Nectoneanthes uchiwa Sato, 2013

Hsueh, Pan-Wen, 2018, First records of Composetia, Eunereis and Nectoneanthes (Annelida: Nereididae) from Taiwan, with descriptions of two new species, Zootaxa 4531 (2), pp. 211-224 : 220

Nectoneanthes uchiwa Sato, 2013

Figs 7A ̄H, 8ĀE

Nectoneanthes uchiwa Sato 2013: 24 (for complete synonym), figs 4A, 9‾14.

Material examined. One specimen (NMNS 7898-008), Station 5 (23˚ 52´37.8 ̋ N 120˚ 16´55.3 ̋ E), mouth of Yuliao Creek, Chunghwa County, intertidal sandy mud bottom, 21 March 2009; 2 specimens ( NMNS 7898-009 ̄010), Station 6 (23˚ 52´32.9 ̋ N 120˚ 16´56.2 ̋ E), collection habitat and date information same as previous specimen ; 2 specimens ( NMNS 7898-011 ̄012), Station 6, collection habitat information same as previous specimens, 4 June 2009 ; 1 specimen ( NMNS 7898-013 ), Wuchi port (24° 17´36.5 ̋N, 120° 31´11.0 ̋E), Taichung City, in fouling community on wall of boat ducks, 22 January 2011 ; 2 specimens ( NMNS 7898-014 ̄015), Shinjei (23°54´2.5̎N 120°17´51.8˝E), Chunghwa County, intertidal sandy mud bottom, 17 November 2014 .

Brief description. Prostomium anterior margin entire, one pair of antennae arising anteriorly, one pairs of biarticulated palps with conical palpostyles; four pairs of tentacular cirri, longest posterior cirri reaching chaetiger 3̄5 (n=3). Peristomium about 1.2 times as long as chaetiger 1. Jaws light brownish, each with 10̄14 lateral teeth (n=4); conical paragnaths as: Area I=0̄2 (n=4; sample size of Area II to VII/VIII same as Area I), in longitudinal line when 2 cones present; II=13̄20 (left), 13̄22 (right), in 2 oblique rows; III=3̄6, in a transverse row; IV=13̄23 (left), 14̄22 (right); Area VI=8̄12 (left), 9̄13 (right), in cluster; Areas V & VII/VIII=159̄277, in a broad band ( Fig. 7A ̄D).

First 2 chaetigers with neuroaciculae only, thereafter noto-aciculae also present. Notopodial dorsal ligule triangular with tapering tip on anterior parapodia ( Fig. 7E, F ), base expanded dorsally to large ovoid lobe on middle and posterior chaetigers ( Fig. 7G ); first ovoid lobe appearing at chaetigers 13̄14 (n=4) ( Fig. 7H ). Dorsal cirri attached 1/3 from base of dorsal ligule, shorter than dorsal ligule throughout. Notopodial prechaetal lobe present throughout, digitiform on anterior chaetigers, less developed from middle to posterior chaetigers ( Fig. 7E ̄H). Neuropodia a slender inferior lobe and a prominent postchaetal lobe present throughout. Notopodial ventral ligule digitiform, blunt tipped. Neuropodial ventral ligule digitiform with tapering tip; ventral cirri attached to middle of neuropodial ventral surface, shorter than ventral ligule. Notochaetae: homogomph ( Fig. 8A ). Neurochaetae, dorsal fascicle: homogomph spinigers and sesquigomph falcigers ( Fig. 8B, C ). Neurochaetae, ventral neurochaetae: homogomph spinigers and sesquigomph spinigers ( Fig. 8D, E ).

Remarks. Sato (2013) distinguishes N. uchiwa from N. oxypoda by the presence of a broad band of many paragnaths in both dorsal and ventral areas of pharyngeal oral ring, with the exception of Area VI, in the former species ( Sato 2013: 4, 26, figs 2ĀC, 10C̄E). Specimens examined in the present study show a continuous broad band of numerous paragnaths on Areas V & VII/VIII of the pharynx ( Fig. 7A ̄D), which agrees with the key character of N. uchiwa ( Sato 2013: 26, fig. 10C̄E). Other morphological characters observed in the present specimens also agree with the origin description of the species, including the paragnaths pattern on maxillary and oral rings of the pharynx, the presence of ovoid lobe above dorsal cirri and the chaetiger number of the first appearing of ovoid lobe, the presence of notopodial prechaetal lobe, and the presence of neuropodial homogomph and sesquigomph spinigers ( Sato 2013: 26̄28, figs 11̄14; Figs 7E ̄H, 8B̄E). However, there is a slight difference on the paragnath count of the broad band on oral ring of the pharynx between the original description and the present specimens. Sato (2013) stated more than 200 paragnaths (about 300 in holotype) counted for this broad band on Areas V & VII/VIII of the pharynx; however, that of paragnath count for specimens examined in the present study ranges from 159 to 277. Nectoneanthes uchiwa is found along east coasts of China, including coastal areas in Fujian Province, which locate on the west site of the Taiwan Strait ( Sato 2013: 22, fig. 9A). It is not surprising that this species can be found on coastal areas on the east site of the Taiwan Strait.

Figures

FIGURE 7. Nectoneanthes c.f. uchiwa Sato, 2013; A, B, E, F (NMNS 7898-013); C, D (NMNS 7898-014); G, H (NMNS 7898-008). A, eversible pharynx, dorsal view; B, eversible pharynx, ventral view; C, eversible pharynx, dorsal view; D, eversible pharynx, ventral view; E, right parapodium, chaetiger 9, anterior view; F, right parapodium, chaetiger 9, anterior view; G, left parapodium, chaetiger 14, posterior view; H, left parapodium, chaetiger 33, anterior view. Abbreviations: DC, dorsal cirrus; IL, inferior lobe; NePL, neuropodial postchaetal lobe; NeVL, neuropodial ventral ligule; NoDL, notopodial dorsal ligule; NoPL, notopodial prechaetal lobe; NoVL, notopodial ventral ligule; OL, ovoid lobe; SL, superior lobe; VC, ventral cirrus. Roman numeric numbers: Areas of the pharynx. Scale: A–D, 1.0 mm; E–H, 0.5 mm.

FIGURE 8. Nectoneanthes c.f. uchiwa Sato, 2013 (NMNS 7898-008). A, notopodial homogomph spiniger, chaetiger 66; B, neuropodial homogomph spiniger, dorsal fascicle, chaetiger 66; C, neuropodial sesquigomph spiniger, dorsal fascicle, chaetiger 66; D, neuropodial homogomph spiniger, ventral fascicle, chaetiger 66; E, neuropodial sesquigomph falciger, ventral fascicle, chaetiger 66. Scale: A–E, 0.01 mm.