Platynereis polyscalma Chamberlin, 1919

Hadiyanto, Hadiyanto, 2023, Nereididae (Annelida: Phyllodocida) from intertidal macroalgae in Western Australia, Zootaxa 5239 (2), pp. 151-203 : 178-180

Platynereis polyscalma Chamberlin, 1919

Figs 15A–H , 20E–F

Platynereis polyscalma Chamberlin, 1919: 219–226 , pl. 30 figs 5–8, Pl. 31 figs 1–10, pl. 32 figs 1–2; Horst 1923: 223–224; Hartman 1940: 229–231, pl. 38 figs 76–83; Fauvel 1953: 221–222, fig. 112a–e; Hutchings & Reid 1991: 56–57; Glasby 2015: 230–231 , fig. 5.D–E.

Type locality. Ellice Islands and Gilbert Islands.

Material examined. Western Australia: Cape Keraudren , 19°57′46.76″S 119°46′58.51″E, 5 November 2020, 2 specimens ( WAM V11681 ) . South Mandu, Ningaloo , 22°10′07.05″S 113°51′37.79″E, 24 September 2020, 1 specimen ( WAM V11682 ) . Kalbarri , 27°43′17.09″S 114°09′11.39″E, 15 November 2020, 2 specimens ( WAM V11683 ) . Avalon Point, Mandurah , 32°35′40.25″S 115°38′00.16″E, 13 January 2021, 1 specimen ( WAM V11684 ) . Coral Bay , 23°09′16.27″S 113°46′04.40″E, 26 July 2016, 1 specimen ( WAM V11685 ) .

Comparative material. Platynereis polyscalma , det. C. Glasby, Channel Island, Middle Arm, Darwin Harbour , Northern Territory, 12°34.9′S 130°55.4′E, reef at 5–10 m, coll. S.M. Gregg & T . Bakken, 22 September 2000, 1 ( NTM W19031 ) .

Description. Complete specimens with 31–46 chaetigers, body 5.3–30.4 mm long and 0.4–2.4 mm wide; cream yellow in alcohol. Incomplete specimens with 31–39 chaetigers, posterior end missing, remaining body 5.3–31.7 mm long and 0.4–2.3 mm wide; cream yellow in alcohol.

Prostomium as long as wide. Eyes black, two pairs, outer eyes slightly larger than inner ones, in trapezoidal arrangement. Palps one pair, palpophores globose, palpostyles conical. Antennae one pair, slightly shorter than palps. Tentacular cirri four pairs with basal articulation, longest one extending to chaetiger 7–8. Pharyngeal jaws translucent reddish black, curved at tips, with nine teeth on each jaw. Paragnaths reddish black, pectinate bars, present on maxillary and oral rings, arranged as follows: Area I= 0, Area II= 0, Area III= 2 patches in two rows, Area IV= 4 curved rows, lateral ones shorter, Area V= 0, Area VI= two curved rows, Areas VII–VIII= 5 patches in one row at lateral and two rows at ventral ( Fig. 15A–B ).

Apodous segment as long as first chaetiger. First two chaetigers uniramous. Notopodia present with conical dorsal and ventral ligules in anterior chaetigers, those ligules become digitiform in posterior chaetigers. Dorsal cirri cirriform, attached near edge of dorsal parapodia, about three times longer than dorsal ligules. Neuropodia with conical ventral ligules, acicular ligules, and triangular 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 shorter than ventral ligules ( Fig. 15C ).

Notochaetae present with homogomph spinigers in anterior chaetigers, homogomph spinigers and falcigers ( Fig. 15D ), latter from chaetiger 13–17. Notopodial falcigerous blades short, smooth, curved, with a hooked tip connected to blade. Neurochaetae present with homogomph spinigers ( Fig. 15E ) and heterogomph falcigers in dorsal fascicles, heterogomph spinigers ( Fig. 15F ) and falcigers ( Fig. 15G–H ) in ventral fascicles. All spinigerous blades short, with fine serrations. Neuropodial falcigerous blades medium size, with fine serrations and sometimes a tip connected to blade present. Acicula translucent. Pygidium with anus on dorsal side, anal cirri cirriform, as long as last one chaetiger.

Remarks. The present specimens fit the description of the species by Hutchings & Reid (1991). They are also very similar to the comparative specimens from Darwin Harbour ( Fig. 20E–F ). The species is reported by these authors to be widespread in tropical and warm temperate waters of northern Australia. Our specimen from Falcon, Mandurah extends slightly the southernmost record in Western Australia to 32°35′S. However, as pointed out by Read (2007) cryptic species exist for New Zealand forms of Platynereis australis , and museum specimens cannot be separated into species by morphology. Separation to species requires a consideration of living colour patterns, morphological features of the epitokes, and molecular data ( Teixeira et al. 2022). Thus, the Australian fauna of Platynereis , excluding the distinctive P. bicanaliculata Baird, 1863 , is each likely to encompass undescribed cryptic species.

Living specimens show green pigmentation with white spots on the dorsum and white patch on the prostomium. The pectinate bars in Areas VII–VIII can be arranged in 5–6 patches ( Glasby 2015).

Distribution. Tropical Indian and Pacific Ocean, warm temperate waters of Australia ( Table 2 ).

Habitat. Intertidal and subtidal, rocky shores including coralline habitats, sand, mud ( Table 2 ).

Figures

FIGURE 15. Platynereis polyscalma Chamberlin, 1919 (WAM V11684); A, head, dorsal view; B, head, ventral view; C, parapodium, chaetiger 35, posterior view; D, notochaetae, homogomph falciger, chaetiger 35; E, neurochaetae, dorsal fascicle, homogomph spiniger, chaetiger 35; F, neurochaetae, ventral fascicle, heterogomph spiniger, chaetiger 35; G, neurochaetae, ventral fascicle, heterogomph falciger, chaetiger 18; H, neurochaetae, ventral fascicle, heterogomph falciger, chaetiger 35. Scale: A–B, 1 mm; C, 0.05 mm; D–H, 0.02 mm.s

FIGURE 20. Comparative material from Western Australia and the Northern Territory sourced from the Museum & Art Gallery of the Northern Territory. Perinereis helleri (Grube, 1878) (NTM W19020; 2.0 mm wide at chaetiger 1): A, head, dorsal view; B, head, ventral view. Perinereis variodentata (Augener, 1913) (NTM W18369; 1.8 mm wide at chaetiger 1): C, anterior segments, dorsal view; D, proboscis, ventral dissection. Platynereis polyscalma Chamberlin, 1919 (NTM W19031; 2.8 mm wide at chaetiger 1): E, anterior segments, dorsal view; F, proboscis, ventral dissection. Platynereis uniseris Hutchings & Reid, 1991 (NTM W19003; 1.4 mm wide at chaetiger 1): A, anterior segments, dorsal view; B, proboscis, ventral dissection.