Nephtys ciliata (O. F. Müller, 1776 )

Ravara, Ascensão, Cunha, Marina R. & Pleijel, Fredrik, 2010, Nephtyidae (Annelida, Polychaeta) from southern Europe 2682, Zootaxa 2682 (1), pp. 1-68 : 37-38

Nephtys ciliata (O. F. Müller, 1776)

Figures 13 , 14

Nereis ciliata Müller, 1776: 17 ; Müller 1789: 14, pl. LXXXIX, figs. 1–4.

Nephtys borealis Örsted, 1843a: 32 .

Nephthys ciliata Malmgren 1865: 104 , pl. XII, fig. 17; Malmgren 1867: 17; Ehlers 1868: 629, pl. XXIII, fig. 36; Kupffer 1873: 150; Möbius 1873: 113; Malm 1874: 76;? McIntosh 1879: 501; Théel 1879: 24; Moore 1903: 433; Nordgaard 1905: 162, 235; not McIntosh 1908: 23; Heinen 1911: 21, fig. 5 (partim); Izuka 1912: 215; not Augener 1912: 192; Fauvel 1923: 371, fig. 145A–B; Ditlevsen 1937: 20; Takahashi 1938: 204; Pettibone 1954: 270.

Nephthys caeca Möbius 1875: 168 (partim).

Nephtys ciliata Hartman 1944: 339 , pl. 47, fig. 10; Hartman 1950: 95; Imajima 1961: 91; Eliason 1962: 249; Fauchald 1963: 5, figs. 1B, 2E and 3A; Pettibone 1963: 202, fig. 51C (partim); Imajima and Hartman 1964: 157; Wolff 1968: 4, fig. 9; not Kirkegaard 1969: 46, fig. 19 (= N. pente ); Hartmann-Schröder 1971: 218, fig. 71A (partim); not Banse and Hobson 1974: 75, fig. 19I (?= N. pente ); Campoy 1982: 511;? Imajima and Takeda 1987: 67; Jirkov 1989: 77, Figs. 16.4 and 16.5 ; Rainer 1991: 70, fig. 3A; Kirkegaard 1992: 333, fig. 162; Hartmann-Schröder 1996: 221, fig. 96; Dnestrovskaya and Jirkov 2001: 197,1 fig; Laborda 2004: 399, fig. 146D; not McIntosh 1908: 23.

Nephthys hombergi Augener 1913: 202 (partim).

Nephtys ciliata form longosetosa not Augener 1939: 137.

Nephtys hombergii var. ehlersi Augener 1939: 137 (partim).

Type locality. Norway .

Material examined. Arctic Ocean. Svalbard, S Hinlopenstretet, E Olav V Land: RV Jan Mayen, 78º40.623’N, 21º23.796’E, 60 m, Sneli-sledge, Sep 2003, 1 incomplete spm ( MB36000139 ) .

Atlantic Ocean. Iceland. Sandgerdi: collected at low tide, Jul 2001, 2 complete and 2 incomplete spms ( DBUA 00179-01 to 04); NW Iceland, Langeness Bank: between 80 and 95 fms, Otter trawl, Aug 1953, 1 incomplete spm ( NHM 1954.1.1.198 as N. hombergii ). North Sea, Sweden, Skagerrak, Bohuslän: 58º10.856’N – 58º11.049’N, 10º53.439’E – 10º53,024’E, 162–191 m, Aug 2006, 1 complete spm ( MB 36000157). Scotland, St. Andrews: 1 incomplete spm ( NHM 1921.5.1.855/856 as N. cirrosa ).

Description. Examined specimens up to 69 mm long for up to 90 chaetigers. See Fig. 13 for length and width measurements. Body segments of about the same width, last segments tapering abruptly. Poor dorsal delineation between anterior segments. Colour in ethanol cream; chaetae amber; aciculae of anterior segments with red tips and in median and posterior segments with dark tips. Eyes not visible. Pharynx distal region with 10 pairs of terminal bifid papillae, separated by small dorsal and ventral elevations; middorsal papilla long and cirriform ( Fig. 13D ); midventral papilla small, similar in size and shape to distalmost subterminal ones; subdistal region with 22 rows of 4–6 (sometimes 3–7) conical subterminal papillae, extending over 1/2 length of pharynx; proximal region covered with small warts ( Fig. 14A ). Jaws conical ( Fig. 14B ). Prostomium subquadrangular, anterior margin straight, posterior margin V-shaped ( Fig. 14A ); antennae and palps conical, short, subequal in length; palps inserted ventrolaterally on anterior region of prostomium, slightly behind antennae. Nuchal organs rounded. Parapodia biramous; interramal space “U-shaped”, heavily ciliated. Parapodia of chaetiger 1 equal in size to subsequent ones, directed anteriorly, parallel to prostomium; notopodial acicular lobes conical, prechaetal lamellae rudimentary, postchaetal lamellae well developed but not extending beyond acicular lobes, rounded; neuropodial pre- and postchaetal lamellae forming a cylinder covering acicular lobes; dorsal cirri conical; ventral cirri digitiform, with broad base and cirriform tip. Acicular lobes bilobed in anterior and median parapodia, rounded in posterior parapodia; prechaetal lamellae poorly developed, rounded, becoming rudimentary in posterior parapodia; postchaetal lamellae well developed but not extending beyond acicular lobes, rounded, directed dorsaly in neuropodium; dorsal and ventral cirri conical ( Fig. 14C–H ). Branchiae recurved, short and thick, heavily ciliated; present from chaetigers 7–11 to near posterior end; occupy all interramal space when fully developed, rapidly decrease in size posteriorly and become vestigial or absent in last chaetigers. Chaetae of three kinds: barred chaetae in preacicular position ( Fig. 14I ), spinulated chaetae in postacicular position ( Fig. 14J ), and capillary chaetae in neuropodia of chaetiger 1. One acicula per ramus, posterior ones with curved tips (difficult to see in all specimens observed; Fig. 14L ).

Remarks. Nephtys ciliata was recorded only once for the Mediterranean Sea by Desbruyères et al. (1972), and that is the reason of being included here. Campoy (1982) and Laborda (2004) also include this species in the Iberian Peninsula fauna based on that same reference. However, specimens from that locality were not examined and there are no other records of this species for areas southern than English Channel. Furthermore, the descriptions given by Campoy (1982) and Laborda (2004) mention a wide range of chaetigers where branchiae first appear, which indicates that they may have dealt with a complex of species. We therefore consider those references as doubtful and believe this species have a more circumpolar distribution. Also the references of Hartman (1950) and Imajima and Takeda (1987) refer to the occurrence of the first branchiae on chaetigers 5–7 rather than 7–10. These references must be considered with caution since they probably also include N. pente , another circumpolar species.

Distribution. Arctic Ocean; Atlantic Ocean ( Greenland, Iceland, Norway, Skagerrak, Kattegat, western and middle Baltic Sea, Denmark, North Sea); Pacific Ocean (Alaska; Bering Sea; Sea of Okhotsk, Japan) ( Hartman 1938; Imajima & Takeda 1987; Rainer 1991). There are further reports of this species from the Mediterranean Sea ( Spain, as far as the Black Sea) ( Campoy 1982; Laborda 2004), but these records require confirmation.

Habitat. Sand and mud, from the intertidal to 960 m depth ( Rainer 1991; Laborda 2004).

Figures

FIGURE 13. Relationships between: A. Number of segments and body length. B. Body length and body width. C. Length of ventral cirri (VC) and dorsal cirri (DC) of chaetiger 1. D. Length of pharynx distalmost subterminal papillae and middorsal papilla. Nephtys caeca. N. ciliata. × N. longosetosa.

FIGURE 14. Nephtys ciliata. A. Pharynx, prostomium and anteriormost chaetigers, dorsal view. B. Jaw. C. Right parapodium of chaetiger 10, anterior view. D. Same, posterior view. E. Right parapodium of chaetiger 40, anterior view. F. Same, posterior view. G. Right parapodium of chaetiger 70, anterior view. H. Same, posterior view. I. Preacicular chaeta from chaetiger 20. J. Postacicular chaeta from chaetiger 20. K. Acicula from chaetiger 20.

FIGURE 16. Relationships between: A. Number of segments and body length. B. Body length and body width. C. Length of ventral cirri (VC) and dorsal cirri (DC) of chaetiger 1. D. Length of pharynx distalmost subterminal papillae and middorsal papilla. Nephtys cirrosa. N. paradoxa. Minute dorsal cirri were scored as 0.01.