Neanthes shigungensis, 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 : 190-191

Neanthes shigungensis n. sp.

Figs 15A – G , 16A – E , Table 2

Material examined. Holotype ( NMNS 7946-030 ), Shigung (23˚51.31'N 120˚15.81' E), Changhua County, Taiwan, intertidal mud bottom, 13 January 2009. Paratypes: 4 specimens ( NMNS 7946-031 – 034 ), collection location, habitat and date information same as holotype .

Description. Holotype, complete, body length 118.5 mm (85–113, n=4) with 168 (138–152, n=4) chaetigers, maximum width 3.0 (1.2–2.6, n=4) mm at chaetiger 9 (5–9, n=4), excluding parapodia; light brown in alcohol ( Fig. 15A ). Prostomium wider than long, one pair antennae arise antero-laterally; palpophores spherical, biarticulate with sub-conical palpostyles, four pairs tentacular cirri, longest posterior tentacular cirri reaching chaetiger 3 ( Fig. 15B ). Two pairs of black eyes, in trapezoidal arrangement, subequal in size. One apodous anterior segment present, about 1.3 times as long as chaetiger 1. Pharynx with dark brown jaws, each with 6~7 lateral teeth; brown conical paragnaths as: I=7 (8, n=2, sample size of Areas II to VIII same as Area I), in a cluster; II=24 (6, 16), 27 (16, 18), in 2–3 crescentic rows; III=65 (48, 56), in 5–6 transverse row; IV=25 (17, 23), 32 (15, 24), in 2–4 crescentic rows; V=7 (3, 5), in a cluster; VI=3 (2), 3 (2), in 1 oblique row; VI/VIII=58 (57), in 3–4 rows ( Fig. 15C ).

Notopodial dorsal ligule narrowed triangular with a pointed tip throughout ( Fig. 15 D–G). Dorsal cirri attached 1/3 from base of dorsal ligule, shorter than dorsal ligule throughout ( Fig. 15 D–G). Notopodial ventral ligule narrowed triangular with a pointed tip throughout. Neuropodium with prominent inferior and superior lobes, both lobes elongate, projecting beyond neuropodial postchaetal lobe ( Fig. 15F ). Neuropodial postchaetal lobe present, rounded triangular with a blunt tip throughout. Neuropodial ventral ligule digitiform throughout; ventral cirri midventrally attached to ventral edge of parapodia, shorter than ventral ligule throughout ( Fig. 15 D–G).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers ( Fig. 16A ). Neurochaetae dorsal fascicle: homogomph spinigers ( Fig. 16B ), and heterogomph falcigers with long, serrated terminal blade ( Fig. 16C ). Neurochaetae ventral fascicle: heterogomph spinigers ( Fig. 16D ), heterogomph falcigers with long, basally serrated terminal blade ( Fig. 16E ). Pygidium not observed.

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

Type locality. Shigung , Changhua County, Taiwan .

Distribution. Only known from the type locality.

Remarks. Of the 22 Neanthes species reported from East and Southeast Asia, only N. crucifera from Philippines has somewhat similar number of conical paragnaths on Area V of the pharynx as in N. shigungensis n. sp. (6 versus 7–8) ( Grube 1878: 81, pl. V, fig. 6; Table 2). However, conical paragnaths counts on Areas I, II, III, IV, VI & VII/VIII of the pharynx in N. crucifera are greatly different from that of N. shigungensis n. sp. (3, 17–18, 29, 26–33, 6 & 164 versus 7, 24–27, 65, 25–32, 3 & 39, respectively) ( Grube 1878: 81, Pl. V, fig. 6, 6 a; Table 2). Moreover, N. shigungensis n. sp. is the only species of the nine species reported in the present study that has 7–8 conical paragnaths on Area V of the pharynx ( Table 2). Of the four species that possesses long heterogomph falcigers in the present study, only shigungensis n. sp. has long heterogomph falcigers serrated at the base of terminal blade, comparing to that of in N. babuzai n. sp., N. kinmenensis n. sp., and N. cf. nanhaiensis ( Figs 2C, E , 10C, E , 12F , 16C, E , Table 2).

Figures

FIGURE 2. Neanthes babuzai n. sp.; holotype (NMNS 7946-001): A, notochaeta, homogomph spiniger, chaetiger 142; B, neurochaeta of dorsal fascicle, homogomph spiniger, chaetiger 129; C, neurochaeta of dorsal fascicle, long heterogomph falciger, chaetiger 129; D, neurochaeta of ventral fascicle, heterogomph spiniger, chaetiger 129; E, neurochaeta of ventral fascicle, long heterogomph falciger, chaetiger 129. Scale: A–E, 0.05 mm.

FIGURE 10. Neanthes kinmenensis n. sp.; holotype (NMNS 7946-027): A, notochaeta, homogomph spiniger, chaetiger 82; I, neurochaeta of dorsal fascicle, homogomph spiniger, chaetiger 82; J, neurochaeta of dorsal fascicle, heterogomph falciger, chaetiger 82; K, neurochaeta of ventral fascicle, heterogomph spiniger, chaetiger 82; L, neurochaeta of ventral fascicle, heterogomph falciger, chaetiger 82. Scale: A–E, 0.05 mm.

FIGURE 12. Neanthes cf. nanhaiensis Wu, Sun & Yang, 1981 (NMNS 7946-029): A, notochaeta, homogomph spiniger, chaetiger 32; B, neurochaeta of dorsal fascicle, homogomph spiniger, chaetiger 32; C, neurochaeta of dorsal fascicle, medium heterogomph falciger, chaetiger 32; D, neurochaeta of ventral fascicle, homogomph spiniger, chaetiger 32; E, neurochaeta of ventral fascicle, medium heterogomph falciger, chaetiger 32; F, neurochaeta of ventral fascicle, long heterogomph falciger, chaetiger 32. Scale: A–B, D, 0.05 mm; C, E–F, 0.01 mm.

FIGURE 15. Neanthes shigungensis n. sp.; holotype (NMNS 7946-030): A, whole animal; B, anterior body; C, paragnaths of the pharynx; D, right parapodium, anterior view, chaetiger 10; E, right parapodium, posterior view, chaetiger 10; F, right parapodium, anterior view, chaetiger 136; G, right parapodium, posterior view, chaetiger 136. Abbreviations: DC, dorsal cirrus; VC, ventral cirrus. Scale: A, 10.0 mm; B–C, 1.0 mm; D–G, 0.5 mm.

FIGURE 16. Neanthes shigungensis n. sp.; holotype (NMNS 7946-030): A, notochaeta, homogomph spiniger, chaetiger 136; B, neurochaeta of dorsal fascicle, homogomph spiniger, chaetiger 136; C, neurochaeta of dorsal fascicle, long heterogomph falciger, chaetiger 136; D, neurochaeta of ventral fascicle, heterogomph spiniger, chaetiger 136; E, neurochaeta of ventral fascicle, long heterogomph falciger, chaetiger 136. Scale: A–E, 0.05 mm.