Neanthes kaomeiensis, Hsueh, 2019

Hsueh, Pan-Wen, 2019, Neanthes (Annelida: Nereididae) from Taiwanese waters, with description of seven new species and one new species record, Zootaxa 4554 (1), pp. 173-198 : 181-182

Neanthes kaomeiensis n. sp.

Figs 7A – K , 8A – D , Table 2

Material examined. Holotype ( NMNS 7946-022 ), Kaomei (24°18.9´N 120°32.68´E), Taichung City, Taiwan, intertidal soft bottom, 22 October 2005 . Paratypes: 4 specimens ( NMNS 7946-023 – 026 ), collection location, habitat and date information same as holotype .

Description. Holotype, incomplete, posterior end missing, remaining body length 18.0 mm (6.0-22.5) with 57 (22–87) chaetigers, maximum width 2.0 mm (1.0) on chaetiger 7, excluding parapodia; beige in alcohol ( Fig. 7A ). Prostomium wider than long, one pair antennae arise antero-laterally; palpophores spherical and biarticulate with sub-conical palpostyles, four pairs of tentacular cirri, longest posterior tentacular cirri reaching chaetiger 8 (7–9, n=3) ( Fig. 7B ). Two pairs of black eyes, in trapezoidal arrangement, subequal in size. One apodous anterior segment present, about 1.1 times as long as chaetiger 1. Pharynx with light brown jaws, each jaw with 6 (4–5, n=1) lateral teeth; light brown conical paragnaths as: I=6 (7, n=1, sample size of Areas II to VIII same as Area I), in a cluster; II=12 (9) (left), 12 (10) (right), in crescentic rows; III=36 (30), in 3–4 transvers rows; IV=11 (8) (left), 12 (8) (right), in 2–3 crescentic rows; V=0; VI=1 (left), 1 (right); VII/VIII=0 ( Fig. 7B, C ).

Notopodial dorsal ligule narrowed triangular with a pointed tip throughout ( Fig. 7 D–G). Dorsal cirri basally attached to dorsal ligule throughout, shorter than dorsal ligule throughout ( Fig. 7 D–G). Notopodial prechaetal lobe present on chaetiger 3 to 24, cirriform, about 2/3 as long as notopodial ventral ligule ( Fig. 7D, E ). Notopodial ventral ligule narrowed triangular throughout. Neuropodium with prominent inferior and superior lobes on anterior chaetigers, both lobes elongated projecting beyond neuropodial postchaetal lobe. Notopodial postchaetal lobe present, triangular with a pointed tip on anterior chaetigers, digitiform on posterior chaetigers. Neuropodial ventral ligule narrowed triangular on anterior chaetigers, less developing on posterior chaetigers; ventral cirri basally attached to parapodia, shorter than ventral ligule throughout ( Fig. 7 D–G).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers ( Fig. 8A ). Neurochaetae dorsal fascicle: homogomph spinigers ( Fig. 8B ). Neurochaetae ventral fascicle: sesquigomph spinigers ( Fig. 8C ), and sesquigomph falcigers with long, serrated terminal blade ( Fig. 8D ). Pygidium round, one pair of filamentous anal cirri attached ventrally, extending 18 chaetigers.

Etymology. The name is derived from the name of nearby village, Kaomei, where the worm was collected.

Type locality. Kaomei , Taichung City, Taiwan .

Distribution. Only known from the type locality.

Remarks. Of the 22 Neanthes species reported from East and Southeast Asia, N. glandicincta and N. wilsonchani are two only species similar to N. kaomeiensis n. sp., which have 0 & 1 conical paragnath on Areas V & VI of the pharynx, respectively and the presence of a prechaetal lobe on anterior chaetigers ( Southern 1921: 590–591, text-fig. 5b–e, pl. XXIII, fig. 9A, C; Lee & Glasby 2015: 82, 85; Fig. 7D, E ; Table 2). However, N. kaomeiensis n. sp. can be readily distinguished from N. glandicincta by the following characters: 1) the length ratio of the peristomium to chaetiger 1, 2) the length of the longest posterior tentacular cirri, 3) numbers of lateral teeth on jaws, 4) numbers of conical paragnaths on Areas III & VII/III, and 5) number of chaetigers with a notopodial prechaetal lobe and length of pygidial cirri. The length ratio of the peristomium to chaetiger 1 in N. kaomeiensis sp. nov. is about 1.1 ( Table 2), whereas that of N. glandicincta exceeds 2.0 ( Southern 1921: pl. XXIII, fig. 9A). The longest posterior tentacular cirri of N. kaomeiensis n. sp. reach to chaetiger 8~9 ( Table 2), but that of N. glandicincta reaches to chaetiger 3 ( Southern 1921: 590). Neanthes kaomeiensis n. sp. has fewer lateral teeth on jaws than N. glandicincta (4–6 versus 15–16) ( Southern 1921: 590; Table 2). Numbers of conical paragnaths on Areas III & VII/III of the pharynx in N. kaomeiensis n. sp. are 30–36 & 0, respectively ( Table 2), but that of N. glandicincta is 50 & 7, respectively ( Southern 1921: 590). Neanthes kaomeiensis n. sp. has prechaetal lobes on chaetiger 3 to 24, whereas N. glandicincta has prechaetal lobes on chaetiger 3 to 100+ ( Southern 1921: 591–592, text-fig. 5b–e, pl. XXIII, fig. 9H, G). Neanthes kaomeiensis n. sp. differs from N. wilsonchani by having greater numbers of conical paragnaths on Areas I & III of the pharynx (6–7 & 3 0–36 versus 0–4 & 6–7, respectively) ( Lee & Glasby 2015: 85; Table 2). Moreover, N. kaomeiensis n. sp. has prechaetal lobes only on chaetiger 3 to 24, but that of N. wilsonchani are found on anterior to posterior chaetigers ( Lee & Glasby 2015: 89). Lastly, N. kaomeiensis n. sp. is the only species of the nine species reported in the present study that has neuropodial sesquigomph spinigers and long sesquigomph falcigers ( Fig. 8C, D ; Table 2). Neanthes glandicincta reported from Taiwan by Wu (1967) was not encountered in the present study.

Figures

FIGURE 7. Neanthes kaomeiensis n. sp.; A–C, H–L, holotype (NMNS 7946-022); D–G, paratype (NMNS 7946-024). A, whole animal; B, anterior body; C, paragnaths of the pharynx; D, left parapodium, anterior view, chaetiger 7; E, left parapodium, posterior view, chaetiger 7; F, right parapodium, anterior view, chaetiger 67; G, right parapodium, posterior view, chaetiger 67. Abbreviations: IL, inferior lobe; NePL, neuropodial postchaetal lobe; NoPL, notopodial prechaetal lobe; SL, superior lobe. Scale: A, 0.5 mm; B–C, 0.1 mm; D–G, 0.1 mm.

FIGURE 8. Neanthes kaomeiensis n. sp.; paratype (NMNS 7946-024). A, notochaeta, homogomph spiniger, chaetiger 57; B, neurochaeta of dorsal fascicle, homogomph spiniger, chaetiger 57; C, neurochaeta of ventral fascicle, sesquigomph spiniger, chaetiger 57; D, neurochaeta of ventral fascicle, long sesquigomph falciger, chaetiger 57. Scale: A–B, 0.05 mm; C–D, 0.01 mm.