Additions of new species to Thelepus (Thelepodidae), with description of a new Terebellides (Trichobranchidae) from Taiwan Author Hsueh, Pan-Wen Author Li, Kuo-Rong text Zootaxa 2017 4244 3 429 439 journal article 36224 10.11646/zootaxa.4244.3.10 5ea8eae5-1706-497f-a745-78852f555e13 1175-5326 432117 A36107A7-7E9F-4995-94A4-E62175719D91 Terebellides baliensis sp. nov. Figs 4 A–G, 5A–D, 6A–D Material examined. Holotype ( NMNS 7743-4 ), station D13 (25°11´35˝ N 121°21´ 34˝E), Bali, New Taipei City , subtidal muddy bottom, 10 January 2010 ; paratypes (all type information the same as holotype): one specimen (NMNS7743-5), station D7 (25°13´14˝N 121°22´38˝E), 4 October 2008 ; one specimen (NMNS7743-6), station D9 (25°12´32˝N 121°22´38˝E), 8 April 2009 ; two specimens (NMNS7743-7), station B4 (25°11´48˝N 121°23´48˝E), 11 January 2010 ; one specimen (NMNS7743-8), station D6 (25°12´50˝N 121°22´20˝E), 11 January 2010 ; one specimen (NMNS7743-9), station D1 (25°12´18˝N 121°23´02˝E), 21 April 2011 ; one specimen (NMNS7743-10), station B3 (25°10´48˝N 121°23´15˝E), 8 August 2011 ; one specimen (NMNS7743-11), station D8 (25°11´36˝N 121°21´35˝E), 26 March 2012 ; one specimen (NMNS7743-12), station D8 (25°11´36˝N 121°21´35˝E), 6 January 2013 ; one specimen (NMNS7743-13), station D8 (25°11´36˝N 121°21´35˝E), 6 January 2013 ; three specimens (NMNS7743-14), station D8 (25°11´36˝N 121°21´35˝E), 6 January 2013 ; one specimen (NMNS7743-15), station D7 (25°13´14˝N 121°22´38˝E), 2 January 2014 ; one specimen (NMNS7743-16), station B1 (25°8´33˝N 121°20´30˝E), 9 January 2015 . Description. Holotype , complete, branchiae partially deformed; in fresh paratype (NMNS7743-10, Fig. 4 A), anterior body mostly bright yellow; preserved holotype mostly beige in alcohol ( Fig. 4 B); body length 24.5 mm with 55 segments, maximum width 1.9 mm on segment 10. Prostomium attached to dorsal surface of upper lip, basal part without eyespots; buccal tentacles of two forms, mostly simple with tapering tips, regardless of tentacle length, and others tentacles long with expanding tips ( Fig. 4 C–D); peristomium forming lips, continuing dorsally; upper lip compact, low ridge; lower lip large, triangular ( Fig. 4 C–D). Segment 1 conspicuous dorsally, eversible proboscis protruded, cone-shaped ( Fig. 4 A–E); segment 2 to 12 with various degrees of thickened on lateral and ventral body, forming short lobes, collar-like, across ventrum covering posterior portion of preceeding segments; hump-like thickening of ventrum more marked on segment 3 to 7 ( Fig. 4 C, E). Branchiae formed by single mid-dorsal stem arising between segment 2 to 4 and four-lobed (two large and two small) lamellate branchiae ( Fig. 4 F); large lamellae mostly fused basally, small partly fused basally. Notopodia as 18 pairs, on segment 3 to 20; first pair of notopodia less developed than subsequent ones ( Fig. 4 C, E), second to six pairs with short notopodia, thereafter progressively longer to maximum length on segment 13, similar length on remaining notopodia ( Fig. 4 B–C). First pair of notopodia with few notochaetae ( Fig. 4 C, E); notopodia on segment 4 to 20 with two rows of narrowly-winged notochaetae ( Fig. 4 G). Neuropodia present from segment 8 to last segment prior to pygidium (48 pairs); neurochaetae emerging from body wall; first thoracic pair bearing geniculate hooks, about 4–7 on each side, moderate to strongly bent, with pointed tip ( Fig. 5 A); subsequent thoracic neuropodia with long-handled acicular uncini ( Fig. 5 B), with 5–6 rows of secondary teeth ( Fig. 5 C–D); abdominal neuropodia present from segment 21, ginkgo leaf-like, bearing single row of avicular uncini on neuropodia margin, uncini short-handled with about 4 rows of secondary teeth ( Fig. 5 E– F). FIGURE 4. Terebellides baliensis sp. nov. A, anterior view of a fresh specimen; B, lateral view of whole animal; C, lateral view of anterior body; D, dorsal view of anterior body; E, ventral view of anterior body; F, detail of branchiae, lateral view; G, thoracic chaeta, segment 11. A, from paratype (NMNS7743-10); B–E, G, from holotype (NMNS7743-4); F, from paratype (NMNS7743-5). Arrow and numerical numbers indicate the first neuropodia and the number of body segment, respectively. B, Branchiae; Bl, Branchial lobes; Bt, Buccal tentacles; Ll, Lower lip; Pr, Proboscis. Scale: A, 1.0 mm; B, 5.0 mm; C, 1.0 mm; D– E, 0.5 mm; F, 1.0 mm; G, 0.1 mm. FIGURE 5. Terebellides baliensis sp. nov. Holotype (NMNS7743-4): A, the geniculate hook on the first thoracic neuropodia, segment 8; B, the long shaft uncini on the second thoracic neuropodia, segment 9; paratype (NMNS7743-13): C, thoracic uncini, frontal view, segment 15; D, thoracic uncini, lateral view, segment 16; E, abdominal uncini, frontal view, segment 23; F, abdominal uncini, frontal view, segment 33. Scale: A, 1.0 mm; B, 0.1 mm. Genital and nephridial papillae not observed. Pygidium round ( Fig. 4 B). Variations: based on complete specimens (NMNS7743-6; 31 mm in length; NMNS7743-15, 22 mm in length). First neuropodia bearing 6–6/7–9 geniculate hooks on right and left side, respectively; tip of geniculate hooks with various degrees of bending; abdomen with 38 and 33+ segments. Etymology. The name is derived from the name of nearby township south to the Tensui River mouth where the worm was collected. Type locality. Offshore from Bali , New Taipei City , Taiwan . Distribution. Known only from the type locality. Remarks. Of currently known Terebellides , five species were described from the East Asia and one species from the Southeast Asia. They are: Terebellides brevis Imajima & Williams, 1985 ( Japan ) , Terebellides horikoshii Imajima & Williams, 1985 ( Japan ) , Terebellides intoshi Caullery, 1915 ( Indonesia ) , Terebellides japonica Moore, 1903 ( Japan ) , Terebellides kobei Hessle, 1917 ( Japan ) , and Terebellides lineata Imajima & Williams, 1985 ( Japan ) ( Schüller & Hutching 2013 ). Disregarding the presence of eversible proboscis in T . baliensis sp. nov. , only T . brevis , T . japonica and T . lineata of these six species are remotely similar to the former species by having the first thoracic chaetiger distinctively less developed than subsequent ones ( Imajima & Williams 1985 ). Moreover, T . brevis has mucronate tips on geniculate hooks and 20–25 abdominal segments ( Imajima & Williams 1985: 12–13, fig. 3e ), whereas T . baliensis sp. nov. has no mucronate tips on geniculate hooks ( Fig. 5 A) and 35 abdominal segments. Terebellides japonica has pointed sheath covering blunt tipped geniculate hooks and an exceptionally long abdomen, with almost 2/3 the length of the animal (45–50 abdominal segments) ( Imajima & Williams 1985 ). In contrast, T . baliensis sp. nov. has pointed tips and without sheath covering geniculate hooks and 35 abdominal segments. Terebellides lineata can be distinguished from T . baliensis sp. nov. by having four free and subequal sized branchial lobes ( Imajima & Williams 1985 ), comparing to the presence of two large and two small basally fused branchial lobes in the latter species.