New enchytraeid species from Mount Hallasan (Jeju Island, Korea) (Enchytraeidae, Oligochaeta) Author Dózsa-Farkas, Klára Author Felföldi, Tamás Author Nagy, Hajnalka Author Hong, Yong text Zootaxa 2018 2018-10-05 4496 1 337 381 journal article 29257 10.11646/zootaxa.4496.1.27 e8ba8a68-c584-48d8-bfba-f4d2fd163e97 1175-5326 1446851 7C536E1E-5D5A-4E2D-9E4F-28F3CEA9664C Achaeta koreana sp. n. ( Figures 1 , 2 , 5A–C ) Type material. Holotype : NIBRIV0000810584 slide No. 2210, adult, stained whole mounted specimen. Type locality: site 4, Baekrokdam crater on the summit of Mt. Hallasan , Jeju Island, Korea , soil of grass on highland in North slope (N 33˚21'46.0", E 126˚31'58.0"), 1843 m elevation, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 9 stained, adult specimens on slides and 37 specimens in 70% ethanol): NIBRIV0000810585, slide No. 2198, site 1, NIBRIV0000811380, slide No. 2276, site 2, P.113.1. slide No. 2212, from type locality, P.113.2.1–113.2.3. slides No . 2193–2195 , site 6, P.113.3. slide No. 2196, site 5, P.113.4.1, slides No. 2197, site 1. In 70% ethanol: P.113.5, from type locality 10 specimens ; P.113.6 site 2 seven specimens; P.113.7 site 5 eight specimens; P.113.8, site 6 twelve specimens. TABLE 1. Detected enchytraeid species (and the two polychaetes) and their distribution at the study sites in Mt. Hallasan, Korea (site 1-4 Baekrokdam crater, 5-11 Gwaneumsa trail, 12 Gwaneumsa temple, 13-15 Seongpanak trail). New species described here are highlighted in bold, while species new for the Korean fauna are marked with an asterisk.

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Achaeta koreana sp. n.	+	+	+	+	+	+	+
Achaeta macroampullacea sp. n .	+	+
Bryodrilus hallasanensis sp. n.	+	+	+	+	+	+	+
Chamaedrilus baekrokdamensis sp. n.	+	+	+
Enchytraeus buchholzi Vejdovský, 1879 sensu lato	+	+	+
Enchytraeus dichaetus Rota & Healy, 1994	+	+
Enchytronia seongpanakiensis sp. n.	+
Fridericia bulboides Nielsen & Christensen, 1959	+
Fridericia cusanicaformis Dózsa-Farkas, Felföldi & Hong, 1915	+	+
Fridericia cf. paroniana * Issel, 1904	+
Fridericia perrieri * (Vejdovský, 1878)	+
Fridericia sp. 1	+
Fridericia sp. 2	+	+
Fridericia sp. 3	+	+
Hemienchytraeus jeonjuensis Dózsa-Farkas & Hong, 2010	+	+	+	+	+	+	+	+	+
Hemienchytraeus quadratus Dózsa-Farkas & Hong, 2010	+	+	+	+	+	+	+	+	+	+
Hemienchytraeus koreanus Dózsa-Farkas & Hong, 2010	+	+	+	+	+	+	+
Henlea perpusilla Friend, 1911	+
Mesenchytraeus jungsaihoi sp. n.	+	+	+	+	+
Xetadrilus jejuensis sp. n.	+	+	+	+	+	+
Xetadrilus aphanoides sp. n.	+	+	+	+	+	+	+	+	+	+
Enchytraeid species number (total: 21)	2	7	6	8	6	5	4	6	1	3	12	13	4	5	1
Hrabeiella periglandulata Pižl & Chalupský, 1984	1	1	1
Parergodrilus heideri Reisinger, 1925	1	1	1

Further material examined. 15 specimens investigated in vivo , 3 of them processed for DNA analysis. Etymology. Named after the country where it was found. Diagnosis. The new species can be recognized by the following combination of characters: (1) small, stout worms ( 2–3 mm long and 200–280 µm wide at clitellum in vivo ), segments 17–22; (2) no pyriform glands; (3) clitellum developed only laterally: dorso-lateral area with hyalocytes in disordered three or four longitudinal rows; (4) dorsal blood vessel from VI; (5) pharyngeal glands at 4/5–5/6 connected dorsally, at 6/7 separate dorsally, the first ventral lobes separate from the dorsal lobes in IV, secondary ventral glands absent; (6) three pairs of preclitellar nephridia; (7) pars tumida of midgut from XIII–XIV, extending over 2 segments; (8) sperm funnel small, barrel-shaped, collar narrower than funnel body; (9) male pores in XII, ventrolaterally, no glandular body, only the pore surrounded by small inconspicuous glands; (10) spermathecae confined to V. FIGURE 1. Micrographs of Achaeta koreana sp. n. A. Thick cuticle terminally dorsally thicker (white arrow) than ventrally (black arrow). B. Clitellar glands, dorsal view (interruption marked with arrow). C. Clitellar glands, lateral view (arrows: hyaline glands). D. Entire individual (head marked with arrow). E. Clitellar glands, lateral view. F–G. Head (white arrows: head pore; black arrows: prostomial ganglia; b=brain, ph=pharynx). A–E, G in vivo , F fixed, stained. Scale bars A–D, F, G 50 µm; E 20 µm). FIGURE 2. Micrographs of Achaeta koreana sp. n. A. Pharyngeal glands, lateral view (marked with arrows, o= oesophageal appendage, dv= dorsal vessel, n=first nephridium). B. Midgut pars tumida XIII – XV. C. Coelomocytes. D. First nephridium. E. Nephridium terminally. F–G. Sperm funnels. H. Clitellar glands, lateral view (arrow: male opening). I. Male opening with small surrounding glands (arrow). J–L. Spermathecae (arrow in L: ectal gland). M. Spermathecal ectal gland (marked with arrow). A–G, I–M in vivo , H fixed, stained. Scale bars A–H, J–L 50 µm; I, M 20 µm. Description. Small worm ( Fig. 1D ). Holotype 2.8 mm long, 275 µm wide at VIII and 315 µm at clitellum (fixed), 21 segments. Length of paratypes 2.5–3.8 mm , width 200–250 µm at VIII and 220–280 µm at clitellum in vivo , length of fixed specimens 2–3 mm , width 220–270 µm at VIII and 2 30–300 µm at clitellum, segments 17–22. No pyriform glands. Body wall thick, thickness dorsally 22–24 µm, cuticle 4–7 µm, ventrally 17–18 µm and 2–3 µm, respectively, in vivo ( Fig. 1A ). Clitellum in XII–1 /2 XIII developed only laterally, dorso-lateral areas with hyalocytes in two or three disordered longitudinal rows ( Fig. 1C ), hyalocytes large and conspicuous, 28–32 µm high and 17–19 µm wide, granulocytes 20–24 by 16–14 µm ( Fig. 1E ). Ventro-laterally only granulocytes. The dorsal interruption 60–70 µm wide in vivo , dorsal borderline consisting of granular cells only in one longitudinal row ( Fig. 1B ). Ventral borderlines inconspicuous. Head pore on the top of prostomium ( Figs. 1F–G ). Spermathecal pores at 4/ 5 in lateral position. Male pores in XII. Brain egg-shaped 1.5 times longer than wide, 80–90 µm long, fixed ( Fig. 1F ). The prostomial ganglion ( Figs. 1F,G ) well visible, 37–40 µm long (fixed). Pharyngeal glands at 4/5–6/7 ( Figs. 2A , 5A ), all with ventral lobes. The first and secondary dorsal lobes united dorsally, the third pair separate dorsally. Three pairs of preclitellar nephridia at 6/7–8/9 constricted by septum. Length ratio anteseptale: postseptale 1: 2.5 preclitellarly, postseptale tapers gradually into efferent duct, with small terminal vesicle ( Figs. 2D–E ). Dorsal blood vessel from VI ( Figs. 2A , 5A ). Coelomocytes about 40–53 µm long in vivo , flat, cytoplasm pale, margin with indefinite contour in top view, but spindle-shaped in side view ( Fig. 2C ), the length measurable only in side view. Oesophageal appendages in V, well developed without canal in IV ( Figs. 2A , 5A ). Chloragocytes yellowish-brown, about 15 µm long in vivo. Midgut pars tumida XIII–XIV (occupying 2 segments) ( Fig. 2B ). Sperm funnel small, barrel-shaped, 65–90 µm long in vivo (53–62 µm fixed), about 1.2–2 times longer than wide, collar narrower than funnel body ( Figs. 2F–G , 5C ). Sperm duct 6 µm thick in vivo . Spermatozoa 75–90 µm, heads 30–38 µm long in vivo (52–60 µm and 17–23 µm, fixed). Seminal vesicle absent. Male copulatory organs small, widely separate ventro-laterally, no glandular body or bursa, only the pore surrounded by small inconspicuous glands ( Figs. 2H,I ). Spermathecae small, free, confined to V. The short ectal duct (20–30 µm long 20–23 µm wide in vivo ) has a small gland ( Figs. 2L,M ). In welldeveloped specimens the duct widens slightly into a narrow dilation of ampulla (25–28 µm wide). After the dilation the connecting tube (about 60 µm long and 20 µm wide) ends in an elongated globular ental reservoir (35–50 µm long, 25–35 µm wide in vivo ) in V. The surface of the reservoir is granulated, sperm is visible only in the ampullar dilation and the connecting tube ( Figs. 2J–L , 5B ). Distribution and habitat. In Korea , Mt. Hallasan, above 1306 m elevation, at site 1–7. Differential diagnosis. Among the previously described 12 small Achaeta species without pyriform glands and the spermathecae confined to segments V–VI, none has the origin of the dorsal vessel from VI; moreover, secondary pharyngeal glands are, with one exception ( A. hanagarthi Schmelz, 2008 ), present, and the spermathecal opening is without a small gland. In A. camerani (Cognetti, 1899) the dorsal blood vessel originates in VIII and in the all other species in VII. A. brevivasa Graefe, 1980 , A. diddeni Graefe, 2007 , A. hallensis Möller,1976 , A. antefolliculata Dózsa-Farkas & Boros, 2005 , A. afolliculata S esma & Dózsa-Farkas, 1993 and A. singularis Schmelz, 2008 have two pairs of preclitellar nephridia, further A. hanagarthi and A. paranensis Schmelz, 2008 have only one pair. Only A. pannonica Graefe, 1989 , A. iberica Graefe, 1989 and A. etrusca Rota, 1995 similarly to A. koreana sp. n. have three pairs of preclitellar nephridia, as in the new species. But in A. pannonica all reproductive organs except the spermathecae are shifted one segment forward, so the male pores are in XI, while in the new species, in A. iberica and in A. etrusca they are in the usual position in XII. A. etrusca differs from A. koreana sp. n. by his paired knob-like cutaneous gland structures dorsolateral in II–VI and by the shorter spermatozoa (40 µm long, sperm heads 15 µm ( Rota 2015 ) vs. 75–90 µm and 30–38 µm, respectively), moreover the penial bulbs are compact. Finally, in A. iberica , hyalocytes of the clitellar glands are lined in 4 distinct longitudinal rows.