Nereis cockburnensis Augener, 1913

Hadiyanto, Hadiyanto, 2023, Nereididae (Annelida: Phyllodocida) from intertidal macroalgae in Western Australia, Zootaxa 5239 (2), pp. 151-203 : 164-166

Nereis cockburnensis Augener, 1913

Figs 7A–H , 19E–F

Nereis cockburnensis Augener, 1913: 153–156 , fig. 15.a–c, pl. 3 fig. 47; Hartman 1954: 33, figs 30–32; Knox & Cameron 1971: 28; Day 1975: 191; Hutchings & Turvey 1982: 121–124, fig. 4D; Wilson (1985): 132 –133.

Nereis (Nereis) cockburnensis .— Hartmann-Schröder 1983: 138; Hartmann-Schröder 1984: 27; Hartmann-Schröder 1986: 49; Hartmann-Schröder 1989: 37; Hartmann-Schröder 1990: 61.

Type locality. Shark Bay and Cockburn Sound , Western Australia .

Material examined. Western Australia: Kalbarri , 27°43′17.09″S 114°9′11.39″E, 15 November 2020, 5 specimens ( WAM V11633 ) . Kalbarri , 27°43′17.09″S 114° 9′11.39″E, 15 November 2020, female epitoke, 1 specimen ( WAM V11634 ) . Horrock , 28°23′23.32″S 114°25′48.98″E, 18 November 2020, 1 specimen ( WAM V11635 ) . Glenfield Beach , 28°41′01.32″S 114°36′21.65″E, 17 November 2020, 1 specimen ( WAM V11636 ) . Dynamite Bay, Green Head , 30° 4′15.62″S 114°57′44.93″E, 28 December 2020, 2 specimens ( WAM V11637 ) . Yanchep Beach , 31°33′02.36″S 115°37′24.86″E, 14 January 2021, 1 specimen ( WAM V11638 ) . Avalon Point, Mandurah , 32°35′40.25″S 115°38′00.16″E, 13 January 2021, 1 specimen ( WAM V11639 ) . Ellensbrook Beach , 33°54′25.59″S 114°59′16.29″E, 18 December 2020, 3 specimens ( WAM V11640 ) . Cape Mentelle , 33°57′45.04″S 114°58′46.85″E, 17 December 2020, 1 specimen ( WAM V11641 ) .

Comparative material. Nereis cockburnensis det. C. Glasby, Tanker Jetty, Esperance, Western Australia, 33°51′S 121°55′E, coll. Mulligan, Esperance Port Survey , March 2002, 1 ( NTM W18361 ) .

Description. Complete specimens with 38–65 chaetigers, body 21.4–32.6 mm long and 1.5–2.2 mm wide; cream yellow in alcohol. An incomplete specimen 34 chaetigers, posterior end missing, remaining body 11.2 mm long and 1.3 mm wide; cream yellow in alcohol.

Prostomium longer than wide. Eyes black, two pairs, equal sizes, in trapezoidal arrangement. Palps one pair, palpophores globose, palpostyles conical. Antennae one pair, as long as palps. Tentacular cirri four pairs with basal articulation, longest one extending to chaetiger 3–5. Pharyngeal jaws black, curved at tips, with seven teeth on each jaw. Paragnaths, reddish black, conical, present on maxillary and oral rings, arranged as follows: Area I= 1, Area II= 8–9 in two rows, Area III= 1–6, Area IV= 14–23, Area V= 3–17 in an irregular cluster and most cones extending onto Area VI, Area VI= 4–5 in two rows, Areas VII–VIII= numerous cones in 2–6 irregular rows, cones smaller toward posterior rows (as viewed on everted pharynx), most antero-ventral row present with alternating large and small cones, posterior rows present with small cones only ( Fig. 7A–B ).

Apodous segment longer than first chaetiger. First two chaetigers uniramous. Notopodia present with digitiform dorsal and conical ventral ligules in anterior chaetigers, ventral ligules become digitiform in posterior chaetigers. Dorsal cirri cirriform, attached on middle of dorsal parapodia, three times longer than dorsal ligules, similar length throughout chaetigers. Neuropodia with conical ventral ligules, acicular ligules, and conical postchaetal lobes extending to same level of acicular ligule tips; ventral ligules become digitiform in posterior chaetigers. Ventral cirri cirriform, attached basally on ventral parapodia, slightly longer than ventral ligules ( Fig. 7C ).

Notochaetae present with homogomph spinigers ( Fig. 7D ) and falcigers ( Fig. 7E ) from chaetiger 3, homogomph falcigers ( Fig. 7F ) in posterior chaetigers. First notopodial falcigerous blades (at chaetiger 3) long, with serrated lateral teeth, remaining notopodial falcigerous blades short, with long terminal tooth and three smaller lateral teeth distally. Neurochaetae present with homogomph spinigers and heterogomph falcigers in dorsal fascicles, heterogomph spinigers ( Fig. 7G ) and falcigers ( Fig. 7H ) in ventral fascicles. All spinigerous blades long, with fine serrations. Neuropodial falcigerous blades short, with fine serrations. Acicula black. Pygidium with anus on dorsal side, with cirriform anal cirri, as long as last four chaetigers.

An incomplete, female epitokous specimen with 62 chaetigers, posterior end missing, remaining body 32.5 mm long and 2.5 mm wide; cream yellow in alcohol. Specimen present with black, enlarged, overlapping paired eyes. Body divided into 16 pre-natatory chaetigers, 39 natatory chaetigers, and 7 post-natatory chaetigers. Neuropodial postchaetal lobes modified into large, flat lamella in natatory chaetigers. Dorsal and ventral cirri unmodified but developing small basal lamella in natatory chaetigers. Paddle-shaped notochaetae in natatory chaetigers.

Remarks. Juveniles have been observed to have a single, bifurcated antenna, instead of one pair, as their bases are fused together ( Hartmann-Schröder 1986); this condition has been observed in several other nereidid species in the Australian region by CJG and is thought to represent an abnormality. Area V in our specimens and materials examined by Hutchings & Turvey (1982) have the same number of paragnaths but have more paragnaths than that of specimens examined by Augener (1913) (6 cones), Hartman (1954) (1–8 cones), Day (1975) (1–8 cones), and Wilson (1985) (1–3 cones). Those paragnaths are arranged in an irregular cluster, instead of two rows ( Augener 1913). Nereis thompsoni Kott, 1951 was synonymised with N. cockburnensis by Hutchings & Turvey (1982). Our specimens agree well with the original description of N. thompsoni , except that Area V of this species has fewer paragnaths (3 large cones) ( Kott 1951; Hartman 1954).

The comparative specimen was collected within the same general area of the survey material. It matches closely the survey specimens and the type description.A characteristic feature of this species is the combination of large and small cones in Areas VII–VIII; the colour images also revealed pseudo-articulation of the antennae and tentacular cirri, which is unusual among nereidids and may be another characteristic feature of the species ( Fig. 19E–F ).

Distribution. Temperate Australia: Western Australia, South Australia, Victoria, New South Wales ( Table 2 ).

Habitat. Intertidal, subtidal, rocky shores ( Table 2 ).

Figures

FIGURE 7. Nereis cockburnensis Augener, 1913 (WAM V11637); A, head, dorsal view; B, head, ventral view; C, parapodium, chaetiger 47, anterior view; D, notochaetae, homogomph spiniger, chaetiger 4; E, notochaetae, homogomph falciger, chaetiger 3; F, notochaetae, homogomph falciger, chaetiger 47; G, neurochaetae, ventral fascicle, heterogomph spiniger, chaetiger 47; H, neurochaetae, ventral fascicle, heterogomph falciger, chaetiger 47. Scale: A–B, 1 mm; C, 0.1 mm; D–H, 0.02 mm.

FIGURE 19. Comparativematerial fromWesternAustralia and the Northern Territory sourced from the Museum &Art Gallery of the Northern Territory. Neanthes cricognatha (Ehlers, 1904) (NTM W18357; 1.8 mm wide at chaetiger 1): A, anterior segments, dorsal view; B, anterior segments, ventral view. Neanthes unifasciata (Willey, 1905) (NTM W19021; 1.5 mm wide at chaetiger 1): C, anterior segments, dorsal view; D, proboscis, ventral dissection. Nereis cockburnensis Augener, 1913 (NTM W18361; 2.0 mm wide at chaetiger 1): E, anterior segments, dorsal view; F, proboscis, ventral dissection. Nereis denhamensis Augener, 1913 (NTM W19015; 1.5 mm wide at chaetiger 1): G, anterior segments, dorsal view; H, anterior segments, ventral view.