 2 January 2010, coll. R. Nishizawa, 1 (BW, 3.0 mm, ZMH P-26033) . Narumi-bashi Bridge, Ougi-gawa River, Nagoya , Aichi Prefecture, 25 September 2007, coll. Y. Sakakibara, 1 (BW, 2.7 mm; MS) . Intertidal flats in Shinano-gawa River (35 ◦ 07 ′ 22 ′′ N, 136 ◦ 07 ′ 31 ′′ E), Tokai , Aichi Prefecture, 22 September 2010, coll. R. Nishizawa, 2 (BW, 2.5 mm; NSMT Pol 11416) . Honjo area (processing area for reclamation), Lake Nakaumi , Shimane Prefecture, 25 April 2007, coll. K. Toda, 10 (BW, 0.7–2.5 mm; 35 ◦ 07 ′ 56.1 ′′ N, 133 ◦ 07 ′ 27 ′′ E; NSMT Pol 11418), 2 (BW, 2.3–3.1 mm; 35 ◦ 07 ′ 11.1 ′′ N, 133 ◦ 07 ′ 57 ′′ E; NSMT Pol 11417), 3 (BW, 2.5–2.8 mm; 35 ◦ 07 ′ 16.8 ′′ N, 133 ◦ 07 ′ 41.8 ′′ E; ZMH P-26032) . Intertidal flats at the inner part of Dokai Bay (33 ◦ 07 ′ 30 ′′ –53 ′ 20 ′′ N, 130 ◦ 07 ′ –47 ′′ E), Kitakyushu , Fukuoka Prefecture, 13 September 2011, coll. N. Ueda, 11 (BW, 0.5–2.7 mm; MS) . Korea: Sta. 1 (35 ◦ 07 ′ 59 ′′ N, 128 ◦ 07 ′ 07 ′′ E, 12 m deep), Masan Bay , February 2004, coll. J.-W. Choi, 23 (BW, 1.1–3.0 mm; KIOST) ; April 2004, coll. J.-W. Choi, 3 (BW, 1.5–1.8 mm; KIOST) . Germany: Sta. 1 (11 m deep), Banter See, Wilhelmshaven , North Sea , 17 February 1977, coll. J. Dörjes, 1 (BW, 1.6 mm; SMF 5414 / 5) . Wilhelmshaven, North Sea , 15 May 2008, coll. R. Bastrop, 6 (BW, 0.8– 3.0 mm; MS) . Jadebusen (8–13 m deep), North Sea , 22 May 1995, coll. M. Türkay, 2 (BW, 1.0– 2.3 mm; SMF 8051 / 1, 8052 / 1) . Romania: Sta. 71 (intertidal), Mamaja, Black Sea , 12 August 1999, coll. V. Surugiu, 1 (BW, 2.0 mm; SMF 12659 / 1) . USA (Atlantic coast): Sta. 11–3, Little Sippewisset Marsh , Buzzards Bay, MA, 1975, coll. J. Dörjes, 5 ( SMF 10987) . USA (Pacific coast): Eld Inlet at Olympia (47 ◦ 07 ′ 48 ′′ N, 122 ◦ 07 ′ 21 ′′ W), WA, 27 October 2009 and 2 November 2009, coll. H. Tosuji and T. Furota, 17 (BW, 2.1–3.7 mm; NSMT Pol 11421; MS) .

Epitokes collected from sediment samples. Japan: Honjo area (processing area for reclamation, 35 ◦ 07 ′ 56.1 ′′ N, 133 ◦ 07 ′ 27 ′′ E), Lake Nakaumi, Shimane Prefecture, 25 April 2007, coll. K. Toda, 1 male (BW, 2.5 mm; NSMT Pol 11419); Honjo area (35 ◦ 07 ′ 22.8 ′′ N, 133 ◦ 07 ′ 44.8 ′′ E), 10 December 2007, coll. K. Toda, 4 males (BW, 1.6–2.0 mm; MS) . Intertidal flats at the inner part of Dokai Bay (33 ◦ 07 ′ 30 ′′ –53 ′ 20 ′′ N, 130 ◦ 07 ′ –47 ′′ E), Kitakyushu , Fukuoka Prefecture, 13 September 2011, coll. N. Ueda, 1 male (BW, 1.5 mm; MS) . Germany: Wilhelmshaven, North Sea , 15 May 2008, coll. R. Bastrop, 1 male (BW, 2.0 mm; MS) . Insel Poel (54 ◦ 07 ′ 27 ′′ N, 11 ◦ 07 ′ 07 ′′ E), Wismar Bay, Baltic Sea , 26 June 2008, coll. M. Sato, 1 male (BW, 2.5 mm; NSMT Pol 11420) . Sta. 15b, Langeoog, North Sea , 10 August 1987, coll. J. Dörjes, 1 male (BW, 1.9 mm; SMF 8049 / 1) .

Diagnosis

Body length up to 190 mm, with 170 chaetigers.

Two pairs of eyes almost equal in size, arranged trapezoidally; anterior pair reniform; posterior pair round (subdermal eyes unclear in some epitokous specimens).

Peristomium with four pairs of tentacular cirri of unequal length; posterior dorsal tentacular cirri longest, reaching back to chaetigers 4 to 15.

Paragnath numbers as follows, group I: 1–6, II: around 20 on each side in two or three arched rows, III: 20–60 in three or four transverse rows, IV: around 25 on each side in two or three arched rows, V: 0–6, VI: around 10 on each side in circular cluster, VII–VIII: two or three rows of paragnaths, extending to lateral surface, not reaching group VI ( Figure 15 B–E).

Parapodia of first two chaetigers sub-biramous, all following parapodia biramous. Sub-biramous parapodia with thin notoacicula and thick neuroacicula ( Figure 16 A–C).

Notopodia consisting of dorsal cirrus, dorsal ligule, prechaetal lobe and ventral ligule in biramous parapodia. Notopodial prechaetal lobe two-thirds to one-half in length to notopodial ventral ligule in anterior parapodia ( Figure 16D ), reduced gradually in middle parapodia ( Figure 16E ), lacking in posterior parapodia ( Figure 16F, G ). Notopodial dorsal ligule markedly elongated, broadened, flattened to leaf-like, with dorsal cirrus in terminal position in posterior parapodia ( Figure 16F, G ).

Neuropodia consisting of inferior lobe, postchaetal lobe, ventral ligule and ventral cirrus. Neuropodial inferior and postchaetal lobes conical with tapering tip in anterior parapodia (postchaetal lobe slightly larger than inferior lobe); inferior lobe reduced with round tip in posterior parapodia. Neuropodial postchaetal lobe prominent even in posterior parapodia ( Figure 16F, G ). Neuropodial ventral ligule similar in length to postchaetal lobe.

Notochaetae all homogomph spinigers ( Figure 4B ). Upper neurochaetae consisting of heterogomph falcigers at superior / anterior position, and homogomph spinigers at inferior / posterior position. Lower neurochaetae consisting of heterogomph spinigers at superior / posterior position, and heterogomph falcigers at inferior / anterior position.

Epitokous modification of parapodia in middle body of sexually mature specimens, appearing from chaetigers 14–16 in males, from chaetigers 14–19 in females. Neuropodial postchaetal lobe developing into large round flat lamella with single tiny protrusion on lateral edge, without digitate protrusion on inner side of lower edge in males ( Figure 16H ); neuropodial postchaetal lobe developing into small round lamella in females.

Eggs about 140 µm in diameter.

Description of lectotype and paralectotype

Lectotype, incomplete atokous individual about 50 mm BL, 2.0 mm BW, with 67 chaetigers, with proboscis everted ( Figure 15A ); body swollen and decolorized. One of paralectotypes, incomplete atokous individual about 80 mm BL, 3.0 mm BW, with 69 chaetigers, with proboscis everted.

Peristomium slightly longer than subsequent chaetigers, with four pairs of tentacular cirri of unequal length; posterior dorsal tentacular cirri longest, reaching back to chaetigers 4 in both lectotype and paralectotype.

Proboscis with pair of brown jaws, each with seven or eight teeth ( Figure 15B, C ). Brown paragnaths with usually pointed tip present on both maxillary and oral rings. Paragnath numbers of lectotype and paralectotype (in parentheses) as follows, group I: 3 (1); II: 16 (13) on both sides, total 32 (26); III: 35 (16); IV: 26 (19) on right and 29 (18) on left, total 55 (37); V: 0 (0); VI: 9 (6) on both sides, total 18 (12); VII–VIII: 51 (43), arranged in two or three rows (distal single transverse row of large paragnaths and proximal single or two irregular rows of large and small paragnaths, Figure 15C ).

Thin notoacicula present in chaetigers 1 and 2, decolorized from long-term preservation ( Figure 16A, B ).

Posterior gut of paralectotype filled with mud or sand particles.

Reproduction

Epitokous mature males and females swarm at the surface, soon after sunset from March to early October in the Woods Hole region ( Pettibone 1963). The smallest epitokous male was 1.5 mm BW and 16 mm BL in the present study.

Habitat

This species is notably euryhaline, and found in various habitats, e.g. sandy or muddy bottoms, under stones, among masses of sessile organisms such as oysters, barnacles,

mussels and sponges in intertidal or subtidal areas (up to 50 m deep) in or around estuaries ( Pettibone 1963; the present study).

Geographical distribution

Atlantic coasts of Europe (north to western Baltic Sea and North Sea, south to Spain, Mediterranean Sea, Black Sea, Sea of Azov), western and southern Africa, North America (north to Gulf of St Lawrence, south to Mexico), West Indies ( Puerto Rico), Central America ( Panama) and South America ( Venezuela, Brazil, Uruguay, Argentine); Pacific coasts of North America (north to Washington, south to Mexico), Central America ( El Salvador, Panama), eastern Asia (Far East Russia, Bohai Wan in China, Korea, Japan, Figure 17 ), and southern Australia (Victoria, Figure 17 ). Based on Pettibone (1963), Wilson (1984), Wu et al. (1985), Khlebovich (1996), Ieno and Bastida (1998), de León-González and Solís-Weiss (2000), Braga et al. (2011) and the present study.

Remarks

The syntype specimens were preserved in an old glass vial in ZMH. Because the original label attached to the outer surface of the vial was damaged, we could read nothing of its inscription (K. Philipps-Bussau, personal communication). However, another new label written with a typewriter is attached to the outer surface of the vial, with a description “474 Nereis succinea, (Original-Exp.) , Helgoland ”. The same description (474 Nereis succinea, Org. Expl. , Helgoland) was found in the old catalog “Polychaeten Katalog, Sammlung Ehlers” for the polychaete collection in ZMH. “Org. Expl” was judged as “Original Exemplar” in German. “ Helgoland ” is exactly one of the sampling sites ( Helgoland and Cuxhaven ) shown in the original description ( Leuckart 1847). Therefore, I decided the specimens were the syntypes .

The diagnosis of this species was amended by adding the present findings to what was previously known about this species ( Leuckart 1847; Pettibone 1963; Imajima 1972; Wilson 1984; Wu et al. 1985; Hartmann-Schröder 1996; Khlebovich 1996; Bakken and Wilson 2005). Most characteristics of specimens examined in the present study agreed well with the previous description of this species. An important characteristic, i.e. the presence of notoaciculae on chaetigers 1 and 2, which has been recognized in a few genera in Nereididae ( Bakken and Wilson 2005) , was newly recorded for this species by the present study. The other morphological characteristics were adequately drawn in Leuckart (1847), Pettibone (1963), Imajima (1972, 1996), Wu et al. (1985), Wilson (1984), Hartmann-Schröder (1996) and Khlebovich (1996).

Neanthes succinea was transferred to the genus Alitta by Bakken and Wilson (2005) based on a phylogenetic analysis using a character set of 52 informative characters. But, this character set included a serious mistake that notoaciculae are absent from chaetigers 1 and 2 in Neanthes succinea ( Bakken and Wilson 2005: Appendix 3, p. 545). Here, therefore, the combination Neanthes succinea is resurrected, reversing its placement in Alitta .

Neanthes succinea is similar to both the three Alitta species ( Khlebovich 1996) and the two Nectoneanthes species (present study) in terms of the presence of an expanded notopodial dorsal ligule in atokes, but different from the Nectoneanthes species in several characteristics (see remarks in description of Nectoneanthes oxypoda ), and different from the Alitta species in terms of the presence of notoaciculae on chaetigers 1 and 2; the Alitta species lack notoaciculae from chaetigers 1 and 2 ( Bakken and Wilson 2005; my unpublished data on Danish specimens of Alitta virens or Alitta grandis , and Japanese specimens of Alitta brandti ).

Paragnath numbers on proboscis of the lectotype were comparable to those of nontype atokes (n = 4, MS) newly collected from Wilhelmshaven , German North Sea (the vicinity of type locality) in 2008 (group I: 2–3; II: 19–26 on each side, total 40–52; III: 32–41; IV: 24–27 on each side, total 49–53; V: 1–4; VI: 8–10 on each side, total 16–18). Paragnath numbers of the paralectotype were, however, unusually small, probably caused by loss or invisibility of some paragnaths during long-term preservation .

Description of female epitokous metamorphosis (development of small round lamella) of the neuropodial postchaetal lobe depended on Pettibone (1963), because no epitokous female was observed in the present study. However, Wilson (1984) described the female neuropodial postchaetal lobe divided along the line of the neuroacicula into unequal discoid lobes, the dorsal lobe being the larger.

The Australian records of Wilson (1984) seem to include both Neanthes succinea and Nectoneanthes oxypoda ; only specimens collected from Victoria (Hobson’s Bay) could be judged as Neanthes succinea based on drawings of the parapodia and paragnath numbers of group III.

Figures

Figure 3. Comparison of anterior views of atokous parapodia between Nectoneanthes oxypoda (A–C; non-type collected from off Kisarazu, Chiba, NSMT Pol 11395) and Neanthes succinea (D–F; non-type collected from Lake Nakaumi, Shimane, NSMT Pol 11417) with the same BW (3.2 mm). (A) Chaetiger 10; (B) chaetiger 49; (C) chaetiger 115; (D) chaetiger 10; (E) chaetiger 54; (F) chaetiger 114; dc, dorsal cirrus; ol, ovoid lobe above dorsal cirrus; nod, notopodial dorsal ligule; nop, notopodial prechaetal lobe; nov, notopodial ventral ligule; nei, neuropodial inferior lobe; nep, neuropodial postchaetal lobe; nev, neuropodial ventral ligule; vc, ventral cirrus; no, notoacicula; ne, neuroacicula. Arrows indicate development of neuropodial inferior lobe throughout in Nectoneanthes oxypoda. Scale bar, 1 mm.

Figure 4. Schematic diagrams of atokous chaetal arrangement in distal view of right parapodium around chaetiger 50 in adults. (A) Nectoneanthes oxypoda and Nectoneanthes uchiwa sp. nov. (B) Neanthes succinea. Closed circles: homogomph or sesquigomph spinigers. Closed squares: heterogomph spinigers. Closed stars: heterogomph falcigers. Abbreviations same as for those in Figure 3.

Figure 15. Atokes of Neanthes succinea. (A–C) Lectotype (ZMH P-25975), with everted proboscis: (A) dorsal view of the whole body; (B) dorsal view of anterior end; (C) ventral view of anterior end. (D, E) Non-type (NSMT-Pol 11415) collected from Nagoya, Japan, anterior end with everted proboscis: (D) dorsal view; (E) ventral view. Seven groups of paragnaths in different areas on proboscis are shown as I to VII–VIII. Scale bars, 5 mm in A; 1 mm in B–E.

Figure 16. Parapodia of Neanthes succinea. (A, B) Lectotype (ZMH P-25975), left parapodium 1: (A) anterior view; (B) enlargement of (A). (C–G) Non-type atoke (NSMT-Pol 11415) collected from Nagoya, Japan: (C) anterior view of right parapodium 2; (D) anterior view of right parapodium 16; (E) anterior view of right parapodium 24; (F) posterior view of left parapodium 66; (G) anterior view of right parapodium 100. (H) Non-type epitokous male (NSMT-Pol 11420) collected from Insel Poel, Germany, posterior view of left parapodium 30. Abbreviations same as for those in Figures 11 and 13. Arrow indicates an epitokous development of an ovoid lobe above the dorsal cirrus. Scale bars, 0.1 mm in A, B; 0.5 mm in C–H.

Figure 17. Distribution of Neanthes succinea in eastern Asia and Australia. Based on Imajima (1972, 1996), Nunomura et al. (1975), Wilson (1984), Wu et al. (1985), Yamanishi (1988), Ueda et al. (1992), Kimura et al. (1993), Hiraoka (1994), Khlebovich (1996), Hong et al. (1997), Nishi et al. (1998), Fujioka and Kimura (2000), Hori et al. (2000), Lee et al. (2003), Otani et al. (2004), Nishi (2005), Iwamatsu et al. (2007), Seo et al. (2007), Yamanishi and Sato (2007), and the present study. The locations of large cities and big projects of coastal development are also shown.