Eunereis shichengensis, Hsueh, 2018

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 : 218-219

publication ID	https://doi.org/ 10.11646/zootaxa.4531.2.3
publication LSID	lsid:zoobank.org:pub:219E64CC-F656-4A4D-BE3B-AC4B42991682
DOI	https://doi.org/10.5281/zenodo.4631759
persistent identifier	https://treatment.plazi.org/id/03A087A0-FFF8-CC14-FF7C-B65FFAC7C728
treatment provided by	Plazi
scientific name	Eunereis shichengensis
status	sp. nov.

Treatment

Eunereis shichengensis View in CoL n. sp.

Figs 3 View FIGURE 3 A–C, 4A–D, 5A–E

Material examined. Holotype ( NMNS 7898-007 View Materials ), Shicheng (24°58´46˝N 121°57´01˝E), in oyster clusters on cement wall of the Shicheng harbour, Ilan County, 21 July 2016. GoogleMaps

Diagnosis. Body nereidid form, longest posterior tentacular cirri reaching chaetiger 4. Jaws dark brownish, each with 5 to 6 lateral teeth; maxillary ring of pharynx without paragnaths, oral ring paragnaths as: Area V=3 cones, in triangle; Area VI=1, 1 shield-shaped bars; Areas VII/VIII=33 cones, in 2 to 3 rows. Notopodial prechaetal lobes present throughout. Notochaetae: homogomph spinigers. Neurochaetae, dorsal fascicle: homogomph spinigers and short heterogomph falcigers. Neurochaetae, ventral neurochaetae: heterogomph spinigers and short heterogomph falcigers.

Description. Holotype, ovigerous female, complete, body length 55.1 mm with 78 chaetigers, maximum width 3.3 mm at chaetiger 6, excluding parapodia; dorsal and lateral body surfaces dark brown pigmented, light brown to beige on parapodia and ventral surface in alcohol ( Fig. 4A View FIGURE 4 ).

Prostomium anterior margin entire, one pair of antennae, one pair of biarticulated palps, with conical palpostyles; four pairs of tentacular cirri with distinct cirrophores, longest tentacular cirri reaching chaetiger 4 ( Fig. 4B View FIGURE 4 ). Two pairs of eyes, anterior pairs and posterior pairs similar in size, trapezoidal arranged. Apodous segment present, about 1.3 times as long as chaetiger 1. Jaws dark brownish, with 5–6 lateral teeth; pharyngeal maxillary ring without paragnaths, oral ring paragnaths as: Area V=3 cones, in triangle; Area VI=1, 1 shield-shaped bars ( Fig. 4C View FIGURE 4 ); Areas VII/VIII=33 cones, in 2 to 3 rows.

First 2 chaetigers with neuroaciculae only, thereafter noto-aciculae also present. Notopodial dorsal ligule conical, base slightly dorsal expanded on anterior chaetigers ( Fig. 5A, B View FIGURE 5 ); triangular, shorter and laterally compressed on middle chaetigers; triangular with base significantly elongate and laterally expanded from chaetiger 44 to chaetiger 75 ( Fig. 5C, D View FIGURE 5 ); drastically reduced to small size but remaining laterally expanded in next five chaetigers prior to pygidium; basal dorsal edge of dorsal ligule sporadically filled with glands on anterior to middle chaetigers, entirely filled with gland on posterior chaetigers ( Fig. 5C, D View FIGURE 5 ). Dorsal cirri attached basally to dorsal ligule, longer than dorsal ligule on anterior chaetigers ( Fig. 5A, B View FIGURE 5 ), becoming subequal to dorsal ligule on middle chaetigers, shorter than dorsal ligule on posterior chaetigers. Notopodial ventral ligule conical on anterior chaetigers, triangular and blunt tipped on posterior chaetigers. Notopodial prechaetal lobes present throughout ( Fig. 5A, C View FIGURE 5 ). Neuropodia with prominent inferior lobe on anterior chaetigers, blunt tipped. Superior lobe present on anterior chaetigers, digitiform with a blunt tip ( Fig. 5A, B View FIGURE 5 ). Neuropodial postchaetal lobe present on anterior chaetigers, wide triangular with a blunt tip ( Fig. 5B View FIGURE 5 ). Neuropodia without inferior, postchaetal or superior lobe on posterior chaetigers, acicular lobes rounded distally ( Figs 5 View FIGURE 5 C–E). Neuropodial ventral ligule conical throughout; ventral cirri attached to middle of neuropodial ventral surface, shorter than ventral ligule ( Fig. 5 View FIGURE 5 A–D).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers ( Fig. 6A View FIGURE 6 ). Neurochaetae, dorsal fascicle: homogomph spinigers ( Fig. 6B View FIGURE 6 ) and short heterogomph falcigers present ( Fig. 6C View FIGURE 6 ). Neurochaetae, ventral fascicle: heterogomph spinigers and short heterogomph falcigers present, terminal blade with serrations ( Fig. 6D, E View FIGURE 6 ). Pygidium rounded with one pair of non-articulate ventral cirri extending back about 5 chaetigers ( Fig. 4A View FIGURE 4 ).

Etymology. The species name is derived from the name of the village, Shicheng where the worm was collected.

Type locality. Shicheng Harbour , Ilan County, Taiwan .

Distribution. Only known from the type locality.

Remarks. León-González & Solís-Weiss (2000) divided the known species of the genus into two groups on the basis of the absence/presence of notopodial homogomph falcigers. The group with notopodial homogomph falcigers includes E. eugeniae León-González and Solís-Weiss, 2000 , E. longipes ( Hartman, 1936) , E. longissima , E. marri and E. wailesi ( Berkeley & Berkeley, 1954) , whereas the group without notopodial homogomph falcigers includes E. caeca Hartman, 1960 , E. elittoralis , E. paitillae Fauchald, 1977 and E. patagonica ( McIntosh, 1885) ( McIntosh 1885; Hartman 1960; Eliason 1962; Fauchald 1977). Eunereis shichengensis n. sp. has only notopodial homogomph spinigers ( Fig. 6A View FIGURE 6 ) and can be included in the latter group. Of the 5 species without notopodial homogomph falcigers, only E. paitillae has bar-shaped paragnaths on pharyngeal oral ring (i.e., one each on Area VI and three smooth bars on Area VII) ( Fauchald 1977: 25, fig. 5a, e). Eunereis shichengensis n. sp., however, differs from E. paitillae by having one shield-shaped bar on Area VI and 33 conical paragnaths on Area VII/VIII of the pharynx, respectively. Moreover, E. shichengensis n. sp. has homogomph spinigers and heterogomph falcigers in dorsal fascicle of neuropodia, but that of E. paitillae has heterogomph spinigers and heterogomph falcigers ( Fauchald 1977: 25; Fig. 6B, D View FIGURE 6 ). It is worth mentioning that the presence of the shield-shaped bars on Area VI of the pharynx in the present species is also observed for the group of Perinereis species with a single Area VI paragnaths and several Pseudonereis species ( Bakken 2007; Bakken et al. 2009, 2018; Conde-Vela 2018).