Streblosoma wuchiensis, Hsueh, Pan-Wen & Li, Kuo-Rong, 2016

Hsueh, Pan-Wen & Li, Kuo-Rong, 2016, New species of Thelepodidae (Terebelliformia, Polychaeta) from Taiwan, Zootaxa 4170 (3), pp. 510-524 : 514-516

publication ID	https://doi.org/ 10.11646/zootaxa.4170.3.5
publication LSID	lsid:zoobank.org:pub:20326200-D115-4C21-9B71-1206AEAA973E
DOI	https://doi.org/10.5281/zenodo.6075283
persistent identifier	https://treatment.plazi.org/id/038087AC-5427-FFA9-FF4B-7731FE8EFD35
treatment provided by	Plazi
scientific name	Streblosoma wuchiensis
status	sp. nov.

Treatment

Streblosoma wuchiensis View in CoL sp. nov.

Figs 3 View FIGURE 3 A–F, 4A–D

Material examined. Holotype ( NMNS 7516-2 View Materials ), Wuchi fishing port (24°17´36˝ N 120°31´11˝E), Taichung, Taiwan; on clusters of sessile biota, including algae, anemones, barnacles, ectoproctans, bivalves, solitary tunicates, and sponges attached to the boat docks; 2 May 2014 . Paratypes, eighteen specimens (seven complete and eleven incomplete specimens; NMNS7516-3 to NMNS7516-20), collection date, location and habitat information same as holotype.

Description. Holotype complete, female with many eggs in posterior thoracic segments, complete specimen, broken into two fragments due to handlings; in life, body orange brownish (paratype, NMNS7516-16) ( Fig. 3 View FIGURE 3 A), preserved specimen colourless ( Fig. 3 View FIGURE 3 B); body length 35.0 mm with 49 segments, maximum width 2.3 mm on segment 12.

Prostomium at base of upper lip; upper lip small and thick, low ridge, horseshoe-shaped; lower lip small and thick, low ridge, rectangular, with surface smooth ( Fig. 3 View FIGURE 3 B). Buccal tentacles slender, basal part of prostomium short and compact, with many eyespots irregularly distributed to form a band encircling almost entire basal part of prostomium with exception of ventral area ( Fig. 3 View FIGURE 3 B–C); peristomium forming lips and continue dorsally; ventral surface of anterior segments corrugated.

Lateral lobes absent ( Fig. 3 View FIGURE 3 B–C). Three pairs of branchiae on segments 2 to 4 ( Fig. 3 View FIGURE 3 B, D); most filaments arising from body wall near the base of notopodia, few filaments arising from body wall at medial gap between pairs of notopodia, first pair filaments extending laterally beyond notopodia ( Fig. 3 View FIGURE 3 B, D); segments 2 to 4 with 20, 16 and 12 independent filaments in each pair, respectively.

Notopodia present from segments 2 to 40. Anterior parapodia elongate, rectangular, with distinct glandular pre- and post-chaetal lobes, notochaetae emerging between lobes ( Fig. 3 View FIGURE 3 C–D), mid to posterior notopodia becoming trapezoidal processes, less glandular than anterior ones; notopodia on segment 2 clearly more dorsal than following ones ( Fig. 3 View FIGURE 3 D), reaching maximum length on segment 4, thereafter becoming progressively shorter. Notochaetae with two rows of winged chaetae, anterior row slightly shorter than those from posterior row, all tapering to tips ( Fig. 3 View FIGURE 3 E–F).

Neuropodia swollen from segments 5 to 17; uncini arranged in straight rows ( Fig. 3 View FIGURE 3 C), dental formula MF:2– 3:1 (mostly MF:2:1 with few MF:3:1), with elongate prow and slightly upturned terminal button ( Fig. 4 View FIGURE 4 A); neuropodia becoming trapezoidal processes on segment 18 to 25, thereafter round and low to near posterior end. Uncini on segments 18 to 25 arranged in figure 8-shaped looped rows, with dorsal edge slightly curved and on segments 26 to 42 arranged in C-shaped, all with openings toward dorsal side ( Fig. 4 View FIGURE 4 B–C), uncini with elongate prow and slightly upturned terminal button, dental formula MF:2–3:1 ( Fig. 4 View FIGURE 4 D).

Nephridial and genital papillae absent; pygidium rounded, without papillae.

Variations. Based on three complete paratypes (NMNS7516-4, 5, 14; corresponding body length 32.5, 51.6 and 81.5 mm). Eyespots distribution patterns on tentacular membrane of the worm varied from a single row to several rows. Number of branchial filaments on segments 2 to 4 and number of pairs of notopodia of the small to large worm varied from 18:10:12, 14:12:10, 24:12:12 and from 51, 63 and 64, respectively.

Etymology. The name is derived from the fishing port name where the worm was collected.

Type locality. Wuchi fishing port, Taichung, Taiwan.

Distribution. Only known from type locality.

Remarks. As in Streblosoma chiguensis sp. nov., uncini of Streblosoma wuchiensis sp. nov. are also arranged in curved rows and branchial filaments extending laterally to notopodia on segment 2. Therefore, members of Streblosoma with uncini arranged in curved rows has increased to eight species. Streblosoma wuchiensis sp. nov.

also differs from S. curvus and S. duplicata by the presence of lateral extension of branchial filaments on segment 2 ( Nogueira et al. 2004; Hutchings et al. 2015; Fig. 1 View FIGURE 1 C–D). Streblosoma wuchiensis sp. nov. varies from S. hesslei , S. porchatensis , S. toddae , and S. uncinatus by number of pairs of notopodia, the occurrence of notopodia on body segments, and the morphology of uncini. Streblosoma wuchiensis sp. nov. has 49 segments with 39 pairs of notopodia occurring from segments 2–40, whereas S. hesslei , S. porchatensis , S. toddae , and S. uncinatus have 73 segments with 36 pairs of notopodia occurring from segments 2–35, 57 segments with notopodia occurring from segment 2 to near pygidium, 150 segments with notopodia occurring from segment 2 to near pygidium, and 62 segments with notopodia occurring from segment 2 to near pygidium, respectively ( Nogueira et al. 2004: 99, Table 1). Uncini of Streblosoma wuchiensis sp. nov. have a large subterminal dorsal button on uncini, whereas those of the four species have either no dorsal button or with a small dorsal button ( Nogueira et al. 2004: 99, Table 1; Fig. 4 View FIGURE 4 D). Moreover, S. wuchiensis sp. nov has first pair of neuropodia started on segment 5 and uncini arranged in Cshaped rows on posterior segments, but S. toddae has first pair of neuropodia from segment 4 and S. uncinatus has uncini arranged in straight rows on posterior segments ( Nogueira et al. 2004: 99, Table 1; Fig. 4 View FIGURE 4 C).

Lastly, Streblosoma wuchiensis sp. nov. is different from S. chiguensis sp. nov. by having many eyespots and uncinial dental formula MF:2–3:1 (mostly MF:2:1), whereas the latter species has no eyespots and uncinial dental formula MF:2:3.