Platynereis uniseris Hutchings & Reid, 1991

Figs 16A–G, 20G–H

Platynereis uniseris Hutchings & Reid, 1991: 57–59, fig. 3.a–j; Glasby 2015: 231, fig. 5F, G.

Type locality. Ningaloo, Western Australia .

Material examined. Western Australia: Cape Keraudren, 19°57′46.76″S 119°46′58.51″E, 5 November 2020, 4 specimens (WAM V11686) . Bateman Bay, 23°02′32.68″S 113°49′39.59″E, 20 September 2020, 2 specimens (WAM V11687) . Three Mile, 23°52′32.41″S 113°29′38.72″E, 23 September 2020, 2 specimens (WAM V11688) . Coral Bay, 23°09′16.27″S 113°46′04.40″E, 26 July 2016, 1 specimen (WAM V11689) .

Comparative material. Platynereis uniseris, det. C. Glasby, Ashmore Reef, Western Australia, 12°15′S 123°0′E, coll. B.C. Russell, 23 February 1983, 1 (NTM W19003) .

Description. Complete specimens with 50–81 chaetigers, body 6.2–27.3 mm long and 0.6–1.4 mm wide; cream yellow to reddish brown in alcohol. Incomplete specimens with 29–33 chaetigers, posterior end missing, remaining body 9.5–15.0 mm long and 1.1–1.4 mm wide; cream yellow in alcohol.

Prostomium as long as wide. Eyes black, two pairs, outer eyes slightly larger than inner ones, in rectangular arrangement. Palps one pair, palpophores globose, palpostyles conical. Antennae one pair, extend to level of palps. Tentacular cirri four pairs with basal articulation, longest one extending to chaetiger 5–11. Pharyngeal jaws translucent reddish black, curved at tips, with eight 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= 7 patches in two rows at lateral and three rows in central, Area IV= four curved rows, lateral ones shorter, Area V= 0, Area VI= one slightly curved row, Areas VII–VIII= 5 patches in one row (Fig. 16A–B).

Apodous segment as long as first chaetiger. First two chaetigers uniramous. Notopodia present with conical dorsal and ventral ligules in anterior chaetigers, and those ligules become digitiform in posterior chaetigers. Dorsal cirri cirriform, attached on middle of dorsal parapodia, about twice 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. 16C).

Notochaetae present with homogomph spinigers in first three chaetigers, homogomph spinigers (Fig. 16D) and falcigers (Fig. 16E) from chaetiger 4. Notopodial falcigerous blades short, smooth, curved, with a hooked tip connected to blade. Neurochaetae present with homogomph spinigers and heterogomph falcigers in dorsal fascicles, heterogomph spinigers (Fig. 16F) and falcigers (Fig. 16G) in ventral fascicles. All spinigerous blades short, with fine serrations. Neuropodial falcigerous blades medium-sized, with fine serrations. 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 Ashmore Reef, Western Australia (Fig. 20G–H). As mentioned by these authors, the species is distinguishable from other Australian Platynereis by the presence of a single row of long pectinate bars in the oral ring ( P. antipoda and P. polyscalma have two rows). Platynereis uniseris is reported by these authors to be widespread in tropical and warm temperate waters of northern Australia; the present record at Three Mile extends slightly the southern limit of this species for Western Australia.

Living specimens show pink pigmentation (Glasby 2015).

Distribution. Northern Australia: North-West Australia, Northern Territory, Queensland (Table 2).

Habitat. Intertidal, subtidal, rocky shores, dead coral substrate (Table 2).