Neanthes Limnicola Class: Polychaeta Order: Phyllodocida a Mussel Worm Family: Nereididae

Phylum: Annelida Neanthes limnicola Class: Polychaeta Order: Phyllodocida A mussel worm Family: Nereididae

Taxonomy: Depending on the author, Trunk: Very thick segments that are Neanthes is currently considered a separate wider than they are long, gently tapers or subspecies to the genus Nereis (Hilbig to posterior (Fig. 1). 1997). Nereis sensu stricto differs from the Posterior: Pygidium bears two, genus Neanthes because the latter genus styliform ventrolateral anal cirri that includes species with spinigerous notosetae are as long as last seven segments only. Furthermore, N. limnicola has most (Fig. 1) (Hartman 1938). recently been included in the genus (or Parapodia: The first two setigers are subgenus) Hediste due to the neuropodial uniramous. All other parapodia are biramous setal morphology (Sato 1999; Bakken and (Nereididae, Blake and Ruff 2007) where both Wilson 2005; Tusuji and Sato 2012). notopodia and neuropodia have acicular However, reproduction is markedly different in lobes and each lobe bears 1–3 additional, N. limnicola than other Hediste species (Sato medial and triangular lobes (above and 1999). Thus, synonyms of Neanthes below), called ligules (Blake and Ruff 2007) limnicola include Nereis limnicola (which was (Figs. 1, 5). The notopodial ligule is always synonymized with Neanthes lighti in 1959 smaller than the neuropodial one. The (Smith)), Nereis (Neanthes) limnicola, Nereis parapodial lobes are conical and not leaf-like (Hediste) limnicola and Hediste limnicola. or globular as in the family Phyllodocidae. (A The predominating name in current local parapodium should be removed and viewed intertidal guides (e.g. Blake and Ruff 2007) is at 100x for accurate identification). Neanthes limnicola. Notopodial lobes at posterior end of animal are normal, not elongate, but smaller than Description anterior lobes (Hartman 1938). Size: Individuals 25–45 mm in length, 2.5–4 Setae (chaetae): All setae are composite. mm in width (without parapodia) and have The notopodia (Fig. 5) bears only one kind of 45–82 segments (Hartman 1938). The seta – homogomph spinigers, which are long, illustrated specimen, from Coos Bay, was 25 sharp composite spines with basal prongs of mm long. equal length (Fig. 4a). The neuropodia (Fig. Color: The illustrated specimen was pale, 5) contain several each of three kinds of translucent to pale yellow green. setae – homogomph and heterogomph General Morphology: Very thick worms that spinigers, and heterogomph falcigers (with are rather wide for their length (Fig. 1). basal prongs of unequal length) (Fig. 4a, b, Body: Individuals are flattened dorso- c). They also have heterogorph and ventrally and extremely active. Nereids are homogomph falcigers with blunt, short and recognizable by their anterior appendages curved setae (Fig. 4c) (Fauchald 1977). N. including two prostomial palps and four limnicola has one special fused falciger in the peristomial tentacular cirri upper acicular neuropodium (Figs. 4d, 5) (see Anterior appendages) (Blake and Ruff (Johnson 1903). (Differentiation among these 2007). setae must be made with a compound Anterior: Prostomium trapezoidal, microscope after placing the parapodium in wider than long, with a longitudinal glycerin or mounting medium, on a slide.) depression (Fig. 2b). Acicula or heavy, black spines, are present at the base of each parapodial lobe (Fig. 5).

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12671 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Eyes/Eyespots: Two pairs of eyes in shares with Hediste, but without the fused trapezoidal arrangement on prostomium (Fig. falcigers. Some authors currently place N. 2b) (Nereididae, Hartman 1968; Blake and limnicola in the genus Hediste (Sato 1999; Ruff 2007). The eyes of epitokous individuals Bakken and Wilson 2005; Tusuji and Sato are enlarged (Hilbig 1997). 2012). The genus Neanthes is further Anterior Appendages: One small pair of distinguished by having only conical frontal antennae, which are separated at their paragnaths on both proboscis rings, and bases, occurs on the prostomium (Fig. 2b). biramous parapodia with composite setae Also on the prostomium are a pair of palps, (Hartman and Reish 1950). Neanthes with cylindrical processes and small limnicola is distinct because individuals are hemispherical palpostyles at the distal ends usually pale and translucent, not dark green (Fig. 2b). Four pairs of tentacular cirri are and its posterior parapodial lobes are not found on the peristomium. The second of expanded like those of N. brandti. dorsal pairs longest (Fig. 2b) (Johnson 1903) Neanthes brandti has been at times and the others, including a more ventral pair, considered a subspecies or a synonym of are quite short for a nereid. N. virens, the large (50–50 cm in length), Branchiae: Absent (Blake and Ruff 2007). cold-water form (Breton et al. 2004). This Burrow/Tube: Individuals build thin, pale latter species, however, has only a few brown, loosely constructed tubes in vertical paragnaths on its proboscis rings, (i.e. 2–3 burrows that are Y-shaped and mucus lined rows in Areas VII, VIII), not many as in N. (Smith 1950). Newly hatched young build brandti (4–5 rows in Areas VII, VIII). The protective tubes of sand grains and mucus. prostomium of N. virens is small and Pharynx: The pharynx bears a distinct triangular, its eyes are small and on the eversible proboscis. The everted proboscis posterior half of the prostomium. It has short has two rings, oral (or proximal) and distal (or antennae and massive palps. These maxillary) and terminates with two fang- species exhibit overlapping geographic shaped jaws (Fig. 3). The oral ring is used distributions and it is possible that they are largely in burrowing, while the distal ring is the same species (Breton et al. 2004). used in feeding (Barnes and Head 1977). Neanthes succinea is one of the most Each ring is equipped with many papillae and common nereids in the NE Pacific but is conical paragnaths and their patterns are recognizable from N. brandti by its very taxonomically relevant. In this species Area I enlarged posterior notopodial lobes, with a usually has one tooth; Area II has the largest small distal dorsal cirrus attached at the end teeth and about 12 in a crescent; Area Ill has of the lobe (Blake and Ruff 2007). It has a a broad patch of 20–25; IV has broad heteronereid form and N. limnicola does crescents of 30–35; V usually has no not. N. succinea is thought to be a more paragnaths (Hartman 1938); VI has three southern form (although it has been small points and Areas VII and VllI have two reported from Netarts Bay). continuous rows (Figs. 3a,b). Neanthes species have spinigerous Genitalia: notosetae only (Hilbig 1997). The Nephridia: morphologically similar genus, Nereis sensu stricto, is characterized by species with Possible Misidentifications spinigerous notosetae in the anterior half of The prostomia of nereid worms are quite the body and falcigerous notosetae alike, with four eyes, a pair of frontal posteriorly (Pettibone 1963; Smith 1959). antennae and biarticulate palps, and 3–4 Common Nereis species include the very pairs of tentacular cirri. The genus abundant Nereis vexillosa, an olive green to Neanthes currently, includes 3–4 local brown worm found in many diverse marine species (Blake and Ruff 2007). Neanthes environments, especially in mussel beds. It species have only homogomph spinigerous has greatly elongated, strap-like notopodial setae in the posterior notopodia, a trait it lobes in the posterior parapodia. Nereis

Hiebert, T.C. 2015. Neanthes limnicola. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. eakini, from rocky habitats, has a long with Nereis vexillosa or Neanthes brandti prostomium and proboscis rings covered (Coos Bay, 1970 unpublished student report). with small round paragnaths. The bright Abundance: Abundant at Coos bay, green Nereis grubei has greatly expanded especially the east side of Coos Bay (L.C. posterior notopodial parapodial lobes and Oglesby, pers. com.). Populations are no paragnaths in Area V of the proboscis. irregularly distributed and tend to occur in Nereis procera is subtidal in sand, has tiny isolation in shallow water in Salinas River, eyes, a very long body, and unusually California (Smith 1950, 1958). inconspicuous paragnaths on its proboscis (Hartman 1968). The genus Nereis differs Life-History Information from Hediste because members of the latter Reproduction: The reproduction and genus has 1–3 fused falcigers on the supra- development of Neanthes limnicola acicular bunch of posterior neuropodial (=Neanthes lighti) was described by Smith setae (no local species are known, Blake (1950). N. limnicola is a unique nereid in that and Ruff 2007). individuals are viviparous, hermaphroditic and self-fertile. Although individuals are self- Ecological Information fertile, genetic evidence suggests that they Range: Type locality is Lake Merced, are capable of outcrossing to maintain genetic California (Johnson 1903). Known range diversity (Fong and Garthwaite 1994). includes Salinas River, California, north to Oocytes are approximately 120–170 µm in Vancouver Island, B.C. (Smith 1958). diameter (Sato 1999; Fernald et a. 1987) and Local Distribution: Coos Bay distribution develop within the adult coelom, by typical includes sites along the South Slough estuary spiral cleavage, until they are 4–8 mm in as well as Coos Bay, Kentuck Inlet and the length (20 setiger stage). Adults have been Coos River mouth. found with larvae within their coelom in July– Habitat: Isolated populations occur in loose August (Washington, Fernald et al. 1987). burrows in sand and clay banks. Individuals Breeding occurs in late winter through spring prefer soft mud, sometimes in channels with and summer, when high temperatures and Salicornia (Smith 1953). However, N. salinity suppress sexual activity (Salinas River limnicola is not limited by substrate and can Estuary, CA, Smith 1953). survive in almost entirely dry mud. Thus, this Larva: Larvae grow rapidly into ciliated species can survive in unstable environment trochophores. At the 20-setiger stage, larvae (e.g. Salinas River, Smith 1953). The unique hatch by rupturing of the body wall of the reproductive strategy (see Reproduction) of parent (Smith 1950). Total development time N. limnicola may have evolved in response to ranges from 21–28 days. Newly hatched the unstable or extreme habitats in which they young immediately build protective tubes of live (Tosuji et al. 2010). sand grains and mucus. Salinity: Adapts to a wide range in salinity Juvenile: from 2–25, but is usually found in areas of Longevity: reduced salinity (Smith 1950). This species is Growth Rate: known to inhabit brackish or freshwater (Sato Food: Nereids use their jaws to tear apart 1999; Blake and Ruff 2007) and eat pieces of algae and diatomaceous Temperature: From cool and temperate detritus from the surface of the bottom (Smith waters and, although warmth (30°C) 1950; Kozloff 1993). negatively affects reproduction, it does not Predators: cause fatalities (Smith 1953). Behavior: Free-living and constructs a Tidal Level: Shallow intertidal. mucus-lined burrow, which is somewhat Y- Associates: In the Salinas River, associates shaped and deep (Kozloff 1993). Worm include the isopod Gnorimosphaeroma exists above the fork of the “Y” and can oregonensis, and amphipods Corophium escape down into the burrow during dry spinicorne, Anisogammarus contervicolus periods. N. limnicola individuals can swim (Smith 1953). N. limnicola does not overlap well.

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