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Setaphyes algarvensis sp. nov. urn:lsid:zoobank.org:act: EC8A3AB5-D8E0-46D5-8A07-436FB91199EA Figs 2–4, Tables 1–2 Diagnosis Setaphyes with middorsal elevations on segments 1–6, superficially covered by tufts of elongated, thick hairs whose tips sometimes surpass the posterior margin of segment, and middorsal processes on segments 7–9. Paired paradorsal setae on segments 2–7 and 9; seta on segment 8 unpaired. Laterodorsal setae on segments 2–3 and 6–9 in males and 2–9 in females. Paralateral setae on segment 1. Lateroventral setae on segments 2–10 (two pairs on segment 5). Ventrolateral setae on segment 1 in males and 1–3 in females. Ventromedial setae on segments 3–9 in males and 4–9 in females. Small and abundant cuticular scars (likely outlets of glandular cells) scattered throughout the trunk. Lateral terminal spines present, short, slender. Etymology The species name, algarvensis, refers to the Algarve, the southern region of Portugal where the new species was found. Material examined Holotype PORTUGAL • adult ♂, mounted in Fluoromount G ® on a glass slide; Alvor; 37°07.714′ N, 08°36.329′ W; 16 Dec. 2012; intertidal mud with Zostera sp.; NHMD-921475. Paratypes PORTUGAL • 13 adult ♂♂, 1 adult ♀, mounted as the holotype; same collection data as for holotype; NHMD-921477–921489 (♂♂), NHMD-921476 (♀). Additional material PORTUGAL • 8 adult ♂♂, five of them mounted as the holotype and three mounted for SEM; same collection data as for holotype; UCM Meiofauna Collection. Description See Table 1 for measurements and dimensions and Table 2 for a summary of the middorsal cuticular specialization, seta, tube, nephridiopore and sensory spot locations. HEAD. With retractable mouth cone and introvert. Although two of the examined specimens had the head everted, their structures tend to collapse when mounted for LM; hence, only some details on the morphology of oral styles and scalids can be provided. Internal part of mouth cone with several rings of inner oral styles; exact number, arrangement and morphology not determined. External part of mouth cone with single ring of nine equally-sized outer oral styles, arranged as one anterior to each introvert sector, except for middorsal sector 6 where style is missing. Each outer oral style composed of single, flexible unit, wider at base, bearing fringed sheath, progressively tapering toward distally pointed tip. Introvert with six transverse rings of scalids and 10 longitudinal sectors defined by arrangement of primary spinoscalids. Primary spinoscalids larger than remaining scalids, each one composed of basal, rectangular, wide sheath and distal, elongated, distally pointed end-piece. Scalids from remaining rings regular-sized, similar in morphology to primary spinoscalids but smaller, also composed of a longer distal end-piece and a shorter basal sheath. Exact number, arrangement and detailed morphology of scalids not determined. NECK. With four dorsal and two ventral sclerotized placids (Fig. 2A–B). Dorsal placids rectangular, with a slightly convex anterior margin; mesial ones broader (ca 31–33 µm wide at base) than lateral ones (ca 28–30 µm wide at base) (Fig. 2B). Ventral placids (ca 22–23 µm wide at base) morphologically similar to dorsal ones but much more elongated, getting thinner towards lateral sides (Fig. 2A, C). TRUNK HABITUS. With eleven segments (Figs 2A–D, 3A, 4A, G). Segment 1 with one tergal, two episternal and one trapezoidal, midsternal plate; remaining segments with one tergal and two sternal cuticular plates (Figs 2A–D, 3A, 4A, G). Tergal cuticular plates slightly bulging middorsally (Fig. 4A). Sternal plates reach maximum width at segment 7, but almost constant in width across trunk. Sternal cuticular plates relatively narrow in ratio maximum width to total trunk length (MSW:TL average ratio = 25.23%), giving the animal a relatively slender appearance. Middorsal elevations on segments 1–6, rectangular, narrow, distally blunted, not projecting beyond posterior margin of segments (Figs 2B, 3B, F, H, 4A, E). Middorsal elevations covered by tufts of elongated, thick cuticular hairs whose tips may surpass posterior margin of segment (Figs 2B, 4A, E). Middorsal processes on segments 7–9, exceeding posterior margin of segment, also covered by tufts of elongated, thick cuticular hairs (Figs 2B, 3L, 4A, I). Middorsal processes progressively longer towards posterior trunk, reaching maximum length on segment 9 (Figs 2B, 4A, I). Paired, paradorsal, intracuticular butterfly- to trident-like atria associated with middorsal structures (Figs 3B, F, H). Glandular cell outlets as minute, dot-shaped, rounded to oval perforations throughout cuticle on segments 1–11 (Figs 2A–D, 3B, D, F–M, 4H); number and position of these structures vary greatly among examined specimens, not showing any specific pattern. Up to three pairs of conspicuous laterodorsal and ventromedial cuticular ridges on segments 2–10 (Figs 2A–D, 3E, H–J). Cuticular hairs acicular, non-bracteate, distributed across trunk on segments 1–10, not following any particular pattern (Fig. 4F, H, J). Pachycycli and ball-and-socket joints conspicuous on segments 2–9, reduced on segments 10 and 11 (Fig. 2A–B). Apodemes on segments 9–10 (Fig. 2A). Primary pectinate fringes finely serrated (Figs 2A–D, 3L, 4A, C–E, G–I); secondary pectinate fringes as wavy, quite inconspicuous single line (Figs 2A–D, 3J, 4H). Muscular scars as conspicuous, rounded to oval, hairless areas in laterodorsal and ventrolateral positions on segments 1–10 (Fig. 2A–D). SEGMENT 1. Middorsal elevation not projecting beyond posterior margin of segment (Figs 2B, 3B, 4A). Anterolateral margins of tergal plate as triangular, short, wide, distally rounded extensions (Figs 2A–C, 3C–D, 4G). Paired setae in paralateral and ventromedial positions (Figs 2A–C, 3C–E, 4B–C). Two pairs of sensory spots in subdorsal positions; and one pair in paradorsal and ventromedial positions (Figs 2A–C, 3B, D, 4B–C, F). Sensory spots on this and following segments as oval areas with several rows of cuticular micropapillae surrounding a single pore (Figs 2A–D, 3B, D, F–J, L–M, 4B–C, F, I–J). SEGMENT 2. Middorsal elevation as on preceding segment (Figs 2B, 3F, 4A). Paired setae in paradorsal, laterodorsal and lateroventral position; females with additional, sexually dimorphic pair in ventrolateral position (Figs 2A–C, 3E–G, 4C). Males with sexually dimorphic tubes in ventromedial position (Figs 2A, 3G, 4C, G). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Figs 2A–C, 3F–G, 4C). SEGMENT 3. Middorsal elevation as on preceding segments (Figs 2B, 3F, 4A). Paired setae in paradorsal, laterodorsal, lateroventral and ventral positions. Additional paired setae in ventromedial position in males and in ventrolateral position in females (Figs 2A–C, 3E–G, 4C). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Figs 2A–C, 3F–G, 4C). SEGMENT 4. Middorsal elevation as on preceding segments (Figs 2B, 4A). Paired setae in paradorsal (except for a single specimen, NHMD-921488, with unpaired paradorsal seta), lateroventral and ventromedial positions; females with additional, sexually dimorphic pair in laterodorsal position (Figs 2A–B, 4C). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Figs 2A–B, 4C). SEGMENT 5. Middorsal elevation as on preceding segments (Figs 2B, 3H, 4A, E). One pair of setae in paradorsal (except for one additional male specimen, with unpaired paradorsal seta) and ventromedial positions, and two pairs in lateroventral position; females with additional, sexually dimorphic pair in laterodorsal position (Figs 2A–B, 3H–I, 4D–E). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Figs 2A–B, 3H–I). SEGMENT 6. Middorsal elevation as on preceding segments (Figs 2B, 4A). Paired setae in paradorsal, laterodorsal, lateroventral and ventromedial positions (except for single specimen, NHMD-921489, with unpaired paradorsal seta) (Figs 2A–B, 4D). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Fig. 2A–B); two specimens with deviation in pattern of sensory spots in this segment: one (NHMD-921475) with two ventral sensory spots on right half of segment (one ventromedial and one ventrolateral) and only ventromedial pair on left half, and another (NHMD- 921486) with one ventromedial sensory spot on left half of segment and without ventral sensory spot on right half of segment. SEGMENT 7. Middorsal process extending beyond posterior margin of segment (Figs 2B, 4A, I). Paired setae in paradorsal (except for single specimen, NHMD-921487, with unpaired paradorsal seta), laterodorsal, lateroventral and ventromedial positions (Fig. 2A–B). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Fig. 2A–B). SEGMENT 8. Middorsal process as on preceding segment, slightly longer (Figs 2B, 3L, 4A, I). Unpaired seta in paradorsal position; paired setae in laterodorsal, lateroventral and ventromedial positions (Figs 2A–B, 3L–M, 4I–J). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventromedial positions (Figs 2A–B, 3L–M, 4I–J). SEGMENT 9. Middorsal process as on preceding segment, slightly longer (Figs 2B, 4A, I). Paired setae in paradorsal, laterodorsal, lateroventral and ventromedial positions (Figs 2A–B, D, 4I). Paired sensory spots in paradorsal, subdorsal, laterodorsal and ventrolateral positions (Figs 2A–B, D, 4I). Nephridiopore in lateroventral position. SEGMENT 10. Without middorsal cuticular specialization. Paired setae in lateroventral position (Figs 2A– B, D, 3J). Paired sensory spots in subdorsal, laterodorsal and ventrolateral positions (Figs 2A–B, D, 3J, 4I). SEGMENT 11. Without middorsal cuticular specialization. Tergal plate triangular, with concave and distally pointed posterior margin; sternal plates with pair of ventral extensions distally rounded (Figs 2A–B, D, 3J–K, 4A, G, I). Males with two sexually dimorphic pairs of stout, thick penile spines (Fig. 2A). Short lateral terminal spines, sexually dimorphic in length (LTS/TL average ratio ca 20% in males and ca 10% in females) (2A–B, D, 3A, J–K, 4G). Statistical analysis (Fig. 5, Table 1) The comparison of the total trunk length (TL) between Setaphyes algarvensis sp. nov. and S. kielensis revealed statistically significant differences (p S. kielensis (Fig. 5B), the ratio LTS/TL was compared between males and females in order to find sexually dimorphic differences. The statistical analysis revealed highly significant gender-based differences within this species (p S. algarvensis sp. nov. as well (Fig. 5B, the arrow points out the single female value), but this fact could not be statistically verified due to the fact that only a single female of this species was collected. Therefore, the LTS/TL ratio was only tested between males of both species, which revealed significant differences (p

Echinoderes gizoensis Thormar & Sørensen, 2010 Material examined Holotype SOLOMON ISLANDS • 1 ♀; Ghizo Island, Grand Central Station diving locality; 08°00′49″ S, 156°45′26″ E; 14 m b.s.l.; 4 Jan. 2007; J. Thormar leg.; coral sand; NHMD-099742. Specimen mounted for LM. Paratypes SOLOMON ISLANDS • 1 ♀, 1 ♂; same collection data as for holotype; NHMD-099743 to 099744. Specimens mounted for SEM. See Table 1 for an overview. Description All details followed the original description by Thormar & Sørensen (2010), hence, we would only address two additional points. First of all, we can confirm the absence of glandular cell outlets type 2 in this species. Secondly, we can confirm the presence of female papillae in ventromedial positions on segment 7. They consist of circular openings, and quite broad, sort of rhomboid tubular intracuticular substructures. Tergal extensions of segment 11 are pointed, and extending into long, flexible seta-like tips, formed by a terminal fringe. Sternal extensions are rounded, without any particular fringe differentiation., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on page 26, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Thormar J. & Sorensen M. V. 2010. Two new species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Solomon Islands. Meiofauna Marina 18: 67 - 96."]}

Echinoderes gerardi Higgins, 1978 Figs 5–6, Tables 4, 6 Echinoderes gerardi Higgins, 1978: 172–176, figs 1–8. Echinoderes gerardi – Dal Zotto & Todaro 2016: 132–134, 138, table 6. E. dujardinii – Mari & Morselli 1987: 117. — Sánchez-Tocino et al. 2011: 179–184, figs 1–4, tables 1–2. — Sánchez et al. 2012: 26 [Algeciras, Granada, Murcia, Alicante]. — Ürkmez et al. 2016: 1–8, figs 2–4. Echinoderes aff. gerardi – Sönmez et al. 2016: 8–9, figs 1–2. Emended diagnosis Echinoderes with very short middorsal spines on segments 4 to 8 not even reaching the pectinate fringes of posterior segment margins; middorsal spines on segments 4 to 7 lanceolate, i.e., narrower proximally and distally than medially, whereas middorsal spine on segment 8 is more parallel-sided and only narrowing distally. Lateroventral spines on segments 6 to 9. Tubes present in lateroventral positions on segments 2 and 5, in lateral accessory positions on segment 8, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9; outlets on segment 9 anterior to laterodorsal sensory spots. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips. Females with ventromedial female papillae resembling glandular cell outlets type 2 on segments 6 to 8. Material examined Holotype TUNISIA • 1 ♀; Gulf of Tunis, Korbous; 36°49′ N, 010°34′ E; 0 m b.s.l.; Dr K. Ruetzler leg.; choanocytes of the sponge Tethya aurantium (see Higgins 1978); USNM-54841. Specimen mounted for LM. Additional material TURKEY – Aegean Coast of Turkey • 3 ♀♀, 3 ♂♂; K̹ç̹kb̹k; 37°08′27″ N, 027°21′28″ E; 0 m b.s.l.; 23 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616808 to 616813 • 4 ♀♀, 1 ♂; Akbük Sonrası; 37°23′59″ N, 027°22′10″ E; 0 m b.s.l.; 24 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616814 to 616818 • 1 ♀; Öncesi; 37°59′40″ N, 027°07′15″ E; 0 m b.s.l.; 25 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616819 • 1 ♀, 1 ♂; Çalış; 36°39′33″ N, 029°06′35″ E; 0 m b.s.l.; 16 May 2012; Sönmez and S. Sak leg.; intertidal sand from type locality of Cephalorhyncha flosculosa Yildiz et al., 2016 (see Yildiz et al. 2016); NHMD-616820 to 616821 • 3 ♀♀, 1 ♂; Çatal Island; 37°00′24″ N, 027°13′06″ E; 0 m b.s.l.; 17 June 2011; N. Özlem Yıldız leg.; intertidal macroalgae; personal reference collection of the first author. – Antalya Coast of Turkey • 7 ♀♀, 5 ♂♂; Antalya, Bilem Beach; 36°51′17″ N, 030°44′38″ E; 3 m b.s.l.; 20 Oct. 2012; F. Durucan leg.; red algae (Laurencia obtusa) on sandy bottom at type locality of Echinoderes antalyaensis Yamasaki & Durucan, 2018 (see Yamasaki & Durucan 2018); personal reference collection of the last author. SPAIN – Andalusian Atlantic south coast of Spain • 2 ♀♀, 1 ♂; Cadiz; F. Pardos leg.; UCM • 2 ♀♀, 1 ♂; slightly west of the Gibraltar Strait, Algeciras; F. Pardos leg.; UCM. – Spanish Territory on African mainland at the Gibraltar Strait • 3 ♀♀, 3 ♂♂; Ceuta; F. Pardos leg.; UCM. – Andalusian Mediterranean south coast of Spain • 1 ♀; Málaga; F. Pardos leg.; UCM • 1 ♀; Almería; F. Pardos leg.; UCM.– Murcian Mediterranean southeast coast of Spain • 1 ♀, 2 ♂♂; Cabo de Palos; F. Pardos leg.; UCM. – Valencian Mediterranean east coast of Spain • 1 ♂; Denia; F. Pardos leg.; UCM. All Spanish and Turkish Aegean specimens mounted for LM; all Turkish specimens from Antalya mounted for SEM. See Table 1 for an overview. Description Measurements of spine and segments length and dimensions were made on the Turkish and Spanish specimens. They are presented separately and summarized together with the original measurements of the type material in Table 6. LM and SEM examinations of E. gerardi revealed that it is morphologically very similar with E. dujardinii. Positions of cuticular structures, i.e., spines, tubes, most sensory spots and glandular cell outlets (Figs 5 A–H, 6A–F, I–K) followed the pattern observed in E. dujardinii, hence, the distribution of these structures is summarized in the same table (see Table 4). The only observed difference in distribution of sensory spots regarded the ventrolateral sensory spots on segment 10, that in E. dujardinii are restricted to males, but occur in both sexes in E. gerardi (Fig. 6 J–K). Since the The middorsal spines in E. gerardi are extremely short, and never even reaching the pectinate fringes of the posterior segment margins (Figs 5 B–D, F–G, 6D). Opposite to typical acicular spines, the middorsal spines in E. gerardi are tapered at their attachment point, broadest around ⅓ from proximal end, and then gradually tapering from this point towards the tip, giving them a lanceolate appearance (Figs 5 F–G, 6D). Female papillae are present on sternal plates of segments 6, 7 and 8 (Figs 5E, 6 F–H), and have the same intracuticular structure as described from E. dujardinii. However, while the position of the papillae in E. dujardinii appeared to be rather fixed within the centre of the ventromedial area, the position on segment 6 in E. gerardi varied from centred ventromedial to a much more lateral position, very close to the ventrolateral line. But other than this, the morphology is very similar with the one in E. dujardinii, including the presence of laterodorsal glandular cell outlets type 2 on segments 8 and 9 (Figs 5F, 6I). The only other differences are meristic (see Tables 3 and 6, and Discussion)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 21-22, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. 1978. Echinoderes gerardi n. sp. and E. riedli (Kinorhyncha) from the Gulf of Tunis. Transactions of the American Microscopical Society 97: 171 - 180. https: // doi. org / 10.2307 / 3225589","Dal Zotto M. & Todaro A. 2016. Kinorhyncha from Italy, a revision of the current checklist and an account of the recent investigations. Zoologischer Anzeiger 265: 90 - 107. https: // doi. org / 10.1016 / j. jcz. 2016.01.004","Mari M. & Morselli I. 1987. Acari (Alacaridi ed Idracnelle) e Chinorinchi nella spugna Hymeniacidon sanguinea (Grant) della Laguna Veneta. Atti della Societa dei Naturalisti e Matematici de Modena 118: 115 - 117.","Sanchez-Tocino L., Tierno de Figueroa J. M., Lopez-Rodriguez M. J. & Liebanas G. 2011. First record of Echinoderes dujardinii Claparede, 1863 (Kinorhyncha, Cyclorhagida) in Iberian Peninsula coastal waters. Zoologica Baetica 22: 179 - 184.","Sanchez N., Herranz M., Benito J. & Pardos F. 2012. Kinorhyncha from the Iberian Peninsula: new data from the first intensive sampling campaigns. Zootaxa 3402: 24 - 44. https: // doi. org / 10.11646 / zootaxa. 3402.1.2","Urkmez D., Pardos F., Sezgin M., Karacuha M. E. & Oks ʾ z I. 2016. Echinoderes dujardinii Claparede, 1863 (Kinorhyncha, Cyclorhagida): a new record for the kinorhynch fauna of Turkey. Ecologica Montenegrina 6: 1 - 8.","Sonmez S., Koroglu N. O. & Karaytug S. 2016. First record of Family Echinoderidae Zelinka, 1894 (Kinorhyncha: Cyclorhagida) from Turkish marine waters. Biharean Biologist 10: 8 - 11.","Yildiz N. O., Sorensen M. V. & Karaytug S. 2016. A new species of Cephalorhyncha Adrianov, 1999 (Kinorhyncha: Cyclorhagida) from the Aegean Coast of Turkey. Helgoland Marine Research 70: 24. https: // doi. org / 10.1186 / s 10152 - 016 - 0476 - 5","Yamasaki H. & Durucan F. 2018. Echinoderes antalyaensis sp. nov. (Cyclorhagida: Kinorhyncha) from Antalya, Turkey, Levantine Sea, Eastern Mediterranean Sea. Species Diversity 23: 193 - 207. https: // doi. org / 10.12782 / specdiv. 23.193"]}

Echinoderes aureus Adrianov, Murakami & Shirayama, 2002 Fig. 1; Table 2 Echinoderes aureus Adrianov Murakami & Shirayama, 2002: 51–57, figs 2–6, table 1. Echinoderes lanceolatus Chang & Song, 2002: 204–210, figs 1–2. Syn. nov. Echinoderes lanceolatus – Sørensen et al. 2012: 162, 180, 183. — Neuhaus 2013: tables 2, 6. Emended diagnosis Echinoderes with slender middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on posterior segments reach well beyond the posterior margin of their respective segments and overlap ca 50% of the following segment. Tubes present in ventrolateral positions on segment 2, in lateroventral positions on segment 5, and in midlateral positions on segment 10. Incomplete midventral, intracuticular fissure present on anterior half of segment 2. Glandular cell outlets type 1 distributed in following pattern on dorsal side: middorsal on segments 1, 2, 3, 5, 7, 10 and 11 (two longitudinally aligned outlets on segments 10 and 11), and paradorsal on segments 4, 6, 8 and 9. Glandular cell outlets type 2 are not present on any segment. Tergal extensions of segment 11 are relatively slender, pointed and well-spaced, with strong pectinate fringe between extensions; sternal extensions short, nearly straight. Females with female papillae in ventrolateral positions on segments 7 and ventromedial positions on 8. Material examined Paratypes JAPAN • 1 ♀, 1 ♂; Honshu Island, Tanabe Bay; 33°42′12″ N, 135°22′54″ E; 0 m b.s.l.; Mar. 2001; A. Adrianov, C. Murakami and Y. Shirayama leg.; brown algae (Padina arborescens) in tidal pool; SMBL-397, SMBL-398. Specimens mounted for LM. Holotype and additional paratypes were not available. Additional material JAPAN • 1 ♀; Honshu Island, Tanabe Bay; 33°41′31″ N, 135°20′10″ E; 0 m b.s.l.; 12 Sep. 2012; H. Yamasaki leg.; detritus and mixed sediment in tidal pool; ICHUM-6124 • 2 ♀♀, 2 ♂♂; Tanegashima, Mihama Beach; 30°44′35″ N, 130°59′39″ E; 0 m b.s.l.; 3 Mar. 2014; H. Yamasaki leg.; detritus and mixed sediment in tidal pool; NHMD-664219, NHMD-664220, ICHUM-6125, ICHUM-6126. REPUBLIC OF KOREA • 1 ♀, 1 ♂; Jeju Island, Munseum Islet; 33°13′31″ N, 126°33′55″ E; 0 m b.s.l.; 26 Feb. 1999; J. Lee and Y.H. Song leg.; intertidal macroalgae; NHMD-662029, NHMD-662030 • 2 ♀♀, 3 ♂♂; Jeju Island, Beomseom Islet; 33°13′03″ N, 126°30′52″ E; 0 m b.s.l.; 3 Mar. 2000; J. Lee and Y.H. Song leg.; intertidal macroalgae; NHMD-662031 to NHMD-662033, NHMD-662034 to NHMD-662036. All specimens are mounted for LM. One of the specimens from Beomseom Islet was designated as paratype for Echinoderes lanceolatus. In addition to these specimens, photographs of the holotype of E. lanceolatus, also collected at Beomseom Islet, were examined. No specimens mounted for SEM were available. See Table 1 for an overview. Description The appearance of the species generally follows the description provided by Adrianov et al. (2002a), hence the following notes only provide additional information not included in the original description. The presence of an incomplete midventral, intracuticular fissure on anterior half of segment 2 is confirmed from all examined specimens (Fig. 1E). Our observations also confirmed the presence of rounded ventromedial, intra- or subcuticular markings on segment 1, but it should be stressed that these markings can be very difficult to visualize, and seem to get even harder to see in older specimens. We can furthermore confirm the absence of glandular cell outlets type 2 on any segment. Middorsal spines are thin, and the spine of segment 8 extends well beyond the posterior segment margin and overlaps half of segment 9 (Fig. 1I). Female papillae forming a short, tubular intracuticular structure are present in ventrolateral positions on segment 7 and ventromedial positions on segment 8 (Fig. 1H). Tergal plates of segment 11 have conspicuously strong pectinate fringes in the area between the tergal extensions (Fig. 1J). Seta-like fringe tips not observed from neither tergal nor sternal extensions. Lateral terminal accessory spines short (about ⅓ of lateral terminal spine length), and conspicuously thick and stout (Fig. 1J). The distribution of cuticular structures, i.e., sensory spots, glandular cell outlets, tubes, and spines is summarized in Table 2. Distribution of sensory spots generally follows the original species description, but with several differences. Dorsal series: original description: paradorsal sensory spots on segment 2 present in males; specimens examined herein: paradorsal sensory spots absent on segment 2 in males, but middorsal sensory spot present in both sexes. Original description: one pair of laterodorsal sensory spots on segment 2 present in males; specimens examined herein: two pairs of laterodorsal sensory spots on segment 2 present in both sexes (Fig. 1D). Original description: midlateral sensory spots on segment 3 absent in males; specimens examined herein: midlateral sensory spots on segment 3 present in both sexes. Original description: laterodorsal sensory spots on segment 3 present in females; specimens examined herein: these sensory spots are present in both sexes but appear in midlateral rather than laterodorsal positions (Fig. 1D). Original description: laterodorsal sensory spots on segments 4 to 7 present in males; specimens examined herein: these sensory spots appear in midlateral rather than laterodorsal positions (Fig. 1 F–G), and are also present on segment 8. Original description: no mention of laterodorsal or midlateral sensory spots on segments 4 to 8 in females; specimens examined herein: midlateral sensory spots present on segments 4 to 8 in females (Fig. 1 F–G). Original description: subdorsal sensory spots on segments 5 and 7 absent in males; specimens examined herein: subdorsal sensory spots on segments 5 and 7 present in males. Original description: one pair of subdorsal sensory spots on segment 6 present in females; specimens examined herein: two pairs of subdorsal sensory spots on segment 6 present in females (Fig. 1G). Original description: no mention of laterodorsal sensory spots on segment 9 in any sex; specimens examined herein: laterodorsal sensory spots present on segment 9 in both sexes. Original description: segments 10 and 11 have a middorsal sensory spot anterior to a middorsal glandular cell outlet type 1; specimens examined herein: segments 10 and 11 have two middorsal, longitudinally aligned glandular cell outlets type 1. The distribution of glandular cell outlets type 1 on the dorsal side of segments 1 to 9 fits the original description. Ventral series: Original description: ventromedial sensory spots on segment 1 in males; specimens examined herein: ventromedial sensory spots absent on segment 1 in both sexes. Original description: ventromedial sensory spots are illustrated on segments 2 to 10; specimens examined herein: these structures are glandular cell outlets type 1 (Fig. 1E, H, K), and not sensory spots; however besides these outlets, both sexes have ventromedial sensory spots on segments 5 and 7, and ventrolateral ones on segment 9; males furthermore with ventrolateral sensory spots on segment 10., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 9-10, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Chang C. Y. & Song Y. H. 2002. Echinoderes lanceolatus, a new kinorhynch from Korea (Kinorhyncha, Cyclorhagida, Echinoderidae). The Korean Journal of Systematic Zoology 18: 203 - 211.","Sorensen M. V., Rho H. S., Min W., Kim D. & Chang CY. 2012. An exploration of Echinoderes (Kinorhyncha: Cyclorhagida) in Korean and neighboring waters, with the description of four new species and a redescription of E. tchefouensis Lou, 1934. Zootaxa 3368: 161 - 196. https: // doi. org / 10.11646 / zootaxa. 3368.1.8","Neuhaus B. 2013. Kinorhyncha (= Echinodera). In: Schmidt-Rhaesa A. (ed.) Handbook of Zoology. Gastrotricha, Cycloneuralia and Gnathifera. Vol. 1: Nematomorpha, Priapulida, Kinorhyncha, Loricifera: 181 - 348. De Gruyter, Berlin / Boston.","Adrianov A. V., Murakami C. & Shirayama Y. 2002 a. Echinoderes aureus n. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay (Honshu) - first representative of the genus in the Pacific Ocean. Proceedings of the Biological Society of Washington 115: 205 - 216."]}

Echinoderes imperforatus Higgins, 1983 Fig. 7 Emended diagnosis Echinoderes with short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9, never extending beyond the posterior margin of their respective segments. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short with ventrolateral seta-like tuft of extended fringe tips. Females with ventromedial female papillae resembling glandular cell outlets type 2 on segments 6 to 8. Trunk segments with cuticular hairs, but perforation sites are indistinct. Material examined Holotype BELIZE • 1 ♀; Carrie Bow Cay; 16°50′ N, 088°06′ W; 14 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH 442, fine coral sand with mangrove and seagrass detritus; USNM-69972. Specimen mounted for LM. Paratypes BELIZE – Carrie Bow Cay • 1 ♀; same collection data as for holotype; USNM-69974 • 1 ♀, 1 ♂; 500 m southwest of type locality; 3 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH443, coralline mud with mangrove and seagrass detritus; USNM-69975 • 1 ♀; 500 m south of RH443; 3 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH444, very fine coralline mud with mangrove and seagrass detritus; USNM-69976. All specimens mounted for LM. See Table 1 for an overview. Description The appearance of the species generally follows the description provided by Higgins (1983), hence the following notes only provide additional information not included in the original description. Introvert with six trichoscalids attached to trichoscalid plates (four dorsal and two ventral). Tubes present in lateroventral positions on segments 2 and 5 (Fig. 7C, E), and in laterodorsal positions on segment 10 (Fig. 7 G–H). Spines are present in middorsal positions on segments 4 to 8 (Fig. 7D), and lateroventral positions on segments 6 to 9 (Fig. 7E); spines never extend beyond the posterior margins of their respective segments. Sensory spots could not be observed on all segments, but it is positively confirmed that sensory spots are present in following positions: paradorsal positions on segments 6 to 8, subdorsal positions on segments 4 to 9 (Fig. 7F), and ventromedial positions on segment 1. Glandular cell outlets type 1 are present in following positions: middorsal position on segments 1 to 3 (Fig. 7B), subdorsal positions on segments 4 to 9 (closer to paradorsal positions on segment 9) (Fig. 7B, D, F), lateroventral positions on segment 1 (Fig. 7C), and ventromedial positions on segments 2 to 10 (Fig. 7C, E). Minute glandular cell outlets type 2 present in laterodorsal positions on segments 8 and 9 (Fig. 7F). Females with ventromedial female papillae in ventromedial positions on segments 6 to 8 (Fig. 7E); outlet of papillae on segments 6 and 7 close to the ventrolateral positions, whereas outlets on segment 8 are closer to the midventral line. The intracuticular structures of the papillae on segment 6 form a semicircle with a small protuberance in the curved part of the structure; substructure of segment 7 and 8 papillae forms very short intracuticular tubes. Tergal extensions triangular and well-spaced (Fig. 7 G–H). Posterior margins of sternal plates of terminal segment obliquely straight towards a ventrolateral point; pectinate fringe well-developed, with differentiated fringe tips forming seta-like extensions (Fig. 7G). Perforation sites of cuticular hairs are not invisible on most segments, however, they can be visualized as indistinct dots on segments 1 and 2., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 26-28, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. 1983. The Atlantic barrier reef ecosystem at Carrie Bow Cay, Belize, II. Kinorhyncha. Smithsonian Contributions to Marine Science 18: 1 - 131. https: // doi. org / 10.5479 / si. 01960768.18.1"]}

Echinoderes sensibilis Adrianov, Murakami & Shirayama, 2002 Figs 11–15; Tables 11–12 Emended diagnosis Echinoderes with short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on posterior segments barely or just reaching the posterior margin of their respective segments. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in midlateral positions on segments 8 and 9. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips. Females with ventromedial female papillae resembling glandular cell outlets type 2 on segments 6 to 8; intracuticular substructure of female papillae crescentic on segment 6, and tubular on segments 7 and 8. Material examined Holotype JAPAN • ♂; Honshu Island, Tanabe Bay; 33°42′12″ N, 135°22′54″ E; 0 m b.s.l.; Mar. 2001; A. Adrianov, C. Murakami and Y. Shirayama leg.; calcareous red algae (Corallina pilulifera) in tidal pool; SMBL CM-A-JAP-E04. Specimen mounted for LM. Paratypes JAPAN • 3 ♂♂; same collection data as for holotype; SMBL CM-A-JAP-E01, CM-A-JAP-E05 and CM-A-JAP-E08. Specimens mounted for LM. One specimen was incorrectly identified as female in the original description. Additional material JAPAN • 1 ♀; Honshu Island, Tanabe Bay; 33°41′31″ N, 135°20′10″ E; 0 m b.s.l.; 12 Sep. 2012; H. Yamasaki leg.; detritus and mixed sediment in tidal pool; GenBank: LC557098; ICHUM-6127. DNA was extracted from this specimen, and cytochrome oxidase subunit 1 was sequenced. The cuticle of the specimen was subsequently recovered and mounted for LM (ICHUM- 6127). JAPAN • 3 ♂♂; same collection data as specimen above; personal reference collection of the last author. Specimens mounted for SEM. Additional specimens from the same locality were collected by C.Y. Chang, mounted for SEM, and stored in the personal reference collection of the first author. JAPAN • 1 ♀; Okinawa, Sesoko Station; 26°39′00″ N, 127°51′22″ E; 0 m b.s.l.; 10 Nov. 2016; S. Fujimoto leg.; coarse sand in tidal pool; NHMD-115257. Specimen mounted for LM. REPUBLIC OF KOREA • 2 ♂♂; Korean west coast, Wido Island; 35°36′52″ N, 126°17′01″ E; 0 m b.s.l.; 31 Feb. 2000; J. Lee and Y.H. Song leg.; intertidal macroalgae; NHMD-664200, NHMD-664201 • 1 ♀, 1 ♂; Jeju Island, Gimnyeong; 33°33′33″ N, 126°45′16″ E; 0 m b.s.l.; 1 Mar. 2000; C.Y. Chang, J. Lee and Y.H. Song leg.; intertidal macroalgae; NHMD-664202, NHMD-664203 • 1 ♂; Jeju Island, Udo Islet; 33°31′03″ N, 126°57′40″ E; 0 m b.s.l.; 3 May 2000; C.Y. Chang and J. Lee leg.; intertidal macroalgae; NHMD-664204. All Korean specimens mounted for LM. HAWAII • 4 ♀♀, 6♂♂; Oahu, Kaneohe Bay, lagoon at Coconut Island, St. MVS-0224-HI-01 (= workshop St. KANM005); 21°26′09″ N, 157°47′18″ W; 0,5 m b.s.l.; 22 May 2017; M. V. Sørensen leg.; subtidal black mud, rich in organic matter; GenBank: MT999943; NHMD-662049 to 662058. Specimens were mounted for LM. Additional 5 ♀♀, 5 ♂♂ collected at the same station were mounted for SEM and stored in the first author’s personal reference collection. One specimen was picked up for molecular barcoding and a 625 bp long cytochrome oxidase subunit 1 sequence was deposited in GenBank under accession number MT999943; the cuticle could not be recovered afterwards, but the specimen used for DNA extraction is shown on Fig. 11. HAWAII • 6 ♀♀, 4 ♂♂; Oahu, Kaneohe Bay, He’ia Fish Pond, St. MVS-0229-HI-06 (= St. KANM034); 21°26′05″ N, 157°48′19″ W; 3 m b.s.l.; 24 May 2017; workshop participants leg.; subtidal black mud, very rich in organic matter; NHMD-662059 to 662068. Specimens were mounted for LM. Additional 7 ♀♀, 3 ♂♂ collected at the same station were mounted for SEM and stored in the first author’s personal reference collection. See Table 1 for an overview. Redescription Since the present redescription adds several new features to the species, including information on head structures, observations of live material, and significant diagnostic traits, and since the distributional range of the species is extended considerably, we are providing a full description for the species. As much information as possible is based on observations of the type material, but the specimens are partly deteriorated, hence structures such as sensory spots could no longer be observed. Additional information is primary based on examination of topotypes, supplemented with information from Okinawa and Hawaii populations that morphologically agreed completely with the topotypes. Adults with head, neck and eleven trunk segments (Figs 11–13, 14A, 15A). Glandular cells appear brown-red in live specimens, giving the species a conspicuous longitudinal colour pattern along its trunk (Fig. 11). The colouring fades, and eventually disappears, when the animal is fixed. The trunk appears stout, with nearly equally broad sternal plates on segments 6 to 10 (Figs 11A, C, 14A). Segments 1 to 4 were often strongly contracted in fixed specimens. Lateral terminal spines slender, from 40% to 55% of trunk length. For complete overview of measurements and dimensions, see Table 11. Secondary pectinate fringe present near anterior segment margin on segments 2 to 10, but it is usually covered by the preceding segment. Distribution of cuticular structures, i.e., sensory spots, glandular cell outlets, spines and tubes, is summarized in Table 12. The head consists of a retractable mouth cone and an introvert (Figs 13, 15 B–C). Three rings of inner oral styles present, with five styles in each ring (Fig. 13). The external mouth cone armature consists of nine outer oral styles; bases of outer oral styles each with a V-shaped row of short fringe tips and a central bristle of much longer fringe tips (Fig. 15B). The introvert sectors are defined by the ten primary spinoscalids in Ring 01 (Figs 13, 15C). Each primary spinoscalid consists of a basal sheath and a distal end piece with a blunt tip. The sheaths have a well-defined basal, transverse fringe, and a less distinct fringe more distally on their exterior surfaces; fringe tips of the distal fringe attach along a longitudinal line and alternatingly projects to the left and to the right (see inset Fig. 4B for a similar morphology in a different species). End pieces are smooth and flexible. Rings 02 and 04 have 10 spinoscalids and Rings 03 and 05 have 20. All spinoscalids in these rings are well-developed, and consist of a basal sheath and a pointed end piece (Fig. 15C). The basal sheaths terminate into fine, fringed margins in spinoscalids of Rings 02 to 05, and those of Rings 03 to 05 have in addition a basal median spike. A ring of short fringes extend around the introvert in between spinoscalid Rings 04 and 05. Ring 06 has only six spinoscalids, located in sectors 1, 3, 5, 6, 7, and 9 (Fig. 13); Ring 06 spinoscalids resemble those in preceding sectors, but without a distinct differentiation into sheath and end piece. Ring 07 also has 6 spinoscalids, located as pairs in sectors 3 and 9, and unpaired but laterally displaced in sectors 5 and 7 (trichoscalids are taking up the space in the opposite side of each sector); Ring 07 spinoscalids resemble those in preceding sector. Described sector-wise (Fig. 13), sectors 1 and 6 are similar, having spinoscalids arranged as two double diamonds. Sectors 2, 4, 8 and 10 all have spinoscalids arranged as a quincunx, located in between a medial anterior spinoscalid (Ring 02) and a trichoscalid plate. Sectors 3 and 9 have spinoscalids forming double diamonds anterior to a pair of spinoscalids. Sectors 5 and 7 also have spinoscalids forming double diamonds, but anterior to an unpaired, lateral spinoscalid (Fig. 13). Regular trichoscalids with trichoscalid plates are present in sectors 2, 4, 5, 7, 8, and 10. In addition, a single trichoscalid without trichoscalid plate is present in sector 1 (Figs 13, 14H, 15C). The trichoscalid has the typical furry appearance (Figs 14H, 15C), but basally it also has a series of more well-organized pointed denticles. The neck has 16 placids, measuring 18 µm in length. The midventral placid is broadest, measuring 15 µm in width at its base, whereas all other are narrower, measuring 11 µm in width at their bases. The trichoscalid plates are well-developed; subdorsal and laterodorsal ones are narrow and elongated, and ventromedial ones broadly oval. Segment 1 consists of a complete cuticular ring. Sensory spots are located near the anterior margin in subdorsal and laterodorsal positions, and slightly more posterior in sublateral and ventromedial positions (Figs 12 A–B, 14B, 15D–E); sensory spots are large, and rounded to oval, with numerous micropapillae, two pores, and often a cilium emerging from one of the pores. Glandular cell outlets type 1 present in middorsal and lateroventral positions (Figs 12 A–B, 14B–C, 15D–E); all glandular cells with type 1 outlets on this and following segments with conspicuous brown-red colouring that gets lost during fixation (Fig. 11 A–B). Dorsal and lateral sides, and posterior half of ventral side, with scattered cuticular hairs emerging through rounded perforation sites. The posterior segment margin is straight around the segment, terminating into a pectinate fringe with short, uniform fringe tips. Segment 2 consists of a complete cuticular ring. Pachycyclus of the anterior segment margin is of medium thickness and not interrupted (Figs 11B, 14 A–C). Sensory spots are located in middorsal (but slightly laterally displaced), laterodorsal (twin pair) and ventromedial positions (Figs 12 A–B, 15D–E); sensory spots on this and all following segments as on segment 1, but slightly smaller. Glandular cell outlets type 1 present in middorsal and ventromedial positions, and quite well-developed tubes present in lateroventral positions (Figs 12 A–B, 14B–C, 15D–E). The segment is densely covered with bracteate hairs; hair cover slightly thinner between ventromedial sensory spots. The posterior segment margin is nearly straight; pectinate fringe from middorsal to midlateral positions with short fringe tips, as on segment 1; fringe tips from midlateral to ventromedial positions conspicuously longer, and then again very short between ventromedial positions. Segment 3, and remaining segments, consisting of one tergal and two sternal plates. Pachycyclus of the anterior segment margin of medium thickness, and interrupted only at tergosternal junctions (Figs 11 B–C, 14C). Sensory spots present in subdorsal, laterodorsal and sublateral positions (Fig. 12 A– B). Glandular cell outlets type 1 present in middorsal and ventromedial positions (Figs 12 A–B, 14B–C). Bracteate cuticular hairs are densely covering the segment from middorsal to ventromedial positions; paraventral areas densely covered by non-bracteate, hair-like extensions. Pectinate fringe of posterior margin hairs as on preceding segment. Segment 4 with short acicular spine in middorsal position, not reaching the posterior margin of the segment (Figs 12A, 14B). Sensory spots present in subdorsal, midlateral and ventromedial positions (Fig. 12 A–B); midlateral and ventromedial sensory spots considerably smaller than all other sensory spots in the species, but they occur consistently in all examined specimens. Glandular cell outlets type 1 present in subdorsal and ventromedial positions (Figs 12 A–B, 14B–C). Pectinate fringe of posterior segment margin with long fringe tips from middorsal to ventromedial positions, and with very short tips between ventromedial positions. Pachycycli and cuticular hairs as on preceding segment. Segment 5 with short acicular spine in middorsal position, not reaching the posterior margin of the segment (Figs 12A, 14D), and well-developed tubes in lateroventral positions (Figs 12B, 14E). Sensory spots present in subdorsal, midlateral and ventromedial positions (Fig. 12 A–B). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 6 with short acicular spines in middorsal and lateroventral positions (Figs 12 A–B, 14D– E, 14G–H), not reaching the posterior margin of the segment. Sensory spots present in paradorsal, subdorsal, midlateral and ventromedial positions (Figs 12 A–B, 15G). Females with female papillae in ventromedial positions, close to and lateral to sensory spots (Figs 12B, 14E, 15H); openings of papillae resemble small glandular cell outlets type 2 (Fig. 15H), and intracuticular substructures each form a semicircle with a small protuberance in the curved part of the structure (Fig. 14E). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 7 with short acicular spines in middorsal and lateroventral positions, barely reaching the posterior margin of the segment (Figs 12 A–B, 14D–E, 15G–I). Females with female papillae as on segment 6, but with openings slightly more anterior and lateral to sensory spots (Figs 12B, 14E, 15 H–I); the substructure of these papillae differs from those on preceding segment, and forms instead a small intracuticular tube (Fig. 14E). Sensory spots, glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 8 with short acicular spines in middorsal and lateroventral positions, barely or just reaching the posterior margin of the segment (Figs 12 A–B, 14D–G, 15G, I). Minute glandular cell outlets type 2 present in midlateral positions, but very close to the laterodorsal areas (Figs 12A, 14G, 15F). Sensory spots present in paradorsal, subdorsal, midlateral (posterior to glandular cell outlets), ventrolateral positions (Figs 12 A–B, 15F, I). Females with female papillae similar to those on segment 7, but with openings slightly more anterior and closer to midventral line (Figs 12B, 14E, 15I). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 9 with acicular spines in lateroventral positions, just reaching the posterior margin of the segment (Figs 12B, 15F). Sensory spots, glandular cell outlets type 1 and 2 as on preceding segment, but female papillae not present (Figs 12 A–B, 14F–G, 15F). Small, rounded nephridial sieve plates present in lateral accessory positions. Pectinate fringe of posterior segment margin with uniformly long fringe tips around the segment. Pachycycli and cuticular hairs as on preceding segment. Segment 10 with well-developed laterodorsal tubes near posterior segment margin (Figs 12, 14J, 15 J–L). Sensory spots present in subdorsal (but close to paradorsal) positions (Figs 12A, C, 15J, L); males furthermore with sensory spots in ventrolateral positions (Fig. 12D). Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones and in ventromedial positions (Figs 12, 14I). The posterior segment margin of the tergal plate is straight, whereas margins of sternal plates are concave and extend midventrally into a point that almost reaches the posterior margin of the terminal segment; fringe tips of pectinate fringe are considerably shorter than those on preceding segments. Pachycycli and cuticular hairs as on preceding segment. Segment 11 with lateral terminal spines (Figs 11A, 12 A–B, 14A). Males with three pairs of penile spines (Figs 12 C–D, 14J, 15K–L); dorsal and ventral penile spines are thin, flexible tubes, whereas the median ones are slightly thicker, conical, and more rigid; females with short, thin lateral terminal accessory spines (Figs 12 A–B, 14I, 15J). Two pairs of sensory spots present in subdorsal positions and one pair in ventrolateral positions; one pair of subdorsal sensory spots medially on segment, other pair at posterior margin (Fig. 15J). Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones and in subdorsal positions, anterior on segment. The dorsal and most of the ventral side of the segment are densely covered with non-bracteate hair-like extensions. Tergal extensions are wellspaced, short and pointed (Figs 12, 14 I–J, 15J, L); sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips (Figs 14J, 15J). Notes on habitat and ecology The specimens collected in Kaneohe Bay, Hawaii, showed a very clear preference for muddy localities, rich in organic matter. They seemed to thrive very well in it, and appeared in high numbers. Especially at the locality in He’ia Fish Pond (St. MVS-0229-HI-06) – an 800 year old fish pond established by isolating a part of the coastal water with a 2 km long lava rock wall – specimens of E. sensibilis occurred in ball-like aggregations composed of detritus, and up to 40 specimens. At low magnification, these balls would just resemble detritus pellets, but by gently opening the ball with a needle, it would appear that the balls mainly consisted of mass aggregated kinorhynchs., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 39-49, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973

Echinoderes chandrasekharai Sørensen & Chatterjee sp. nov. urn:lsid:zoobank.org:act: F8BC0D7A-18AD-455C-9A82-542A062C9BC2 Figs 22–24; Tables 17–18 Echinoderes cf. ehlersi – Higgins & Rao 1979: 79–83, fig. 2 (specimens USNM-55391, USNM-55392, USNM-55394, USNM-55395, USNM-55397). — Adrianov & Malakhov 1999: 18–19, fig. 5.29. Diagnosis Echinoderes with short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines never reach the pectinate fringes of the posterior margins of their segments. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips. Females with female papillae with crescentic intracuticular substructure in ventrolateral positions on segments 6 and 7 and in ventromedial positions on segment 8. Etymology The species is dedicated to Dr G. Chandrasekhara Rao in recognition of his contributions to Indian kinorhynch studies, and for being the first to collect the new species (see Higgins & Rao 1979). Material examined Holotype INDIA • ♀; Andaman Islands, Havelock Island, East Point; 11°54′ N, 093°03′ E; Paratypes INDIA • 3 ♀♀, 1 ♂; same collection data as for holotype; USNM-55392, 55394, 55395 and 55397. Mounted as holotype. The specimens were originally reported as Echinoderes cf. ehlersi (Higgins & Rao 1979). Additional material INDIA • 1 ♀, 1 ♂; South Andaman Islands, Wandoor; 11°40′33″ N, 092°45′07″ E; E. dujardinii and a summary can be seen in Fig. 3. Rings 02 and 04 have 10 spinoscalids and Rings 03 and 05 have 20. All spinoscalids in these rings are well-developed, and consist of a basal sheath and a pointed end piece. The basal sheaths terminate into fine, fringed margins in spinoscalids of Rings 02 to 05, and those of Rings 03 to 05 have in addition a basal median spike also. A ring of short fringes extend around the introvert in between spinoscalid Rings 04 and 05. Ring 06 has only six spinoscalids, located in sectors 1, 3, 5, 6, 7, and 9; ring 06 spinoscalids resemble those in preceding sectors, but without a distinct differentiation into sheath and end piece. Ring 07 has 7 spinoscalids, located as pairs in sectors 3 and 9, unpaired but laterally displaced in sectors 5 and 7 (trichoscalids are taking up the space in the opposite side of each sector), and unpaired but centred in sector 1 (Fig. 23I). Described sector-wise, sector 1 has spinoscalids arranged as two double diamonds anterior to a single spinoscalid in Ring 7. Sectors 2, 4, 8 and 10 all have spinoscalids arranged as a quincunx, located in between a medial anterior spinoscalid (Ring 02) and a trichoscalid plate. Sectors 3 and 9 have spinoscalids forming double diamonds anterior to a pair of spinoscalids in Ring 7. Sectors 5 and 7 also have spinoscalids forming double diamonds, but anterior to an unpaired, laterally spinoscalid. Sector 6 has spinoscalids arranged as two double diamonds (Fig. 3). Trichoscalids with trichoscalid plates are present in sectors 2, 4, 5, 7, 8 and 10. The neck has 16 placids, measuring 16 µm in length. The midventral placid is broadest, measuring 13 µm in width at its base, whereas all other are narrower, measuring 8 µm in width at their bases. The trichoscalid plates in the dorsal sectors are composed of a distal part and a slightly broader proximal part, whereas the proximal parts of the ventral trichoscalid plates are much broader (Fig. 23I). Segment 1 consists of a complete cuticular ring. Sensory spots are located near the anterior margin in subdorsal and laterodorsal positions, and slightly more posterior in sublateral and ventrolateral positions (Figs 22 A–B, 24D–E); sensory spots are large, and rounded to oval, with numerous micropapillae, two pores, and often a cilium emerging from one of the pores. Glandular cell outlets type 1 present in middorsal and sublateral positions (Figs 22 A–B, 23B–C, 24D). Cuticular hairs emerging through rounded perforation sites are covering the segment, except in a W-shaped ventral area on anterior segment half (Fig. 24E). The posterior segment margin is straight around the segment, terminating into a pectinate fringe with short, uniform fringe tips. Segment 2 consists of a complete cuticular ring. Pachycyclus of the anterior segment margin is of medium thickness and not interrupted (Fig. 23 B–C). Well-developed tubes present in lateroventral positions (Figs 22B, 23C, 24E). Sensory spots are located in middorsal (but slightly laterally displaced), laterodorsal (twin pair) and ventromedial positions (Figs 22 A–B, 24D–E); sensory spots on this and all following segment oval, and same size or only slightly smaller than those on segment 1. Glandular cell outlets type 1 present in middorsal and ventromedial positions (Figs 22 A–B, 23B–C). The segment is densely covered with bracteate hairs; hair cover slightly thinner between ventromedial sensory spots. The posterior segment margin is nearly straight; pectinate fringe from middorsal to midlateral positions with short fringe tips, as on segment 1; fringe tips from midlateral to ventromedial positions conspicuously longer, and then very short again between ventromedial positions. Segment 3, and remaining segments, consisting of one tergal and two sternal plates. Pachycyclus of the anterior segment margin of medium thickness, and interrupted only at tergosternal junctions (Fig. 23 A– B). Sensory spots present in subdorsal, laterodorsal and sublateral positions (Figs 22 A–B). Glandular cell outlets type 1 present in middorsal and ventromedial positions (Figs 22 A–B, 23B–C). Bracteate cuticular hairs are densely covering the segment from middorsal to ventromedial positions; shieldshaped paraventral areas densely covered by non-bracteate, hair-like extensions. Pectinate fringe of posterior margin hairs as on preceding segment. Segment 4 with short acicular spine in middorsal position, not reaching the posterior margin of the segment (Figs 22A, 23B, D). Sensory spots present in subdorsal, midlateral and ventromedial positions (Fig. 23 A–B); midlateral sensory spots considerably smaller than all other sensory spots on the animals, but they occur consistently in all examined specimens. Glandular cell outlets type 1 present in subdorsal and ventromedial positions (Figs 22 A–B, 23C, 24B–D). Pectinate fringe of posterior segment margin with long fringe tips from middorsal to ventromedial positions conspicuously long, but very short between ventromedial positions. Pachycycli and cuticular hairs as on preceding segment. Segment 5 with short acicular spine in middorsal position, not reaching the posterior margin of the segment, and well-developed tubes in lateroventral positions (Figs 22 A–B, 23D–E, 24G). Sensory spots present in subdorsal, midlateral and ventromedial positions (Figs 22 A–B). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 6 with short acicular spines in middorsal and lateroventral positions (Figs 22 A–B, 23D–E, 24G); middorsal spine not reaching the posterior margin of the segment, and lateroventral spine just reaching the primary pectinate fringe. Sensory spots present in paradorsal, subdorsal, midlateral and ventromedial positions (Figs 22 A–B, 24G). Females with female papillae resembling small glandular cell outlets type 2 in ventrolateral positions; the intracuticular structures of the papillae are crescentic with a small protuberance in the curved part of the structure (Fig. 22B). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 7 with short acicular spines in middorsal and lateroventral positions (Figs 22 A–B, 23D–E, 24G–H); middorsal spine not reaching the posterior margin of the segment, and lateroventral spine just reaching the primary pectinate fringe. Females with female papillae resembling small glandular cell outlets type 2 (Fig. 24H), in ventrolateral positions (Figs 22B, 23E, 24H); the intracuticular structures of the papillae are crescentic with a small protuberance in the curved part of the structure (Fig. 23E). Sensory spots, glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 8 with short acicular spines in middorsal and lateroventral positions (Figs 22 A–B, 23D–F, 24G, I); middorsal spine not reaching the posterior margin of the segment, and lateroventral spine slightly overlapping the primary pectinate fringe. Minute glandular cell outlets type 2 present in laterodorsal positions (Figs 22A, 23D, F, 24F), but very close to the midlateral areas. Sensory spots present in paradorsal, subdorsal, midlateral (posterior to glandular cell outlets), ventrolateral positions (Figs 22 A– B, 23D–E, 24F–G, I). Females with female papillae showing same substructure as those on segment 7, but with openings in ventromedial positions (Figs 22B, 23E, H, 24I). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 9 with acicular spines in lateroventral positions, protruding slightly beyond primary pectinate fringe of posterior segment margin (Figs 22B). Sensory spots, glandular cell outlets type 1 and 2 as on preceding segment, but female papillae not present (Figs 22 A–B, 24F). Small, rounded nephridial sieve plates present in lateral accessory positions (Fig. 24F). Pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 10 with well-developed laterodorsal tubes near posterior segment margin (Figs 22, 23 J–K, 24J, L). Sensory spots present in subdorsal (but close to paradorsal) and ventrolateral positions (Figs 22, 24 J–L). Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones and in ventromedial positions. The posterior segment margin of the tergal plate is straight, whereas margins of sternal plates are concave (most deeply concave in males) and extend midventrally into a point that almost reaches the posterior margin of the terminal segment (Fig. 24 K–L); fringe tips of pectinate fringe are considerably shorter than those on preceding segments. Pachycycli and cuticular hairs as on preceding segment. Segment 11 with lateral terminal spines (Figs 22, 23A, J–K, 24A, J–L). Males with three pairs of tubular penile spines (Figs 22 C–D, 23K, 24J–K); dorsal and ventral penile spines are thin, flexible tubes, whereas the median ones are slightly thicker; females with short, thin lateral terminal accessory spines. Sensory spots present in subdorsal and ventrolateral positions (Figs 22, 23 J–K, 24J–K). The dorsal and most of the ventral sides are densely covered with non-bracteate hair-like extensions, except in some areas near the anterior margin of the segment. Tergal extensions are well-spaced, short and pointed (Figs 22, 23K, 24J, L); sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips (Figs 22, 24K)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 66-73, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. & Rao G. C. 1979. Kinorhynchs from the Andaman Islands. Zoological Journal of the Linnean Society 67: 75 - 85. https: // doi. org / 10.1111 / j. 1096 - 3642.1979. tb 01106. x","Adrianov A. V. & Malakhov V. V. 1999. Cephalorhyncha of the world ocean. KMK Scientific Press, Moscow."]}

Echinoderes pilosus Lang, 1949 Figs 9–10; Tables 9–10 Emended diagnosis Echinoderes with middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; all middorsal spines slender and flexible and projecting well beyond the posterior margin of their respective segments. Long and slender tubes present in ventrolateral positions on segment 2, lateroventral positions on segment 5, and in laterodorsal positions on 10. Incomplete midventral, intracuticular fissure present on anterior half of segment 2. Two middorsal, longitudinally aligned glandular cell outlets type on segment 1. Minute glandular cell outlets type 2 in subdorsal positions on segment 2, and in laterodorsal positions on segments 8 and 9. Tergal extensions of segment 11 short and pointed; margin of sternal extensions straight, with ventrolateral seta-like tuft of extended fringe tips. Females with female papillae with tubular substructure in ventrolateral positions on segment 7 and ventromedial positions on segment 8; males with ventrolateral sensory spots on segment 10. Material examined Lectotype (here designated) SOUTH GEORGIA ISLANDS • ♀; Grytviken; 54°16′59″ S, 36°30′29″ W; 22–23 May 1902; collected during the Swedish Antarctic Expedition in Grytviken; SMNH 3930. Specimen mounted for LM. Paralectotypes SOUTH GEORGE ISLANDS • 15 ♀♀, 18 ♂♂, 3 uncertain sex; same collection data as for lectotype; SMNH-1007, SMNH-9256 to 9282. SMNH-1007, SMNH-9256 to 9282. 9 ♀♀, 13 ♂♂ and 3 uncertain sex mounted for LM; 6 ♀♀, 5 ♂♂ mounted for SEM; Remarks Higgins (1986) mentions that he accessed the type material of E. pilosus in SMNH, mounted and observed two paratypic specimens. However, such mounted specimens were found in neither the SMNH nor the USNM. After examining the syntypes and providing the present redescription we choose, in the interest of assuring future taxonomic stability, to designate one of the female syntype as lectotype for Echinoderes pilosus with the catalogue number SMNH-3930, and consequently designate the remaining specimens as paralectotypes (SMNH-1007, 9256–9282). Description The species was described by Lang (1949), and more recently redescribed by Higgins (1986). However, since information from SEM not previously has been available for the species, and since the present examinations with LM and SEM resulted in substantial new information about the morphology of the species, we are here providing a full redescription. Adults with head, neck and eleven trunk segments. The anterior part of the trunk is relatively stout, and maximum width is reached around segments 6 and 7 (Fig. 9 A–B). From segment 8 the segments taper significantly, giving the species an appearance of a pointed hind end (Fig. 9 A–B). The trunk cuticle appears thin in SEM specimens (Fig. 10A), and tends to collapse posterior to the stronger pachycycli. Secondary pectinate fringe present near anterior segment margin on segments 2 to 10. For complete overview of measurements and dimensions, see Table 9. Distribution of cuticular structures, i.e., sensory spots, glandular cell outlets, spines and tubes, is summarized in Table 10. The head consists of a retractable mouth cone and an introvert. Inner oral styles could not be examined. Nine outer oral styles are present; nine tufts with ca. six long, rigid and distally bifurcated tips in each, attach basally on the mouth cone, posterior to each outer oral style. The exact arrangement of scalids could not be examined. The neck has 16 placids, measuring 19 µm in length. The midventral placid is broadest, measuring 17 µm in width at its base, whereas all other are narrower, measuring 10 µm in width at their bases. The trichoscalid plates are well-developed, subdorsal and laterodorsal ones narrow and elongated, and ventromedial ones broadly oval. Segment 1 consists of a complete cuticular ring. Sensory spots are located on the anterior segment half in subdorsal, laterodorsal, and sublateral positions, and medially on segment, in ventromedial positions (Figs 9C, 10 B–C); sensory spots on this all following segments are small, and rounded, with numerous micropapillae. Two longitudinally arranged glandular cell outlets type 1 are present in middorsal position (Figs 9C, 10B); anteriormost outlet appears narrower and more elongate than the posterior one; an additional pair of glandular cell outlets type 1 is present in ventrolateral positions (Fig. 10C). Dorsal and lateral sides, with scattered cuticular hairs emerging through rounded perforation sites; posterior half of ventral side with similar hair covering, but anterior part with large, W-shaped hairless area (Fig. 10 B–C). The posterior segment margin is straight along the dorsal and lateral sides, and slightly convex ventrally, terminating into a pectinate fringe with short and very flexible fringe tips. Pachycyclus thin to medium thickness, and not interrupted. Segment 2 consists of a complete cuticular ring, but with indication of an intracuticular, partial, midventral fissure (Figs 9F, 10C). Sensory spots are located in middorsal (but slightly laterally displaced), laterodorsal (twin pair) (Figs 9E, 10B) and ventromedial positions (Fig. 10C). Minute glandular cell outlets type 2 present in subdorsal positions (Figs 9C, 10B), and tubes present in ventrolateral positions (Figs 9D, 10C). Glandular cell outlets type 1 present in middorsal and ventromedial positions (Figs 9 C– D, 10B). The segment is densely covered with bracteate hairs, but interrupted by hairless areas posterior to ventrolateral tubes, and in paraventral areas. Pachycyclus of the anterior segment margin is of medium thickness and not interrupted. The posterior segment margin is straight along dorsal and lateral sides, and extend into V-shaped flap on the ventral side; pectinate fringe from middorsal to midlateral positions with short fringe tips, as on segment 1; fringe tips from midlateral to ventromedial positions longer and very flexible, and then very short between ventromedial positions. Segment 3, and remaining segments, consisting of one tergal and two sternal plates. Pachycyclus of the anterior segment margin of medium thickness, and interrupted only at tergosternal junctions. Sensory spots present in subdorsal, laterodorsal (Figs 9E, 10D) and sublateral positions. Glandular cell outlets type 1 present in middorsal (Fig. 9E, H) and ventromedial positions. Bracteate cuticular hairs are densely covering the segment from middorsal to ventromedial positions (except in V-shaped areas in laterodorsal positions anterior on segment); paraventral areas that are devoid of any hair-like structures. Pectinate fringe of posterior margin as on preceding segment, but with ventromedial fringe tips being slightly longer. Segment 4 with acicular spine in middorsal position, reaching attachment point of middorsal spine on following segment (Fig. 10D); this and all other spines on following five segments are slender and flexible. Sensory spots present in subdorsal (Figs 9H, 10D), midlateral and ventromedial positions; midlateral and ventromedial sensory spots considerably smaller than most other sensory spots in the species, but they occur consistently in all examined specimens. Glandular cell outlets type 1 present in subdorsal (Fig. 9H) and ventromedial positions. Pectinate fringe of posterior segment margin, pachycycli and cuticular hairs as on preceding segment. Segment 5 with acicular spine in middorsal position, reaching attachment point of middorsal spine on following segment, and long, slender tubes in lateroventral positions (Fig. 10E). Sensory spots present in subdorsal, midlateral (Figs 9H, 10E) and ventromedial positions; ventromedial sensory spots considerably smaller than most other sensory spots in the species. Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 6 with acicular spine in middorsal position, reaching attachment point of middorsal spine on following segment, and in lateroventral positions (Fig. 10 E–F), reaching beyond the posterior margin of the segment. Females with female papillae in ventrolateral positions; openings of papillae with fine fringes around their margins (Fig. 10F inset); intracuticular substructures each form an indistinct tubular structure (Fig. 9G). Sensory spots present in paradorsal, midlateral and ventromedial (Fig. 10F) positions. Pectinate fringe of posterior segment margin with uniform long fringe tips on tergal plate and on most lateral halves of sternal plates; fringe tips shorter between ventromedial positions. Glandular cell outlets type 1, pachycycli and cuticular hairs as on preceding segment. Segment 7 with acicular spine in middorsal position, extending about halfway over the following segment, and in lateroventral positions, reaching beyond the posterior margin of the segment. Female papillae (Figs 9G, J, 10F, I), sensory spots, glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 8 with acicular spine in middorsal position, extending more than halfway over the following segment (Fig. 10G), and in lateroventral positions (Fig. 9J), reaching beyond the posterior margin of the segment (Fig. 10I). Minute glandular cell outlets type 2 present in laterodorsal positions (Figs 9L, 10H). Sensory spots present in paradorsal, laterodorsal (posterior to glandular cell outlets) and ventrolateral positions (Fig. 10 G–I). Females with female papillae in ventromedial positions (Figs 9J, 10I); openings of papillae with fine fringes around their margins (Fig. 10I inset); intracuticular substructures each form an indistinct tubular structure. Glandular cell outlets type 1 as on preceding segment, but subdorsal ones are situated slightly closer to each other (Fig. 9I). Pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 9 with acicular spines in lateroventral positions, extending about halfway over the following segment. Minute glandular cell outlets type 2 present in laterodorsal positions (Figs 9L, 10H). Sensory spots present in paradorsal, subdorsal, laterodorsal (Fig. 10 G–H), and ventrolateral positions. Female papillae absent. Glandular cell outlets type 1 as on preceding segment, but with subdorsal ones situated even closer to each other, very close to paradorsal positions. Small, rounded nephridial sieve plates present in lateral accessory positions. Pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 10 with long, slender laterodorsal tubes near posterior segment margin (Figs 9M, 10J, L). Sensory spots present in paradorsal positions (Fig. 10J); males with additional pair of sensory spots in ventrolateral positions (Fig. 10K). Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones and in ventromedial positions. The posterior segment margin of the tergal plate is straight, whereas margins of sternal plates are concave and extend into a midventral point (Fig. 10K); fringe tips of pectinate fringe are as on preceding segment on tergal plate, but considerably shorter on sternal plates. Cuticular hairs as on preceding segments on tergal plates, but more sparse on sternal plates. Pachycycli as on preceding segment. Segment 11 with lateral terminal spines (Fig. 9B, K, M). Males with three pairs of penile spines (Figs 9M, 10K); dorsal and ventral penile spines are stout but still flexible tubes, whereas the median ones are slightly thicker and more rigid; females with short, and relatively stout lateral terminal accessory spines (Figs 9K, 10J, L). Sensory spots present in subdorsal positions medially on segment. Two longitudinally arranged glandular cell outlets type 1 present in middorsal position, anterior on segment. The dorsal side of the segment is sparsely covered with thin, non-bracteate hair-like extensions; ventral side is almost hair-less. Tergal extensions are well-spaced, short and pointed; sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips (Fig. 10 K–L)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 32-39, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Lang K. 1949. Echinoderida. In: Odhner N. H. (ed.) Further Zoological Results of the Swedish Antarctic Expedition 1901 - 1903, Vol. 4: 1 - 22. P. A. Norstedt & Soner, Stockholm.","Higgins R. P. 1986. Redescription of Echinoderes pilosus (Kinorhyncha: Cyclorhagida). Proceedings of the Biological Society of Washington 99: 399 - 405. Available from https: // www. biodiversitylibrary. org / part / 45462 # / summary [accessed 27 Nov. 2020]."]}

Echinoderes kozloffi Higgins, 1977 Fig. 8B, E, H Material examined Holotype WASHINGTON STATE • 1 ♂; San Juan Island, North Bay, Argyle Lagoon; 48°31′ N, 123°01′ W; 1 m b.s.l.; 9 Aug. 1975; E. Kozloff leg.; muddy sand gravel, rich in organic matter; USNM-53337. Specimen mounted for LM. Paratypes WASHINGTON STATE • 4 ♀♀, 1 ♂; same collection data as for holotype; USNM-53339. Specimen mounted for LM. The description by Higgins (1977a) does not state clearly from which habitat the type material was collected, but sampling was done by E. Kozloff who probably collected the species from muddy sand gravel, rich in organic matter (Kozloff 1972). Additional material CANADA – British Columbia • 2 ♀♀, 1 ♂; Vancouver Island, Clover Point; 48°24′14″ N, 123°21′04″ W; 0 m b.s.l.; May 2015; M. Herranz leg.; intertidal brown algae (see Herranz & Leander 2016); NHMD- 100304 to 100305 and NHMD-616637 • 1 ♀; Archaeology Beach; 51°39′52″ N, 128°05′50″ W; 0 m b.s.l.; July 2015; M. Herranz leg.; intertidal brown algae (see Herranz & Leander 2016); NHMD-100306. All specimens mounted for LM. Numerous additional specimens from the same localities, mounted for LM and SEM, are stored in Herranz’ personal reference collection. See Table 1 for an overview. Description The species was recently redescribed by Herranz & Leander (2016), and the specimens follow this rather accurate description. The only details that should be added regard the intracuticular substructures related to the female papillae on segments 6 to 8, and middorsal spine length. Female papillae are present in ventrolateral positions on segments 6 and 7 (Fig. 8E), and they have a short, somewhat rhomboid intracuticular tube leading to the rounded outlet. Female papillae on segment 8 are ventromedial (Fig. 8E), and the intracuticular substructures are crescentic with a small protuberance in the curved part of the structure. Middorsal spine of segment 8 extends well onto segment 9, but never reaches posterior margin of segment (Fig. 8B). It was furthermore confirmed that laterodorsal glandular cell outlets type 2 are present on segment 8 only (Fig. 8B)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 28-30, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. 1977 a. Redescription of Echinoderes dujardinii (Kinorhyncha) with descriptions of closely related species. Smithsonian Contributions to Zoology 248: 1 - 26. https: // doi. org / 10.5479 / si. 00810282.248","Kozloff E. N. 1972. Some aspects of development in Echinoderes (Kinorhyncha). Transactions of the American Microscopical Society 91: 119 - 130. https: // doi. org / 10.2307 / 3225404","Schmidt P. 1974. Interstitielle Fauna von Galapagos. 10. Kinorhyncha. Microfauna des Meeresbodens 43: 1 - 15.","Herranz M. & Leander B. 2016. Redescription of Echinoderes ohtsukai Yamasaki and Kajihara, 2012 and E. kozloffi Higgins, 1977 from the northeastern Pacific coast, including the first report of a potential invasive species of kinorhynch. Zoologischer Anzeiger 265: 108 - 126. https: // doi. org / 10.1016 / j. jcz. 2016.02.004"]}

Echinoderes sp. Fig. 25; Table 19 Echinoderes cf. ehlersi – Higgins & Rao 1979: 79–83 (specimens USNM-55393, USNM-55396, USNM-55398 to 55400). Material examined INDIA • 1 ♀, 4 ♂♂; Andaman Islands, Havelock Island, East Point; 11°54′ N, 093°03′ E; Echinoderes cf. ehlersi (Higgins & Rao 1979). See Table 1 for an overview. Description The five specimens were collected together with another five specimens that all together were reported as Echinoderes cf. ehlersi by Higgins & Rao (1979). However, our examinations suggested that the latter five specimens represent a new species. The five specimens, addressed in the following, differ from E. chandrasekharai Sørensen & Chatterjee sp. nov. and as E. ehlersi in some significant points, but since the specimens' condition (e.g., the disability to observe sensory spots consistently) did not provide sufficient information for a complete description and specimens for SEM were not available, we will for now only provide a short description of the observed characters without providing a formal species description. The examined specimens resemble species like E. kozloffi, E. pacificus and E. sublicarum in general trunk appearance (Fig. 25A) and dimensions (see Table 19). The distribution of glandular cell outlets type 1 (Fig. 25 B–G) is similar to the distribution in E. pacificus also (see Table 8), and so is the distribution of those sensory spots that could be observed. However, the presence or absence of sensory spots could not be confirmed in the following positions: sublateral segment 1, middorsal segment 2, midlateral segment 4 and segment 9. The spine/tube pattern and the approximate dimensions are similar with those of E. kozloffi, i.e., the middorsal spine on segment 8 reaches to a point around the midline of segment 9 (Fig. 25D, F), but never onto segment 10. Glandular cell outlets type 2 are present in midlateral positions, but only on segment 8 (Fig. 25F). Female papillae are present in ventromedial positions on segments 7 (more lateral) and 8 (more medial) (Fig. 25E). The substructures of the papillae on segment 7 are crescentic with a small protuberance in the curved parts of the structures, whereas the substructures on segment 8 form narrow tubes (Fig. 25E). Tergal extensions of terminal segment and shape of lateral terminal spines resemble those in E. kozloffi (Fig. 25G)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 73-75, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. & Rao G. C. 1979. Kinorhynchs from the Andaman Islands. Zoological Journal of the Linnean Society 67: 75 - 85. https: // doi. org / 10.1111 / j. 1096 - 3642.1979. tb 01106. x"]}

Echinoderes pacificus Schmidt, 1974 Fig. 8A, D, G; Tables 7–8 Emended diagnosis Echinoderes with middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on segments 5 to 8 extend well beyond the posterior margin of their respective segments. Tubes present in lateroventral positions on segments 2 and 5, and in midlateral positions on 10; tubes on segment 10 short and stout. Minute glandular cell outlets type 2 in laterodorsal positions on segment 8. Tergal extensions of segment 11 triangular, pointed, well-spaced. Females with female papillae with crescentic and tubular substructure in ventrolateral positions on segment 7 and ventromedial on segment 8. Lateral terminal spines thick in proximal ⅓, but tapered abruptly into very thin distal ⅔. Material examined Holotype GALAPAGOS • 1 ♂; Santa Cruz; 00°45′ S, 090°19′ W; Paratypes GALAPAGOS • 5 ♀♀, 4 ♂♂; same collection data as for holotype; USNM-53336. Specimens mounted for LM. Most of the paratypes were in surprisingly good condition, whereas the mounting medium around the holotype was dried out. SEM specimens were not available. See Table 1 for an overview. Description The appearance of the species generally follows the original description by Schmidt (1974), and in particular the redescription by Higgins (1977a), hence the following notes only provide additional information not included in the two previous descriptions. For complete overview of measurements and dimensions, see Table 7. Distribution of cuticular structures, i.e., sensory spots, glandular cell outlets, spines and tubes, is summarized in Table 8. Spines and tubes are as described by Higgins (1977a), and middorsal spines on segments 5 to 8 extend well beyond the posterior margins of segments from which they originate (Fig. 8A). The line art illustrations provided with the redescription also summarize and show the distribution of glandular cell outlets type 1 correctly (white open circles in Higgins 1977a: figs 26–27), even though the nature of these structures are misinterpreted, mostly as sensory spots in the text. Same illustrations also picture laterodorsal glandular cell outlets type 2 on segment 8, and female papillae with a crescentic substructure in ventrolateral positions on segment 7 and ventromedial positions on segment 8. Our observations confirm the presence of these structures (Fig. 8D). The substructure of the female papillae is crescentic, as reported by Higgins (1977a), and in addition they also have a relatively strong tubular substructure. Higgins (1977a) furthermore noted the short, curved midlateral tubes on segment 10 (described as “lateral spine of segment 12”, following the old terminology). We can confirm the distinct appearance of these tubes, and add that they, besides being curved, are conspicuously short and stout, and somewhat truncate (Fig. 8G), which make them differ from segment 10 tubes in other species examined for the present study. Another highly characteristic feature regards the shape of the lateral terminal spines. The proximal parts of the spines are conspicuously thick, or swollen, but around ⅓ from the proximal end the spines taper abruptly, and become very thin and nearly seta-like (Fig. 8G). Tergal extensions are triangular and well-spaced; sternal extensions are short with ventrolateral seta-like tuft of extended fringe tips., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 30-32, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Schmidt P. 1974. Interstitielle Fauna von Galapagos. 10. Kinorhyncha. Microfauna des Meeresbodens 43: 1 - 15.","Higgins R. P. 1977 a. Redescription of Echinoderes dujardinii (Kinorhyncha) with descriptions of closely related species. Smithsonian Contributions to Zoology 248: 1 - 26. https: // doi. org / 10.5479 / si. 00810282.248"]}

Echinoderes sublicarum Higgins, 1977 Fig. 8C, F, I Emended diagnosis Echinoderes with middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on segments 5 to 8 extend well beyond the posterior margin of their respective segments. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10; tubes on segment 10 are long and slender. Minute glandular cell outlets type 2 in laterodorsal positions on segment 8. Tergal extensions of segment 11 pointed, with additional tooth on inferior margin. Females with ventromedial female papillae formed by crescentic substructure and a tube on segment 8; similar ventrolateral female papillae might also be present on segment 7. Material examined Holotype SOUTH CAROLINA • 1 ♀; Georgetown, North Inlet Estuary, Clambank docks; 33°20′ N, 079°11′ W; Eudendrium sp.; USNM-54397. Specimen mounted for LM. Paratypes SOUTH CAROLINA • 4 ♀♀, 4 ♂♂; same collection data as for holotype; USNM-54399 to 54400. Specimens mounted for LM. Most of the types were in good condition, although the mounting medium was partly or fully dried out. While it was easy to see spines and tubes, it was very difficult or impossible to see the mostly subcuticular structures, such as glandular cell out type 1, female papillae and sensory spots. SEM specimens were not available. See Table 1 for an overview. Description The appearance of the species generally follows the description provided by Higgins (1977b), hence the following notes only provide additional information not included in the original description. Males and females with minute laterodorsal glandular cell outlets type 2 on segment 8 (Fig. 8C). Spines and tubes as described by Higgins (1977b). Glandular cell outlets type 1 present in middorsal positions on segments 1 to 3, 10 (two longitudinally aligned) and 11, in subdorsal positions on segments 4 to 9, in sublateral positions on segment 1, and ventromedial positions on segments 2 to 10 (most of these structures are also included in the original description, but generally referred to as ‘sensory spots’).Actual sensory spots were only observed in paradorsal positions on segments 6 to 8, but more sensory spots are most likely present. Female papillae are present in ventromedial positions on segment 8 (Fig. 8F). The intracuticular substructures indicate the presence of a very weak crescentic line, and a more distinct tube extending from the centre of this line. Higgins (1977b) also reports these structures but refers to them as “bracket-shaped muscle scars”. He does not mention that they are restricted to females, but we can confirm that this is the case. Higgins (1977b) furthermore reports the present of “bracket-shaped muscle scars” in ventrolateral positions of segment 7. This suggests that female papillae also could be present on this segment. We cannot confirm their presence, but this is most likely due to the age and condition of the type specimens. Hence, based on own observations and information provided by Higgins (1977b) we find it likely that female papillae are present in ventrolateral positions of segment 7 and ventromedial positions of segment 8. Laterodorsal tubes on segment 10 are quite long and slender (Fig. 8I). Tergal extensions of segment 11 are well-spaced and pointed (Fig. 8I). Lateral terminal spines are regular acicular, and gradually tapered towards tips., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 49-50, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Higgins R. P. 1977 b. Two new species of Echinoderes (Kinorhyncha) from South Carolina. Transactions of the American Microscopical Society 96: 340 - 354. https: // doi. org / 10.2307 / 3225864"]}

Echinoderes worthingi Zelinka, 1928 Figs 16–17; Table 13 Emended diagnosis Echinoderes with middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on segments 4 to 6 are barely reaching posterior segment margins of respective segments, whereas middorsal spine on segment 8 is more than twice as long as any other middorsal spine, extending to the posterior margin of segment 9 or onto segment 10. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Glandular cell outlets type 2 not present. Paradorsal glandular cell outlets type 1 on segment 11. Primary pectinate fringe on ventral sides of segments 1 to 3 very well-developed, in particular on segment 1. Tergal extensions of segment 11 pointed, with tips extending into long, seta-like fringe. Females with ventromedial female papillae formed by conspicuously strong spatulate tubular substructures on segments 7 and 8. Material examined FRANCE • 1 ♀; Roscoff; 48°43′ N, 003°59′ W, Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 50-51, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Zelinka C. 1928. Monographie der Echinodera. Wilhelm Engelmann, Leipzig.","Higgins R. P. 1985. The genus Echinoderes (Kinorhyncha, Cyclorhagida) from the English Channel. Journal of the Marine Biological Association of the United Kingdom 65: 785 - 800. https: // doi. org / 10.1017 / S 0025315400052590"]}

Echinoderes dujardinii Claparède, 1863 Figs 2–4; Tables 3–4 l’Echinodère Dujardin 1851: 158, pl. 3, figs 1–4. Echinoderes Dujardinii Claparède, 1863: 90–92, pl. 16, figs 7–13. Echinoderes dujardinii – Higgins 1977a: 4–13, figs 1–12. — Sánchez et al. 2012: 26 [South Galicia]. Non Echinoderes dujardinii – Mari & Morselli 1987: 117. — Sánchez-Tocino et al. 2011: 179–184, figs 1–4, tables 1–2. — Sánchez et al. 2012: 26 [Algeciras, Granada, Murcia, Alicante]. — Ürkmez et al. 2016: 1–8, figs 2–4. Emended diagnosis Echinoderes with short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines on segments 7 and 8 might reach posterior margins of their respective segments, but they never extend beyond the margins. Tubes present in lateroventral positions on segments 2 and 5, in lateral accessory positions on segment 8, and in laterodorsal positions on segment 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9; those on segment 9 situated anterior to laterodorsal sensory spots. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips. Females with ventromedial female papillae resembling glandular cell outlets type 2 on segments 6 to 8; intracuticular substructure of papillae on segment 6 is crescentic, substructure on segments 7 and 8 is tubular. Material examined FRANCE • 18 ♀♀, 24 ♂♂; Roscoff; 48°43′ N, 003°58′ W; 0 m b.s.l.; 19 Oct. 1973; E. Kozloff leg.; sandy mud (see Higgins 1977a); USNM-53342. Specimens mounted for LM. SPAIN – Atlantic north coast of Spain • 1 ♀, 4 ♂♂; Cantabric Sea, outlet of Eo River; F. Pardos leg.; UCM. – Galician Atlantic west coast of Spain • 1 ♀; Arousa; F. Pardos leg.; UCM • 1 ♂; Vigo; F. Pardos leg.; UCM. – Andalusian Atlantic south coast of Spain • 3 ♀♀, 1 ♂; Huelva; F. Pardos leg.; UCM. Specimens mounted for LM. PORTUGAL • 6 ♀♀, 4 ♂♂; Faro, Ria Formosa; 37°00′ N, 007°49′ W; 0 m b.s.l.; 21 Oct. 2012; R.C. Neves and M. Herranz leg.; mud with Zostera; NHMD-616804 to 616807, NHMD-616822 to 616827. Specimens mounted for LM. About 30 specimens from the same locality at Faro were mounted for SEM and stored in the first author’s personal reference collection. Type material was not available. See Table 1 for an overview. Description Echinoderes dujardinii was redescribed by Higgins (1977a), but due to the numerous new details (mainly revealed by SEM), reinterpretations of cuticular structures, and considerable changes in terminology over the past 40 years, we are providing a full description of the species. Adults with head, neck and eleven trunk segments (Figs 2A, 3, 4A). Trunk with nearly equally broad sternal plates on segments 5 to 10 (Fig. 2A). Lateral terminal spines slender, from 40% to 55% of trunk length. Secondary pectinate fringe formed as one fringed band near anterior segment margin is present on segments 2 to 10. For complete overview of measurements and dimensions of Portuguese and Spanish populations, see Table 3. Distribution of cuticular structures, i.e., sensory spots, glandular cell outlets, spines and tubes, is summarized in Table 4. The head consists of a retractable mouth cone and an introvert (Figs 3, 4B). Three rings of inner oral styles, apparently with five styles in each ring. The external mouth cone armature consists of nine outer oral styles, each consisting of two joined units and arranged as one style anterior to each introvert sector, except the middorsal sector 6; each outer oral style basally flanked by pair of lateral spikes, followed by more basal V-shaped row of fringe tips, and again followed by even more basal brush-like arch of bristles (Fig. 4B). The introvert sectors are defined by the ten primary spinoscalids in Ring 01 (Fig. 3). Each primary spinoscalid consists of a basal sheath and a distal end piece with a blunt tip. The sheaths have two distinctively differentiated fringes: a most basal, transverse fringe, and a slightly more distal fringe where the fringe tips bend in a curve near their attachment point, and fuse to the scalid along a longitudinal line, giving the attachment area a conspicuous appearance (see inset Fig. 4B). End pieces are smooth and flexible. Rings 02 and 04 have 10 spinoscalids and Rings 03 and 05 have 20. All spinoscalids in these rings are well-developed, and consist of a basal sheath and a pointed end piece. The basal sheaths terminate into fine, fringed margins in spinoscalids of Rings 02 to 05, and those of Ring 03 have in addition a basal median spike (Fig. 4B inset). A ring of short fringes extend around the introvert in between spinoscalid Rings 05 and 06. Ring 06 has only six spinoscalids, located in sectors 1, 3, 5, 6, 7, and 9; ring 06 spinoscalids resemble those in preceding sectors, but are much shorter and with densely haired end pieces. Ring 07 has 7 spinoscalids, located as pairs in sectors 3 and 9, unpaired but laterally displaced in sectors 5 and 7 (trichoscalids are taking up the space in the opposite side of each sector), and unpaired but centred in sector 1; ring 07 spinoscalids resemble those in preceding sector but are even shorter. Described sector-wise (Fig. 3), sector 1 has spinoscalids arranged as two double diamonds anterior to a single Ring 7 spinoscalid. Sectors 2, 4, 8 and 10 all have spinoscalids arranged as a quincunx, located in between a medial anterior spinoscalid (Ring 02) and a trichoscalid plate. Sectors 3 and 9 have spinoscalids forming double diamonds anterior to a pair of spinoscalids in Ring 7. Sectors 5 and 7 also have spinoscalids forming double diamonds, but anterior to an unpaired, lateral spinoscalid. Sector 6 has spinoscalids arranged as two double diamonds. The neck has 16 placids, measuring 20 µm in length. The midventral placid is broadest, measuring 15 µm in width at its base, whereas all other are narrower, measuring 11 µm in width at their bases. The trichoscalid plates in the dorsal sectors are composed of a distal part and a slightly broader proximal part, whereas the proximal parts of the ventral trichoscalid plates are much broader. Trichoscalids with trichoscalid plates are present in sectors 2, 4, 5, 7, 8, and 10. Segment 1 consists of a complete cuticular ring. Sensory spots are located close to the anterior margin in subdorsal, laterodorsal and sublateral positions (Figs 2B, 4 C–D), and slightly more posterior in ventrolateral positions (Figs 2C, 4E); sensory spots are rounded to oval, with numerous micropapillae, two pores, and often a cilium emerging from one of the pores. Glandular cell outlets type 1 present in middorsal and lateroventral positions (Fig. 2 B–C). Dorsal and lateral sides, and posterior half of ventral side, densely covered with cuticular hairs emerging through rounded perforation sites (Fig. 4 C–D); an anterior W-shaped area on the ventral side is completely devoid of hairs (Fig. 4E). The posterior segment margin is straight around the segment, terminating into a pectinate fringe with very short, uniform fringe tips. Segment 2 consists of a complete cuticular ring. Pachycyclus of the anterior segment margin is of medium thickness and not interrupted (Fig. 2 B–C). Sensory spots are located in middorsal (but slightly laterally displaced), laterodorsal (twin pair) (Figs 2 B–C, 4C–D) and ventromedial positions (Fig. 4E); appearance sensory spots on this and all following segments as those on segment 1, but droplet-shaped. Glandular cell outlets type 1 present in middorsal and ventromedial positions (Fig. 2 B–C); and quite well-developed tubes present in lateroventral positions (Figs 2C, 4E). The segment is densely covered with bracteate hairs. The posterior segment margin is nearly straight; pectinate fringe from middorsal to lateroventral positions with short fringe tips, as on segment 1; fringe tips from lateroventral to ventromedial positions conspicuously longer, and then slightly shorter again between ventromedial positions. Segment 3, and remaining segments, consisting of one tergal and two sternal plates (Fig. 2C). Pachycyclus of the anterior segment margin of medium thickness, and interrupted only at tergosternal junctions. Sensory spots present in subdorsal, laterodorsal (Fig. 2B) and sublateral positions. Glandular cell outlets type 1 present in middorsal and ventromedial positions. Bracteate cuticular hairs are densely covering the segment from middorsal to ventromedial positions; paraventral parts densely covered by non-bracteate, hair-like extensions, forming a conspicuous shield-shaped area. Pectinate fringe of posterior margin with slightly longer fringe tips on dorsal and lateral sides, compared to those on preceding segment, and conspicuously long tips in lateroventral to ventromedial positions. Segment 4 with short acicular spine in middorsal position, not reaching the posterior margin of the segment (Fig. 4F); all spines on this segment and until segment 9 with cylindrical proximal part that halfway to the tip begins to taper gradually. Sensory spots present in subdorsal, midlateral (Figs 2D, 4F) and ventromedial positions; midlateral sensory spots considerably smaller than all other sensory spots on the animals (Fig. 4F inset), but they occur consistently in all examined specimens. Glandular cell outlets type 1 present in subdorsal (Fig. 2D) and ventromedial positions. Pectinate fringe of posterior segment margin with long fringe tips from middorsal to ventromedial positions, and then very short again between ventromedial positions. Pachycycli and cuticular hairs as on preceding segment. Segment 5 with short acicular spine in middorsal position (Fig. 4F), not reaching the posterior margin of the segment, and well-developed tubes in lateroventral positions (Figs 2E, 4H). Sensory spots present in subdorsal, midlateral (Figs 2D, 4F) and ventromedial positions. Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 6 with short acicular spines in middorsal and lateroventral positions (Fig. 4F, H); middorsal spine does not reach the posterior margin of the segment, whereas lateroventral spines reach pectinate fringe. Sensory spots present in paradorsal, subdorsal, midlateral (Fig. 4F) and ventromedial (Fig. 4H) positions. Females with female papillae with openings, resembling small glandular cell outlets type 2 (Fig. 4H inset), in ventromedial positions, close to and lateral to sensory spots (Fig. 4H); the intracuticular structures of the papillae are crescentic with a small protuberance in the curved part of each structure (Fig. 2E). Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 7 with short acicular spines in middorsal (one specimen with two spines emerging from the same opening) and lateroventral positions (Figs 2 D–E, 4F, H); middorsal spine does not reach the posterior margin of the segment, whereas lateroventral spines reach pectinate fringe. Females with female papillae as on segment 6, but with openings slightly more anterior and lateral to sensory spots (Figs 2E, 4H); the substructure of these papillae differs from those on preceding segment, and forms instead a small intracuticular tube (Fig. 2E). Sensory spots, glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 8 with short acicular spines in middorsal and lateroventral positions (Figs 2 D–E, 4F, H), both reaching the pectinate fringe of the posterior margin of the segment. Tubes are present in lateral accessory positions (Fig. 4G). Minute glandular cell outlets type 2 present in laterodorsal positions, but very close to the midlateral lines (Figs 2D, F, 4G). Sensory spots present in paradorsal, subdorsal, and ventrolateral positions. Females with female papillae with same substructure as those on segment 7, but with openings more anterior and closer to midventral line. Glandular cell outlets type 1, pachycycli, pectinate fringe of posterior margin and cuticular hairs as on preceding segment. Segment 9 with acicular spines in lateroventral positions (Fig. 4G), just reaching the posterior margin of the segment. Sensory spots present in paradorsal, subdorsal, laterodorsal (posterior to glandular cell outlet type 2), and ventrolateral positions. Glandular cell outlets type 1 and 2 (Figs 2F, 4G) as on preceding segment, but female papillae not present. Paired nephridiopore areas each consists of a small, rounded sieve plate anterior to a single pore that we consider to be part of the nephridial system, present in lateral accessory positions (Fig. 4G, inset). Pectinate fringe of posterior segment margin with uniformly long fringe tips around the segment. Pachycycli and cuticular hairs as on preceding segment. Segment 10 with well-developed laterodorsal tubes near posterior segment margin (Figs 2 G–H, 4I– J). Sensory spots present in subdorsal (but very close to paradorsal) positions; males furthermore with sensory spots in ventrolateral positions (Fig. 4I). Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones and in ventromedial positions. The posterior segment margin of the tergal plate is straight, whereas margins of sternal plates are deeply concave (Fig. 4K); fringe tips of pectinate fringe are considerably shorter than those on preceding segments. Pachycycli and cuticular hairs as on preceding segment. Segment 11 with lateral terminal spines (Fig. 2A, G). Males with three pairs of penile spines (Figs 2G, 4 I–J); all three penile spines resemble each other, with thicker and rigid proximal parts that taper towards more flexible, distal tips; median penile spines slightly thicker than dorsal and ventral ones. Females with short, thin lateral terminal accessory spines (Figs 2H, 4K). Sensory spots present in subdorsal and ventrolateral positions. Glandular cell outlets type 1 present as two longitudinally arranged middorsal ones. The dorsal and most of the ventral side of the segment are densely covered with non-bracteate hair-like extensions. Tergal extensions are well-spaced, short and pointed (Figs 2 G–H, 4I, K); sternal extensions short, with ventrolateral seta-like tuft of extended fringe tips (Figs 2H, 4I)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 12-20, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Claparede A. R. E. 1863. Zur Kenntnis der Gattung Echinoderes Duj. In: Beobachtungen uber Anatomie und Entwicklungsgeschichte wirbelloser Thiere an der Kuste von Normandie angestellt: 90 - 92, 119. Wilhelm Engelmann, Leipzig. https: // doi. org / 10.5962 / bhl. title. 10030","Dujardin F. 1851. Sur un petit animal marin, l'Echinodere, formant un type intermediaire entre les Crustaces et les Vers. Annales des Sciences naturelles Zoologie 15: 158 - 173.","Higgins R. P. 1977 a. Redescription of Echinoderes dujardinii (Kinorhyncha) with descriptions of closely related species. Smithsonian Contributions to Zoology 248: 1 - 26. https: // doi. org / 10.5479 / si. 00810282.248","Sanchez N., Herranz M., Benito J. & Pardos F. 2012. Kinorhyncha from the Iberian Peninsula: new data from the first intensive sampling campaigns. Zootaxa 3402: 24 - 44. https: // doi. org / 10.11646 / zootaxa. 3402.1.2","Mari M. & Morselli I. 1987. Acari (Alacaridi ed Idracnelle) e Chinorinchi nella spugna Hymeniacidon sanguinea (Grant) della Laguna Veneta. Atti della Societa dei Naturalisti e Matematici de Modena 118: 115 - 117.","Sanchez-Tocino L., Tierno de Figueroa J. M., Lopez-Rodriguez M. J. & Liebanas G. 2011. First record of Echinoderes dujardinii Claparede, 1863 (Kinorhyncha, Cyclorhagida) in Iberian Peninsula coastal waters. Zoologica Baetica 22: 179 - 184.","Urkmez D., Pardos F., Sezgin M., Karacuha M. E. & Oks ʾ z I. 2016. Echinoderes dujardinii Claparede, 1863 (Kinorhyncha, Cyclorhagida): a new record for the kinorhynch fauna of Turkey. Ecologica Montenegrina 6: 1 - 8.","Higgins R. P. 1978. Echinoderes gerardi n. sp. and E. riedli (Kinorhyncha) from the Gulf of Tunis. Transactions of the American Microscopical Society 97: 171 - 180. https: // doi. org / 10.2307 / 3225589"]}

Echinoderes ehlersi Zelinka, 1913 Table 5 Echinoderes ehlersi Zelinka, 1913: 419–424, pl. 39, figs 6–9. Echinoderes ehlersi – Zelinka 1928: 237–240, fig. 41. Non Echinoderes ehlersi – Higgins & Rao 1979: 79–82, fig. 2. Description The species was collected and described from Zanzibar, Tanzania, at the African east coast. No type or topotype specimens were available for the present study. The species has not been collected since its description, hence, the present notes are a summary of taxonomically relevant information extracted from Zelinka (1913, 1928). Small Echinoderes, with a trunk length of 228 µm, and lateral terminal spines reaching ¾ of trunk length. Very short middorsal spines present on segments 4 to 8, not even reaching the pectinate fringes of posterior segment margins, and lateroventral spines on segments 6 to 9. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. The presence of glandular cell outlets type 2 in laterodorsal positions on segments 8 and/or 9 are not mentioned in the description, but they could possibly be present. Tergal extensions of segment are 11 short, pointed and well-spaced, and sternal extensions rounded, with ventrolateral seta-like tuft of extended fringe tips. Females with lateral terminal accessory spines. The presence of ventromedial female papillae is not mentioned in the description, but they could possibly be present in ventromedial or ventrolateral positions on some sternal plates., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on page 20, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Zelinka C. 1913. Der Echinoderen der Deutschen Sudpolar-Expedition 1901 - 1903. In: von Drygalski E. (ed.) Deutsche Sudpolar-Expedition, 1901 - 1903, im Auftrage des Reichsamtes des Innern 14 (3): 417 - 436. Reimer, Berlin.","Zelinka C. 1928. Monographie der Echinodera. Wilhelm Engelmann, Leipzig.","Higgins R. P. & Rao G. C. 1979. Kinorhynchs from the Andaman Islands. Zoological Journal of the Linnean Society 67: 75 - 85. https: // doi. org / 10.1111 / j. 1096 - 3642.1979. tb 01106. x"]}

Echinoderes lanceolatus Chang & Song, 2002 Fig. 18 Material examined Holotype REPUBLIC OF KOREA • ♀; Jeju Island, Boemseom Islet; 33°11′53″ N, 126°30′58″ E; 25 m b.s.l.; 3 Mar. 2000; J. Lee and Y.H. Song leg.; muddy sand; EWNHM60268. Specimen mounted for LM. Additional material Additional examined material included all specimens listed as “additional material examined” in Chang & Song (2002: 206). This material was collected from other islands in the Korean East Sea, along the south coast of the Korean Peninsula, and around Jeju Island (see further details in Table 1 and below under description of Echinoderes songae Sørensen & Chang sp. nov.). Morphological notes on female holotype Specimen with slender middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spine on segment 6 reaches posterior segment margin, whereas middorsal spines on segments 7 and 8 reach well beyond their respective posterior margins (Fig. 18B). Tubes present in ventrolateral positions on segment 2 (Fig. 18D) and lateroventral positions on 5, and in midlateral positions on 10. An incomplete midventral, intracuticular fissure is present on anterior half of segment 2 (Fig. 18D). Complete overview of glandular cell outlets type 1 distribution could not be obtained, but we see indications of paradorsal outlets on segment 6. Glandular cell outlets type 2 are not present on any segment (Fig. 18E). Female lateral terminal accessory spines are short, with stout bases. Female papillae were difficult to examine, but indications of ventrolateral papillae with a tubular substructure were observed on segment 7 (Fig. 18C). All characters that could be observed fit the emended diagnosis of E. aureus, which suggest that E. lanceolatus is a junior synonym of this species. Morphological notes on additional material All examined paratypes and non-types supposed to represent the morphology of E. lanceolatus were similar, but differed from the holotype of E. lanceolatus. The specimens have short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9; middorsal spines never reach the pectinate fringes of the posterior margins of their segments – not even middorsal spines on more posterior segments. Tubes are present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 are present in laterodorsal positions on segments 8, but lacking on segment 9. Tergal extensions of segment 11 are short, pointed and well-spaced, whereas sternal extensions are short and triangular, but not as pointed as the tergal ones. Seta-like, ventrolateral tufts of extended fringe tips project from the sternal extensions. Females have slender lateral terminal accessory spines, and female papillae with tubular intracuticular substructure in ventrolateral positions on segments 7 and in ventromedial positions on segment 8. These traits suggest that the specimens are not conspecific with the holotype of E. lanceolatus, but represent a new species (see following description of E. songae Sørensen & Chang sp. nov.)., Published as part of Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group - the Echinoderes dujardinii group, pp. 1-101 in European Journal of Taxonomy 730 on pages 54-55, DOI: 10.5852/ejt.2020.730.1197, http://zenodo.org/record/4418973, {"references":["Chang C. Y. & Song Y. H. 2002. Echinoderes lanceolatus, a new kinorhynch from Korea (Kinorhyncha, Cyclorhagida, Echinoderidae). The Korean Journal of Systematic Zoology 18: 203 - 211."]}

Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria, Neves, Ricardo C. (2016): First report of kinorhynchs from Singapore, with the description of three new species. Raffles Bulletin of Zoology 64: 3-27, DOI: http://doi.org/10.5281/zenodo.4502533, {"references":["Adrianov AV (1989) The first report of Kinorhyncha of the Sea of Japan. Zoologicheskii Zhurnal, 68: 17-27.","Adrianov AV & Malakhov VV (1999) Cephalorhyncha of the World Ocean. KMK Scientific Press, Moscow, 328 pp.","Adrianov AV, Murakami C & Shirayama Y (2002a) Taxonomic study of the Kinorhyncha in Japan. II. Condyloderes setoensis, a new species (Kinorhyncha: Cyclorhagida) from Tanabe Bay (Honshu Island) - first representative of the genus in the Pacific Ocean. Proceedings of the Biological Society of Washington, 115: 189-216.","Adrianov AV, Murakami C & Shirayama Y (2002b) Echinoderes aureus n. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay (Honshu) - first representative of the genus in the Pacific Ocean. Proceedings of the Biological Society of Washington, 115: 205-216.","Adrianov AV, Murakami C & Shirayama Y (2002c) Taxonomic study of the Kinorhyncha in Japan. III. Echinoderes sensibilis n. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay. Zoological Science, 19: 463-473.","Altenburger A, Rho HS, Chang CY & Sorensen MV (2015) Zelinkaderes yong sp. nov. from Korea - the first recording of Zelinkaderes (Kinorhyncha: Cyclorhagida) in Asia. Zoological Studies, 54: 24.","Brown R (1985) Developmental and taxonomic studies of Sydney Harbour Kinorhyncha. Dissertation, Macquarie University, Australia.","Chang CY & Song YH (2002) Echinoderes lanceolatus, a new kinorhynch from Korea (Kinorhyncha, Cyclorhagida, Echinoderidae). The Korean Journal of Systematic Zoology, 18: 203-211.","Claparede ARE (1863) Zur Kenntnis der Gattung Echinoderes Duj. Beobachtungen uber Anatomie und Entwicklungsgeschichte wirbelloser Thiere an der Kuste von Normandie angestellt. Verlag von Wilhelm Engelmann, Leipzig, pls. XVI-XVII, pp. 90-92, 119.","Coull BC (1970) Shallow water meiobenthos of the Bermuda platform. Oecologia, 4: 325-357.","Higgins RP (1964). Three new kinorhynchs from the North Carolina Coast. Bulletin of Marine Science of the Gulf and Caribbean, 14: 479-493.","Higgins RP (1968) Taxonomy and postembryonic development of the Cryptorhagae, a new suborder for the mesopsammic kinorhynch genus Cateria. Transactions of the American Microscopical Society, 87: 21-39.","Higgins RP (1969a) Indian Ocean Kinorhyncha, 1: Condyloderes and Sphenoderes, new cyclorhagid genera. Smithsonian Contributions to Zoology, 14: 1-13.","Higgins RP (1969b) Indian Ocean Kinorhyncha, 2:Neocentrophyidae, a new homalorhagid family. Proceedings of the Biological Society of Washington, 82: 113-128.","Higgins RP (1977) Two new species of Echinoderes (Kinorhyncha) from South Carolina.Transactions of the American Microscopical Society, 96: 340-354.","Higgins RP (1978) Echinoderes gerardi n. sp. and E. riedli (Kinorhyncha) from the Gulf of Tunis. Transactions of the American Microscopical Society, 97: 171-180.","Higgins RP (1982) Three new species of Kinorhyncha from Bermuda. Transactions of the American Microscopical Society, 101: 305-316.","Higgins RP (1983) The Atlantic barrier reef ecosystem at Carrie Bow Cay, Belize, II: Kinorhyncha. Smithsonian Contributions to Marine Science, 18: 1-131.","Higgins RP (1986) Kinorhyncha. In: Sterrer W & Schopfer-Sterrer C (eds) Marine Fauna and Flora of Bermuda: A Systematic Guide to the Identification of Marine Organisms. John Wiley & Sons New York. Pp. 220-222.","Higgins RP & Kristensen RM (1988) Kinorhyncha from Disko Island, West Greenland. Smithsonian Contributions to Zoology, 458: 1-56.","Higgins RP & Rao GC (1979) Kinorhynchs from the Andaman Islands. Zoological Journal of the Linnean Society, 67: 75-85.","Higgins RP & Shirayama Y (1990) Dracoderidae, a new family of the cyclorhagid Kinorhyncha from the Inland Sea of Japan. Zoological Science, 7: 939-946.","Lang K (1949) Echinoderida. In: Odhner NH (ed.) Further zoological results of the Swedish Antartic Expedition 1901-1903. Vol. IV, No. 2, Norstedt and Soner, Stockholm. Pp. 1-22.","Lou TH (1934) Sur la presence d'un nouveau kinorhynque a Tchefou: Echinoderes tchefouensis sp. nov. Contributions from the Institute of Zoology, National Academy of Peiping, 1: 1-9. [In Mandarin with French translation]","Lundbye H, Rho HS & Sorensen MV (2011) Echinoderes rex n. sp. (Kinorhyncha: Cyclorhagida) - the largest Echinoderes species found so far. Scientia Marina, 75: 41-51.","Neuhaus B (2013) Kinorhyncha (=Echinodera). In: Schmidt-Rhaesa A (ed.) Handbook of Zoology. Gastrotricha, Cycloneuralia and Gnathifera. Volume 1. Nematomorpha, Priapulida, Kinorhyncha, Loricifera. De Gruyter, Berlin/Boston. Pp. 181-348.","Neuhaus B, Pardos F, Sorensen MV & Higgins RP (2013). Redescription, morphology, and biogeography of Centroderes spinosus (Reinhard, 1881) (Kinorhyncha, Cyclorhagida) from Europe. Cahiers de Biologie Marine, 54: 109-131.","Neuhaus B, Pardos F, Sorensen MV & Higgins RP (2014) New species of Centroderes (Kinorhyncha: Cyclorhagida) from the Northwest Atlantic Ocean, life cycle, and ground pattern of the genus. Zootaxa, 3901: 1-69.","Neves RC, Brand J, Gan BQ & Reichert H (in press). First time surveying meiofauna in Singapore. Raffles Bulletin of Zoology, Supplement.","Omer-Cooper J (1957) Deux nouvelle especes de Kinorhyncha en provenance de L'Afrique du Sud. Bulletin Mensuel de la Societe Linneenne De Lyon, 26: 213-216.","Ostmann A, Nordhaus I & Sorensen MV (2012) First recording of kinorhynchs from Java, with the description of a new brackish water species from a mangrove-fringed lagoon. Marine Biodiversity, 42: 79-91.","Rao GC & Ganapati PN (1968) The interstitial fauna inhabiting the beach sands of Waltair coast. Proceedings of the National Institute of Sciences, India, 34: 82-125.","Reinhard W (1881) Uber Echinoderes und Desmoscolex der Umgegend von Odessa. Zoologischer Anzeiger, 4: 588-592.","Sanchez N, Herranz M, Benito J & Pardos F (2014a) Pycnophyes almansae sp. nov. and Pycnophyes lageria sp. nov., two new homalorhagid kinorhynchs (Kinorhyncha: Homalorhagida) from the Iberian Peninsula, with special focus on the introvert features. Marine Biology Research, 10: 17-36.","Sanchez N, Pardos F & Sorensen MV (2014b) Deep-sea Kinorhyncha: two new species from the Guinea Basin, with evaluation of an unusual male feature. Organisms Diversity and Evolution, 14: 349-361.","Sanchez N, Rho HS, Min W G, Kim D & Sorensen MV (2013) Four new species of Pycnophyes (Kinorhyncha: Homalorhagida) from Korea and the East China Sea. Scientia Marina, 77: 353-380.","Sanchez N, Yamasaki H, Pardos F, Sorensen MV & Martinez, A. (in press). Morphology disentangles the systematics of a ubiquitous but elusive meiofaunal group (Kinorhyncha: Pycnophyidae). Cladistics","Sarma NSR & Mohan PC (1981) On the ecology of the interstitial fauna inhabiting the Bhimilipatnam coast (Bay of Bengal). Mahasagar-Bulletin of the National Institute of Oceanography, 14: 257-263.","Song YH & Chang CY (2001) First record of Campyloderes macquariae Jonhston (Kinorhyncha, Cyclorhagida, Centroderidae) from the North Pacific. The Korean Journal of Systematic Zoology, 17: 207-216.","Sonmez S, Koroglu NO & Karaytug S (in press) First record of the family Echinoderidae Zelinka, 1894 (Kinorhyncha: Cyclorhagida) from Turkish marine waters. Biharean Biologist, 10: art.151205","Sorensen MV (2014) First account of echinoderid kinorhynchs from Brazil, with the description of three new species. Marine Biodiversity, 44: 251-274.","Sorensen MV, Dal Zotto M, Rho HS, Herranz M, Sanchez N, Pardos F & Yamasaki H (2015) Phylogeny of Kinorhyncha based on morphology and two molecular loci. PLoS ONE 10(7): e0133440.","Sorensen MV, Herranz M, Rho HS, Min W, Yamasaki H, Sanchez N & Pardos F (2012b) On the genus Dracoderes Higgins & Shirayama, 1990 (Kinorhyncha: Cyclorhagida) with a redescription of its type species, D. abei, and a description of a new species from Spain. Marine Biology Research, 8: 210-232.","Sorensen MV & Pardos F (2008) Kinorhynch systematics and biology - an introduction to the study of kinorhynchs, inclusive identification keys to the genera. Meiofauna Marina, 16: 21-73.","Sorensen MV, Pardos F, Herranz M & Rho HS (2010a) New data on the genus Paracentrophyes (Homalorhagida, Kinorhyncha), with the description of a new species from the West Pacific. The Open Zoology Journal, 3: 42-59.","Sorensen MV, Rho HS & Kim D (2010b) A new species of the rare genus Sphenoderes (Cyclorhagida, Kinorhyncha), with differential notes on S. indicus Higgins, 1969. Marine Biology Research, 6: 472-484.","Sorensen MV, Rho HS & Kim D (2010c) A new species of Condyloderes (Cyclorhagida, Kinorhyncha) from Korea. Zoological Science, 27: 234-242.","Sorensen MV, Rho HS, Min W, Kim D & Chang CY (2012a) An exploration of Echinoderes (Kinorhyncha: Cyclorhagida) in Korean and neighboring waters, with the description of four new species and a redescription of E. tchefouensis Lou, 1934. Zootaxa, 3368: 161-196.","Sorensen MV, Rho H, Min W-G, Kim D & Chang C (2013) Occurrence of the newly described kinorhynch genus Meristoderes (Cyclorhagida: Echinoderidae) in Korea, with the description of four new species. Helgoland Marine Research, 67: 291-319.","Thomsen VG, Rho HS, Kim D & Sorensen MV (2013) A new species of Dracoderes (Kinorhyncha: Dracoderidae) from Korea provides further support for a dracoderid-homalorhagid relationship. Zootaxa, 3682: 133-142.","Timm RW (1958) Two new species of Echinoderella (Phylum Kinorhyncha) from the Bay of Bengal. Journal of the Bombay Natural History Society, 55: 107-109.","Yamasaki H & Fujimoto S (2014) Two new species in the Echinoderes coulli group (Echinoderidae, Cyclorhagida, Kinorhyncha) from the Ryukyu Islands, Japan. ZooKeys, 382: 27-52.","Yamasaki H, Hiruta SF, Kajihara H & Dick MH (2014) Two kinorhynch species (Cyclorhagida, Echinoderidae, Echinoderes) show different distribution patterns across Tsugaru Strait, Northern Japan. Zoological Science, 31: 421-429.","Yamasaki H & Kajihara H (2012) A new brackish-water species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Seto Inland Sea, Japan. Species Diversity, 17: 109-118.","Yamasaki H, Kajihara H & Mawatari SF (2012) First report of kinorhynchs from Hokkaido, Japan, including a new species of Pycnophyes (Pycnophyidae: Homalorhagida). Zootaxa, 3425: 23-41.","Zelinka K (1894) Uber die Organisation von Echinoderes. Verhandlungen der Deutschen Zoologischen Gesellschaft, 4: 46-49.","Zelinka K (1896) Demonstration von Tafeln der Echinoderes - Monographie. Verhandlungen der Deutschen Zoologischen Gesellschaft, 6: 197-199.","Zelinka K (1907) Zur Kenntnis der Echinoderen. Zoologischer Anzeiger, 32: 130-136.","Zelinka K (1913) Der Echinoderen der Deutschen Sudpolar- Expedition, 1901-1903. Band 14. Reimer, Berlin."]}

Echinoderes tchefouensis Lou, 1934 Material examined. Echinoderes tchefouensis appeared on stations SI-01, SI-03, and SI-06, and was hence the most ubiquitous species in the area. A total of six adult specimens were mounted for LM, and deposited at the Natural History Museum of Denmark, under catalogue numbers ZMUC KIN- 857 to KIN- 862. Notes on taxonomy and distribution. The species was originally described from the Yantai area on the Chinese Northeast Coast (Lou, 1934). The original description was rather poor, and would in itself fit dozens of Echinoderes species. However, R. P. Higgins later collected specimens of Echinoderes in the area, and considered these to be conspecific with E. tchefouensis. Later, Higgins & Kristensen (1988) provided a note about the unusual lateral spine pattern in these specimens, with lateroventral spines/tubes on segments 5, 8 and 9 only. This enabled Sørensen et al. (2012a) to identify numerous specimens from adjacent waters as E. tchefouensis, and, based on these, provide a redescription that met present days’ requirements. The species is easily recognised because it lacks lateroventral spines on segments 6 and 7, combined with the presence of regular-sized glandular cell outlets type 2 in subdorsal position on segment 2, and a pair of extraordinary large outlets in laterodorsal positions on segment 8 (see Sørensen et al., 2012a for additional characters). The record of E. tchefouensis in Singapore increases the known distributional range of the species, and makes it one of the apparently most widely distributed species of Echinoderes. According to the collectings of Sørensen et al. (2012a) the species covers an area from the Korean Peninsula in northeast, to an easternmost occurrence near Saipan Islands in the West Pacific, and south through the East China Sea and the Philippines, to Sipadan in Malaysian Borneo that until now has marked its southernmost point of distribution. However, the record of the species in Singapore, suggests that it not only has a wide West Pacific distribution, but also could be widespread in the Indonesian Archipelago, and perhaps even could extent into the Indian Ocean. With such a wide distribution, the species would be ideal for population genetic studies, where haplotypes from geographically very distant populations could be compared. Another interesting finding is the appearance of E. tchefouensis at the intertidal station SI-06. Until now, the species has mostly been recorded from subtidal stations (9–140 m according to Sørensen et al., 2012a). The only other intertidal record of the species is from Saipan in the Northern Mariana Islands (Sørensen et al., 2012a). Apparently the species is not only widely distributed, but also highly opportunistic and able to adapt to different habitats., Published as part of Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria & Neves, Ricardo C., 2016, First report of kinorhynchs from Singapore, with the description of three new species, pp. 3-27 in Raffles Bulletin of Zoology 64 on page 19, DOI: 10.5281/zenodo.4502533, {"references":["Lou TH (1934) Sur la presence d'un nouveau kinorhynque a Tchefou: Echinoderes tchefouensis sp. nov. Contributions from the Institute of Zoology, National Academy of Peiping, 1: 1 - 9. [In Mandarin with French translation]","Higgins RP & Kristensen RM (1988) Kinorhyncha from Disko Island, West Greenland. Smithsonian Contributions to Zoology, 458: 1 - 56.","Sorensen MV, Rho HS, Min W, Kim D & Chang CY (2012 a) An exploration of Echinoderes (Kinorhyncha: Cyclorhagida) in Korean and neighboring waters, with the description of four new species and a redescription of E. tchefouensis Lou, 1934. Zootaxa, 3368: 161 - 196."]}

Echinoderes sp. 1 Material examined. Two specimens of an unknown species, Echinoderes sp. 1, were collected at station SI-03. One specimen was mounted for SEM, but was useless for examination. The other was mounted for LM (Fig. 10 A–E), and deposited at the Natural History Museum of Denmark, under catalogue number ZMUC KIN- 855. Descriptive notes. Female Echinoderes (Fig. 10A) with middorsal spines on segments 4 and 6 (Fig. 10C), and laterodorsal tubes on segment 10. Ventral side with ventrolateral tubes on segment 2 (Fig. 10B), lateroventral tubes on segment 5, lateroventral spines on segments 6, 8 and 9, but not on 7, and lateral accessory tubes on segment 8 (Fig. 10D). Tergal extensions, triangular, with curved external margins, and almost straight, serrated/hairy inferior margins (Fig. 10E). Glandular cell outlets of type 2 are not present. The observed spine pattern quite clearly reveals that the species is new to science. Only two other species, namely, Echinoderes bispinosus Higgins, 1982 and Echinoderes astridae Sørensen, 2014, have their middorsal spines restricted to segments 4 and 6, but both species have lateroventral spines on segments 6 to 9, segment 7 included (see Higgins, 1982; Sørensen, 2014). Echinoderes bispinosus furthermore lacks tubes in any position on segment 8, whereas the tubes on segment 8 in E. astridae are located in sublateral position. Also the lateral spine pattern in Echinoderes sp. 1, with lateroventral spines on segments 6, 8 and 9, but not on 7, is unique among all species of Echinoderes. With the shared presence of middorsal spines on segments 4 and 6, and a similarity in general habitus, it is not unlikely that Echinoderes sp. 1 represents a Southeast Asian relative to E. bispinosus and E. astridae. Echinoderes astridae is known from São Sebastião in Brazil only (Sørensen, 2014), whereas E. bispinosus is described from Bermuda (Higgins, 1982). A species very similar to E. bispinosus was furthermore quite recently reported from Turkey (Sönmez et al., in press), but the geographic distance between Bermuda and the East Mediterranean suggests that the Turkish record represents a similar, but yet new species., Published as part of Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria & Neves, Ricardo C., 2016, First report of kinorhynchs from Singapore, with the description of three new species, pp. 3-27 in Raffles Bulletin of Zoology 64 on page 20, DOI: 10.5281/zenodo.4502533, {"references":["Higgins RP (1982) Three new species of Kinorhyncha from Bermuda. Transactions of the American Microscopical Society, 101: 305 - 316.","Sorensen MV (2014) First account of echinoderid kinorhynchs from Brazil, with the description of three new species. Marine Biodiversity, 44: 251 - 274."]}

Centroderes impurus sp. nov. (Figs. 2–5) Material examined. Holotype adult stage- 2 male, collected from sand with mud on 16 May 2014, at station SI-03 (Fig. 1, Table 1), at 9 m depth, between Bedok Jetty and Sungei Bedok in the southeast part of Singapore Island (01°18.387’N, 103°57.591’E), mounted in Fluoromount G, deposited at the Lee Kong Chian Natural History Museum, under catalogue number ZRC.MIS.0001. Paratypes include two specimens of uncertain sex, probably either adult stage- 1 male or female, or eventually preadult stages (J6), collected at same locality as holotype, mounted in Fluoromount G, and deposited at the Natural History Museum of Denmark, under catalogue numbers ZMUC KIN-846 and KIN-847. Additional, non-type material, includes one adult stage- 2 male and two putatively stage- 1 specimens of uncertain sex, collected at same locality as holotype, and mounted for SEM. The SEM specimens are very dirty, and contributed only with limited information. Diagnosis. Centroderes with middorsal acicular spines on segments 1–9 and 11; long, flexible, ventromedial acicular spines on segment 1; rigid lateroventral acicular spines on segments 8 and 9, with spine on segment 9 being conspicuously stout and robust.Male stage-2 with middorsal and midlateral crenulated spines on segment 10. Putative adult stage- 1 specimens, or alternatively preadults, with middorsal and midlateral acicular spines on segment 10, and with minute tubes present in ventrolateral positions on segment 2 and lateroventral positions on segment 5. Sensory spots present paradorsally on segments 2–6 and 8–9, subdorsally on segment 1 (in male stage-2 only) and segment 11 (two pairs), laterodorsally on segments 1 (in putative J6 or stage- 1 specimen only) and 3–10, midlaterally on segment 2, in a lateral accessory position on segments 1, 3–4 and 6–9 and ventromedially on segments 3–4 and 6–10. Etymology. The species is named after the Latin word “ impurus ”, meaning “unclean” or “covered with dirt”, referring to the severe dirt problems that were experienced during the examination of the specimens. Description. Adult with head, neck and eleven trunk segments (Figs. 2, 3A, B, 4A, B). For measurements and dimensions, see Table 2. Distribution of cuticular structures (spines, tubes and sensory spots) is summarised in Table 3. The head consists of a retractable mouth cone and an introvert. The mouth cone is equipped with nine outer oral styles, each consisting of two joined units, arranged as one style anterior to each introvert sector, except at the middorsal sector 6. A double fringe consisting of numerous tips is located basally to each style. Scalid arrangement could not be examined in detail. The neck has 16 placids that dorsally and laterally alternate in size width between broader (15–16 µm width) and narrower (6–8 µm width) ones; all placids measure 15–17 µm length. The midventral placid is broader and flanked by two narrower placids on each side. Segment 1 consists of one complete cuticular ring with middorsal acicular spine, being short and stout in male stage-2 (Fig. 3A), and two slender, elongated spines in ventromedial positions, which extend over two following segments (Figs. 2, 5B). All spines on this and following segments are at least partly covered with minute cuticular hairs, however, frequently the proximal 1/3 of the surface is smooth. At least until segment 6 or 7, the middorsal spines appear stout in male stage-2, whereas they are more slender and acicular in the putative J6 or stage- 1 specimens (compare Fig. 3A with 3B). A midventral process is present between the two ventromedial spines (Figs. 2, 4B). Sensory spots are located medially on the segment in either subdorsal (male stage-2) or laterodorsal (putative J6 or stage- 1 adults) positions, and always in lateral accessory position (Fig. 4C). Sensory spots in subdorsal/laterodorsal positions are circular and composed of micropapillae arranged around a central pore (Fig. 4C); all sensory spots on all the following segments show the same appearance. The sensory spots in the lateral accessory positions differ though, and are more oval with cuticular papillae arranged in three rows and adhering to the cuticle surface (Fig. 4D). Minute, densely distributed cuticular hairs are present on the posterior half of the segment. Segment 2 and all remaining segments consist of one tergal and two sternal plates. A middorsal spine is present in all specimens. Furthermore, minute ventrolateral tubes were observed in the putative J6 or stage- 1 specimens (Fig. 5B). In male stage-2 no such structure was observed neither in LM nor in SEM; in the single specimen examined with SEM it was evident that the position where the tube would attach was filled with densely arranged prominent hairs. Similar hairs were spotted on other segments as well (Fig. 4F). Sensory spots are present in paradorsal and midlateral position. The paradorsal sensory spots are located very close to the posterior segment margin, next to the base of the middorsal spine. Secondary pectinate fringe consisting of minute cuticular hairs present on anterior part of segment; the fringe may be partially covered by the posterior margin of preceding segment. Additional hairs are densely and evenly distributed over the posterior half of the segment. Hairs in the tergosternal junction region are distinctly longer, especially anteriorly. A similar arrangement of hairs is present on segments 3–10 (Figs. 2, 4E). Segments 3 and 4 with middorsal acicular spine. Sensory spots are present in paradorsal, laterodorsal, lateral accessory and ventromedial positions (Figs. 2, 5A). Cuticular hairs as on preceding segment. Segment 5 with middorsal acicular spine. Minute lateroventral tubes are present in putative J6 or stage- 1 specimens (Figs. 4E, 5D). Stage- 2 specimens without such tubes, and instead with densely arranged prominent hairs in the areas where the tubes would attach (Fig. 4F). Sensory spots are present in paradorsal and laterodorsal positions (Figs. 2, 5A). Cuticular hairs as on preceding segment. Segment 6 with middorsal acicular spine. Sensory spots present in paradorsal, laterodorsal, lateral accessory and ventromedial positions (Figs. 2, 5A). Cuticular hairs as on preceding segment. Segment 7 with middorsal acicular spine. Sensory spots present in laterodorsal, lateral accessory and ventromedial positions. On this and the following segments, the laterodorsal sensory spots are located slightly closer to the midlateral position. Putative J6 or stage- 1 specimens show no indication of female specific glands, as observed in other Centroderes (see Neuhaus et al., 2014). Cuticular hairs as on preceding segment. Segment 8 with prominent, long middorsal acicular spine (Figs. 2, 3A). Small acicular spines present in lateroventral positions (Figs. 4G, 5E, F). Sensory spots present in paradorsal, laterodorsal, lateral accessory and ventromedial position. Putative J6 or stage- 1 specimens show no indication of female specific glands. Cuticular hairs as on preceding segment. Segment 9 with prominent, long middorsal acicular spine (Figs. 2, 3A). Conspicuously robust acicular spines are present in lateroventral positions; these spines can be twice as long as the corresponding spines on segment 8 (Figs. 4G, 5E, F, see also Table 2), especially in the male stage-2. Sensory spots present in paradorsal, laterodorsal, lateral accessory and ventromedial position. Cuticular hairs as on preceding segment. Segment 10 with middorsal and midlateral acicular spines in putative J6 or stage- 1 specimens (Figs. 3B, 5F) and with middorsal and midlateral crenulated spines in stage- 2 males (Figs. 2, 3A, 4H, 5C, E). Sensory spots present in laterodorsal and ventromedial positions. Cuticular hairs as on preceding segment. Segment 11 with middorsal, lateral terminal, lateral terminal accessory, and midterminal spines (Figs. 2, 3, 4A, B, 5F). The midterminal spine is considerably longer than the other spines on this segment (Table 2). Two pairs of subdorsal sensory spots, one pair being more anterior than the other, are present. The whole cuticular surface is covered with minute cuticular hairs which turn slightly longer and denser in the terminal part of the segment.

Condyloderes paradoxus Higgins, 1969 (Fig. 6) Material examined. Three adult specimens, two from station SI-03 and one from SI-04 (Fig. 1, Table 1). One specimen from SI-03 was mounted for LM, and subsequently deposited at the Natural History Museum of Denmark, under catalogue number ZMUC KIN- 848. The remaining two specimens were mounted for SEM, but due to the dirt covering, they only contributed with very little information. Notes on taxonomy and distribution. Condyloderes paradoxus (Fig. 6A) and its four congeners can be discriminated by the segmental distributions of minute cuspidate spines in the lateroventral positions. In C. paradoxus, lateroventral cuspidate spines are present on segments 2, 4, 5, 8 and 9 (Higgins, 1969a). This distribution corresponds to the cuspidate spine distribution in the recorded specimens from Singapore (Fig. 6B, C). Other characters in the examined specimens from Singapore, including the general spine distribution and dimensions, correspond with the data in the original description provided by Higgins (1969a), hence, we feel confident to identify the recorded species as C. paradoxus. Condyloderes paradoxus was originally described from two localities in the Bay of Bengal, off the Indian coast near Visakhapatnam (Higgins, 1969a). Collecting the species in Singapore also suggests that C. paradoxus might be distributed throughout the coastal waters of the Bay of Bengal, Andaman Sea and Malacca Strait. Besides the occurrence of this species at its type locality in India, and its presence in Singapore, no other records of C. paradoxus appear in the literature. However, during the extensive work on the kinorhynch fauna of the Korean Peninsula and the East China Sea, carried out by the first author and Dr H. S. Rho (see Sørensen et al., 2010a–c, 2012a, b, 2013; Lundbye et al., 2011; Thomsen et al., 2013; Sánchez et al., 2013; Altenburger et al., 2015) some specimens were actually identified as Condyloderes cf. paradoxus (Sørensen, unpubl.). The specimens occurred in samples taken at 132 m depth in the Korea Strait and between 79–103 m depth in the central part of the East China Sea, but by the time of the examinations, the identity of the specimens were considered doubtful, due to the distance between these sampling localities and the Bay of Bengal. However, with the current record of C. paradoxus from Singapore, which represents a biogeographic transitional point between the Indian Ocean and the West Pacific, it becomes more likely that the species has a wide distribution that ranges from the Bay of Bengal to the Korean Peninsula., Published as part of Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria & Neves, Ricardo C., 2016, First report of kinorhynchs from Singapore, with the description of three new species, pp. 3-27 in Raffles Bulletin of Zoology 64 on page 12, DOI: 10.5281/zenodo.4502533, {"references":["Higgins RP (1969 a) Indian Ocean Kinorhyncha, 1: Condyloderes and Sphenoderes, new cyclorhagid genera. Smithsonian Contributions to Zoology, 14: 1 - 13.","Lundbye H, Rho HS & Sorensen MV (2011) Echinoderes rex n. sp. (Kinorhyncha: Cyclorhagida) - the largest Echinoderes species found so far. Scientia Marina, 75: 41 - 51.","Thomsen VG, Rho HS, Kim D & Sorensen MV (2013) A new species of Dracoderes (Kinorhyncha: Dracoderidae) from Korea provides further support for a dracoderid-homalorhagid relationship. Zootaxa, 3682: 133 - 142.","Sanchez N, Rho HS, Min W G, Kim D & Sorensen MV (2013) Four new species of Pycnophyes (Kinorhyncha: Homalorhagida) from Korea and the East China Sea. Scientia Marina, 77: 353 - 380.","Altenburger A, Rho HS, Chang CY & Sorensen MV (2015) Zelinkaderes yong sp. nov. from Korea - the first recording of Zelinkaderes (Kinorhyncha: Cyclorhagida) in Asia. Zoological Studies, 54: 24."]}

Echinoderes annae sp. nov. (Figs. 7–9) Material examined. Holotype adult female, collected from muddy, intertidal seagrass aggregations on 19 May 2014, at station SI-06 (Fig. 1, Table 1), on Saringat Island, just south of Singapore Island (01°13.531’N 103°51.299’E), mounted in Fluoromount G, deposited at the Lee Kong Chian Natural History Museum, under catalogue number ZRC.MIS.0002. Paratypes, all mounted in Fluoromount G, were collected at same locality as holotype and include one male, deposited at the Lee Kong Chian Natural History Museum, under catalogue number ZRC.MIS.0003, and two additional males, one female, and one juvenile deposited at the Natural History Museum of Denmark under catalogue numbers ZMUC KIN- 851 to KIN-854. Additional, non-type material includes six specimens, from same locality as the holotype, mounted for SEM. The SEM specimens were extremely dirty, and contributed with very limited information. Diagnosis. Echinoderes with short middorsal spine on segment 4, and without any lateroventral acicular spines; tubes present in lateroventral positions on segments 5 and 8, midlateral positions on segment 9, and, in laterodorsal positions on segment 10. Glandular cell outlets type 2 present in subdorsal positions on segments 2 and 4, in laterodorsal positions on segments 2, 6 and 8, in sublateral positions on segments 5 and 7, and in lateroventral positions on segment 2. Sensory spots of type 1 and very small. Large, but narrow and elongated sieve plates present in sublateral positions on segment 9. Males with three pairs of penile spines; females with conspicuously short and stout lateral terminal accessory spines. Etymology. The new species, Echinoderes annae, is named after Anna – the girlfriend of the author PVR. Description. Adult with head, neck and eleven trunk segments (Figs. 7A, B, 8A, 9G). For measurements and dimensions see Table 4. Distribution of cuticular structures (spines, tubes, glandular cell outlets and sensory spots) is summarised in Table 5. Since all specimens mounted for SEM were covered with dirt to different degrees, the species may have additional sensory spots that were not observed and hence are not reported in the present description. The head consists of a retractable mouth cone and an introvert. Arrangement of styles and scalids could not be examined. The neck bears 16 placids (Figs. 8B, 9A, B, G), measuring 18 µm in length. Midventral placid broadest, measuring 19 µm in width. Trichoscalid plates present ventrally on placids 2 and 16 and dorsally on placids 6, 8, 10 and 12 (Figs. 7A, B, 8B). Ventral trichoscalid plates much broader than dorsal ones. Segment 1 consists of a complete cuticular ring with sensory spots located near the anterior segment margin in subdorsal and laterodorsal positions (Fig. 9A), and medially in ventromedial positions (Figs. 9B). Sensory spots on this and following segments are small and rounded with seven to eight short cuticular papillae surrounding two small pores (Fig. 9D). Glandular cell outlets type 1 are present in sublateral positions. Cuticular hairs emerge through rounded perforation sites and are distributed evenly around the segment except in the anterior part of segment and around the sensory spots. The segment terminates into a pectinate fringe. Fringe with very short tips along the dorsal and lateral parts of segment margins, whereas the margins of the ventral parts have significantly longer fringe tips. Ventromedial fringe tips longest. Segment 2 consists of a complete cuticular ring with sensory spots at least in middorsal (Fig. 9E), subdorsal and ventromedial positions (Fig. 9B). Glandular cell outlets type 1 present in middorsal and ventromedial positions; glandular cell outlets type 2 present in subdorsal, laterodorsal and lateroventral positions (Figs. 8B, C). Cuticular hairs and pectinate fringe as on segment 1. Pectinate fringe of segments 1 and 2 considerably shorter than on following segments. Segment 3, and all following segments, consists of one tergal plate and two sternal plates. Glandular cell outlets type 1 present in middorsal and ventromedial positions. Cuticular hairs as on segment 2. Pectinate fringe of this segment with considerably longer tips than that of preceding segments. Midlateral parts of segment margin with slightly shorter fringe tips. Sensory spots not observed. Segment 4 with very short middorsal acicular spine (Figs. 7A, 8E), and sensory spots at least, in laterodorsal positions. Glandular cell outlets type 1 present only ventromedially; glandular cell outlets type 2 present in subdorsal positions (Fig. 8E). Cuticular hairs and pectinate fringe as on segment 3. Segment 5 with relatively long lateroventral tubes (Figs. 8D, 9C). Sensory spots present at least, in subdorsal, midlateral and ventromedial positions (Fig. 9C). Glandular cell outlets type 1 present only ventromedially; glandular cell outlets type 2 present in sublateral positions (Fig. 8D). Cuticular hairs and pectinate fringe as on segment 4, but without variations in tip length around the segment. Segment 6 with sensory spots at least in ventromedial positions (Fig. 9C). Glandular cell outlets type 1 present in paradorsal and ventromedial positions; glandular cell outlets type 2 present in laterodorsal positions (Fig. 8D, G). Cuticular hairs and pectinate fringe as on preceding segment. Segment 7 with sensory spots present, at least in subdorsal and ventrolateral positions (Fig. 9F). Glandular cell outlets type 1 present in paradorsal and ventromedial positions; glandular cell outlets type 2 present in sublateral positions (Fig. 8G), as on segment 5. Fringe tips of pectinate fringe slightly longer on middorsal margin than those on preceding segments. Cuticular hairs as on preceding segment. Segment 8 with lateroventral tubes (Figs. 8F, 9F). Sensory spots present at least in ventromedial positions (Fig. 9F). Glandular cell outlets type 1 present in paradorsal (Fig. 8G) and ventromedial positions; glandular cell outlets type 2 present in laterodorsal positions (Fig. 8F, G), as on segment 6. Segment 9 with midlateral tubes (Figs. 8F, J, 9I), and a pair of large, elongated sieve plates in sublateral positions (Fig. 8F). Sensory spots present at least in laterodorsal positions. Glandular cell outlets type 1 present in paradorsal and ventromedial positions (Figs. 8F, J). Pectinate fringe and cuticular hairs as on preceding segment. Segment 10 with sexually dimorphic laterodorsal tubes near the posterior segment margin (Fig. 8H). Tubes are apparently similar in length but differ in width of both the proximal shaft and the distal tip. In males, the distal parts of the tubes are much thinner, and the proximal shaft is slightly longer than those in females (Figs. 7A, C, 8H). Sensory spots present at least in subdorsal positions. Glandular cell outlets type 1 present in paradorsal and ventromedial positions (Fig. 8F). Cuticular hairs as on preceding segments. Pectinate fringe of posterior margin with shorter and thinner tips than those on preceding segments. Segment 11 with conspicuously short and stout lateral terminal spines (Fig. 8H, I), with a ring of fine trichoids or cuticular markings around each spine, about 1/3 from its proximal end. Males with three pairs of penile spines (Fig. 8H); females with short lateral terminal accessory spines (Fig. 8I). Segment with few cuticular hairs only. Sensory spots not observed. Glandular cell outlets absent. Tergal extensions elongate and triangular (Figs. 7, 8I).

Leiocanthus nagini sp. nov. (Figs. 11–13) Material examined. Holotype adult male, collected from sand with mud on 16 May 2014, at station SI-05 (Fig. 1, Table 1), at 52 m depth, at the locality “ Eastern Fairway ” southeast of Singapore Island (01°15.589’N 103°56.680’E), mounted in Fluoromount G, deposited at the Lee Kong Chian Natural History Museum, under catalogue number ZRC. MIS.0004. Additional, non-type material, includes one adult female, collected from sand with mud on 16 May 2014, at station SI-03 (Fig. 1, Table 1), at 9 m depth, between Bedok Jetty and Sungei Bedok in the southeast part of Singapore Island (01°18.387’N 103°57.591’E), and mounted for SEM. Diagnosis. Leiocanthus without middorsal elevations. Paradorsal setae present on segments 2–9, paired ones on segment 4. Tergal anterior margin of segment 1 strongly denticulated and followed by a broad, ornamented area. Dorsal and ventral sides on segment 10 with longitudinal cuticular thickenings, visible with LM and SEM. Type 1 sensory spots present on segments 1–10, but not detectable on segment 11. Etymology. The species name, nagini, is the female version of Nāgá – the Sanskrit word for a group of divine dragons or serpent deities known from Hindu and Buddhist mythology. Nagini is furthermore Lord Voldemort’s serpent, known from J. K. Rowling’s Harry Potter novels. Description. The single specimen available for SEM was not suitable for introvert examinations, and detailed information on number and arrangement of scalids and oral teeth was thus not possible to obtain. Neck with four dorsal and two ventral placids (Figs. 11A, B, 13A, B). All placids are thick and hard, with a depressed surface, and articulating with the anterior edge of the first trunk segment. Dorsal placids are rectangular and of similar size, whereas the ventral ones are broader and curve towards the lateral sides. Cuticular folds appear between dorsal and ventral placids. Trichoscalid plates are absent. Trunk consisting of 11 segments (Figs. 11A, B, 12A, B). First segment with one tergal and three sternal plates (Figs. 11A, B, 13A, B); segments 2–11 with one tergal and two sternal plates (Figs. 11A, B, 12B). Dimensions and measurements of holotype are summarised in Table 6, and distribution of spines, sensory spots and setae in Table 7. The segment width is nearly constant along the trunk, reaching the maximum width at segment 5 and tapering slightly from this segment towards the posterior ones. Pachycycli of tergal and sternal plates are well-developed, with regular sized peg-and-socket joints from segments 2–10. Hairy tergosternal junctions, with numerous short cuticular hairs present on segments 2–10. Conspicuous, oval glandular cell outlets present in laterodorsal and ventromedial positions on segments 2–10 (Fig. 11A, B). Indistinct, rounded muscular scars present in laterodorsal and ventromedial positions on segments 2–10. One pair of laterodorsal and ventrolateral cuticular ridges present on segments 2–10. One pair of apodemes near the anterior margins of segments 9 and 10 (Fig. 11A). Segment 1 with anterolateral margins of tergal plate projecting into horn-like extensions. Tergal, anterior margin of the segment strongly denticulated, followed by a broad, longitudinal cuticular ornamentation (Figs. 11B, 12E, 13A). Posterior margin of dorsal plate smooth, without middorsal structure specialisation (middorsal process or elevation) or intracuticular atria. Tergal plate with one pair of subdorsal glandular cell outlets, one pair of paralateral setae (Fig. 13B) and three pairs of sensory spots: one pair in subdorsal and two pairs in laterodorsal positions. Sensory spots on this and all following segments belong to type 1, which are rounded and small, consisting of several small cuticular papillae around a central collar of wider papillae. Ventral side with two episternal plates and one trapezoidal midsternal plate, the latter one overhanging the anterior edge of the segment (Figs. 11A, C, 13B). Anterior margin of each sternal plate is ornamented and followed by a contiguous depressed area (Fig. 13B). Each episternal plate with a glandular cell outlet in the medial region and two ventromedial sensory spots. Pectinate fringe on both dorsal and ventral sides thin, only visible with SEM. Conspicuous parallel, cuticular wrinkles present in the posterior parts of tergal and episternal plates, but absent in the midsternal one. Segment 2 without middorsal elevation or intracuticular atria at the posterior margin of the dorsal plate. Tergal plate with a single paradorsal seta, and paired setae in laterodorsal and lateroventral positions. Paired sensory spots present in subdorsal and laterodorsal positions. Dorsal side with short secondary pectinate fringes in the anterior part of the segment, present from the tergosternal junction to the laterodorsal longitudinal ridge. Sternal plates with one pair of ventromedial sensory spots. Males with a pair of thick ventromedial tubes (Fig. 11A). Females instead with a pair of ventrolateral setae (Figs. 11C, 12F). Ventral side with secondary pectinate fringe similar to that on the dorsal side, stretching from the tergosternal junction to the ventromedial cuticular ridge. Posterior margin of tergal and sternal plates with conspicuous parallel, cuticular wrinkles. Tergosternal junctions with numerous short cuticular hairs. Muscular scars and glandular cell outlets present in laterodorsal and ventromedial positions. Pachycycli of tergal and sternal plates well-developed, with regular sized peg-and-socket joints. Pectinate fringe as on the preceding segment. Segment 3 without middorsal elevation or associated intracuticular atria on tergal plate. A single paradorsal seta, one pair of laterodorsal setae, and two pairs of laterodorsal sensory spots are present on tergal plate. Both pairs of laterodorsal sensory spots are located mesially to the laterodorsal setae. Lateroventral setae absent. Sternal plates with one pair of ventromedial setae and sensory spots, with the sensory spots located lateral to the setae (Fig. 12F). Otherwise similar to preceding segment. Segment 4 without middorsal elevation or associated intracuticular atria on tergal plate. Paired setae present in paradorsal, laterodorsal and lateroventral positions. Three pairs of sensory spots present, one in subdorsal and two in laterodorsal positions, all of them located mesially to the laterodorsal setae. Sternal plates as on segment 3. Otherwise similar to preceding segments. Segment 5 with tergal plate (Fig. 13C) almost similar to that of segment 3 (Fig. 11B), but only with a single pair of laterodorsal sensory spots. Sternal plates similar to those on segment 3, except for the presence of paired ventrolateral setae. Otherwise similar to preceding segments. Segment 6 with tergal plate (Figs. 11B, 12D, 13C) almost similar to that of segment 4, but with a single paradorsal seta. Sternal plates same as those of segment 3, but with the ventral setae in females displaced to a ventrolateral position (Figs. 11A, 13D). Otherwise similar to preceding segments. Segment 7 with tergal and sternal plates (Figs. 11A, B, 12D, 13D) almost as those of segment 5, except for the ventral setae that are displaced to a ventrolateral position (Figs. 11A, 13D). Otherwise similar to preceding segments. Segment 8 with tergal plate (Figs. 11B, 12C, 13F) similar to that of segment 6, but with one additional pair of laterodorsal sensory spots, making it three laterodorsal pairs in total (Fig. 11B). Sternal plates as those on segment 3. Otherwise similar to preceding segments. Segment 9 with tergal (Figs. 11B, 12C, 13F) and sternal plates similar to those of segment 3. Protonephridial opening in paralateral position, with the pore surrounded by a few short cuticular hairs; opening not sieve-like. Paired apodemes (or anteromesial thickenings of ventral pachycycli) present near the anterior margin of segment (Fig. 11A). Otherwise similar to preceding segment. Segment 10 without dorsal structures (Figs. 11B, 12G). Tergal plate with one pair of lateroventral setae and a pair of laterodorsal sensory spots. Sternal plates with ventrolateral setae. Ventromedial sensory spots not found. Paired apodemes present near the anterior margin of the segment (Figs. 11A, 13E). Lateral margins of tergal and sternal plates with conspicuous, longitudinal cuticular thickening visible with LM and SEM (Figs. 12G, 13E). Otherwise similar to preceding segment. Segment 11 with a pair of lateral terminal spines (Fig. 11A, B, D). Males with two pairs of penile spines and genital pores surrounded by a tuft of long hairs. Posterior segment margin with characteristic, irregularly fringed shape (Fig. 13E).

Cycliophora is a recently described phylum to which only two species have been assigned so far, Symbionpandora and S. americanus. The cycliophoran life cycle is complex and alternates between asexual and sexual stages.Although not recognized as an entirely independent freeswimming stage when the phylum was first described, thedwarf male has a remarkably complex bodyplan albeit its very small size (approx. 30–40 lm in length). Aiming toincrease the knowledge on the gross morphology of the cycliophoran dwarf male, specimens from S. pandora andS. americanus were analyzed by scanning electron microscopy. In both species, anterior and ventral ciliatedfields, as well as paired lateral sensorial organs, were identified, thus confirming previous observations. However,new details are described herein such as the penial pouch that encloses the penis. We compare our findings onboth Symbion species with the data currently available on other metazoan dwarf males.