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 Author Sørensen, Martin V. 4143D650-12FC-4914-93F5-2C39339A7156 Natural History Museum of Denmark, University of Copenhagen, DK- 2100 Copenhagen, Denmark. Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC 20560, USA. Department of Biological Science, College of Natural and Life Sciences, Daegu University, Gyeongsan 38453, Korea. Crescent International School, Bario, Govindpur, Dhanbad 828109, Jharkhand, India. Isparta University of Applied Sciences, Department of Aquaculture, 32260 Isparta, Turkey. Department of Biology, University of Copenhagen, DK- 2100 Copenhagen, Denmark. Silifke Vocational School Aquaculture Program, Mersin University, 33940 Mersin, Turkey. Faculty of Arts and Science, Kyushu University, Fukuoka 819 - 0395, Japan. mvsorensen@snm.ku.dk Author Goetz, Freya E. 5849A537-F762-4B25-9493-E8B32690C49D Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC 20560, USA. GoetzF@si.edu Author Herranz, María 2A7DE5DC-FF82-49CC-9DD4-CC0AFA1B281B Natural History Museum of Denmark, University of Copenhagen, DK- 2100 Copenhagen, Denmark. Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC 20560, USA. Department of Biological Science, College of Natural and Life Sciences, Daegu University, Gyeongsan 38453, Korea. Crescent International School, Bario, Govindpur, Dhanbad 828109, Jharkhand, India. Isparta University of Applied Sciences, Department of Aquaculture, 32260 Isparta, Turkey. Department of Biology, University of Copenhagen, DK- 2100 Copenhagen, Denmark. Silifke Vocational School Aquaculture Program, Mersin University, 33940 Mersin, Turkey. Faculty of Arts and Science, Kyushu University, Fukuoka 819 - 0395, Japan. maria.herranz@bio.ku.dk Author Chang, Cheon Young 497A5735-AA95-498A-A1B8-58180C2ACA33 Department of Biological Science, College of Natural and Life Sciences, Daegu University, Gyeongsan 38453, Korea cychang@daegu.ac.kr Author Chatterjee, Tapas F35C0625-55F6-4307-A7BE-93416BE6F0D7 Crescent International School, Bario, Govindpur, Dhanbad 828109, Jharkhand, India. drtchatterjee@gmail.com Author Durucan, Furkan 62189A90-E675-49B1-BE3C-F4657CA40EE4 Isparta University of Applied Sciences, Department of Aquaculture, 32260 Isparta, Turkey. f_durucan@hotmail.com Author Neves, Ricardo C. C2B164FF-E8D8-468E-A07E-C39E1C71E65E Department of Biology, University of Copenhagen, DK- 2100 Copenhagen, Denmark. ricardon.6@gmail.com Author Yildiz, N. Özlem CE2E097A-4499-498C-980E-F21A4156F76E Silifke Vocational School Aquaculture Program, Mersin University, 33940 Mersin, Turkey. nozlemkoroglu@gmail.com Author Norenburg, Jon B8710D9A-1549-4E17-AF4F-6B598744C02E Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC 20560, USA. NORENBUR@si.edu Author Yamasaki, Hiroshi Faculty of Arts and Science, Kyushu University, Fukuoka 819 - 0395, Japan. text European Journal of Taxonomy 2020 2020-12-30 730 1 101 journal article 9069 10.5852/ejt.2020.730.1197 d640faf0-b3db-4fad-baaf-9eeaef7350e4 4418973 857A9432-9083-46B3-B0BF-B34D619EB350 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.