Nereis paporae, Hsueh, 2020

Hsueh, Pan-Wen, 2020, New species of Nereis (Annelida, Polychaeta, Nereididae) from Taiwanese waters, Zootaxa 4802 (1), pp. 1-31 : 14-15

Nereis paporae n. sp.

Figs 7A–E, 8A–G

Material examined. Holotype ( NMNS 8174-004 ), Wuchi Port (24°17.61´N 120°31.18´E), Taichung City, Taiwan, subtidal fouling community on boat piers, 2 May 2014.

Description. Holotype (NMNS 8174-004), incomplete with posterior end missing, remaining body length 28.0 mm with 45 chaetigers, maximum width 1.0 mm at chaetiger 10, excluding parapodia; beige in alcohol (Fig. 7A). Prostomium wider than long, lateral antennae antero-lateral; palpophores globose, palpostyles conical, four pairs of tentacular cirri, surface smooth, longest one reaching chaetiger 2 (Fig. 7B). Two pairs of eyes, in trapezoidal arrangement, subequal in size. Apodous anterior segment about 2.1 times as long as chaetiger 1. Pharynx with dark brown jaws, each with 7 teeth; I=1; II=11 (left), 12 (right), in 2 oblique rows; III=7, in 1 transverse row; IV=18 (left), 14 (right), in 3 oblique rows; V=0; VI=6 (left), 8 (right), in a cluster; VII/VIII=110, in 4–5 rows (Fig. 7C).

Notopodial dorsal ligules triangular on anterior chaetigers, narrow triangular on posterior chaetigers, acute (Fig. 7D, E). Dorsal cirri basally attached to dorsal ligules, acute, about 2.0 times as long as dorsal ligules on anterior chaetigers, about 3.0 times as long as dorsal ligules on posterior chaetigers (Fig. 7D, E). Notopodial prechaetal lobes absent. Notopodial ventral ligules conical, blunt-tipped, on anterior chaetigers, narrow triangular with acute tip on posterior chaetigers (Fig. 7D, E). Neuropodial postchaetal lobes absent. Neuropodial ventral ligules triangular, blunt-tipped, on anterior chaetigers, digitiform on posterior chaetigers; ventral cirri mid-ventrally attached to ventral edge of parapodia, acute, about as long as ventral ligules (Fig. 7D, E).

Notochaetae present from chaetiger 3 to posterior segments, homogomph spinigers present on anterior chaetigers (Fig. 8A), homogomph falcigers present from chaetiger 20 to posterior segments, blade robust, strongly bent, tapered, base with a few or without serrations (Fig. 8B, C). Neurochaetae upper fascicle: homogomph spinigers present (Fig. 8D), heterogomph falcigers with serrated medium-sized blade (Fig. 8E). Neurochaetae ventral fascicle: heterogomph spinigers present (Fig. 8F), heterogomph falcigers with serrated medium-sized blade (Fig. 8G).

Etymology. The name is derived from the Papora aboriginal tribe lived on coastal areas of Taichung during the prehistoric ages of Taiwan.

Type locality. Wuchi fishing port, Taichung City, Taiwan .

Distribution. Only known from the type locality.

FIG. 8. Nereis paporae n. sp.; holotype (NMNS 8174-004): A, chaetiger 45, notochaetal homogomph spiniger; B–C, same, notochaetal homogomph falciger, same side parapodium and chaetiger; D, chaetiger 10, neurochaetal upper fascicle, homogomph spiniger; E, same, neurochaetal upper fascicle, medium-sized blade heterogomph falciger; F, same, neurochaetal ventral fascicle, heterogomph spiniger; G, same neurochaetal ventral fascicle, medium-sized blade heterogomph falciger. Scale: A, D, F, 0.025 mm; B, C, E, G, 0.01 mm.

Remarks. As aforementioned, five Nereis species reported from East Asia have Areas VII & VIII with 1 row of large teeth anteriorly and 4 or more rows of small teeth posteriorly. Of these five species, the morphology of N. paporae n. sp. is similar to that of N. wuchiensis n. sp. Paragnath patterns on the pharynx of N. paporae n. sp. are mostly within the range of N. wuchiensis n. sp. ( Table 2). Other features in N. paporae n. sp., such as the length ratio of peristomium/chaetiger 1, chaetigers reached by longest tentacular cirri, number of teeth on jaws, first chaetiger with notopodial homogomph falcigers, chaetal composition on neuropodia, and type of neuropodial heterogomph falcigers, are all in the range or the same as N. wuchiensis n. sp. ( Table 2). However, N. paporae n. sp. differs from N. wuchiensis n. sp. by having triangular, blunt tipped, dorsal ligules on anterior chaetigers (versus narrow triangular with an acute tip or digitiform) and blade of notopodial falcigers sickle-shaped, robust, with or without short serrations at base (versus sickle-shaped, slender, blade with 2–3 teeth) (Figs 7D, E; 8B, C).

FIG. 9. Nereis shitipingensis n. sp.; holotype ( NMNS 8174-005 ): A, whole animal; B, anterior body; C, paragnaths of the maxillary ring (arrows point to VI, VII / VIII paragnaths); D, chaetiger 10, posterior view. (Abbreviations: DC, dorsal cirrus; NeVL, neuropodial ventral ligule; NoDL, notopodial dorsal ligule; NoVL, notopodial ventral ligule; VC, ventral cirrus). Scale: A, B, 1.0 mm; C, D, 0.1 mm .