Nereimyra, BLAINVILLE, 1828

Pleijel, Fredrik, Rouse, Greg W. & Nygren, Arne, 2012, A revision of Nereimyra (Psamathini, Hesionidae, Aciculata, Annelida), Zoological Journal of the Linnean Society 164 (1), pp. 36-51 : 41-45

NEREIMYRA BLAINVILLE, 1828

Nereimyra Blainville, 1828: 468 .

Castalia Savigny, 1822: 45–46 . Type species Nereis rosea Fabricius (1780) , by monotypy.

Junior homonym of Castalia Lamarck, 1819: 66 (Mollusca) .

Halimede Rathke, 1843: 161–168 . Type species Halimede venusta Rathke, 1843 , by monotypy. Junior homonym of Halimede de Haan in Siebold, 1835: 35 (Crustacea). Neopodarke Hartman, 1965: 68 . Type species Neopodarke woodsholea Hartman, 1965 , by original designation.

Type species: Nereis rosea Fabricius, 1780 , by subsequent designation ( Hartman, 1959: 189)

Description: Psamathini with stout body shape, anteriorly truncate and posteriorly tapered. Prostomium quadrangular, with posterior incision, large facial tubercle present, lip glands present. Proboscis with ten terminal papillae, ventral incision, and pair of small ventral jaws. With or without capillary notochaeta, notopodial lobes absent. Neurochaetae and neuropodial lobes from segment 4. Dorsal cirri very long, ventral cirri subdistally inserted. Elevated and slightly stouter dorsal cirri on segment 5, 8, 10, 12, 15, 17, 20, 22, 25, 28, and every third segment thereafter. Pygidial papilla present.

Remarks: The delineation of Nereimyra has been unclear and several species have been referred to Nereimyra that here are not considered closely related. We here delineate the taxon to include three species, N. aphroditoides , N. punctata , and N. woodsholea . These three species are morphologically similar and we provide a detailed description of N. punctata only (being the species of the three for which we have most information) and then detail the few differentiating characters for the other two species.

There has been some confusion in the literature regarding the type species of Nereimyra . Blainville (1828) in his original description of Nereimyra included two species, Nereis rosea and Nereis longissima , of which the latter has by some authors (e.g. Hartman, 1959) been referred to the Phyllodocidae . Hartman (1959: 189) designated Nereis punctata as the type species of Nereimyra , a species that was not mentioned in Blainville’s original description of the genus. However, she also placed Nereis rosea in synonymy with Nereimyra punctata , and because Nereis rosea was included in Nereimyra by Blainville, this act then constitutes a valid designation of Nereis rosea as type species ( International Commission on Zoological Nomenclature, 1999, Article 69.2.2). Pettibone (1963) instead referred the typification to Støp-Bowitz (1948), but this is erroneous because Støp-Bowitz’s study made no mention of a type species. See further the Remarks section for Nereimyra aphroditoides regarding synonymy between this species and Nereis rosea .

Ruta et al. (2007) showed that Syllidia is the sister group to Nereimyra , and that result also has strong support in our study. Morphologically the two taxa can be separated by the much larger and more elaborated dark jaws with serrated, rather than cutting, edges in Syllidia , the shorter dorsal cirri on the anterior segments, and the simpler neuropodia without three distinct lobes.

Nereimyra appears to have a distribution limited to the boreal parts of the North Atlantic, possibly extending south in Europe to the Iberian Peninsula and the Mediterranean (unverified records) and on the United States east coast to the Gulf of Mexico.

NEREIMYRA PUNCTATA (O.F. MÜLLER, 1776)

( FIGS 3 , 4 )

Nereis punctata O.F. Müller, 1776: 217 ; 1780: pl. LXII, figs 4, 5 (‘Punkt-Nereiden’); 1788: 28, 29).

Halimede venusta Rathke, 1843: 168–169 , pl. 7, figs 1–4.

Castalia punctata Malm, 1874: 82 ; McIntosh, 1908: 121–125, pl. 46, fig. 2, pl. 69, fig. 14, pl. 78, fig. 2; Fauvel, 1923: 240–241, fig. 89F–K.

Nereimyra punctata, Ørsted, 1843 (p. 24, figs 15, 63–65, 69); Banse, 1956: 17–24, figs 1–8; Hartmann- Schröder, 1971: 128–129, fig. 40E–H, Hartmann- Schröder, 1996: 134–135, fig. 54; Oug, 1980: 175–191, figs 1–3; Schram & Haaland, 1984: 169–181, figs 1– 13, 14I–L, in part; Kirkegaard, 1992: 213–215, fig. 104; Nygren, Pleijel & Sundberg, 2005: 273–276, fig. 1.

Psamathe punctata Quatrefages, 1866: 102 .

Type material: No type material.

Type locality: Norway, Drøbak .

Material examined: DENMARK. 1 spm ( ZMUC), Store Baelt ; 1 spm ( ZMUC), Fredrikshavn; 1 spm ( ZMUC), Helsingør . ICELAND. 8 spms, north Iceland , 66°41,88′N, 20°02,98′W, 148 m, sledge, fine sand, coll. BIOICE 2.x.1994 ; 1 spm, south-west Iceland , 63°59,01′N, 23°34,13′W, 137 m, sledge, fine sand, coll. BIOICE 3.ix.1992 ; 2 spms, north Iceland , 66°36,92′N, 18°14,42′W, 110 m, sledge, fine sand, coll. BIOICE 2.x.1994 ; c. 15 spms, south of Reykjavik , Skejafir ∂i, coll. G.V. Helgason; c. 50 spms, north of Reykjavik, Hvalfjör ∂ur coll. G.V. Helgason; 5 spms, north-east Iceland, Langanes, coll. G.V. Helgason. NORWAY. 2 spms ( SMNH 76993 , 76994 ; fixed in 95% ethanol), Trondheimsfjorden , Tautra, 63°35.14′N, 10°38.87′E, 30–40 m, dredge, 12.i.2002 ; 2 spms ( SMNH 76995 , 76997 ; fixed in 95% ethanol), Trondheimsfjorden , Tautra, 63°35.09′N, 10°36.39′E, 20–40 m, coll. F. P. 28.i.2002 ; 100 + spms (F. P. ’s collection, fixed in ethanol, formaldehyde and osmium tetraoxide), various localities in Trondheimsfjorden , c. 15–300 m, coll. F. P. 1995–2009; 3 spms (F. P. ’s collection, fixed in 95% ethanol), Bergen area , Hjeltefjorden, Føllese, 60°24.825′– 60°24.667′N, 05°08.478′– 05°08.493′E, 101–125 m, dead Lophelia , dredge, coll. F. P. 8.iii.2003 . SWEDEN. 2 spms ( SMNH 76989 , 76990 ; fixed in 95% ethanol), Gullmarsfjorden , Löken, 58°13.154′N, 11°24.416′E, 33–36 m, dredge, coll. F. P. 30.iii.2003 ; 2 spms ( SMNH 76991 , 76992 ; fixed in 95% ethanol), west Gullmarsfjorden , Bondens hamn, 58°12.60′N, 11°18.90′E, 7–12 m, dredge, coll. F. P. 7.iv.2003 ; 100 + spms (F. P.’s collection, fixed in ethanol, formaldehyde and osmium tetraoxide), various localities in Kosterhavet, c. 2–50 m, coll. F. P. 1995–2009.

Description: Length up to 24 mm for 49 segments. Live specimens yellowish transparent with green to black transverse stripes across segments ( Fig. 3 ), always present but varying in amount and more dense on anterior part of body; posterior segments ventrally often with broad, dark longitudinal band. Eyes red. Preserved animals yellowish, black to green pigmentation retained. Body outline in dorsal view anteriorly truncated and posteriorly tapered ( Fig. 3 ). Prostomium rounded rectangular, as wide as long, with small median posterior incision ( Fig. 4A ). Palpophores cylindrical, palpostyles shorter, tapering with rounded tips. Paired antennae as long as palps ( Fig. 4A–C ). Anterior pair of eyes elongated to kidneyshaped, larger than posterior pair; posterior pair rounded. Nuchal organs follow posterodorsal corners of prostomium ( Fig. 4B ). Facial tubercle present. Proboscis with smooth surface on proximal and distal ring, opening with terminal ring of ten long and stout papillae. Ventral part of opening with distinct incision. Single pair of sickle-shaped ventral jaws with cutting edges, situated on inside of proboscis incision. Lip glands present. Non-everted proboscis reaching segments 10–11. Segments 1–3 dorsally fused. Dorsal cirri and cirrophores segments 1–5 much longer and stouter than following ones. Ventral cirri segment 1–3 much longer and stouter cirri than on following segments, ventral cirrophores well delineated ( Fig. 4C ) and absent on following segment. All cirrophores of anterior dorsal and ventral cirri each with one to three aciculae. Segment 4 with neuropodial lobes, neurochaetae, and ventral cirri similar to following segments. Notochaetae from about segment 6. Elevated and slightly stouter dorsal cirri on segments 5, 8, 10, 12, 15, 17, 20, 22, 25, 28, and every third segment thereafter. Dorsal cirri reaching further than neurochaetae. Notopodia consisting of cirrophores only, single acicula and, on most segments, one to five very fine capillaries emerging below base of anterior side of dorsal cirrophores ( Fig. 4D ). Neuropodia with two pre- and two postchaetal, rounded conical lobes, appearing three-lobed in anterior and posterior view ( Fig. 4E ). About 50 neurochaetae, all unidentate compounds with shafts with distinct internal chambers and longitudinal canals, dorsal and median blades up to 2.5 times longer than ventral ones. Some median neurochaetae with prolonged teeth on blade. Usually double noto- and neuroaciculae. Ventral cirri tapering with rounded tips, inserted subdistally on underside of neuropodia ( Fig. 4E ). Pygidium with pair of long cirri, similar to dorsal cirri. Pygidial papillae present ( Fig. 4F ).

Biology: Gulliksen (1977) reported swarming during autumn in Lübeck Bay in the Baltic, and Banse (1956) and Schram & Haaland (1984) described the larval development of N. punctata from Kiel and the Oslofjord, respectively. Schram & Haaland (1984) noted the presence of two colour varieties, and the striped one of these certainly refers to N. punctata and the second, unpigmented, to N. woodsholea . They examined the larval development of both species but found no consistent differences between them. Larvae of N. punctata , like many other hesionids ( Pleijel, 1998), have a median antenna that is subsequently lost during ontogeny. However, this occurs late in N. punctata , and 6–7-mm-long specimens with 25–26 segments may have a median antenna. Oug (1980) described feeding of N. punctata , showing that it is a predator mainly on other polychaetes and small crustaceans, especially harpacticoid copepods.

Habitat: Various hard bottoms and bottoms with shell gravel from shallow waters down to 300 m.

Distribution: Iceland, northern parts of the British Isles (southern limit uncertain), Denmark, Swedish west coast and outer parts of the Baltic, Norway to Trondheim, possibly further north. Nereimyra punctata has been reported a number of times from the Iberian Peninsula and the Mediterranean (e.g. Campoy, 1982; Arvanitidis, 1999; Parapar, Besteiro & Moreira, 2004), but, in spite of dense collecting in habitats where the animals normally occur, we have not been able to verify those records. Based on examined specimens it appears that N. punctata has a boreal distribution.

Remarks: Müller (1776) in his original description did not mention any type locality, although it can be narrowed down to Denmark or Norway, as these were the areas covered by his study. However, in two later studies ( Müller, 1780, 1788), he stated that his specimens were from Drøbak in the Oslofjord and found in oysters. Müller’s material of N. punctata is not extant, nevertheless we at present see no need for a neotype. The majority of the material examined by us is from Kosterhavet on the Swedish west coast and is situated only 50 nautical miles from Drøbak. In this area F. P. has also observed that N. punctata can occur in oysters ( Ostrea edulis ), in agreement with the original description.

The original description of Psamathe pustulata Parfitt, 1866 (as Psammate pustulata ) is brief and without illustrations, and Parfitt (1866) only mentioned the species with reference to a manuscript by Montagu, suggesting that it was a junior synonym of N. punctata . Following International Commission on

Psammate [sic] aphroditoides Chamberlin, 1920: 13 . Nereimyra aphroditoides Wesenberg-Lund, 1950:

44–45.

Zoological Nomenclature (1999), article 11.6, this name is not available and can be disregarded as a nomen nudum.

Rathke (1843) described Halimede venusta from western Norway. The synonymy with N. punctata , rather than with N. woodsholea , is based on his description of the pigmentation.

Specimens from deeper waters tend to have weaker transverse stripes. These are nevertheless visible and provide the best feature for separating this species from the partially sympatric N. woodsholea . The stripes remain after fixation.

Figures

Figure 3. Nereimyra punctata, dorsal view of live relaxed specimen from Bergen, Norway. Exact scale unknown but specimen is c. 2 cm long.

Figure 4. Nereimyra punctata, scanning electron microscopy photographs of specimens from Bergen, Norway. A, anterior end, dorsal view. B, anterior end, anterolateral view. C, anterior end, ventral view. D, median parapodia, anterodorsal view. E, median parapodia, ventral view. F, posterior end, ventral side. Scale bars: A, C–F = 100 Mm; B = 200 Mm.