Hemienchytraeus koreanus
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Ordo: Enchytraeida
Familia: Enchytraeidae
Genus: Hemienchytraeus
Name
Hemienchytraeus koreanus Dózsa-Farkas, Klára, 2010 – Wikispecies link – Pensoft Profile
- Hemienchytraeus koreanus Dózsa-Farkas, Klára, 2010, Zootaxa 2406: 31-41.
Materials Examined
Type material. Holotype: Clitellate (NIBRIV 0000138923). Type locality: Korea, Soil and litter layers in mountain forest nearby experimental farm, College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, (N 35 ˚ 50 ΄ 50.2 ʺ, E 127 ˚08΄0 1.8 ʺ) (site C), collected on 0 3. 0 9. 2007. stained with borax-carmine, whole-mounted on slide (No. 178). Deposited in the National Institute of Biological Resources, Korea. Paratypes: C litellate (NIBRIV 0000138924) one specimen on slide, stained with borax-carmine (No. 156) locality is the same as the locality of the holotype, collected on 0 3 0 9. 2007; NIBRIV 0 0 0 0 138925 one specimen on slide (No. 155) stained with paracarmine-bromophenol blue, locality: Soil and litter layers in maple trees cultivation of experimental farm, College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea (N 35 ˚ 50 ΄ 51.1 ʺ, E 127 ˚08΄ 0.3 ʺ), (site A), collected on 0 3. 0 9. 2007. Deposited in the National Institute of Biological Resources, Korea.
Description
P. 85. 1 – 4 four specimens on four slides (No. 157, 180 – 182), stained with borax-carmine; P. 85. 5 - 7 three specimens on slides (No. 159, 215, 216) stained with paracarmine-bromophenol blue, collected on 0 3. 0 9. 2007; P. 85. 8 three specimens in 70 % ethanol, coll. 0 6.10. 2008. The type locality of all paratypes of P. 85 is the same as the locality of the holotype. Deposited in the collection of K. Dózsa-Farkas at Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest. . Etymology: Named after the country where it was found. Description.Holotype8.2 mm long, 266 µm wide at VIII and 295 µm at the clitellum (fixed), segments 43. Body length of paratypes7.5–12 mm, width 300–380 µm at VIII and 360–440 µm at the clitellum (in vivo), length of fixed specimens 6.4–9 mm, width 250–300 µm at VIII, 290–320 µm at the clitellum, segments 38–45. Chaetae 2 per bundle, absent in XII, slightly sigmoid without nodulus, pointed distally, blunt proximally. Chaetae in preclitellar bundles 35–38 µm long, diameter ca. 5 µm, gradually increasing in size posteriad, in terminal segments 63–71 µm long and 6 µm thick. Prostomium rounded, head pore on the prostomium, dorsal just subterminal (Fig. 1 A), dorsal pores absent. Epidermal gland cells three to four transverse rows per segments, inconspicuous but prostomium and the first segment densely covered with gland cells. Clitellum in XII– 1 / 3 – 1 / 4 XIII girdle-shaped, hyalocytes and granulocytes arranged in dense rows dorsally (Fig. 1 D); mid-ventrally only granulocytes (Fig. 1 C) (occasionally with a few smaller hyalocytes). Body wall 18–20 µm thick, cuticle ca. 2–3 µm (fixed specimens). All preclitellar septa well-developed. Brain (Fig. 1 B) about 1.5–1.7 times as long as wide incised anteriorly and posteriorly. Post-pharyngeal bulbs conspicuous. Ventral nerve cord perikarya concentrated in segmental ganglia, no perikarya in the region of the septa (Fig. 2 A), two or three pairs of lateral nerves, which enter the body wall, arising from ventral nerve cord in each segment (Fig. 2 B). Oesophageal appendage (Fig. 7 A) arises from mid dorsal region of pharynx, with a shorter unpaired root (60–80 µm long, 45–55 µm wide), two longer and thinner primary branches (95–130x 33 –38 µm) (Fig. 2 C) and five to six secondary branches (43– 47 x 17–19 µm) on each side (in vivo) (Fig. 2 D). All three pairs of pharyngeal glands united dorsally with ventral lobes in V and VI. Three pairs of secondary ventral glands (lobes) in V, VI and VII but only the first pair is well-developed, the other two are rudimentary sometimes inconspicuous, smallest in VI (Fig. 3 A, Fig. 7 B). Chloragocytes from V. Dorsal vessel from XIII–XIV, anterior bifurcation at 0/I (Fig 3 B), blood colourless. Inflated ventral gut epithelium from XXVI to XXXIII, extending over two segments, often not visible. Five pairs of preclitellar nephridia from 5 / 6 to 9 / 10, (in one case there was only a single nephridium at 9 / 10). One or two pairs of nephridia are present at 13 /14, 14/ 15 or sometimes only at 15 / 16, then missing in the next few segments, and posterior to this present in all segments until the end of worm. Efferent ducts arise mid-ventrally on the nephridia in preclitellar segments (Fig. 4 B) and sub-terminally (Fig. 4 A) on those of posterior segments; no terminal vesicle. Anteseptal with brownish granules (Fig. 3 C, 3 D). Anterior nephridia 130–180 µm long (in vivo) (Fig 4 B), gradually increasing to a maximum at the first pairs posterior to the clitellum (187–210 µm), then gradually decreasing (Fig. 3 C) to only 95–130 µm (Fig. 4 A) in posteriormost segments. Ratio of lengths of anteseptal: postseptal 1: 1.3–1.5 for most segments but 1: 1 for the posteriormost segments. Nephridia often narrow at the septa (Fig. 3 D). Coelomocytes broadly oval yellowish with clearly visible nucleus and finely granular matrix, 20–33 x15–17 µm (in vivo) (Fig. 4 C).
Seminal vesicles large (in well developed adults) in XII–XIII. Sperm funnels (Fig. 5 A, B and 7 C) welldeveloped, length about equal body diameter, 5–6 times as long as wide tapering distally (340–380 µm long proximally 60–70 µm wide, distally only 20–24 µm, in vivo). In fixed specimens the length of funnels are 176–230 µm. Collar bending out, wider than the funnel body. Spermatozoa ca. 100 µm (in vivo), 75 µm (fixed); head 13 µm in vivo and 8–10 µm fixed specimens. Sperm ducts (Fig. 5 C, D) long in loose or tight coils in XII–XIII, diameter 7–8 µm (fixed). Male copulatory organs (Fig. 5 C, D and 6 A) with distinct musculature, male glandular body globular, diameter ca 45–57 µm (fixed). No accessory copulatory glands. Spermathecae (Fig. 7 D) paired, free, not attached to oesophagus. Ectal duct 100–160 µm long and 11–13 µm wide (fixed), with a short dilation in V (diameter 22–30 µm) (Fig. 6 B), and then continuing as a smooth tube (ca 220–230 µm long); terminating in a thin-walled, cylindrical ampulla in VIII–X. Size of ampulla varying according to the amount of sperm contained, sperm not arranged in packages (Fig. 6 C, D). One mature egg at a time.
Distribution
Distribution and habitat: Soil and litter layers in maple trees cultivation of experimental farm of Agriculture Life Science, Chonbuk National University (site A), soil and litter layers in mountain forest nearby the experimental farm (site C) and soil of earthworm breeding experimental box (site E).
Diagnosis
Diagnosis. The new species can be recognized by the following combination of characters: (1) the size of worms: 7.5–12 mm long, width 300–380 µm in vivo, 38–45 segments; (2) all pairs of pharyngeal glands united dorsally, among the three pairs of secondary ventral glands only the first pair is well developed; (3) five pairs of preclitellar nephridia; (4) nephridia in the posteriormost segments are half the size of the first postclitellar ones; (5) primary branches of oesophageal appendages are longer and thinner than the unpaired trunk, with five–six secondary branches; (6) oval, yellowish, faintly granular coelomocytes with nucleus; (7) girdle-shaped clitellum, ventrally only granulocytes; (8) dorsal vessel from XIII–XIV; (9) large seminal vesicle; (10); large sperm funnel regularly tapering distad, approximately 6 times as long as wide, collar bending out; (11) spermathecae are free, extending into VIII–X, consisting of relatively long ectal ducts, dilations in V and connecting tubes with large cylindrical ampullae. Differential diagnosis. The new species is most similar to Hemienchytraeus loksai Dózsa-Farkas, 1989 (Dózsa-Farkas 1989) from Ecuador, because both have 5 pairs of preclitellar nephridia and a similar form of spermathaecae but in H. koreanus sperm in the spermathecal ampulla is not arranged in packages, in contrast with H. loksai. The size of both species is about the same but H. loksai has more segments (48–55). Further differences include: (1) the terminal chaetae are about twice as large as the largest chaetae near the clitellum in the new species, while only slightly larger in H. loksai. (2) all three pairs of secondary pharyngeal glands are well developed in the H loksai, but only the first pair in H. koreanus. (3) the dorsal vessel origin is farther back (in XIV–XVI) in H. loksai, (4) the sperm ducts extend into XIV–XVII and the male copulatory organs are larger in H. loksai, (6). the sperm funnels are shorter and the sperm duct occurs only in XII–XIII in the new species.
Description
Finally it is necessary to compare the new species to H. siljae Schmelz and Römbke, 2005. These two species are very similar in size, chaetal size distribution patterns (in posterior segments these are two times as large as in preclitellar segments), form of oesophageal appendage although there may be slightly fewer secondary branches in H. siljae (4–5) (Schmelz & Römbke 2005). H. siljae differs from the new species further, by having well-developed secondary lobes of the pharyngeal glands and primary lobes at 6 / 7 that are not connected dorsally, only four pairs of nephridia in preclitellar segments, and slightly more posterior dorsal vessel origin, in XIV–XV.
Taxon Treatment
- Dózsa-Farkas, Klára; Hong, Yong; 2010: Three new Hemienchytraeus species (Enchytraeidae, Oligochaeta, Annelida) from Korea, with first records of other enchytraeids and terrestrial polychaetes (Annelida), Zootaxa 2406: 31-41. doi
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