Search

Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu, Xie, Zhicai (2022): The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species. Journal of Natural History 56: 1957-1996, DOI: 10.1080/00222933.2022.2140085, URL: http://dx.doi.org/10.1080/00222933.2022.2140085

Hemienchytraeus cf. stephensoni Cognetti, 1927 (Figure 18) Hemienchytraeus stephensoni Cognetti, 1927. See Schmelz and Collado (2007) for list of synonymies, and for nomenclatural and taxonomic history of the nominal species. Material investigated GZO202007006, stained and whole-mounted, terminal segments absent, one mature specimen from site H; GZO202007007, stained and whole-mounted, one submature specimen from site H. CJJ 135, one mature specimen from site I, whole worm used for DNA extraction, preserved as total DNA. Further material investigated One mature specimen from site H, two mature specimens and one immature specimen from site I, six mature specimens from site 1, one mature specimen from site C and one mature specimen from site E, 12 in total, preserved in 75% ethanol. Description Small to medium-sized worms. Length 5.8–9.2 mm, diameter 0.21–0.34 mm at VII, 0.29– 0.35 mm at clitellum. Number of segments 32–38. Chaetae faintly sigmoid, anterior chaetae ca. 32.5–40 μm long and 3.75–5 μm thick, terminal chaetae enlarged (about 1.5× as large as anterior), ca. 52.5–62.5 μm long and 5–7.5 μm thick (Figure 18c). Body wall 25.1–29.7 μm thick, cuticle very thin. Epidermal gland cells inconspicuous, cells nearly rectangular, 4–6 transverse rows per segment and arranged in regular order. Clitellum in XII–1/2XIII, girdle-shaped, well developed, granulocytes dense and arranged in reticulate with hyalocytes, hyalocytes isolated from each other, midventrally almost exclusively granulocytes (Figure 18h). Head pore on prostomium mid-dorsally. Brain nearly rectangular, incised anteriorly and slightly concave posteriorly, about 232 μm long and 153 μm wide (in vivo) (Figure 18a). Oesophageal appendages arising mid-dorsally behind the pharynx in III, one root with large proximal chamber, two primary branches longer than root, with smaller branches; each primary branch bifurcating into three secondary branches, secondary branches thinner and shorter than primary branches (Figure 18b). Three pairs of pharyngeal glands in IV–VI, united in IV–V and separated in VI dorsally, two pairs of secondary ventral lobes in V and VI, almost equal size. Dorsal vessel from XII to XIV, blood colourless. Four pairs of preclitellar nephridia from 6/7 to 9/10, anteseptale consisting of funnel and parts of nephridial body, ca. 43 μm long and 36 μm wide (in vivo); narrowed at septum, postseptale ca. 94 μm long and 59 μm wide (in vivo). Efferent duct originating from the middle of postseptale (Figure 18d). Coelomocytes elliptic, brown in transmitted light, diameter 30– 33 μm (in vivo) (Figure 18i). Seminal vesicle absent. Sperm funnel tapering distad, collar indistinct, wider than funnel body, ca. 282–356 μm long and 50–57 μm wide at collar (in vivo) (Figure 18f, g, i). Spermatozoa sparse, about 125 μm long (in vivo). Sperm duct elongate, with few coils in XIII. Male copulatory organ (Figure 18h) small, male glandular body globular, diameter ca. 60 μm (in vivo). Spermathecae (Figure 18e) free, not attached to oesophagus. Ectal pores at 4/5, no ectal gland. Ectal ducts muscular, short, ca. 61 μm long and 9 μm wide (in vivo); ampullae wider than ectal ducts (36 μm long, 14 μm wide, in vivo). Connecting tubes thinner than ampullae (337 μm long, 11 μm wide, in vivo), extending into VII, ending in ellipsoid ental reservoirs (70 μm long, 20 μm wide, in vivo). Ental reservoirs thin-walled, empty or with spermatozoa. Remarks Hemienchytraeus stephensoni was recorded in China by Xie et al. (1999), but the specimens were considered misidentified by the original authors, in a subsequent, detailed taxonomic revision of the species (Schmelz and Collado 2007). The key characters (such as body size, chaetae, oesophageal appendage and spermatheca) of our specimens conform well to the description of H. stephensoni (Schmelz and Collado 2007)., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1987-1989, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Cognetti ML. 1927. Lumbricidi dei Carpazi. Bolllettino dei Musei di Zoologia e Anatomia comparata della Reale Universita di Genova. 2 a (7): 1 - 8.","Schmelz RM, Collado R. 2007. Revision of Hemienchytraeus stephensoni (Cognetti, 1927) (Enchytraeidae, Oligochaeta, Annelida). Folia Facultatis scientiarum naturalium Universitatis Masarykianae Brunensis, Biologia. 110: 67 - 85."]}

Achaeta brevivasa Graefe, 1980 (Figures 9, 10) Achaeta brevivasa Graefe, 1980. Wang et al. 1999; Schmelz and Collado 2010. Material investigated GZO202007004–GZO202007005, stained and whole-mounted, two mature specimens from site H. CJJ 92– CJJ 94, three mature specimens from site 1, whole worm used for DNA extraction, preserved as total DNA. Further material investigated Two mature specimens from site H, two mature specimens from site I, one mature specimen from site A, two mature specimens from site 3, one mature specimen from site 8, one mature specimen from site 11: nine specimens in total, preserved in 75% ethanol. Description Small worm, 3.5–3.8 mm long, 0.15–0.18 mm wide at VII and 0.17–0.2 mm wide at clitellum. Number of segments (18) 20–26. Chaeta absent. Head pore on the tip of prostomium (Figure 9a). Body wall thin, thickness 8–15 mm, cuticle 1–2 mm (in vivo). No pyriform glands. Six lentiform epidermal gland cells per segment (Figure 10e). Clitellum saddled-shaped, hyalocytes in 6 baguette-like longitudinal rows in dorsal, conspicuous and depressed into the coelom, rectangle and closely packed, ca. 30–32 μm long and 9– 14 μm high, granulocytes inserted more or less regularly; granulocytes in dense transverse rows laterally, rectangle, ca. 20 μm long and 11 μm high (Figures 9a, 10h). Brain slightly convex posteriorly, ca. 1.5–2× as long as wide (154 μm long and 91 μm wide, in vivo) (Figures 9a, b, 10a). All three pairs of pharyngeal glands untied dorsally in IV/V–VI/VII, with ventral extension in V–VI, one pair of secondary pharyngeal gland lobes in VI (Figures 9a, 10b, c). One pair of spongy oesophageal appendages in V, small and inconspicuous (diameter ca. 30 μm, in vivo) (Figures 9a, 10b). Dorsal vessel originating from VII, blood colourless. Intestinal diverticula absent. Gut widening gradually in VII (Figures 9a, 10f). Chloragocytes yellowish-brown, sparse in IV–VII and dense from VII on. Nephridia two pairs in preclitellar segments, at 6/7 and 7/8 (Figures 9a, 10d). Nephridia constricted by septa, anteseptale with funnel and parts of nephridial body, ca. 39 μm long and 26 μm wide (in vivo); postseptale ca. 44 μm long and 27 μm wide (in vivo), with a ventral bump in mid-section, tapering gradually into efferent duct. Coelomocytes abundant and round, pale, ca. 9–13 μm in diameter. Seminal vesicle absent. Sperm funnel small, barrel-shaped, ca. 35–38 μm long, collar narrower than funnel body, 18–20 μm wide in collar and 21–27 μm wide in funnel body (in vivo) (Figures 9c, 10i). Spermatozoa short, 23–26 μm long, heads 10–13 μm long (in vivo) (Figures 9c, 10i). Sperm duct in coils, diameter ca. 4–4.5 μm (in vivo). Male copulatory organs small and inconspicuous. Spermathecae small, free, confined to V; ectal pores lateral at 4/5, without ectal glands; ectal ducts short, ca. 40 μm long and 11 μm wide (in vivo), the duct widening into narrow dilations of ampullar, ca. 25 μm long and 17 μm wide (in vivo) (Figures 9a, 10g). Only one mature egg (Figure 10h) at a time, with yellowishbrown granules, occupying 2–3 segments (Figure 9a). Remarks The morphological characters of our specimens correspond well with the original description (Graefe 1980); however, coelomocytes were without attached filaments in the redescription by Wang et al. (1999) based on specimens collected from Hunan Province and Hubei Province. This species has also been found in the Jilin, Gansu and Guizhou Provinces of China (Wang et al. 1999; J.J. Chen, unpublished data). Molecular results show that our specimens differ from Achaeta cf. brevivasa collected in Sweden (Erséus et al. 2010). Clear genetic gaps were observed between the two groups of specimens, with high interspecific distances (up to 18.7%) and low intraspecific distances (0%) based on the K2P distances of COI sequences. Achaeta brevivasa is a widespread morpho-species; it is probably a group of genetic species instead of only one, and the molecular differences are probably caused by weak dispersal capacity and long geographical distance., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1973-1975, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Graefe U. 1980. Systematische Untersuchungen an der Gattung Achaeta (Enchytraeidae, Oligochaeta). 1. Beschreibung von Achaeta brevivasa sp. n. und Achaeta camerani (Cognetti). Mitteilungen aus dem hamburgischen zoologischen Museum und Institut. 77: 35 - 39.","Wang HZ, Xie ZC, Liang YL. 1999. Records of Enchytraeidae (Clitellata) from the People's Republic of China. Hydrobiologia. 406: 57 - 66. doi: 10.1023 / A: 1003732116567.","Schmelz RM, Collado R. 2010. A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Org. 82: 1 - 176.","Erseus C, Rota E, Matamoros L, Wit PD. 2010. Molecular phylogeny of Enchytraeidae (Annelida, Clitellata). Mol Phylogenet Evol. 57 (2): 849 - 858. doi: 10.1016 / j. ympev. 2010.07.005."]}

Hemienchytraeus tenuiculus sp. nov. (Figures 6–8) Holotype Fully mature, whole-mounted specimen, stained, GZO202007012. Type locality Site 2. Soil and moss layer of Cyclobalanopsis glauca forest (108°42′58.7″E, 27°54′28.91″N), 2000 m asl, Fanjing Mountain, Guizhou, China, coll. Z.X. Zhang, Y.H. Ge and J.J. Chen, 25 December 2019. Paratypes GZO202007013, GZO20201010001, stained and whole-mounted, two mature specimens from the type locality, same data as holotype. CJJ81, CJJ125, CJJ126, CJJ130, four mature specimens from site 2, CJJ 82, one mature specimen from site 4, CJJ 83, one mature specimen from site I, CJJ 132, one mature specimen from site 8: seven specimens in total, whole worm used for DNA extraction, preserved as total DNA. Further material investigated One mature specimen from site 6, one mature specimen from site 10 and one mature specimen from site 12: three specimens in total, preserved in 75% ethanol. Etymology Named for the small and thin body. Diagnosis The species can be diagnosed by the following combination of characters: (1) worms small and thin; (2) each primary branch bifurcating into two secondary branches; (3) spermathecae extending to VII–VIII; (4) no secondary pharyngeal glands; (5) three pairs of preclitellar nephridia in 6/7–8/9; (6) dorsal vessel originating from postclitellar segments; (7) clitellum girdle-shaped. Description Small worms, transparent. Length 3.4–7.3 mm, diameter 0.12–0.21 mm at VII and 0.14– 0.23 mm at clitellum. Number of segments 30–43. Chaetae straight without inner hook, with slight proximal bend. Two chaetae per bundle throughout, absent in XII in mature worms (Figure 6a). Ventral chaetae in anterior region ca. 25–37.5 μm long and 5 μm thick, chaetae in caudal region somewhat increasing in size, ca. 30–50 μm long and 5–6.5 μm thick. Lateral chaetae almost of equal size throughout, ca. 25–30 μm long and 5 μm thick. Head pore on prostomium mid-dorsally (Figure 6a). Body wall 18–23 μm thick (in vivo), cuticle thin. Epidermal gland cells inconspicuous, 3–4 rows per segment, nearly rectangular, parallel or at chaetal level (Figure 7c). Clitellum in XII–1/2XIII, scarcely thickening, girdle-shaped, hyalocytes and granulocytes in dense transverse rows (Figures 6a, 7i). Brain ca 1.5× as long as wide (95 μm long, 65 μm wide, in vivo), deeply concave anteriorly, weakly incised posteriorly (Figures 6a, 7a). Oesophageal appendage with unpaired root dorsally behind pharyngeal pad in III, root with large lumen, extending posteriad, bifurcating into two primary branches, with meandering canal; each primary branch bifurcating further into two longer and thinner secondary branches, with smaller canal (Figures 6a, b, 7b, e). Three pairs of pharyngeal glands, poorly developed, pharyngeal glands in IV united dorsally, small, without ventral lobes, in V and VI dorsally separate, with ventral lobes (Figures 6a, 7f). No secondary pharyngeal gland lobes. Dorsal vessel beginning behind clitellum (segment XIV), blood colourless. Three pairs of preclitellar nephridia from 6/7 to 8/9 (Figure 6a), each about 115 μm long and 42 μm wide (in vivo). Anteseptale globular, consisting of funnel and parts of nephridial body, with coils of canal, postseptale elongate, length ratio of anteseptale: postseptale ca 1:1.3. Efferent duct originating from the middle of postseptale. Coelomocytes elongate, elliptical, numerous, 34–42 μm long, 15–18 μm wide (in vivo) (Figure 7g). Seminal vesicle absent. Sperm funnel cylindrical, tapering distally, ca. 106 μm long and 36 μm wide at collar (in vivo). Collar indistinct, as wide as funnel body, canal conspicuous (Figures 6c, 7g). Spermatozoa sparse, short, ca. 150 μm long, head ca. 18 μm long (in vivo) (Figures 6c, 7g). Diameter of sperm ducts ca. 6 μm, long and coiling unregularly in XII (Figure 7h). Male copulatory organs muscular, male glandular body oval, ca. 55 μm long and 23 μm wide (Figure 6a). Spermathecae free, not attached to oesophagus. Ectal pores lateral at 4/5, without ectal glands. Ectal ducts muscular, short, ca. 54 μm long and 10 μm wide (in vivo), with distinct ampullar dilatations in V (ca. 12 μm in diameter, in vivo); ampullar connecting tubes thinner than ectal ducts (ca. 8 μm wide, in vivo), extending into VII or VIII, ending in ellipsoid ental reservoirs, ca. 92 μm long and 19 μm wide (in vivo), ental reservoirs thin-walled, with spermatozoa (Figures 6a, 7d). One mature egg at a time. Remarks Among Hemienchutraeus species, there are six members with the same bifurcate branching pattern of the oesphageal appendage: H. bifurcatus Nielsen and Christensen, 1959, H. csuzdii Dózsa-Farkas, 1989, H. jeonjuensis Dózsa-Farkas and Hong, 2010, H. planisetosus Xie et al., 1999, H. solimoensis Righi, 1978 and H. tanjae Schmelz et al., 2005. Among them, the new species is most similar to H. jeonjuensis in possessing three pairs of preclitellar nephridia from 6/7 to 8/9, spermathecae extending to VII–VIII, a girdle-shaped clitellum and the absence of a seminal vesicle. However, in H. jeonjuensis, there are two pairs of secondary pharyngeal glands in V and VI, respectively, and the dorsal vessel originates in preclitellar segments (X–XI). The new species resembles H. csuzdii in the absence of secondary pharyngeal glands and a seminal vesicle, and in the postclitellar origination of the dorsal vessel. Conspicuous morphological differences from H. csuzdii include a short spermatheca confined to V and the first pair of preclitellar nephridia in 5/6. Hemienchytraeus planisetosus, H. solimoensis and H. tanjae differ from the new species in their longer spermathecae, presence of secondary pharyngeal glands, and the number and position of preclitellar nephridia. The comparison of the new species with H. bifurcatus is difficult due to the lack of several key morphological traits in the original description of the latter; for example, nothing is known about the pharyngeal glands and the preclitellar nephridia. Schmelz et al. (2005) considered H. bifurcatus to be a species inquirenda since its type material is lost. Repeated attempts to collect specimens at the type locality have so far not been successful (Schmelz, unpublished data). However, it is unlikely that H. tenuiculus sp. nov. and H. bifurcatus are the same species: the segments are fewer in the latter, despite some overlap with the former (28–32), and its clitellum is said to be ‘strongly elevated’ (Nielsen and Christensen 1959), while it is flat in the new species. Another difference can be inferred from the original illustration of H. bifurcatus (Nielsen and Christensen 1959, fig. 27), which shows a brain with length:width ratio of 1:1. Furthermore, H. bifurcatus has been recorded only in Europe [Denmark, Germany and Poland (Schmelz and Collado 2010)]. Hemienchytraeus tenuiculus sp. nov. is also clearly different from two species included in the DNA sequence comparison (Figure 8), H. koreanus Dózsa-Farkas and Hong, 2010 and H. wuhanensis Chen et al., 2021. In both species each primary branch of the oesophageal appendage divides into more than two secondary branches. Furthermore, the two species have three pairs of secondary pharyngeal glands and five pairs of preclitellar nephridia, from 5/6 to 9/10. It is noteworthy that the morphological similarity of the new species and H. jeonjuensis is not reflected in the DNA sequences (Figure 8). Phylogenetic analysis of the concatenated sequences (COI, H3 and ITS) shows that H. tenuiculus sp. nov. is monophyletic with respect to the other three species of Hemienchytraeus included in the analysis (Figure 8). However, the clade of the new species includes three branches, which suggests cryptic diversity within this morphospecies. For a detailed analysis see below (in the section on Molecular species delimitation).

Fridericia cf. loretensis Schmelz, 2003 (Figures 13, 14) Fridericia callosa (Eisén, 1872). Černosvitov 1937. Fridericia loretensis Schmelz, 2003. Material investigated GZO202106001–GZO202106002, stained and whole-mounted, two mature specimens from site 7, GZO202106003 stained and whole-mounted, one mature specimen from site 11. CJJ 99– CJJ 100, two mature specimens from site 7, CJJ 123– CJJ 124, two mature specimens from site 11, whole worm used for DNA extraction, preserved as total DNA. Description Small worms, white in stereomicroscope. Length 6.3–7.6 mm, diameter 0.22– 0.34 mm at VII, 0.23–0.4 mm at clitellum. Number of segments 36–46. Chaetae straight, without inner hook, formula 2–4 – 2–3: 4–6 – 2–5. A maximum of 6 per bundle, mostly 5 in ventral preclitellar bundles, the number of chaetae lower towards posterior body end (Figure 14d). Body wall 23–48 μm, cuticle thin. Epidermal gland cells 2–3 rows per segment, one at chaetal level, distinct, rectangular; the other two rows closely before or behind, cells few and scattered (Figure 14g). Brain elongated egg-shaped, anterior margin convex, posterior margin rounded, ca. twice as long as wide (153: 81 μm, in vivo) (Figures 13b, 14a). A pair of oesophageal appendages (Figure 13a) arising from ventral pharynx, free at IV/V, with short primary branches. Three pairs pharyngeal glands in IV – VI, in IV with wide dorsal connection and without ventral lobes; in V and VI dorsally separate and with ventral lobes, those in VI larger than those in V (Figures 13a, 14c). Five pairs preclitellar nephridia from 6/7–10/11, details not seen. Dorsal vessel from XVI–XVII, blood colourless. Coelomocytes two types, mucocytes numerous, with fine granulation and regular outline, diameter ca. 35 μm (in vivo); lenticytes small, millet-shaped. Chylus cells in XIII–XV, occupied about two segments. Clitellum girdle-shaped, well developed, gland cells in dense transverse rows, gland cells much taller (ca. 12.5–20 μm) than wide (ca. 3.8–7.5 μm); granulocytes rectangular, hyalocytes isolated from each other (Figure 14h, i). Seminal vesicle absent or very small. Head of spermatozoa ca. 83 μm (in vivo) (Figures 13c, 14e, f). Sperm funnel cylindrical, 164 μm long and 58 μm wide (funnel body) (in vivo), collar distinct, slightly narrower than funnel body, canal inconspicuous (Figures 13c, 14e, f). Vas deferens long and thin, diameter ca. 10 μm (in vivo), coiled irregularly in XIII. Glandular bulb of male copulatory organ hemispherical, ca. 73 μm long and 38 μm wide, with distinct musculature (Figure 14h). Bursal slit staple-shaped. No subneural glands . Spermathecae. Ectal pores laterally at 4/5, no ectal gland; ectal ducts ca. 12 μm wide and 171 μm long (in vivo), projecting proximally slightly into ampullae, projection nearly as wide as ectal duct. Ampullae without diverticula, distal part globular, diameter ca. 35 μm, thin-walled, sperm in a circle around projected ectal duct endpiece, proximal part cylindrical, 45 μm long and 16 μm wide, lumen small; proximal part of ampullae elongate, forming ental ducts, short, separate opening dorsally into oesophagus (Figures 13a, 14b). Remarks The original description of F. loretensis is based on preserved material from Argentina, first identified as F. callosa (Eisén) (Černosvitov 1937; Schmelz 2003). This is the first record of F. loretensis in China, and the first record of the species after the original description. Our specimens correspond well to the original description, but there are a number of slight differences, difficult to evaluate: smaller body size (length: 6.3–7.6 mm vs 10–11 mm, number of segment: 36–46 vs 51–54), fewer chylus cells (occupying 2 segments vs 3 ½ or 4 segments) and smaller glandular bulb (length: 73 μm vs 150–155 μm). Furthermore, dimensions in vivo and the texture of coleomocytes is unknown in F. loretensis. Due to these uncertainties, our identification remains tentative. In China, this species is also distributed in Guangxi, Yunnan, Jiangsu and Guizhou Provinces (J.J. Chen, unpublished data)., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1979-1982, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Schmelz RM. 2003. Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge. 38: 1 - 415.","Eisen G. 1872. Om nagra arktiska Oligochaeter. - Ofv. Kongl. Vetenskaps-Akad Forh. 1: 119 - 124.","Cernosvitov L. 1937. Notes sur les Oligochaeta (NaIdidees et Enchytraeidees) de l'Argentine. Ann Mus Argent. 39: 135 - 157."]}

Hemienchytraeus tenuiculus sp. nov. (Figures 6–8) Holotype Fully mature, whole-mounted specimen, stained, GZO202007012. Type locality Site 2. Soil and moss layer of Cyclobalanopsis glauca forest (108°42′58.7″E, 27°54′28.91″N), 2000 m asl, Fanjing Mountain, Guizhou, China, coll. Z.X. Zhang, Y.H. Ge and J.J. Chen, 25 December 2019. Paratypes GZO202007013, GZO20201010001, stained and whole-mounted, two mature specimens from the type locality, same data as holotype. CJJ81, CJJ125, CJJ126, CJJ130, four mature specimens from site 2, CJJ 82, one mature specimen from site 4, CJJ 83, one mature specimen from site I, CJJ 132, one mature specimen from site 8: seven specimens in total, whole worm used for DNA extraction, preserved as total DNA. Further material investigated One mature specimen from site 6, one mature specimen from site 10 and one mature specimen from site 12: three specimens in total, preserved in 75% ethanol. Etymology Named for the small and thin body. Diagnosis The species can be diagnosed by the following combination of characters: (1) worms small and thin; (2) each primary branch bifurcating into two secondary branches; (3) spermathecae extending to VII–VIII; (4) no secondary pharyngeal glands; (5) three pairs of preclitellar nephridia in 6/7–8/9; (6) dorsal vessel originating from postclitellar segments; (7) clitellum girdle-shaped. Description Small worms, transparent. Length 3.4–7.3 mm, diameter 0.12–0.21 mm at VII and 0.14– 0.23 mm at clitellum. Number of segments 30–43. Chaetae straight without inner hook, with slight proximal bend. Two chaetae per bundle throughout, absent in XII in mature worms (Figure 6a). Ventral chaetae in anterior region ca. 25–37.5 μm long and 5 μm thick, chaetae in caudal region somewhat increasing in size, ca. 30–50 μm long and 5–6.5 μm thick. Lateral chaetae almost of equal size throughout, ca. 25–30 μm long and 5 μm thick. Head pore on prostomium mid-dorsally (Figure 6a). Body wall 18–23 μm thick (in vivo), cuticle thin. Epidermal gland cells inconspicuous, 3–4 rows per segment, nearly rectangular, parallel or at chaetal level (Figure 7c). Clitellum in XII–1/2XIII, scarcely thickening, girdle-shaped, hyalocytes and granulocytes in dense transverse rows (Figures 6a, 7i). Brain ca 1.5× as long as wide (95 μm long, 65 μm wide, in vivo), deeply concave anteriorly, weakly incised posteriorly (Figures 6a, 7a). Oesophageal appendage with unpaired root dorsally behind pharyngeal pad in III, root with large lumen, extending posteriad, bifurcating into two primary branches, with meandering canal; each primary branch bifurcating further into two longer and thinner secondary branches, with smaller canal (Figures 6a, b, 7b, e). Three pairs of pharyngeal glands, poorly developed, pharyngeal glands in IV united dorsally, small, without ventral lobes, in V and VI dorsally separate, with ventral lobes (Figures 6a, 7f). No secondary pharyngeal gland lobes. Dorsal vessel beginning behind clitellum (segment XIV), blood colourless. Three pairs of preclitellar nephridia from 6/7 to 8/9 (Figure 6a), each about 115 μm long and 42 μm wide (in vivo). Anteseptale globular, consisting of funnel and parts of nephridial body, with coils of canal, postseptale elongate, length ratio of anteseptale: postseptale ca 1:1.3. Efferent duct originating from the middle of postseptale. Coelomocytes elongate, elliptical, numerous, 34–42 μm long, 15–18 μm wide (in vivo) (Figure 7g). Seminal vesicle absent. Sperm funnel cylindrical, tapering distally, ca. 106 μm long and 36 μm wide at collar (in vivo). Collar indistinct, as wide as funnel body, canal conspicuous (Figures 6c, 7g). Spermatozoa sparse, short, ca. 150 μm long, head ca. 18 μm long (in vivo) (Figures 6c, 7g). Diameter of sperm ducts ca. 6 μm, long and coiling unregularly in XII (Figure 7h). Male copulatory organs muscular, male glandular body oval, ca. 55 μm long and 23 μm wide (Figure 6a). Spermathecae free, not attached to oesophagus. Ectal pores lateral at 4/5, without ectal glands. Ectal ducts muscular, short, ca. 54 μm long and 10 μm wide (in vivo), with distinct ampullar dilatations in V (ca. 12 μm in diameter, in vivo); ampullar connecting tubes thinner than ectal ducts (ca. 8 μm wide, in vivo), extending into VII or VIII, ending in ellipsoid ental reservoirs, ca. 92 μm long and 19 μm wide (in vivo), ental reservoirs thin-walled, with spermatozoa (Figures 6a, 7d). One mature egg at a time. Remarks Among Hemienchutraeus species, there are six members with the same bifurcate branching pattern of the oesphageal appendage: H. bifurcatus Nielsen and Christensen, 1959, H. csuzdii Dózsa-Farkas, 1989, H. jeonjuensis Dózsa-Farkas and Hong, 2010, H. planisetosus Xie et al., 1999, H. solimoensis Righi, 1978 and H. tanjae Schmelz et al., 2005. Among them, the new species is most similar to H. jeonjuensis in possessing three pairs of preclitellar nephridia from 6/7 to 8/9, spermathecae extending to VII–VIII, a girdle-shaped clitellum and the absence of a seminal vesicle. However, in H. jeonjuensis, there are two pairs of secondary pharyngeal glands in V and VI, respectively, and the dorsal vessel originates in preclitellar segments (X–XI). The new species resembles H. csuzdii in the absence of secondary pharyngeal glands and a seminal vesicle, and in the postclitellar origination of the dorsal vessel. Conspicuous morphological differences from H. csuzdii include a short spermatheca confined to V and the first pair of preclitellar nephridia in 5/6. Hemienchytraeus planisetosus, H. solimoensis and H. tanjae differ from the new species in their longer spermathecae, presence of secondary pharyngeal glands, and the number and position of preclitellar nephridia. The comparison of the new species with H. bifurcatus is difficult due to the lack of several key morphological traits in the original description of the latter; for example, nothing is known about the pharyngeal glands and the preclitellar nephridia. Schmelz et al. (2005) considered H. bifurcatus to be a species inquirenda since its type material is lost. Repeated attempts to collect specimens at the type locality have so far not been successful (Schmelz, unpublished data). However, it is unlikely that H. tenuiculus sp. nov. and H. bifurcatus are the same species: the segments are fewer in the latter, despite some overlap with the former (28–32), and its clitellum is said to be ‘strongly elevated’ (Nielsen and Christensen 1959), while it is flat in the new species. Another difference can be inferred from the original illustration of H. bifurcatus (Nielsen and Christensen 1959, fig. 27), which shows a brain with length:width ratio of 1:1. Furthermore, H. bifurcatus has been recorded only in Europe [Denmark, Germany and Poland (Schmelz and Collado 2010)]. Hemienchytraeus tenuiculus sp. nov. is also clearly different from two species included in the DNA sequence comparison (Figure 8), H. koreanus Dózsa-Farkas and Hong, 2010 and H. wuhanensis Chen et al., 2021. In both species each primary branch of the oesophageal appendage divides into more than two secondary branches. Furthermore, the two species have three pairs of secondary pharyngeal glands and five pairs of preclitellar nephridia, from 5/6 to 9/10. It is noteworthy that the morphological similarity of the new species and H. jeonjuensis is not reflected in the DNA sequences (Figure 8). Phylogenetic analysis of the concatenated sequences (COI, H3 and ITS) shows that H. tenuiculus sp. nov. is monophyletic with respect to the other three species of Hemienchytraeus included in the analysis (Figure 8). However, the clade of the new species includes three branches, which suggests cryptic diversity within this morphospecies. For a detailed analysis see below (in the section on Molecular species delimitation)., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1967-1973, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Nielsen CO, Christensen B. 1959. The Enchytraeidae. Critical revision and taxonomy of European species (Studies on Enchytraeidae VII). Natura Jutlandica 8 - 9: 1 - 160.","Dozsa-Farkas K. 1989. Neue Enchytraeiden-Arten (Oiigochaeta) aus Ekuador. Acta Zoologica Hungarica. 35 (3 - 4): 191 - 203.","Dozsa-Farkas K, Hong Y. 2010. Three new Hemienchytraeus species (Enchytraeidae, Oligochaeta, Annelida) from Korea, with first records of other enchytraeids and terrestrial polychaetes (Annelida). Zootaxa. 2406 (1): 29 - 56. https: // doi. org / 10.5281 / zenodo. 194222","Righi G. 1978. Notas sobre os Oligochaeta da Amazonia. Acta Amazoniana. 8 (3): 485 - 488. doi: 10. 1590 / 1809 - 43921978083485.","Schmelz RM Arslan N, Bauer R, Didden W, Dozsa-Farkas K, Graefe U, Panchenko I, Pokarzhevski A, Rombke J, Schlaghamersky J, et al. 2005. Estonian Enchytraeidae (Oligochaeta) 2. Results of a faunistic workshop held in May 2004. Proc Est Acad Sci Biol Ecol. 54 (4): 255 - 270. doi: 10.3176 / biol. ecol. 2005.4.02","Schmelz RM, Collado R. 2010. A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Org. 82: 1 - 176."]}

Fridericia sp. (Figures 15, 16) Material investigated GZO202010002, stained and whole-mounted, one mature specimen from site 1, GZO202010003, stained and whole-mounted, one mature specimen from site 7. CJJ 101, CJJ 122, two mature specimens from site 1, whole worm used for DNA extraction, preserved as total DNA. Further material investigated Five mature specimens from site 1, one mature specimen from site 7, one mature specimen from site 12, seven specimens in total, preserved in 75% ethanol. Description Small worms. Length 6–7 mm. Diameter 0.2–0.25 mm at VII, 0.24–0.3 mm at XII. Number of segments 39–46. Chaetae straight, without pronounced ental hook (a small bend is present), formula 2–4 – 2, 3: 3, 4 – 2–4. A maximum of 4 per bundle, mostly 4 in ventral preclitellar bundles, inner pair slightly thinner and shorter than outer pair, mostly 2 in posterior body half. Epidermal gland cells elongate, scattered in 3–4 rows per preclitellar segment, 4–5 cells in first row, followed by a second row with more cells. Body wall ca. 15 μm in thickness (in vivo). Clitellum girdle-shaped, cells arrangement almost reticulate, hyalocytes distinctly larger than granulocytes. Brain ovoid, anteriorly convex, posteriorly rounded. A pair of short, unbranched oesophageal appendages free in ventral part of IV–V (Figure 15a). Pharyngeal glands with dorsal connection present in IV, absent in V and VI. Ventral lobes absent in IV, largest in VI (Figures 15a, 16a). Four pairs of preclitellar nephridia, from 6/7–9/10, anteseptale ca. half as long as postseptale, medial origin of efferent duct. Coelomocytes. Mucocytes with refractile vesicles at the cell periphery, lenticytes milletshaped, scarce. Dorsal vesicle from XVIII, blood colourless. Chylus cells in XIII–XIV, occupying 2 segments (Figure 16d). Seminal vesicle absent. Sperm funnel cylindrical, tapering proximad, collar distinct, somewhat narrower than funnel body, ca. 143 μm long, 41 μm (at collar) and 53 μm (at funnel body) wide (in vivo) (Figures 15d, e, 16e, f). Spermatozoa ca. 150 μm (in vivo). Male copulatory organ medium-size, bursal slit staple-shaped. Subneural glands absent. Spermathecae without ectal gland; ectal ducts elongate (ca. 230 μm, in vivo), slightly projected into ampullae;ampullae without diverticula,onion-like, lumen large, containing sperm; proximal part elongate, forming ental ducts, adjacent or joint opening of the spermathecae into oesophagus dorsally (Figures 15b, c, 16b, c). Remarks The investigated specimens agree in almost all characters with Fridericia bretscheri Southern, 1907, especially when considering the redescriptions by Rota (1995) and Schmelz (2003). However, the absence of spermathecal ectal glands disagrees with the diagnosis of Fridericia bretscheri, where the gland is conspicuously large, its size being one of the key characters of the species. Furthermore, in our specimens postclitellar segments have predominantly 2 chaetae per bundle, while in F. bretscheri there are 4 or 3. The colour of epidermal gland cells and pattern of midventral clitellar gland cells are unknown in our specimens. Before erecting this species as new and different from F. bretscheri, we prefer to wait for more specimens from the Mt. Fanjing site to complete the description and for DNA sequences from European populations of F. bretscheri., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1982-1985, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Southern R. 1907. Oligochaeta of Lambay. Irish Nat J Dublin. 16: 68 - 82.","Rota E. 1995. Italian Enchytraeidae (Oligochaeta). I. Ital J Zool. 62: 183 - 231. doi: 10.1080 / 11250009509356067","Schmelz RM. 2003. Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge. 38: 1 - 415."]}

Henlea perpusilla Friend, 1911 (Figure 17) Henlea perpusilla Friend, 1911. Černosvitov 1937; Nielsen and Christensen 1959; Chalupský 1986; Kasprzak 1986; Rota and Healy 1994; Rota 1995; Rota et al. 1998; Wang et al. 1999; Schmelz and Collado 2010; Lu et al. 2018. Henlea brucei Stephenson, 1922. Henlea balcanica Černosvitov, 1930. Material investigated GZO202007008–GZO202007009, stained and whole-mounted, two mature specimens from site H. CJJ 87, one mature specimen from site 1, whole worm used for DNA extraction, preserved as total DNA. Further material investigated Six mature specimens and one immature specimen from site H, one mature specimen from site B, seven mature specimens from site 1, two mature specimens from site 7 and one mature specimen from site 12, 18 in total, preserved in 75% ethanol. Description Small worms. Length 5.7–10.4 mm (in vivo), diameter 0.32–0.43 mm at VII, 0.35–0.5 mm at clitellum (in vivo). Number of segments 26–39. Chaetae without inner hook, straight distally, slightly bent proximally, fan-shaped, short in the middle and long on the side. Chaetae formula 3–6 – (2)3–5: 4–6 (7,8) – 3–6. Body wall 12.5–25 μm thick, cuticle very thin (Epidermal gland cells rectangular, 2–3 rows per segment (Figure 17c). Clitellum at XII–1/2XIII, girdle-shaped, developed well, thickened both dorsally and ventrally, gland cells reticulate, hyalocytes in contact with each other (Figure 17h). Brain flat anteriorly and weakly concave posteriorly, ca. 130 μm long, 107 μm wide (in vivo) (Figure 17a). Pharyngeal glands 3 pairs in IV–VI, all separate dorsally (Figure 17d). Preclitellar nephridia 5 pairs, 6/7–10/11. Gut abruptly widened at 7/8, no intestine diverticulum (Figure 17e). Dorsal vessel rising in VIII, pulsating and conspicuous, blood pale (Figure 17e). Coelomocytes only mucocytes, finely and regularly vesicular, diameter 40–47 μm (in vivo). Chloragocytes yellowish, forming a thin layer on the intestine from VII. Seminal vesicle absent. Sperm funnel cylindrical, small, collar distinct, nearly as wide as funnel body. Length and width varies among specimens, 49–108 μm long, 35–50 μm wide (in vivo), ca 1.4–2.1 × as long as wide (Figure 17g, i). Vas deferens long, coiled irregular, diameter 6.5 μm (in vivo). Spermathecae without ectal gland. Ectal pores lateral at 4/5; ectal ducts muscular, short, 55.3 μm long, 24.5 μm wide; ampullae spindle-shaped, thiner than ectal ducts, 110.9 μm long, 18.6 μm wide (in vivo); ental ducts narrower than ampullae, united before attachment to oesophagus in V (Figure 17b). 1–2 mature eggs at a time, occupying 1–3 segments (Figure 17f). Remarks This species is common and widespread around the world. In China, the worms have been found in Hunan, Jilin, Gansu, Yunnan, Xinjiang, Guizhou Provinces and Tibet (J.J. Chen, unpublished data). K2P distances were calculated based on COI sequences: high genetic distances were shown between our species and H. perpusilla from Sweden (Erséus et al. 2010) (18.2%), H. perpusilla from Svalbard (Dózsa-Farkas et al. 2015) (16.0%) and H. perpusilla from Switzerland (Vivien et al. 2015) (18.2%). Henlea perpusilla is probably a species complex, containing several species., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1985-1987, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Friend H. 1911. New British Henleas. Zool Ser. 4 (15): 464 - 468.","Cernosvitov L. 1937. Notes sur les Oligochaeta (NaIdidees et Enchytraeidees) de l'Argentine. Ann Mus Argent. 39: 135 - 157.","Nielsen CO, Christensen B. 1959. The Enchytraeidae. Critical revision and taxonomy of European species (Studies on Enchytraeidae VII). Natura Jutlandica 8 - 9: 1 - 160.","Chalupsky J. 1986. Czechoslovak enchytraeids (Oligochaeta, Enchytraeidae) I. Enchytraeids from an apple orchard by Bavorov in South Bohemia. Vestnik Ceskoslovenske spolecnosti zoologicke. 50: 13 - 21.","Kasprzak K. 1986. Skaposzczety wodne i glebowe, II. Rodzina: wazonkowce (Enchytraeidae). Polska Akademia Nauk Instytut Zoologii, Warszawa. 366.","Rota E, Healy B. 1994. The enchytraeid fauna of North Africa. Hydrobiologia. 278 (1 - 3): 53 - 66. doi: 10. 1007 / BF 00142311.","Rota E. 1995. Italian Enchytraeidae (Oligochaeta). I. Ital J Zool. 62: 183 - 231. doi: 10.1080 / 11250009509356067","Rota E, Healy B, Erseus C. 1998. Biogeography and taxonomy of terrestrial Enchytraeidae (Oligochaeta) in Northern Sweden, with comparative remarks on the genus Henlea. Zool Anz. 237: 155 - 169.","Wang HZ, Xie ZC, Liang YL. 1999. Records of Enchytraeidae (Clitellata) from the People's Republic of China. Hydrobiologia. 406: 57 - 66. doi: 10.1023 / A: 1003732116567.","Schmelz RM, Collado R. 2010. A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Org. 82: 1 - 176.","Lu YJ, Xie ZC, Zhang JQ. 2018. Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China. Zootaxa. 4496 (1): 395 - 410. doi: 10.11646 / zoo taxa. 4496.1.29.","Stephenson J (1922) The Oligochaeta of the Oxford University Spitsbergen expedition. Proceedings of the Zoological Society of London, 74, 1109 - 1138. 10.1111 / j. 1469 - 7998.1922. tb 07096. x","Cernosvitov L. 1930. Zur Kenntnis der Oligochatenfauna des Balkans. I. Uber die Oligochaten aus Bosnien. Zool Anz. 86: 319 - 333.","Erseus C, Rota E, Matamoros L, Wit PD. 2010. Molecular phylogeny of Enchytraeidae (Annelida, Clitellata). Mol Phylogenet Evol. 57 (2): 849 - 858. doi: 10.1016 / j. ympev. 2010.07.005.","Dozsa-Farkas K, Felfoldi T, Hong Y. 2015. New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea. Zootaxa. 4006 (1): 171 - 197. doi: 10.11646 / zootaxa. 4006.1.9.","Vivien E, Wyler S, Lafont M, Pawlowski J. 2015. Molecular barcoding of aquatic oligochaetes implications for biomonitoring. PLoS ONE. 10 (4): 1 - 15. https: // journals. plos. org / plosone / article / file? id = 10.1371 / journal. pone. 0125485 & type = printable"]}

Xetadrilus prolixglandus sp. nov. (Figures 2–5) Holotype Fully mature, whole-mounted specimen, stained, GZO202007003. Type locality Site I. Soil and moss layer of Cyclobalanopsis glauca, Pinus taiwanensis and Eurya japonica mixed forest (108°39′ 24.79°E, 27°54′ 43.15°N), 1970 m asl, Fanjing Mountain, Guizhou, China, coll. Z.X. Zhang, X.K. Jiang and J.J. Chen, 25 July 2019. Paratypes GZO202007001, GZO202007002, stained and whole-mounted, two mature specimens from the type locality, same data as holotype. GZO202008001, GZO202008002, stained and whole-mounted, two mature specimens from site F. CJJ91, one mature specimen from site 1, whole worm used for DNA extraction, preserved as total DNA. Further material investigated One mature specimen from site C, nine mature specimens from site F, one mature specimen from site G, two specimens from site H, four specimens from site I; three mature specimens from site 1, three mature specimens from site 2, one mature specimen from site 3, one specimen from site 4, one specimen from site 5, one specimen from site 9, two specimens from site 10: 29 specimens in total, preserved in 75% ethanol. Etymology The Latin prefix ‘prolix-’ means extended and elongate; ‘prolixglandus’ refers to the elongation of the third pair of pharyngeal glands, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII. Diagnosis This new species can be diagnosed by the following combination of traits: (1) ventral chaetae in posterior segments enlarged, ca. 1.5× as large as anterior; (2) the third pair of pharyngeal glands elongate, with separate dorsal lobes in VI; (3) two pairs of secondary pharyngeal gland lobes in V–VI; (4) brown coelomocytes with refractile vesicles completely filled; (5) spermathecae free, confined to V; (6) epidermal gland cells distributed evenly; (7) gut widening gradually in VII, no intestinal diverticula; (8) two pairs of preclitellar nephridia in 7/8–8/9; (9) dorsal vessel originating from XII–XIII, blood colourless. Description Small-sized worms. Length 2.4–3.5 mm, diameter 0.07–0.17 mm in segment VII and 0.08– 0.22 mm in segment XII. Number of segments 23–28. Chaetae two per bundle, formula 2, 0–0: 2–2. Chaetae straight, with proximal bend. Lateral chaetae present in II–VII, absent from VIII on, ventral chaetae absent in XII in mature worms (Figure 2a). Ventral chaetae in preclitellar segments ca. 25–30 μm long and 2.5 μm thick (Figure 3d), increasing in size behind clitellum towards posterior end, ca. 32.5–45 μm long and 2.5–4 μm thick (ca. 1.5× as large as anterior). Prostomium with head pore in mid-dorsal position, slit transverse (Figure 2a). Epidermal gland cells grey, inconspicuous, cells almost round (diameter ca. 2.7–4 μm, in vivo) and evenly distributed in 7–8 separate transverse rows per segment (Figure 4d). Clitellum in XII–1/2XIII, conspicuous thickening, saddle-shaped, clitellum-free mid-ventral field as wide as distance between male pores. Cells in dense transverse rows, roughly rectangular, with hyalocytes (ca. 19–25 μm high and 11–13 μm wide, in vivo) larger than granulocytes (ca. 11–25 μm high and 7.5–10 μm wide, in vivo); with larger proportion of hyalocytes dorsally, and larger proportion of granulocytes laterally (Figures 2a, 4e, f). Body wall thin, 7–12 μm thick, cuticle in vivo). Brain about 2 × as long as wide (ca. 50 μm wide and 100 μm long, in vivo), incised posteriorly, sides converging anteriad (Figures 2a, b, 3a). A pair of prostomial ganglia present on prostomial nerves (Figures 2a, b, 3a). Pharyngeal glands with two unpaired dorsal lobes in IV and V, of almost the same size; primary ventral lobes in V, elongate; secondary ventral lobes in V and VI, spherical, smaller than primary ventral lobes. In VI–VII a pair of separate elongate lobes, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII (Figures 2a, 3c). Oesophageal appendage and intestinal diverticula absent. Gut widening gradually in VII (Figure 2a). Chloragocytes inconspicuous, from V, and dense from VII. Dorsal vessel originating from XII–XIII, blood colourless. Nephridia two pairs in preclitellar segments, at 7/8 and 8/9 (Figures 2a, 3e). Anteseptale with funnel and parts of nephridial body, funnel attached obliquely, anteseptale about 26 μm long and 22 μm wide (in vivo); postseptale larger than anteseptale (ca. 40 μm long and 26 μm wide, in vivo), with a dorsal bump in mid-section; nephridial canal apparently with up and down zig-zag course; efferent duct rising subterminally, nephroporus inconspicuous, situated anteriorly of ventral chaetal bundles, no terminal vesicle. Nephridia in postclitellar segments in varying positions. Coelomocytes one type, nucleate mucocytes slightly longer than wide ca. 17–24 μm long (in vivo); cells brownish in vivo, with small spherical and refractile vesicles (Figure 3f). Seminal vesicle absent. Spermatozoa conspicuous at the opening of sperm funnel, ca. 40 μm long, head ca. 14 μm long (in vivo) (Figure 2a, c). Sperm funnel pear-shaped, with distinct collar, not or only a little wider than funnel body; sperm funnel small, ca. 40 μm long and 26 μm (at collar) wide (in vivo) (Figures 2a, c, 4a). Vas deferens in loose or dense coils ventro-laterally, diameter ca. 5 µm (in vivo) (Figures 2a, 4c). Male copulatory organ inconspicuous, glandular bulb with musculature (Figures 2a, 4f), roughly spherical, ca. 32 μm in diameter (in vivo). No accessory copulatory glands. Spermathecae free, not attached to oesophagus, like a proximally blind-ending tube, confined to V; ectal pores lateral at 4/5, without ectal glands, ectal ducts short (64 µm long, 10 µm wide, in vivo), ampullae wider than ectal ducts (28 µm long, 16 µm wide, in vivo) with thin wall, empty or with spermatozoa (Figures 2a, 3b). Two mature eggs at a time, occupying 3–4 segments (Figures 2a, 4b). Remarks The new species is most similar to Xetadrilus maacki Schmelz, 2011, which also has two pairs of preclitellar nephridia, brown coelomocytes, spermathecae confined to V and intestine widened in VII. However, in X. maacki the pharyngeal glands are dorsally united in VI and there are three pairs of secondary ventral lobes in V–VII. Further conspicuous differences of X. maacki from the new species include sigmoid chaetae in posterior segments and epidermal gland cells only mid-ventrally. A comparison of X. prolixglandus sp. nov. with similar species is presented in Table 4. Molecular analyses confirm that X. prolixglandus sp. nov. is a species distinct from other Xetadrilus species for which sequences are currently available, since its sequences form distinct lineages on the phylogenetic trees based on the COI region (Figure 5). However, our analysis is limited by the lack of sequence data for other species of Xetadrilus., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1962-1967, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Schmelz RM, Collado R, Rombke J. 2011. Mata Atlantica enchytraeids (Parana, Brazil): a new genus, Xetadrilus gen. nov., with three new species, and four new species of Guaranidrilus Cernosvitov (Enchytraeidae, Oligochaeta). Zootaxa. 2838 (1): 1 - 29. doi: 10.11646 / zootaxa. 2838.1.1."]}

Enchytraeus sp., buchholzi group (Enchytraeus buchholzi; Vejdovský, 1879) (Figures 11, 12) = Enchytraeus florentinus Bell, 1947 = Enchytraeus polonicus Dumnicka, 1977 Enchytraeus buchholzi Vejdovsky, 1879; Nielsen and Christensen, 1959; Dash 1970; Chalupský 1992; Rota and Healy 1994; Rota 1995; Schmelz et al. 2005; Schmelz and Collado 2010. Material investigated CJJ 95, one submature specimen from site 7, whole worm used for DNA extraction, preserved as total DNA. One submature specimen from site H and two submature specimens from site 7, preserved in 75% ethanol. Description Small worms, yellowish white in stereomicroscope. Length ca. 3.3–5.0 mm (in vivo), 1.8– 2.8 mm, wide 122.5–180.0 μm in segment VII and 125–200 μm in clitellum. Number of segments 24–25. Chaetae straight, with ental hook, formula: 2–2, 3: (2) 3–3 (2). Head pore at 0/1, transverse slit (Figure 11a). Epidermal gland cells grey, inconspicuous, 4–5 transverse rows per segment. Clitellum in XII–1/2XIII, saddle-shaped, hardly elevated, not fully developed (our specimens are all submature). Body wall ca. 15–26 μm thick (in vivo). Brain trapezoidal, truncate anteriorly and round posteriorly, ca. 124 μm long, 46 μm wide anteriorly and 86 μm wide posteriorly (in vivo) (Figures 11b, 12a). Oesophageal appendages a pair of unbranched tubes with common opening leading dorsally into oesophagus in III, behind pharyngeal pad, tubes extending into IV with meandering cannel (Figures 11a, 12b). All three pairs of pharyngeal glands separated dorsally, pharyngeal gland in VI elongate, with a small constriction at septum (Figures 11a, 12d). Dorsal vessel from XII–XIII, blood colourless. Intestinal diverticula absent, gut widening gradually. Chloragocytes well developed, large and with retractile globules of differing size, present from V and forming a dense layer from segment VII onward, absent in XII (Figures 11a, 12e). Four pairs of preclitellar nephridia from 6/7–9/10, anteseptale with funnel only. Coelomocytes one type, mucocytes, with refractile granula. Seminal vesicle absent. Spermatozoa sparse, ca. 37 μm long and head ca. 15 μm long (in vivo) (Figures 11c, 12f). Sperm funnel cylindrical, small, length about 1/4 body diameter (ca. 33 μm long and 17 μm wide, in vivo), with distinct midline, collar little wider than funnel body (Figures 11c, 12f). Vas deferens long, in tangled coils ventro-laterally, diameter ca. 6 µm (in vivo) (Figure 12f). Male copulatory organ small, globular, not floppy. Spermathecae short, confined to V; ectal pores lateral at 4/5, surrounded by several glands at each pore, glands of varying size, sometimes stretching along ectal duct; ectal ducts ca. 52 μm long and 9 μm wide (in vivo); ampullae spindle-shaped, ca. 43 μm long (in vivo), almost with same diameter as ectal ducts; ental ducts short and narrow; spermathecae attached to oesophagus separately (Figures 11a, 12c, d). No mature eggs observed. Remarks Using the key for European species in Schmelz and Collado (2010), specimens key out as E. buchholzi Vejdovský, 1878, based on the following characters: chaetal formula 2–2, 3: 3–3, oesophageal appendage with meandering canals, four pairs preclitellar nephridia, in 6/7 to 9/10, clitellum saddle-shaped, testis sac, sperm funnel and male glandular bulb small, spermathecal ectal glands covering only ectal part of ectal duct, ampulla small, ental duct present. Enchytraeus buchholzi is a species complex (Rota and Healy 1994; Rota 1995; Schmelz et al. 2005). Descriptions of this species sensu lato usually distinguish two forms based on the texture of the coelomocytes: with or without refractile granula (Schmelz et al. 2005). Specimens from Mount Fanjing have coelomocytes with refractile granules. All specimens are submature, i.e. without eggs or a fully developed clitellum. This record documents the presence of E. buchholzi sensu lato at Mt. Fanjing. It is unknown whether the specimens underlying this account belong to one or more species. In China, E. buchholzi has also been recorded fromMount Changbai, Jilin Province (J.J. Chen, unpublished data). The K2P distances based on COI sequences also confirm the complexity of E. buchholzi. The genetic distance between our specimens and E. buchholzi - Russia (Erséus et al. 2010), E. buchholzi - Switzerland (Vivien et al. 2015) and E. buchholzi - India (GenBank accession number: KX348269) are 18.7%, 20.7% and 19.9%, respectively. However, we failed to match molecular differences to morphological differences because of the lack of morphological descriptions., Published as part of Chen, Juanjuan, Schmelz, Rüdiger M., Zhang, Zuxu & Xie, Zhicai, 2022, The enchytraeid fauna (Enchytraeidae: Clitellata) of the Fanjing Mountain National Nature Reserve (China) with description of two new species, pp. 1957-1996 in Journal of Natural History 56 on pages 1975-1979, DOI: 10.1080/00222933.2022.2140085, http://zenodo.org/record/7426634, {"references":["Vejdovsky F. 1879. Beitrage zur vergleichenden Morphologie der Anneliden. I. Monographie der Enchytraeiden. Verlag von Friedrich Tempsky. 61.","Bell AW. 1947. Some new enchytraeids (Oligochaeta) from the old world. Trans Am Microsc Soc. 66 (2): 190 - 202. doi: 10.2307 / 3223250.","Dumnicka E. 1977. Enchytraeus polonicus sp. n., a new species of Enchytraeidae (Oligochaeta) from a cave in the Krakow-Czestochowa Upland. Bulletin de l'Academie Polonaise des Sciences, Serie des sciences biologiques Classe II. 25: 163 - 166.","Nielsen CO, Christensen B. 1959. The Enchytraeidae. Critical revision and taxonomy of European species (Studies on Enchytraeidae VII). Natura Jutlandica 8 - 9: 1 - 160.","Dash MC. 1970. A taxonomic study of Enchytraeidae (Oligochaeta) from Rocky Mountain forest soils of the Kananaskis region of Alberta, Canada. Can J Zool. 48 (6): 1429 - 1435. doi: 10.1139 / z 70 - 242.","Chalupsky J. 1992. Terrestrial Enchytraeidae (Oligochaeta) and Parergodrilidae (Polychaeta) from Sweden, with description of a new enchytraeid species. Zool Scr. 21 (2): 133 - 150. doi: 10.1111 / j. 1463 - 6409.1992. tb 00316. x.","Rota E, Healy B. 1994. The enchytraeid fauna of North Africa. Hydrobiologia. 278 (1 - 3): 53 - 66. doi: 10. 1007 / BF 00142311.","Rota E. 1995. Italian Enchytraeidae (Oligochaeta). I. Ital J Zool. 62: 183 - 231. doi: 10.1080 / 11250009509356067","Schmelz RM Arslan N, Bauer R, Didden W, Dozsa-Farkas K, Graefe U, Panchenko I, Pokarzhevski A, Rombke J, Schlaghamersky J, et al. 2005. Estonian Enchytraeidae (Oligochaeta) 2. Results of a faunistic workshop held in May 2004. Proc Est Acad Sci Biol Ecol. 54 (4): 255 - 270. doi: 10.3176 / biol. ecol. 2005.4.02","Schmelz RM, Collado R. 2010. A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Org. 82: 1 - 176.","Erseus C, Rota E, Matamoros L, Wit PD. 2010. Molecular phylogeny of Enchytraeidae (Annelida, Clitellata). Mol Phylogenet Evol. 57 (2): 849 - 858. doi: 10.1016 / j. ympev. 2010.07.005.","Vivien E, Wyler S, Lafont M, Pawlowski J. 2015. Molecular barcoding of aquatic oligochaetes implications for biomonitoring. PLoS ONE. 10 (4): 1 - 15. https: // journals. plos. org / plosone / article / file? id = 10.1371 / journal. pone. 0125485 & type = printable"]}

Xetadrilus prolixglandus sp. nov. (Figures 2–5) Holotype Fully mature, whole-mounted specimen, stained, GZO202007003. Type locality Site I. Soil and moss layer of Cyclobalanopsis glauca, Pinus taiwanensis and Eurya japonica mixed forest (108°39′ 24.79°E, 27°54′ 43.15°N), 1970 m asl, Fanjing Mountain, Guizhou, China, coll. Z.X. Zhang, X.K. Jiang and J.J. Chen, 25 July 2019. Paratypes GZO202007001, GZO202007002, stained and whole-mounted, two mature specimens from the type locality, same data as holotype. GZO202008001, GZO202008002, stained and whole-mounted, two mature specimens from site F. CJJ91, one mature specimen from site 1, whole worm used for DNA extraction, preserved as total DNA. Further material investigated One mature specimen from site C, nine mature specimens from site F, one mature specimen from site G, two specimens from site H, four specimens from site I; three mature specimens from site 1, three mature specimens from site 2, one mature specimen from site 3, one specimen from site 4, one specimen from site 5, one specimen from site 9, two specimens from site 10: 29 specimens in total, preserved in 75% ethanol. Etymology The Latin prefix ‘prolix-’ means extended and elongate; ‘prolixglandus’ refers to the elongation of the third pair of pharyngeal glands, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII. Diagnosis This new species can be diagnosed by the following combination of traits: (1) ventral chaetae in posterior segments enlarged, ca. 1.5× as large as anterior; (2) the third pair of pharyngeal glands elongate, with separate dorsal lobes in VI; (3) two pairs of secondary pharyngeal gland lobes in V–VI; (4) brown coelomocytes with refractile vesicles completely filled; (5) spermathecae free, confined to V; (6) epidermal gland cells distributed evenly; (7) gut widening gradually in VII, no intestinal diverticula; (8) two pairs of preclitellar nephridia in 7/8–8/9; (9) dorsal vessel originating from XII–XIII, blood colourless. Description Small-sized worms. Length 2.4–3.5 mm, diameter 0.07–0.17 mm in segment VII and 0.08– 0.22 mm in segment XII. Number of segments 23–28. Chaetae two per bundle, formula 2, 0–0: 2–2. Chaetae straight, with proximal bend. Lateral chaetae present in II–VII, absent from VIII on, ventral chaetae absent in XII in mature worms (Figure 2a). Ventral chaetae in preclitellar segments ca. 25–30 μm long and 2.5 μm thick (Figure 3d), increasing in size behind clitellum towards posterior end, ca. 32.5–45 μm long and 2.5–4 μm thick (ca. 1.5× as large as anterior). Prostomium with head pore in mid-dorsal position, slit transverse (Figure 2a). Epidermal gland cells grey, inconspicuous, cells almost round (diameter ca. 2.7–4 μm, in vivo) and evenly distributed in 7–8 separate transverse rows per segment (Figure 4d). Clitellum in XII–1/2XIII, conspicuous thickening, saddle-shaped, clitellum-free mid-ventral field as wide as distance between male pores. Cells in dense transverse rows, roughly rectangular, with hyalocytes (ca. 19–25 μm high and 11–13 μm wide, in vivo) larger than granulocytes (ca. 11–25 μm high and 7.5–10 μm wide, in vivo); with larger proportion of hyalocytes dorsally, and larger proportion of granulocytes laterally (Figures 2a, 4e, f). Body wall thin, 7–12 μm thick, cuticle in vivo). Brain about 2 × as long as wide (ca. 50 μm wide and 100 μm long, in vivo), incised posteriorly, sides converging anteriad (Figures 2a, b, 3a). A pair of prostomial ganglia present on prostomial nerves (Figures 2a, b, 3a). Pharyngeal glands with two unpaired dorsal lobes in IV and V, of almost the same size; primary ventral lobes in V, elongate; secondary ventral lobes in V and VI, spherical, smaller than primary ventral lobes. In VI–VII a pair of separate elongate lobes, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII (Figures 2a, 3c). Oesophageal appendage and intestinal diverticula absent. Gut widening gradually in VII (Figure 2a). Chloragocytes inconspicuous, from V, and dense from VII. Dorsal vessel originating from XII–XIII, blood colourless. Nephridia two pairs in preclitellar segments, at 7/8 and 8/9 (Figures 2a, 3e). Anteseptale with funnel and parts of nephridial body, funnel attached obliquely, anteseptale about 26 μm long and 22 μm wide (in vivo); postseptale larger than anteseptale (ca. 40 μm long and 26 μm wide, in vivo), with a dorsal bump in mid-section; nephridial canal apparently with up and down zig-zag course; efferent duct rising subterminally, nephroporus inconspicuous, situated anteriorly of ventral chaetal bundles, no terminal vesicle. Nephridia in postclitellar segments in varying positions. Coelomocytes one type, nucleate mucocytes slightly longer than wide ca. 17–24 μm long (in vivo); cells brownish in vivo, with small spherical and refractile vesicles (Figure 3f). Seminal vesicle absent. Spermatozoa conspicuous at the opening of sperm funnel, ca. 40 μm long, head ca. 14 μm long (in vivo) (Figure 2a, c). Sperm funnel pear-shaped, with distinct collar, not or only a little wider than funnel body; sperm funnel small, ca. 40 μm long and 26 μm (at collar) wide (in vivo) (Figures 2a, c, 4a). Vas deferens in loose or dense coils ventro-laterally, diameter ca. 5 µm (in vivo) (Figures 2a, 4c). Male copulatory organ inconspicuous, glandular bulb with musculature (Figures 2a, 4f), roughly spherical, ca. 32 μm in diameter (in vivo). No accessory copulatory glands. Spermathecae free, not attached to oesophagus, like a proximally blind-ending tube, confined to V; ectal pores lateral at 4/5, without ectal glands, ectal ducts short (64 µm long, 10 µm wide, in vivo), ampullae wider than ectal ducts (28 µm long, 16 µm wide, in vivo) with thin wall, empty or with spermatozoa (Figures 2a, 3b). Two mature eggs at a time, occupying 3–4 segments (Figures 2a, 4b). Remarks The new species is most similar to Xetadrilus maacki Schmelz, 2011, which also has two pairs of preclitellar nephridia, brown coelomocytes, spermathecae confined to V and intestine widened in VII. However, in X. maacki the pharyngeal glands are dorsally united in VI and there are three pairs of secondary ventral lobes in V–VII. Further conspicuous differences of X. maacki from the new species include sigmoid chaetae in posterior segments and epidermal gland cells only mid-ventrally. A comparison of X. prolixglandus sp. nov. with similar species is presented in Table 4. Molecular analyses confirm that X. prolixglandus sp. nov. is a species distinct from other Xetadrilus species for which sequences are currently available, since its sequences form distinct lineages on the phylogenetic trees based on the COI region (Figure 5). However, our analysis is limited by the lack of sequence data for other species of Xetadrilus.

Fridericia paroniana Issel, 1904 Fridericia paroniana Issel, 1904. Issel 1905; Nielsen & Christensen 1959; Rota & Healy 1994; Rota 1994; Rota 1995; Xie et al., 1999a; Schmelz 2003; Schmelz & Collado 2010. Fridericia nielseni Dash, 1972. Fridericia maculata Issel ssp. macroglandulosa D��zsa-Farkas, 1989. For further synonymies see Schmelz (2003). Examined materia l. XZO201610001, XZ201610002, XZO20161003, ThREE FUllY maTURE SPEcimENS, FiXEd, STaiNEd, WhOlE mOUNT. MORE ThaN 10 SPEcimENS PRESERVEd iN 70% EThaNOl. Descriptions. Small SiZE. BOdY lENgTh 4���5 mm (4���9 mm iN ViVO). BOdY WidTh 200���250 ��m aT V, 270���330 ��m aT XII. SEgmENT NUmbER 40���45. ChaETaE STOUT, USUallY 2 PER bUNdlE. EPidERmal glaNd cEllS cONSPicUOUS, 2���3 ROWS PER SEgmENT. CliTEllUm aT XII���1 /2XIII, giRdlE-ShaPEd, gRaNUlOcYTES mORE NUmEROUS ThaN hYalOcYTES. BRaiN WEaklY cOVEX aNTERiORlY, ROUNd OR TRUNcaTE POSTERiORlY, 140���170 ��m lONg, 80���100 ��m WidE. OESOPhagEal aPPENdagES STOUT, UNbRaNchEd. ThREE PaiRS OF PhaRYNgEal glaNdS iN IV���VI, ThE FiRST PaiR WiTh dORSal cONNEcTiON. FiVE PaiRS OF PREcliTEllaR NEPhRidia FROm VI/VII���X/XI, aNTESEPTalE 43���48 ��m lONg, 20���26 ��m WidE, POSTSEPTalE 80���94 ��m lONg, 30���47 ��m WidE, EFFERENT dUcT aRiSiNg FROm ThE middlE OF ThE POSTSEPTalE. COElEmO-mUcOcYTES NUmEROUS, 22���36 ��m iN diamETER, lENTicYTES 8���12 ��m iN diamETER. ChYlUS cEllS iN XIV���XVI. DORSal blOOd VESSEl aRiSiNg FROm XVIII. BlOOd cOlORlESS. SPERm FUNNEl Small, cYliNdRical, 95���114 ��m lONg, 40���50 ��m WidE, cOllaR aS WidE aS OR SlighTlY NaRROWER ThaN FUNNEl bOdY, 40���45 ��m WidE. HEadS OF SPERmaTOZOa 45���55 ��m iN lENgTh. VaS dEFERENS 7���9 ��m WidE, iRREgUlaR WOUNd iN lOOP iN XII. BURSal SliT lONgiTUdiNal, SOmETimES ���T-ShaPE���. NO SUbNEURal glaNdS. SPERmaThEca laRgE, WiTh 1���2 laRgE, FlOPPY EcTal glaNdS. AmPUlla ShaPE VaRiOUS, WiTh 2 Sac-likE diVERTicUla, EcTal dUcT lONg, 155��� 173 ��m lONg, 10���13 ��m WidE. ENTal dUcTS cONNEcT SEPaRaTElY TO ThE OESOPhagUS. USUallY 1 OR 2 maTURE Egg aT a TimE. Differential diagnosis. OUR SPEcimENS cONFORm WEll TO ThE dEScRiPTiON OF F. paroniana giVEN bY SchmElZ (2003) aNd XiE et al. (1999a). ThiS SPEciES iS WidESPREad iNclUdiNg GERmaNY, DENmaRk, NEThERlaNdS, IRElaNd, AUSTRia, HUNgaRY, SPaiN, ITalY, AlgERia, TURkEY, NORTh AmERica aNd MOROccO. IN ChiNa, iT WaS FOUNd iN SichUaN, HUbEi, aNd JiliN PROViNcES aNd TibET., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 402-403, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Issel, R. (1904) Due nuove Fridericia. Atti della Societa Ligustica di Scienze Naturali e Geografiche, Genova, 15, 31 - 39.","Issel, R. (1905) Materiali per una fauna dell'Arcipelago Toscano. Isola d'Elba. III. Enchitreidi dell'Isola d'Elba. Annali Del Museo Civico Di Storia Naturale Di Genova, Series 3, 2, 5 - 8.","Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Rota, E. & Healy, B. (1994) The enchytraeid fauna of North Africa Hydrobiologia, 278, 53 - 66. https: // doi. org / 10.1007 / BF 00142311","Rota, E. (1995) Italian Enchytraeidae (Oligochaeta). I. Italian Journal of Zoology 62, 183 - 231. https: // doi. org / 10.1080 / 11250009509356067","Xie, Z. C., Liang, Y. L. & Wang, H. Z. (1999 a) Taxonomical studies on Fridericia (Enchytraeidae, Oligochaeta) along the Changjiang (Yangtze) Basin. Acta Hydrobiologica Sinica, 23 (Supplement), 158 - 163.","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176.","Dash, M. C. (1972). New Enchytraeidae (Oligochaeta) from the Penny Forest soil of British Columbia, Canada. Annales Zoologici Fennici, 9, 15 - 16.","Dozsa-Farkas, K. (1989) Fridericia Arten aus Marokko (Oligochaeta: Enchytraeidae). Acta Zoologica Hungarica, 35, 29 - 39."]}

Henlea perpusilla Friend, 1911 (FigURE 4G���J) Henlea perpusilla Friend, 1911. Černosvitov 1937; Nielsen & Christensen 1959; Chalupsk�� 1986; Kasprzak 1986; Rota & Healy 1994; Rota 1995; Rota et al. 1998; Wang et al. 1999; Schmelz & Collado 2010. Henlea brucei Stephenson, 1922. Henlea balcanica Černosvitov, 1930. Examined material. XZO201604001, XZO201604002, XZO201604003, ThREE adUlTS, FiXEd, STaiNEd aNd WhOlEmOUNTEd SPEcimENS. Description. BOdY lENgTh 5���6.4 mm (5���10 mm iN ViVO). SEgmENT NUmbER 30���38. BOdY WidTh 158���210 ��m aT V aNd 175���290 ��m aT XII (256���280 ��m aNd 340���460 ��m iN ViVO). ChaETaE FORmUla (2)3-5 ��� 3-5: 3-6,(7,8) ��� 2- 5,(7,8), STRaighT diSTallY, SlighTlY bENT PROXimallY. PREcliTEllaR EPidERmal glaNd cEllS cONSPicUOUS, abOUT 3 TRaNSVERSE ROWS PER SEgmENT. BRaiN iN II, WEaklY cONcaVE aNTERiORlY, SlighTlY iNciSEd OR TRUNcaTE POSTERiORlY, 120 ��m iN lENgTh aNd 94 ��m iN WidTh. ThREE PaiRS OF PhaRYNgEal glaNdS iN IV���VI, all WiThOUT dORSal cONNEcTiON. OESOPhagEal aPPENdagES PRESENT iN VI, WiThOUT bRaNchES. INTESTiNal diVERTicUla abSENT. GUT WidENiNg cONSPicUOUSlY aT VII/VIII (Fig. 4G, J). CliTEllUm ElEVaTEd cONSPicUOUSlY, aT XII���XIII, cEllS iN RETicUlaTE PaTTERN, hYalOcYTES iSOlaTEd (Fig. 4H). DORSal blOOd VESSEl FROm VIII. FiVE PaiRS OF PREcliTEllaR NEPhRidia iN VI/VII���X/XI. COElOmOcYTES abUNdaNT, ROUNd OR OVal, 22���26 ��m iN SiZE (Fig. 4G). SPERm FUNNEl Small, cYliNdRical, cOllaR NaRROWER ThaN FUNNEl bOdY, lENgTh 1.5��� 2 TimES aS lONg aS WidTh, 50���86 ��m iN lENgTh aNd 36���57 ��m iN WidTh (Fig. 4I). VaS dEFERENS lONg, WOUNd iN iRREgUlaR lOOPS iN XII. SEmiNal VESiclE WEll-dEVElOPEd, OccUPYiNg iN XI, SOmETimES EXTENdiNg FORWaRdS iNTO X. HEadS OF SPERmaTOZOa 25���30 ��m. SPERmaThEca iN V. NO EcTal glaNdS. EcTal dUcT 68���81 ��m lONg aNd 9���12 ��m WidE. AmPUlla WiThOUT diVERTicUla, SlighTlY WidER ThaN EcTal dUcT, 25���30 ��m lONg aNd 15 ��m WidE. ENTal dUcT 84���96 ��m iN lENgTh aNd 7���11 ��m iN WidTh, UNiTEd PROXimallY aNd cONNEcTiNg JOiNTlY WiTh OESOPhagUS dORSallY iN VI. USUallY 1 OR 2 maTURE EggS aT a TimE. Differential diagnosis. OUR SPEcimENS cONFORm WEll TO ThE dEScRiPTiON OF Henlea perpusilla (ROTa 1995, SchmElZ & COlladO 2010). ThiS SPEciES iS WidESPREad iNclUdiNg iN AmERica, EUROPE aNd ThE ANTaRcTic. IN ChiNa, ThE WORmS WERE FOUNd iN GUiZhOU, HUNaN, JiliN PROViNcES aNd TibET., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 403-405, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Friend, H. (1911) New British Henleas. The Zoologist, Series 4, 15, 464 - 468.","Cernosvitov, L. (1937) Zur Kenntnis der Enchytraeiden. III. Revision der Friendschen Enchytraeidentypen. Zoologischer Anzeiger, 117, 191 - 205.","Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Chalupsky, J. (1986) Czechoslovak enchytraeids (Oligochaeta, Enchytraeidae) I. Enchytraeids from an apple orchard by Bavorov in South Bohemia. Vestnik Ceskoslovenske spolecnosti zoologicke, 50, 13 - 21.","Kasprzak, K. (1986) Skaposzczety wodne i glebowe, II. Rodzina: Wazonkowce (Enchytraeidae). Polska Akademia Nauk Instytut Zoologii, Warszawa, 366 pp.","Rota, E. & Healy, B. (1994) The enchytraeid fauna of North Africa Hydrobiologia, 278, 53 - 66. https: // doi. org / 10.1007 / BF 00142311","Rota, E. (1995) Italian Enchytraeidae (Oligochaeta). I. Italian Journal of Zoology 62, 183 - 231. https: // doi. org / 10.1080 / 11250009509356067","Rota, E., Healy, B. & Erseus, C. (1998) Biogeography and taxonomy of terrestrial Enchytraeidae (Oligochaeta) in Northern Sweden, with comparative remarks on the genus Henlea. Zoologischer Anzeiger, 237, 155 - 169.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176.","Stephenson, J. (1922) The Oligochaeta of the Oxford University Spitsbergen expedition. Proceedings of the Zoological Society of London, 74, 1109 - 1138. https: // doi. org / 10.1111 / j. 1469 - 7998.1922. tb 07096. x","Cernosvitov, L. (1930) Zur Kenntnis der Oligochatenfauna des Balkans. I. Uber die Oligochaten aus Bosnien. Zoologischer Anzeiger, 86, 319 - 333."]}

Fridericia bulboides Nielsen & Christensen, 1959 (FigURE 3A) Fridericia bulboides Nielsen & Christensen, 1959. Christensen 1961; Dash 1970; M��ller 1971; Kasprzak 1979; Chaluspk�� 1986; Kasprzak 1986; Rota 1994; Rota & Healy 1994; Rota 1995; Wang et al. 1999; Schmelz 2002, 2003; Schmelz & Collado 2010. Examined material. XZO201604007, XZO201604008, TWO FUllY maTURE SPEcimENS, WhOlE-mOUNTEd aNd STaiNEd. SiXTEEN FUll maTURE SPEcimENS iN 70% EThaNOl. Description. Small SPEciES. BOdY lENgTh 4���5 mm (6.4���9.2 mm iN ViVO). SEgmENT NUmbER 28���31. ChaETaE USUallY 2���4 PER bUNdlE. ChaETaE FORmUla: 2-4 ��� 2-4: 3,4 ��� 2-4. EPidERmal glaNd cEllS cONSPicUOUS iN PREcliTEllaR REgiON, ONE TRaNSVERSE ROW PER SEgmENT (Fig. 3A). CliTEllUm ElEVaTEd cONSPicUOUSlY, giRdlE-ShaPEd. BRaiN 152���160 ��m iN lENgTh, 75���98 ��m iN WidTh, SlighTlY cONcaVE aNTERiORlY, TRUNcaTE POSTERiORlY. OESOPhagEal aPPENdagES UNbRaNchEd, lONg, USUallY cOilEd iNTO a maSS iN IV/V, ThEN EXTENdiNg backWaRdS iNTO VI OR VII. ThREE PaiRS OF PhaRYNgEal glaNdS iN IV���VI; FiRST PaiR WiTh dORSal cONNEcTiON, SEcONd aNd ThiRd PaiR WiTh VENTRal lObES. FiVE PaiRS OF PREcliTEllaR NEPhRidia FROm VI/VII TO X/XI. ANTESEPTalE 26���31 ��m lONg, 16���18 ��m WidE, POSTSEPTalE 62���68 ��m lONg, 20���32 Um WidE, EFFERENT dUcT RiSiNg mEdiallY OR clOSE TO SEPTUm. MUcOcYTES WiThOUT REFRacTilE VESiclES, 30��� 37 ��m iN diamETER. LENTicYTES ScaRcE. ChYlUS cEllS iN XIII���XIV. DORSal blOOd VESSEl RiSiNg FROm XIV���XVII. BlOOd cOlORlESS. CliTEllUm aT XII���1 /2XIII, WEll-dEVElOPEd, giRdlE-ShaPEd. SPERm FUNNEl 2���3 TimES aS lONg aS WidE, 82���87 ��m iN lENgTh aNd 33���38 ��m iN WidTh. COllaR aS WidE aS FUNNEl bOdY, abOUT 30���35 ��m WidE. HEad OF SPERmaTOZOa abOUT 80 ��m lONg. VaS dEFERENS ThiN aNd lONg, 5���8 ��m WidE, WOUNd iN iRREgUlaR lOOPS iN XII. BURSal SliT lONgiTUdiNal. SUbNEURal glaNdS abSENT. SPERmaThEca iN V, WiTh a ball-ShaPEd EcTal glaNd, 15���19 ��m iN diamETER. EcTal dUcT 112���124 ��m lONg aNd 10���12 ��m WidE. AmPUlla ONiON-ShaPEd, WiThOUT diVERTicUla, diamETER 26���29 ��m, 2���3 TimES WidER ThaN EcTal dUcT. Differential diagnosis. ThE mORPhOlOgical chaRacTERS OF OUR SPEcimENS cORRESPONd WEll TO ThE dEScRiPTiON giVEN bY SchmElZ (2003), EXcEPT FOR ThE SiZE OF ThE FUNNEl cOllaR (aS WidE aS VS. NaRROWER ThaN FUNNEl bOdY). IN ChiNa, ThE WORmS WERE FOUNd iN HUbEi, YUNNaN, JiNliN PROViNcES aNd TibET., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on page 399, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Christensen, B. (1961) Studies on cyto - taxonomy and reproduction in the Enchytraeidae. Hereditas, 47, 387 - 449. https: // doi. org / 10.1111 / j. 1601 - 5223.1961. tb 01782. x","Dash, M. C. (1970) A taxonomic study of Enchytraeidae (Oligochaeta) from Rocky Mountain forest soils of the Kananaskis region of Alberta, Canada. Canadian Journal of Zoology, 48, 1429 - 1435. https: // doi. org / 10.1139 / z 70 - 242","Moller, F. (1971) Systematische Untersuchungen an terricolen Enchytraeiden einiger Grunlandstandorte im Bezirk Potsdam. Mitteilungen aus dem Zoologischen Museum in Berlin, 47, 131 - 167. https: // doi. org / 10.1002 / mmnz. 19710470114","Kasprzak, K. (1979) Skaposzczety (Oligochaeta) Pienin. I. Wazonkowce (Enchytraeidae). Fragmenta faunistica, Warszawa, 24, 7 - 56. https: // doi. org / 10.3161 / 00159301 FF 1979.24.1.007","Kasprzak, K. (1986) Skaposzczety wodne i glebowe, II. Rodzina: Wazonkowce (Enchytraeidae). Polska Akademia Nauk Instytut Zoologii, Warszawa, 366 pp.","Rota, E. & Healy, B. (1994) The enchytraeid fauna of North Africa Hydrobiologia, 278, 53 - 66. https: // doi. org / 10.1007 / BF 00142311","Rota, E. (1995) Italian Enchytraeidae (Oligochaeta). I. Italian Journal of Zoology 62, 183 - 231. https: // doi. org / 10.1080 / 11250009509356067","Schmelz, R. M. (2002) Records and taxonomy of Fridericia species found in the Mols area. Natura Jutlandica Occasional Papers, 2, 75 - 85.","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176."]}

Mesenchytraeus spermatoglomeratus sp. nov. (Figures 1, 2, Tables 1, 3) Holotype. Fully mature, whole-mounted specimen, stained, JLO201412005. Type locality. Mt. Changbai, Jilin Province, hardwood forest, 42°180.607''N, 127°50.453''E, 1034 m asl, dark brown forest soil under Quercus mongolica, coll. Z. J. Piao, Dec. 2014. Paratypes. JLO201412003–JLO201412004, two whole mounted adult specimens from Korean pine broadleaved mixed forest, 42°20.150''N, 127°53.056''E, 1084 m asl, dark brown forest soil under Pinus koraiensis, 10 December 2014, coll. Z. J. Piao; JLO201412006, one whole mounted adult specimen from type locality, same data as holotype. JLO201503001–JLO201503002, two whole mounted specimens, fully mature, from secondary Betula platyphylla forest, 42°22.719''N, 128°01.020''E, 786 m asl, dark brown forest soil under Betula platyphylla, 2 April 2015, coll. Z. J. Piao. Etymology. Named after the shape of sperm bundles: "glomeratus" refers to "condensed into a ball". " spermatoglomeratus " refers to the sperm bundles of the new species, rolled into a round ball shape. Diagnosis. This new species is recognized by the following characters, diagnostic in combination: 1) enlarged ventral chaetae in segments V–VI and XI, 2 per bundle; 2) five pairs of preclitellar nephridia in VI/VII to X/XI; 3) sperm sacs asymmetrically paired from XI–XIV to XV–XXIV, containing curly ball-shaped sperm bundles; 4) spermathecae without diverticula, ental ducts connected with oesophagus in VI–VII; 5) atrium tubular, with 4–6 developed prostate glands, distinct from vas deferens; 6) vas deferens very long, extending backwards to XV– XXII. Description. Small worms, active, twisting when submerged in water, pale in vivo, body wall thin, transparent. Body length 6.5–11.5 mm (holotype 8.0 mm), 7.0– 12.5 mm in vivo; body width 270–355 µm at V (330–450 µm in vivo), 470–575 µm at clitellum (320–625 µm in vivo). Segments 28–46 (holotype 34). Head pore transverse slit near the apex of prostomium (Fig. 2A). Epidermal gland cells inconspicuous, almost absent. Chaetal formula: 2,3 - 3,4: 2–5(6) - 2–5(6), up to 6 per bundle in the last segments. Chaetae sigmoid, nodulated, distally thinner and single-pointed. Lateral chaetae 44–100 µm in length and 3.5–5 µm in maximal width, shortest in II (44–48 µm), gradually increasing in size from III backwards, maximal size in IX (80–100 µm) (Table 1). Ventral chaetae, except those in V, VI and XI, 63–120 µm in length and 4–7.5 µm in maximal width (Fig. 1A, D). Ventral chaetae in V, VI and XI reduced to 2 per bundle (occasionally 3) (Fig. 1B, C, E). Ventral chaetae in V and VI longer and stouter than the others even in immature specimens, 126–158 µm in length and 7.5–11 µm in maximal thickness (Fig. 1B, C). Ventral chaetae in XI shorter and thinner than in V and VI, but thicker than the ordinary ventral ones, 6–8.5 µm in maximal thickness (Fig. 1E). Chaetae of XII lacking in fully mature specimens. Clitellum extending from 1/ 2 XI to XIII, elevated conspicuously. Hyalocytes (12–24 µm in diameter) more abundant than granulocytes, irregularly arranged and in contact with each other. Granulocytes (13–22 µm in diameter) irregular in shape, having some connection with each other and forming a loose net (Fig. 2B, F). Male pores distinct in the ventral middle of XII. Spermathecal pores paired, in the lateral line at IV/V (Fig. 2K). Length of lateral chaetae (µm) 71–90 71–85 71–80 71–80 65–75 Width of lateral chaetae (µm) 3.5–5 3.5–5 3.5–5 3.5–5 3.5–4.5 Number per bundle 3 3 3 3,4 3 Length of ventral chaetae (µm) 110–120 105–120 90–105 85–102 75–85 Width of ventral chaetae (µm) 6–8.5 6–7.5 5–6 5–6 5–6 Number per bundle 2 2,3 4 4 5 Brain in I-II (Figs. 1J, 2E), trapezoidal, deeply concave anteriorly and slightly incised posteriorly, 137–170 µm long and 105–125 µm in maximal width. Blood colourless or slightly yellowish. Dorsal vessel arising from XIV– XVI. Two pairs of primary pharyngeal glands in IV and V, attached to septa of 4/5 and 5/6 respectively, and both not connected dorsally. Three pairs of secondary lobes ventrally in V–VII, largest in VI. No oesophageal appendages. Intestinal diverticula absent. Chloragogen cells developed, originating from VIII, 12–45 µm high, absent in clitellum. Coelomocytes abundant, disc-shaped with conspicuous nuclei, 7.5–15.0 µm in diameter, with uneven refractile granules (Fig. 2C). Five pairs of nephridia in preclitellar segments from VI/VII to X/XI. Anteseptale stalked, containing nephrostome only; postseptale bilobed and with fewer interstitial tissue. Efferent duct arising between the two lobes (Figs. 1F, 2G). Sperm funnels cylindrical, occupying 1/3–1/2 body cavity in XI, 390–440 µm in length and 122–200 µm in maximal width. Their ental openings much narrower than funnel body, 43–73 µm wide. The heads of spermatozoa 17–20 µm in length (Figs. 1I, 2I). Vasa deferentia with conspicuous cilia in the canal, wound in irregular spirals in coelom from XII and posteriorly into XV–XXII, 18–30 µm in width, lumen of vasa deferentia 14–24 µm wide (Fig. 2L). The transition between vas deferens and atrium gradual. Atria in XII–XIII, cylindrical, remarkably wider than vasa deferentia, 415–650 µm long and 65–85 µm in maximal width. No cilia observed in atrial canal. Each atrium possessing 4–6 tubular prostate-like glands (each 117–195 µm in length and 50–68 µm in width) (Figs. 1H, 2I,J). Each atrium divided into two distinct parts, an ental part (length: 217–400 µm; width: 27.5–58 µm) with thin muscle layer and thick epithelium, and an ectal part (length: 200–350 µm; width: 25–44 µm) with a muscular duct connecting with the penial bulb. Penial bulb large, compact in ventral of XII, consisting of muscle strands and surrounded by masses of accessory glands of different size (Figs. 1H, 2J). A pair of sperm sacs large from XI–XIV in different size, and backwards extending to XV–XXIV, each containing numerous ball-shaped sperm bundles (diameter: 50–110 µm), a large number of spermatozoa coiled inside in vivo but much more loose in fixed condition (Fig. 2D,H). Egg sacs paired, large from XIV–XXII, continuing caudad to XVII–XXXIII, usually containing 2–11 mature eggs at a time. One pair of spermathecae in V–VII, without ectal glands. Ectal duct 215–385 µm long and 37–50 µm wide, projecting into ampulla. Ampulla spherical, 83–102 µm in diameter. No diverticula visible. Ampulla filled with spermatozoa in fully mature specimens. Ental ducts stout, 195–244 µm long and 62–67 µm wide, connecting to the dorsal side of oesophagus separately in the posterior of VI or anterior of VII (Figs. 1G, 2K). Differential diagnosis (Table 3). This new species is morphologically most similar to the co-occurring species M. gigachaetus Xie, 2012, M. anisodiverticulus Shen et al., 2012 and M. monodiverticulus Shen et al., 2012 and to a further terrestrial species, M. longiductus Christensen & Dózsa-Farkas, 2012, collected in Korea, which also have enlarged ventral chaetae in V–VI, and atria, egg sacs, and spermathecae attached to oesophagus. However, Mesenchytraeus spermatoglomeratus sp. nov. possesses enlarged ventral chaetae in XI and ball-shaped sperm bundles in the sperm sacs, two characteristics absent in the latter four species. Besides, M. gigachaetus differs from M. spermatoglomeratus by a higher number per bundle of enlarged ventral chaetae (3–4), no sperm sac visible and no atrial prostate gland. Mesenchytraeus anisodiverticulus is distinct from this new species by its absence of atrial prostate glands and the presence of two asymmetrical spermathecal diverticula. Mesenchytraeus monodiverticulus is different from M. spermatoglomeratus by its higher number per bundle of enlarged ventral chaetae (4 or 5), absence of atrial prostate glands, and spermatheca with one diverticulum. In Mesenchytraeus longiductus, atrial prostate glands are less numerous (only 2) and fewer accessory glands surround the penial bulb (only 4–5). Five other species (M. crenobius Timm, 1994, M. kontrimavichusi Piper et al., 1982, M. tetrapodus Timm, 1978, M. monochaetus Bretscher, 1900 and M. calyx Dózsa-Farkas et al., 2015) differ from M. spermatoglomeratus in terms of location and number of enlarged chaetae, chaetae formula, spermatheca, origin of dorsal vessel and habitat requirement. Unlike the new species, M. crenobius, M. tetrapodus and M. monochaetus are aquatic enchytraids. They also have 1–2 spermathecal diverticula. The terrestrial M. kontrimavichusi differs from this new species in: spermatheca with one diverticulum, not attached to oesophagus, atria absent, dorsal vessel arising from XV–XVIII. The other terrestrial member, M. calyx, is different from M. spermatoglomeratus by its larger body size (20–39 mm), the location of enlarged chaetae (VII–IX) and spermatheca with 7–9 pointed diverticula.

Fridericia peregrinabunda Michaelsen, 1913 (FigURES 4A���F) Fridericia peregrinabunda Michaelsen, 1913; Schmelz 2003. Fridericia carmichaeli Stephenson, 1915. Fridericia giniata Springett, 1971. Fridericia bulbosa (Rosa) var. [sic]. Michaelsen 1907. Fridericia bollonsi Christoffersen, 1976. Examined material. XZO201510005, XZO102510006, XZO201510007, ThREE adUlT FiXEd aNd STaiNEd SPEcimENS. MORE ThaN 10 SPEcimENS PRESERVEd iN 70% EThaNOl. Descriptions. MEdiUm SiZE. BOdY SiZE (iN ViVO): lENgTh abOUT 11.3 mm, bOdY WidTh 0.3 mm iN V, 0.4 mm iN XII. SEgmENT NUmbER 39���56. HEad PORE aT 0/I, lONgiTUdiNal SliT (Fig. 4D). ChaETaE ShORT aNd SlENdER, 2 PER bUNdlE ThROUghOUT, OccaSiONallY 3 iN SOmE POSTERiOR SEgmENTS. EPidERmal glaNd cEllS bROWN iN FEW aNTERiOR SEgmENTS, gRadUallY gRaY iN POSTERiOR SEgmENTS, 2 OR 3 ROWS PER SEgmENT. SUbNEURal glaNd abSENT. CliTEllUm aT XII���1 /2XIII, SlighTlY ElEVaTEd. BRaiN SlighTlY cONVEX aNTERiORlY, TRUNcaTE POSTERiORlY, ca. 150 ��m iN lENgTh aNd 100 ��m iN WidTh iN ViVO (Fig. 4D). SEPTa iN V/VI���VIII/IX ThickENEd (ca. 17.5 ��m iN ViVO). OESOPhagEal aPPENdagES WiTh 3���5 TERmiNal bRaNchES, EXTENdiNg iNTO V (Fig. 4B). ThREE PaiRS OF PhaRYNgEal glaNdS, all WiTh WidE dORSal cONNEcTiON. VENTRal lObES PRESENT iN all PaiRS, SmallEST iN IV, dORSal aNd VENTRal lObES iN V aNd VI OF abOUT SamE SiZE (Fig. 4C). FiVE PaiRS OF PREcliTEllaR NEPhRidia iN VI/VII���X/XI, EFFERENT dUcT RiSiNg FROm ThE middlE OF POSTSEPTalE (Fig. 4F). COElOmOcYTE���mUcOcYTES (TYPE ���c���) OVal aNd NUmEROUS, ca. 50 ��m iN ViVO, lENTicYTES abUNdaNT, ca. 5���6 ��m iN ViVO (Fig. 4A). ChYlUS cEllS iN XIII���XV, 1/ 2 XI ���XIII iN SOmE SPEcimENS. DORSal blOOd VESSEl ORigiNaTiNg FROm XV��� XVIII. SEmiNal VESiclE WEll-dEVElOPEd, OccUPYiNg X���XI. SPERm FUNNEl laRgE, hEmiSPhERical, SlighTlY lONgER ThaN WidTh (ca. 180���200 ��m bY 110���144 ��m iN ViVO), OccUPYiNg 1/2 OF ThE caViTY iN XI. COllaR NaRROWER ThaN FUNNEl bOdY, ca. 100 ��m iN WidTh aNd 14 ��m iN hEighT iN ViVO. SPERmaTOZOa mUch lONgER ThaN SPERm FUNNEl, ca. 150���270 ��m iN ViVO. BURSal SliT H-ShaPEd. SPERmaThEca WiThOUT EcTal glaNd. EcTal dUcT VERY lONg, ca. 350 ��m lONg aNd 30 ��m WidE iN ViVO, PROJEcTiNg dEEPlY iNTO amPUlla (Fig. 4E). AmPUlla PYRiFORm, WiThOUT diVERTicUla, 150 ��m lONg aNd 75 ��m WidE iN ViVO, diVidEd iNTO TWO diSTiNcT PaRTS, EcTal aNd PROXimal. ENTal dUcT NaRROWER ThaN amPUlla, WiTh iRREgUlaR OUTliNE aNd ThiN EPiThEliUm, aNd SEPaRaTElY JOiNiNg OESOPhagUS iN VI (Fig. 4E). Differential diagnosis. EXcEPT FOR ThE bOdY SiZE (39���56 SEgmENTS VS. 60���70 SEgmENTS iN F. peregrinabunda), OUR SPEcimENS cONFORm WEll TO ThE dEScRiPTiON OF F. peregrinabunda giVEN bY SchmElZ (2003), SUch aS 2 chaETaE PER bUNdlE aNd ThE STRUcTURE OF SPERmaThEca. ThiS iS ThE FiRST REcORd OF ThE SPEciES iN ChiNa., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on page 403, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Michaelsen, W. (1913) The Oligochaeta of natal and Zululand. Annals of the natal Museum, 2 (4), 397 - 458.","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Stephenson, J. (1915) On some Indian Oligochaeta, mainly from Southern India and Ceylon. Memoirs of the Indian Museum, 6, 35 - 108.","Springett, J. A. (1971) The Enchytraeidae (Oligochaeta) of South Western Australia: The genus Fridericia Michaelsen 1889. Journal of the Royal Society of Western Australia, Perth, 54, 17 - 20.","Michaelsen, W. (1907) Oligochaeten von Natal und dem Zululand. Arkiv for Zoologi, 4, 1 - 12.","Christoffersen, M. L. (1976) Two species of Fridericia Mich., 1889 (Oligochaeta, Enchytraeidae) from Brazil. Boletim de Zoologia, Universidade de Sao Paulo, 1, 239 - 256. https: // doi. org / 10.11606 / issn. 2526 - 3358. bolzoo. 1976.121579"]}

Fridericia ratzeli (Eisen, 1872) sensu stricto (FigURES 1, 2) Enchytraeus ratzeli Eisen, 1872. Fridericia ratzeli (Eisen). Michaelsen 1889; Nielsen & Christensen 1959; Schmelz 2003; Schmelz & Collado 2010. Fridericia canadensis Dash, 1972. Fridericia eiseni Dózsa-Farkas, 2005. See Schmelz (2003) for further synonymies. Examined material. XZO201510003, XZO201510001, XZO201510002, YNO201512001, all FUllY maTURE SPEcimENS, STaiNEd, WhOlE-mOUNTEd, cOllEcTEd aT SiTES 2 aNd 3; ca. 20 SPEcimENS PRESERVEd iN EiThER 10% FORmaliN OR 70% EThaNOl. Description. MEdiUm SiZE. BOdY lENgTh 15–20 mm (18–22 mm iN ViVO). BOdY WidTh 250–500 Μm aT V (ca. 300–500 Μm iN ViVO), 300–700 Μm aT XII (ca. 550 Μm iN ViVO). BOdY cOlOR PalE-WhiTE iN ViVO. SEgmENT NUmbER 44–66. HEad POlE aT 0/I, lONgiTUdiNal SliT. DORSal PORES FROm VII backWaRdS. EPidERmal glaNd cEllS gRaY iN ViVO, cONSPicUOUS iN PREcliTEllaR SEgmENTS, 5–8 TRaNSVERSE ROWS PER SEgmENT (Fig. 2J). ChaETal FORmUla: 4,5,6,(7,8) – 4,5,6,(7,8): 6,(7,8) – 4,5,6,(7,8). ChaETaE STRaighT, WiThOUT NOdUlUS, WEaklY bENT PROXimallY, iN aSYmmETRic FaN- ShaPEd aRRaNgEmENT WiThiN a bUNdlE (Fig. 2L). LENgTh OF chaETaE gRadUallY iNcREaSiNg FROm II TO V, laRgEST aT V (Fig. 1A). VENTRal chaETaE 36–81 Μm iN lENgTh, 5–9 Μm iN WidTh. ChaETaE iN XII abSENT iN maTURE SPEcimENS. CliTEllUm ElEVaTEd SlighTlY iN XII–1 /2XIII, giRdlE-ShaPEd. HYalOcYTES aNd gRaNUlOcYTES iN dENSE PaTTERN, iRREgUlaR aRRaNgEmENT (Fig. 2E, F). SPERmaThEcal PORES PaiREd aT IV/V. TWO SEPaRaTE bURSal SliTS, T-ShaPEd, VENTRallY iN ThE middlE OF XII. ThREE SUbNEURal glaNdS PRESENT iN POSTcliTEllaR SEgmENTS, FROm XIII TO XV, ca. 98 Μm iN lENgTh aNd 78 Μm iN WidTh (Fig. 2H, K). BRaiN iN 0/I, cONcaVE aNTERiORlY, aNd ROUNd OR TRUNcaTE POSTERiORlY ca. 160 Μm iN lENgTh aNd 100 Μm iN WidTh iN ViVO, 70–110 µm WidE aNd 125–180 µm lONg iN FiXaTiON cONdiTiON (Fig. 1B, Fig. 2M). DORSal VESSEl aRiSiNg FROm XX–XXI. BlOOd cOlORlESS. ThREE PaiRS OF PhaRYNgEal glaNdS PRESENT iN IV–VI, ThE FiRST PaiR cOmPaRaTiVElY laRgER WiTh dORSal cONNEcTiON, ThE OThERS Small aNd SEPaRaTEd dORSallY, TWO PaiRS OF VENTRal lObES iN V aNd VI (Fig. 2I). PaiREd OESOPhagEal aPPENdagES ORigiNaTiNg FROm III aNd EXTENdiNg aNd cONTORTiNg backWaRdS TO V, WiTh 6–7 bRaNchES (Fig. 1E, Fig. 2G). INTESTiNal diVERTicUla abSENT. ChlORagOcYTES bEgiNNiNg FROm VII backWaRdS, bROWNiSh, WEll-dEVElOPEd. ChYlUS cEllS USUallY iN XV–XVI. COElOmO-mUcOcYTES, ROUNd OR OVal, ca. 50–55 Μm iN ViVO (TYPE “c”), 25–37 Μm iN WidTh aNd 37–50 Μm iN lENgTh (Fig. 2N). LENTicYTES NUmEROUS, Small, OVal OR SPiNdlE-ShaPEd, 5– 6 Μm lONg aNd 1–1.5 Μm WidE. FOUR PaiRS OF PREcliTEllaR NEPhRidia FROm VII/VIII TO X/XI. NEPhRidial aNTESEPTalE cONSiSTiNg a NEPhROSTOmE aNd a FEW NEPhRidial TiSSUES (Fig. 1B). POSTSEPTalE 60–68 Μm lONg aNd abOUT 39–44 Μm WidE, WiTh aN EFFERENT dUcT aRiSiNg TERmiNallY. SPERm FUNNElS WEll dEVElOPEd, PRESENT iN XI, cYliNdRical, gRadUallY TaPERiNg POSTERiORlY (Fig. 1F, Fig. 2A, B), 350–450 Μm lONg aNd 100–140 Μm WidE iN ViVO. COllaR aS WidE aS OR SlighTlY NaRROWER ThaN FUNNEl bOdY (ca. 15 Μm iN hEighT). HEadS OF SPERmaTOZOa abOUT 97 Μm lONg. VaS dEFERENS cONFiNEd TO XII, ShORT, NaRROW, WOUNd iN iRREgUlaR lOOPS VENTRallY, bETWEEN SPERm FUNNEl aNd malE PORE. SEmiNal VESiclE laRgE, OccUPYiNg X–XI. USUallY 1 Egg maTURE aT a TimE, almOST aS WidE aS WORm diamETER, WiTh SEVERal immaTURE EggS, PRESENT iN XII. SPERmaThEca iN V–VI WiTh 2 EcTal glaNdS (30–50 Μm iN ViVO) aT Each EcTal ORiFicE (Fig. 2C, G). EcTal dUcTS ca. 350–400 Μm iN lENgTh aNd 24–30 Μm iN WidTh iN ViVO (Fig. 1C, Fig. C, D). AmPUlla ROUNd OR ONiON-ShaPEd (ca. 200–220 Μm iN ViVO, 88–103 Μm aFTER FiXaTiON), WiTh 6–8 ROUNd diVERTicUla OF VaRYiNg SiZE, 2 OF ThEm WElldEVElOPEd (ca. 75 Μm iN ViVO, 70 Μm aFTER FiXaTiON) aNd FillEd WiTh SPERmaTOZOa, ThE OThERS Small (ca. 30 Μm iN ViVO) aNd WiThOUT SPERmaTOZOa (Fig. 1C, Fig. 2C, D). ENTal dUcTS ShORT, UNiTEd bEFORE aTTachmENT TO OESOPhagUS iN VI. Differential diagnosis. OUR SPEcimENS aPPaRENTlY bElONg TO Friderica ratzeli SENSU STRicTO (SchmElZ & COlladO 2010). Friderica ratzeli iS cONcEiVEd aS a hETEROgENEOUS SPEciES, aNd a lEaST iNclUdES TWO mORPhOlOgicallY diSTiNgUiShablE FORmS (ChalUPSký 1992, SchmElZ 2003). SchmElZ (2003) idENTiFiEd ThEm aS “ThE FiRST FORm cOmPRiSES laRgE SPEcimENS (UP TO 25 mm lONg aNd 0.8 mm WidE), Which POSSESS SPERmaThEcal diVERTicUla WiTh diSTiNcT lUmiNa, USUallY FillEd WiTh SPERm, a SPERmaThEcal EcTal dUcT ThaT WidENS cONSidERablY PROXimad, aNd a FaiRlY laRgE SUbNEURal glaNd iN XIII”, aNd “ThE SEcONd FORm cOmPRiSES SmallER SPEcimENS (UP TO 15 mm lONg aNd 0.5 mm WidE), Which POSSESS SPERmaThEcal diVERTicUla WiThOUT a diSTiNgUiShablE lUmEN, aN EcTal dUcT ThaT WidENS ONlY SlighTlY PROXimad, aNd ThREE SmallER SUbNEURal glaNdS iN XIII, XIV aNd XV”. ChalUPSký (1992) TENTaTiVElY idENTiFiEd ThE FORmER aS F. dura (EiSEN, 1879) aNd ThE laTTER aS F. ratzeli SENSU STRicTO. SchmElZ aNd COlladO (2010) TREaTEd ThEm aS TWO Valid SPEciES, F. ratzeli SENSU STRicTO aNd F. dura. OUR SPEcimENS aRE clOSE TO F. ratzeli SENSU STRicTO bY almOST TaXONOmical TRaiTS OF chaETal NUmbER PER bUNdlE, bRaNchEd OESOPhagEal aPPENdagES, cOElOmOmUcOcYTES TYPE, SUbNEURal glaNdS PRESENT iN XIII–XV, SPERmaThEca WiTh TWO EcTal glaNdS, aNd amPUlla diSTallY SURROUNdEd bY 6–8 glObUlaR diVERTicUla WiTh laRgE lUmEN. HOWEVER, OUR SPEcimENS diFFERS FROm F. ratzeli SENSU STRicTO bY ThE PRESENcE OF FOUR PaiRS OF PREcliTEllaR NEPhRidia (FiVE PaiRS iN F. ratzeli SENSU STRicTO). ThiS iS ThE FiRST REcORd OF ThE SPEciES FROm ChiNa.

Henlea sp. (FigURES 5, 6) Examined material. XZO201604005, XZO201604004, XZO201604006, XZO201610004���6, 5 STaiNEd aNd WhOlE-mOUNTEd adUlT SPEcimENS. AbOUT 20 maTURE aNd immaTURE SPEcimENS FROm SiTES 1, SiTE 3 aNd SiTE 4. Description. MEdiUm SiZE. BOdY lENgTh 5.7��� 8 mm, bOdY WidTh 280���380 ��m aT V, 290���460 ��m aT XII. SEgmENT NUmbER 34���49. HEad POlE aT 0/I, TRaNSVERSE SliT. EPidERmal glaNdS cEllS iNcONSPicUOUS. ChaETaE FORmUla: 4,5 ��� 3,4,5,6: 2,3,4,5 ��� 2,3,4. ChaETaE STRaighT, WiThOUT NOdUlUS, WEaklY bENT PROXimallY, FaN-ShaPEd aRRaNgEmENT WiThiN a bUNdlE. ChaETaE aT II���V ShORT aNd STOUT, gRadUallY iNcREaSiNg backWaRdS. ThE laRgEST chaETaE PRESENT aT VII (Fig. 5A). ChaETaE OF XII abSENT iN maTURE SPEcimENS. CliTEllUm ElEVaTEd cONSPicUOUSlY iN XII. giRdlE-ShaPEd. HYalOcYTES aNd gRaNUlOcYTES iN RETicUlaTE PaTTERN, iRREgUlaRlY aRRaNgEd, hYalOcYTES iSOlaTEd (Fig. 6A). SPERmaThEcal PORES PaiREd aT IV/V. TWO SEPaRaTE malE PORES, VENTRallY iN ThE middlE OF XII. BRaiN iN I/II, ca. 1.5 TimES aS lONg aS WidE, SlighTlY cONcaVE aNTERiORlY, TRUNcaTE OR WEaklY iNciSEd POSTERiORlY (Fig. 5B). DORSal VESSEl aRiSiNg FROm IX. BlOOd cOlORlESS. ThREE PaiRS OF PhaRYNgEal glaNdS PRESENT iN IV���VI (Fig. 6G), all SEPaRaTE dORSallY aNd aTTachEd TO SEPTa. TWO PaiRS OF VENTRal lObES OccURRiNg iN V aNd VI. AbRUPT TRaNSiTiON bETWEEN OESOPhagUS aNd iNTESTiNE iN IX. OESOPhagEal aPPENdagES PRESENT iN IV���VII, ONE dORSallY aNd ONE VENTRallY. ThE dORSal ONE aRiSiNg iN IV, bUlgiNg backWaRdS iNTO VI���VII, WhERE iT giVES OFF SOmE bRaNchES iNTO ThE caViTY. ThE VENTRal ONE alSO ORigiNaTiNg iN IV, ThEN backWaRdS TO VI, aNd giViNg OFF 2���3 bRaNchES iNTO ThE caViTY. ONE PaiR OF POUch-likE iNTESTiNal diVERTicUla PRESENT iN VIII (Fig. 6I). COElOmOcYTES ROUNd OR OVal, mORE cONcENTRaTEd iN POSTcliTEllaR SEgmENTS. SEVEN PaiRS OF PREcliTEllaR NEPhRidia iN IV/V���X/XI (Fig. 5C, Fig. 6B, D). ANTESEPTalE Small, abOUT 22 ��m lONg. POSTSEPTalE 48���57��m lONg aNd abOUT 29���32 ��m WidE, WiTh aN EFFERENT dUcT aRiSiNg VENTRallY FROm ThE middlE OF ThE POSTSEPTalE. SPERm FUNNElS iN XI, WEll dEVElOPEd, cYliNdRical, lENgTh ca. 2.5 TimES aS WidTh, OccUPYiNg ca. 1/3���1/2 caViTY iN XI (Fig. 5D, Fig. 6C, D). COllaR SlighTlY NaRROWER ThaN FUNNEl bOdY. VaS dEFERENS lONg, cONFiNEd TO XII, WOUNd iN iRREgUlaR lOOPS bETWEEN SPERm FUNNEl aNd malE PORE (Fig. 6E). SEmiNal VESiclE abSENT. USUallY 1���3 maTURE EggS aT a TimE (Fig. 6E). SPERmaTOZOa 25 ��m lONg. SPERmaThEcaE SiTUaTEd aT V. EcTal dUcT 120���150 ��m iN lENgTh aNd 25���55 ��m iN WidTh, WiTh 3���4 WEll-dEVElOPEd EcTal glaNdS. AmPUlla SPhERical, WiThOUT diVERTicUla, 49���88 ��m iN diamETER (Fig. 6F, H). ENTal dUcTS UNiTEd bEFORE aTTachmENT TO OESOPhagUS iN VI. Remarks. AmONg ThE Henlea SPEciES POSSESSiNg ONE PaiR OF iNTESTiNal diVERTicUla aNd ThE ORigiN OF ThE dORSal VESSEl iN IX, OUR SPEcimENS aRE SOmEWhaT clOSE TO H. eiseni BEll, 1942 bY ThE chaETal NUmbER PER bUNdlE, ThE OESOPhagEal aPPENdagES (ONE VENTRal aNd ONE dORSal iN IV���VII), ThE SPERm FUNNEl, aNd ThE abSENcE OF SEmiNal VESiclES (BEll 1942). HOWEVER, iN H. eiseni ThE SPERmaThEcal amPUlla iS iNcONSPicUOUS aNd ONlY liTTlE WidER ThaN ThE EcTal dUcT, WhEREaS iN OUR SPEcimENS ThE amPUlla iS cONSPicUOUS aNd ca. 2 TimES aS WidE aS ThE EcTal dUcT (Fig. 6F, H). MOREOVER, OUR SPEcimENS SOmEWhaT RESEmblE H. africana BEll, 1954, Henlea glandulifera NURmiNEN, 1970, H. conchifera ChRiSTENSEN & D��ZSa-FaRkaS, 1999, H. guatemalae, EiSEN, 1904, H. nasuta (EiSEN, 1878), H. helenae EiSEN, 1904, aNd H. similis NiElSEN & ChRiSTENSEN, 1959, iN haViNg ThEiR SPERmaThEcal amPUlla cONSPicUOUSlY WidER ThaN ThE EcTal dUcT (BEll 1954; SchmElZ & COlladO 2010; ChRiSTENSEN & D��ZSa-FaRkaS 1999; NURmiNEN 1970; NiElSEN & ChRiSTENSEN 1959). BUT H. africana haS mORE cOmPlEX OESOPhagEal aPPENdagES aNd a laRgER bOdY SiZE. Henlea glandulifera, H. nasuta, H. helenae aNd H. similis haVE ThE ORigiN OF ThE dORSal VESSEl iN VIII. H. conchifera haS NO abRUPT WidENiNg bETWEEN OESOPhagUS aNd iNTESTiNE, ONlY ONE EcTal glaNd, aNd OESOPhagEal aPPENdagES cONFiNEd TO VI. Henlea guatemalae haS ThE dORSal VESSEl ORigiN iN VII, ThE TRaNSiTiON bETWEEN OESOPhagUS aNd iNTESTiNE iN VII/VIII, aNd NO SPERmaThEcal EcTal glaNd. TOgEThER, OUR SPEcimENS bElONg PRObablY TO a NEW SPEciES. ITS TaXONOmical STaTUS ShOUld bE iNVESTigaTEd FURThER bOTh mORPhOlOgicallY aNd mOlEcUlaRlY., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 405-407, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Bell, A. W. (1942) Some new Enchytraeid worms (Oligochaeta) from North America. Transactions of American Microscopical Society, 61, 404 - 429. https: // doi. org / 10.2307 / 3222906","Bell, A. W. (1954) Some Enchytraeid worms (Oligochaeta) from East Africa. Transactions of the American Microscopical Society, 73, 297 - 311. https: // doi. org / 10.2307 / 3224072","Nurminen, M. (1970) Records of Enchytraeidae (Oligochaeta) from the west coast of Greenland. Annales Zoologici Fennici, 7, 199 - 209.","Christensen, B. & Dozsa-Farkas, K. (1999) The enchytraeid fauna of the Palearctic tundra (Oligochaeta, Enchytraeidae). The Royal Danish Academy of Sciences and Letters, Biologiske Skrifter, 52, 1 - 37.","Eisen, G. (1904) Enchytraeidae of the West Coast of North America. Harriman Alaska Series, New York, 12, 1 - 126, 20 pls.","Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176."]}

Fridericia ratzeli (Eisen, 1872) sensu stricto (FigURES 1, 2) Enchytraeus ratzeli Eisen, 1872. Fridericia ratzeli (Eisen). Michaelsen 1889; Nielsen & Christensen 1959; Schmelz 2003; Schmelz & Collado 2010. Fridericia canadensis Dash, 1972. Fridericia eiseni D��zsa-Farkas, 2005. See Schmelz (2003) for further synonymies. Examined material. XZO201510003, XZO201510001, XZO201510002, YNO201512001, all FUllY maTURE SPEcimENS, STaiNEd, WhOlE-mOUNTEd, cOllEcTEd aT SiTES 2 aNd 3; ca. 20 SPEcimENS PRESERVEd iN EiThER 10% FORmaliN OR 70% EThaNOl. Description. MEdiUm SiZE. BOdY lENgTh 15���20 mm (18���22 mm iN ViVO). BOdY WidTh 250���500 ��m aT V (ca. 300���500 ��m iN ViVO), 300���700 ��m aT XII (ca. 550 ��m iN ViVO). BOdY cOlOR PalE-WhiTE iN ViVO. SEgmENT NUmbER 44���66. HEad POlE aT 0/I, lONgiTUdiNal SliT. DORSal PORES FROm VII backWaRdS. EPidERmal glaNd cEllS gRaY iN ViVO, cONSPicUOUS iN PREcliTEllaR SEgmENTS, 5���8 TRaNSVERSE ROWS PER SEgmENT (Fig. 2J). ChaETal FORmUla: 4,5,6,(7,8) ��� 4,5,6,(7,8): 6,(7,8) ��� 4,5,6,(7,8). ChaETaE STRaighT, WiThOUT NOdUlUS, WEaklY bENT PROXimallY, iN aSYmmETRic FaN- ShaPEd aRRaNgEmENT WiThiN a bUNdlE (Fig. 2L). LENgTh OF chaETaE gRadUallY iNcREaSiNg FROm II TO V, laRgEST aT V (Fig. 1A). VENTRal chaETaE 36���81 ��m iN lENgTh, 5���9 ��m iN WidTh. ChaETaE iN XII abSENT iN maTURE SPEcimENS. CliTEllUm ElEVaTEd SlighTlY iN XII���1 /2XIII, giRdlE-ShaPEd. HYalOcYTES aNd gRaNUlOcYTES iN dENSE PaTTERN, iRREgUlaR aRRaNgEmENT (Fig. 2E, F). SPERmaThEcal PORES PaiREd aT IV/V. TWO SEPaRaTE bURSal SliTS, T-ShaPEd, VENTRallY iN ThE middlE OF XII. ThREE SUbNEURal glaNdS PRESENT iN POSTcliTEllaR SEgmENTS, FROm XIII TO XV, ca. 98 ��m iN lENgTh aNd 78 ��m iN WidTh (Fig. 2H, K). BRaiN iN 0/I, cONcaVE aNTERiORlY, aNd ROUNd OR TRUNcaTE POSTERiORlY ca. 160 ��m iN lENgTh aNd 100 ��m iN WidTh iN ViVO, 70���110 ��m WidE aNd 125���180 ��m lONg iN FiXaTiON cONdiTiON (Fig. 1B, Fig. 2M). DORSal VESSEl aRiSiNg FROm XX���XXI. BlOOd cOlORlESS. ThREE PaiRS OF PhaRYNgEal glaNdS PRESENT iN IV���VI, ThE FiRST PaiR cOmPaRaTiVElY laRgER WiTh dORSal cONNEcTiON, ThE OThERS Small aNd SEPaRaTEd dORSallY, TWO PaiRS OF VENTRal lObES iN V aNd VI (Fig. 2I). PaiREd OESOPhagEal aPPENdagES ORigiNaTiNg FROm III aNd EXTENdiNg aNd cONTORTiNg backWaRdS TO V, WiTh 6���7 bRaNchES (Fig. 1E, Fig. 2G). INTESTiNal diVERTicUla abSENT. ChlORagOcYTES bEgiNNiNg FROm VII backWaRdS, bROWNiSh, WEll-dEVElOPEd. ChYlUS cEllS USUallY iN XV���XVI. COElOmO-mUcOcYTES, ROUNd OR OVal, ca. 50���55 ��m iN ViVO (TYPE ���c���), 25���37 ��m iN WidTh aNd 37���50 ��m iN lENgTh (Fig. 2N). LENTicYTES NUmEROUS, Small, OVal OR SPiNdlE-ShaPEd, 5��� 6 ��m lONg aNd 1���1.5 ��m WidE. FOUR PaiRS OF PREcliTEllaR NEPhRidia FROm VII/VIII TO X/XI. NEPhRidial aNTESEPTalE cONSiSTiNg a NEPhROSTOmE aNd a FEW NEPhRidial TiSSUES (Fig. 1B). POSTSEPTalE 60���68 ��m lONg aNd abOUT 39���44 ��m WidE, WiTh aN EFFERENT dUcT aRiSiNg TERmiNallY. SPERm FUNNElS WEll dEVElOPEd, PRESENT iN XI, cYliNdRical, gRadUallY TaPERiNg POSTERiORlY (Fig. 1F, Fig. 2A, B), 350���450 ��m lONg aNd 100���140 ��m WidE iN ViVO. COllaR aS WidE aS OR SlighTlY NaRROWER ThaN FUNNEl bOdY (ca. 15 ��m iN hEighT). HEadS OF SPERmaTOZOa abOUT 97 ��m lONg. VaS dEFERENS cONFiNEd TO XII, ShORT, NaRROW, WOUNd iN iRREgUlaR lOOPS VENTRallY, bETWEEN SPERm FUNNEl aNd malE PORE. SEmiNal VESiclE laRgE, OccUPYiNg X���XI. USUallY 1 Egg maTURE aT a TimE, almOST aS WidE aS WORm diamETER, WiTh SEVERal immaTURE EggS, PRESENT iN XII. SPERmaThEca iN V���VI WiTh 2 EcTal glaNdS (30���50 ��m iN ViVO) aT Each EcTal ORiFicE (Fig. 2C, G). EcTal dUcTS ca. 350���400 ��m iN lENgTh aNd 24���30 ��m iN WidTh iN ViVO (Fig. 1C, Fig. C, D). AmPUlla ROUNd OR ONiON-ShaPEd (ca. 200���220 ��m iN ViVO, 88���103 ��m aFTER FiXaTiON), WiTh 6���8 ROUNd diVERTicUla OF VaRYiNg SiZE, 2 OF ThEm WElldEVElOPEd (ca. 75 ��m iN ViVO, 70 ��m aFTER FiXaTiON) aNd FillEd WiTh SPERmaTOZOa, ThE OThERS Small (ca. 30 ��m iN ViVO) aNd WiThOUT SPERmaTOZOa (Fig. 1C, Fig. 2C, D). ENTal dUcTS ShORT, UNiTEd bEFORE aTTachmENT TO OESOPhagUS iN VI. Differential diagnosis. OUR SPEcimENS aPPaRENTlY bElONg TO Friderica ratzeli SENSU STRicTO (SchmElZ & COlladO 2010). Friderica ratzeli iS cONcEiVEd aS a hETEROgENEOUS SPEciES, aNd a lEaST iNclUdES TWO mORPhOlOgicallY diSTiNgUiShablE FORmS (ChalUPSk�� 1992, SchmElZ 2003). SchmElZ (2003) idENTiFiEd ThEm aS ���ThE FiRST FORm cOmPRiSES laRgE SPEcimENS (UP TO 25 mm lONg aNd 0.8 mm WidE), Which POSSESS SPERmaThEcal diVERTicUla WiTh diSTiNcT lUmiNa, USUallY FillEd WiTh SPERm, a SPERmaThEcal EcTal dUcT ThaT WidENS cONSidERablY PROXimad, aNd a FaiRlY laRgE SUbNEURal glaNd iN XIII���, aNd ���ThE SEcONd FORm cOmPRiSES SmallER SPEcimENS (UP TO 15 mm lONg aNd 0.5 mm WidE), Which POSSESS SPERmaThEcal diVERTicUla WiThOUT a diSTiNgUiShablE lUmEN, aN EcTal dUcT ThaT WidENS ONlY SlighTlY PROXimad, aNd ThREE SmallER SUbNEURal glaNdS iN XIII, XIV aNd XV���. ChalUPSk�� (1992) TENTaTiVElY idENTiFiEd ThE FORmER aS F. dura (EiSEN, 1879) aNd ThE laTTER aS F. ratzeli SENSU STRicTO. SchmElZ aNd COlladO (2010) TREaTEd ThEm aS TWO Valid SPEciES, F. ratzeli SENSU STRicTO aNd F. dura. OUR SPEcimENS aRE clOSE TO F. ratzeli SENSU STRicTO bY almOST TaXONOmical TRaiTS OF chaETal NUmbER PER bUNdlE, bRaNchEd OESOPhagEal aPPENdagES, cOElOmOmUcOcYTES TYPE, SUbNEURal glaNdS PRESENT iN XIII���XV, SPERmaThEca WiTh TWO EcTal glaNdS, aNd amPUlla diSTallY SURROUNdEd bY 6���8 glObUlaR diVERTicUla WiTh laRgE lUmEN. HOWEVER, OUR SPEcimENS diFFERS FROm F. ratzeli SENSU STRicTO bY ThE PRESENcE OF FOUR PaiRS OF PREcliTEllaR NEPhRidia (FiVE PaiRS iN F. ratzeli SENSU STRicTO). ThiS iS ThE FiRST REcORd OF ThE SPEciES FROm ChiNa., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 396-399, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Eisen, G. (1872) Om nagra arktiske Oligochaeter. Ofversigt af Kongl Vetenskaps-akademiens forhandlingar, 1, 119 - 124.","Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176.","Dash, M. C. (1972). New Enchytraeidae (Oligochaeta) from the Penny Forest soil of British Columbia, Canada. Annales Zoologici Fennici, 9, 15 - 16.","Dozsa-Farkas, K. (2005) Fridericia eiseni sp. n., a new enchytraeid species close to Fridercia ratzeli (Eisen, 1872). Proceedings of the Estonian Academy of Sciences: Biology, Ecology, 54, 279 - 291.","Chalupsky, J. (1992) Terrestrial Enchytraeidae (Oligochaeta) and Parergodrilidae (Polychaeta) from Sweden, with description of a new enchytraeid species. Zoologica Scripta, 21 (2), 133 - 150. https: // doi. org / 10.1111 / j. 1463 - 6409.1992. tb 00316. x"]}

Fridericia bretscheri Southern, 1907 (FigURES 3F���I) Fridericia bretscheri Southern, 1907. Southern 1909; Nielsen & Christensen 1959; Rota 1995; Schmelz 2003; Schmelz & Collado 2010. Examined material. XZO201604010, ONE STaiNEd, WhOlE-mOUNTEd SPEcimEN. TWO SPEcimENS PRESERVEd iN 70% EThaNOl. Descriptions. Small SiZE. BOdY lENgTh 5.4 mm (6���8 mm iN ViVO). BOdY WidTh 200���250 ��m aT V, 300 ��m aT XII. SEgmENT NUmbER 35���53. HEad PORE aT 0/I. A maXimUm OF 4 chaETaE PER bUNdlE. ChaETaE STRaighT diSTallY, WiThOUT NOdUlUS. ChaETaE FORmUla: 1,2 ��� 2-4: 3,4 ��� 2-4. EPidERmal glaNd cEllS YEllOWiSh, iNcONSPicUOUS, 4���5 TRaNSVERS ROWS PER SEgmENT. CliTEllUm aT XII���XIII, giRdlE-ShaPEd, ElEVaTEd cONSPicOUSlY. HYalOcYTES lESS NUmEROUS ThaN gRaNUlOcYTES (Fig. 3H). BRaiN SlighTlY cONVEX aNTERiORlY, ROUNdEd POSTERiORlY, ca. 160 ��m lONg, 75 ��m WidE. OESOPhagEal aPPENdagES ShORT, UNbRaNchEd, EXTENdiNg backWaRdS TO V (Fig. 3G). ThREE PaiRS OF PhaRYNgEal glaNdS iN IV/V���VI/VII, all WiTh WidE OR NaRROW dORSal cONNEcTiON. VENTRal lObES PRESENT iN V aNd VII. ChYlUS cEllS iN XIII. DORSal blOOd VESSEl ORigiNaTiNg iN XIX. FOUR PaiRS OF PREcliTEllaR NEPhRidia, aNTESEPTalE abOUT 40 ��m lONg aNd 23 ��m WidE, POSTSEPTalE 76 ��m lONg aNd 42 ��m WidE. EFFERENT dUcT RiSiNg FROm ThE middlE OF POSTSEPTalE. COElEmO-mUcOcYTES WiTh diSTiNcT REFRacTilE VESiclES aT ThE cEll PERiPhERY, abUNdaNT, 14���32 ��m iN diamETER. LENTicYTES ScaRcE, 8 ��m iN diamETER (Fig. 3I). SUbNEURal glaNdS abSENT. SPERm FUNNEl cYliNdRical, ca. TWO TimES aS lONg aS WidE, aT lEaST 1/2 aS lONg aS bOdY diamETER, cOllaR NaRROWER ThaN FUNNEl bOdY. SPERmaTOZOa 62���70 ��m lONg. VaS dEFERENS lONg, abOUT 6 ��m WidE, iRREgUlaR lOOPEd iN XII. SEmiNal VESiclE abSENT. BURSal SliT lONgiTUdiNal. SPERmaThEca WiTh a FlOPPY EcTal glaNd, 27 ��m lONg, 20 ��m WidE. EcTal dUcT lONg, 145���160 ��m iN lENgTh, 10���13 ��m iN WidTh. TWO ENTal dUcTS cONNEcT SEPaRaTElY TO ThE OESOPhagUS. AmPUlla WiThOUT diVERTicUla (Fig. 3F). ONE OR TWO EggS aT a TimE. Differential diagnosis. OUR SPEcimENS haVE maNY TRaiTS iN cOmmON WiTh ThE dEScRiPTiONS giVEN bY SchmElZ (2003), SUch aS UP TO 4 chaETaE PER bUNdlE, ThE ShaPE OF bRaiN, OESOPhagEal aPPENdagES, PhaRYNgEal glaNdS, ThE TEXTURE OF cOElEmO-mUcOcYTES, ThE SPERm FUNNEl aNd ThE STRUcTURE OF SPERmaThEca. ThiS SPEciES WaS FOUNd iN IRElaNd, ITalY, AlgERia aNd SWiTZERlaNd. IN ChiNa, ThE WORmS WERE FOUNd iN MT. ChaNgbai OF JiliN PROViNcE aNd TibET., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on page 402, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Southern, R. (1907) Oligochaeta of Lambay. The Irish Naturalist's Journal, Dublin, 16, 68 - 82.","Southern, R. (1909) Contributions towards a monograph of the British and Irish Oligochaeta. Proceedings of the Royal Irish Academy, 27 B (8), 119 - 182.","Nielsen, C. O. & Christensen, B. (1959) The Enchytraeidae, critical revision and taxonomy of European species, Natura Jutlandica, 8 - 9, 1 - 160.","Rota, E. (1995) Italian Enchytraeidae (Oligochaeta). I. Italian Journal of Zoology 62, 183 - 231. https: // doi. org / 10.1080 / 11250009509356067","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176."]}

Buchholzia sp. (FigURES 7A���G) Examined material. XZO201510004, XZO201510008, XZO201510009, XZO201510010, FOUR immaTURE SPEcimEN, STaiNEd, WhOlE-mOUNTEd. MORE ThaN 20 SPEcimENS iN 70% EThaNOl, all immaTURE. Descriptions. MEdiUm SiZE. BOdY cOlOR WhiTE iN ViVO. BOdY lENgTh 3.6���4 mm. BOdY WidTh 140���175 ��m. SEgmENTS 32���36. A maXimUm OF 5 chaETaE PER bUNdlE. ChaETaE WEaklY SigmOid, WiThOUT NOdUlUS (Fig. 7A). ChaETaE 2���3 PER bUNdlE aT aNTERiOR SEgmENTS, 4���5 PER bUNdlE aT POSTERiOR SEgmENTS. EPidERmal glaNd cEllS PRESENT, iRREgUlaR aNd cONSPicUOUS, 2���4 TRaNSVERSE ROWS PER SEgmENT (Fig. 7F). BRaiN SlighTlY cONcaVE POSTERiORlY. ThREE PaiRS OF PhaRYNgEal glaNdS PRESENT iN IV���VI, all WiTh dORSal cONNEcTiON. PaiRS OF V aNd VI laRgER ThaN ThaT OF VII, WiTh WidE cONNEcTiON (Fig. 7C). ONE PaiR OF cONSPicUOUS OESOPhagEal aPPENdagES cONFiNEd TO IV, WiThOUT bRaNchES (Fig. 7D). INTESTiNal diVERTicUla aT VII/VIII, OccaSiONallY iN VI/VII (Fig. 7B). ANTESEPTalE WiTh FUNNEl aNd Small PaRTS OF NEPhRidial bOdY (Fig. 7G). TWO TYPES OF cOElOmOcYTES (Fig. 7E). MUcOcYTES laRgER aNd lESS NUmEROUS ThaN lENTicYTES. COElOmO-lENTicYTES abUNdaNT, SiZE aS 1/4���1/3 aS mUcOcYTES. DORSal blOOd VESSEl ORigiNaTiNg FROm ThE ENd OF VII. BlOOd cOlORlESS. Differential diagnosis. OUR SPEcimENS cORRESPONd WEll TO Buchholzia appendiculata (BUchhOlZ, 1862) (SchmElZ & COlladO 2010), iN haViNg UP TO 5 chaETaE PER bUNdlE, laRgER SiZE OF cOElOmO-lENTicYTES aNd ThE ShaPE OF ThE iNTESTiNal diVERTicUlUm. B. appendiculata REPROdUcES SEXUallY aNd aSEXUallY bY FRagmENTaTiON. AdUlT SPEcimENS OR SigNS OF aSEXUal REPROdUcTiON (FRagmENTS) WERE NOT FOUNd, ThEREFORE ThE SPEciES idENTiTY OF OUR SPEcimEN REmaiNS UNcERTaiN. ThiS gENUS iS NEW REcORd FOR ChiNa., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on page 407, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176."]}

Fridericia cusanica Schmelz, 2003 (FigURES 3B, C) Fridericia cusanica Schmelz, 2003. Schmelz & Collado 2010. Examined material. XZO201603001, ONE adUlT STaiNEd WhOlE-mOUNTEd SPEcimEN aNd ThREE SPEcimENS iN 70% EThaNOl FROm ThE SamE lOcaliTY. Description. Small SiZE. LENgTh abOUT 3.8���8.5 mm iN ViVO. BOdY WidTh 160���200 ��m aT V, 180���230 ��m aT XII (200���230 ��m aNd 250���300 ��m iN ViVO). SEgmENT NUmbER 32���34. ChaETaE 2 PER bUNdlE ThROUghOUT. EPidERmal glaNd cEllS abSENT. BOdY Wall ThiN. BRaiN SlighTlY cONcaVE aNTERiORlY, TRUNcaTE POSTERiORlY, 125���150 ��m iN lENgTh aNd 70���80 ��m iN WidTh. CliTEllUm aT XII���2 /3XIII, giRdlE-ShaPEd, cEllS iRREgUlaRlY aRRaNgEd, hYalOcYTES laRgER, 13��� 17 ��m iN diamETER, gRaNUlOcYTES 7���10 ��m iN diamETER. OESOPhagEal aPPENdagES UNbRaNchEd, EXTENdiNg iNTO V��� VII. ThREE PaiRS OF PhaRYNgEal glaNdS iN IV���VI, all WiTh WidE dORSal cONNEcTiON aNd VENTRal lObES (Fig. 3B). ThE FiRST PaiR cOmPaRaTiVElY SmallER. FiVE PaiRS OF PREcliTEllaR NEPhRidia FROm VI/VII TO X/XI, NEPhRidial aNTESEPTalE cOmPaRaTiVElY laRgE, 43���50 ��m lONg, 20 ��m WidE. POSTSEPTalE 65���80 ��m lONg, 27���40 ��m WidE. EFFERENT dUcT RiSiNg FROm middlE OF POSTSEPTalE. COElOmO-mUcOcYTES WiThOUT diSTiNcT gRaNUlES, ONlY FaiNTlY TEXTUREd, 20���25 Um iN diamETER, lENTicYTES 2���4 ��m iN diamETER. ChYlUS cEllS cONFiNEd TO IX aNd X. DORSal blOOd VESSEl RiSiNg FROm XIV��� XVII. SPERm FUNNEl Small, 85���106 ��m iN lENgTh, 42���53 ��m iN WidTh. COllaR aS WidE aS OR SlighTlY NaRROWER ThaN FUNNEl bOdY. HEadS OF SPERmaTOZOa 97���106 ��m lONg. VaS dEFERENS lONg, 6���10 ��m WidE, WOUNd iN iRREgUlaR lOOPS iN XII. SEmiNal VESiclE abSENT. GlaNdUlaR bUlb iN XII, Small, abOUT 40 ��m iN diamETER. BURSal SliTS T-ShaPEd. SUbNEURal glaNdS abSENT. SPERmaThEca iN V���VI, WiTh a Small EcTal glaNd, 10 ��m iN diamETER (Fig. 3C). EcTal dUcT lONg aNd ThiN, 200���210 ��m lONg, 10���13 ��m WidE. AmPUlla ONiON-ShaPEd, 42���50 ��m iN diamETER, WiThOUT diVERTicUla. ENTal dUcT SlighTlY ThiNNER ThaN amPUlla, 50���58 ��m lONg, 25���30 ��m WidE. ENTal dUcTS UNiTEd PROXimallY aNd cONNEcTiNg WiTh OESOPhagUS dORSallY iN VI. USUallY 1 maTURE Egg aT a TimE. Differential diagnosis. OUR SPEcimENS cONFORm WEll TO ThE dEScRiPTiON OF F. cusanica giVEN bY SchmElZ (2003), SUch aS ThE bOdY SiZE, 2 chaETaE PER bUNdlE ThROUghOUT, ThE STRUcTURE OF SPERmaThEca, ThE ShaPE OF PhaRYNgEal glaNdS aNd SPERm FUNNEl. ThE ONlY diFFERENcES iS ThE ORigiN OF ThE dORSal blOOd VESSEl (XIV���XVII VS XIII���XIV) aNd ThE iNSERTiON OF ThE NEPhRidial EFFERENT dUcT (FROm ThE middlE OF POSTSEPTalE VS SUbTERmiNal). ThiS SPEciES WaS FOUNd iN GERmaNY, GREEcE, ITalY. IN ChiNa, ThE WORmS WERE FOUNd iN ChaNgbai MOUNTaiN OF JiliN PROViNcE aNd TibET. ThiS iS ThE FiRST REcORdEd iN ChiNa., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 399-400, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917, {"references":["Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82, 1 - 176."]}

Mesenchytraeus spermatoglomeratus sp. nov. (Figures 1, 2, Tables 1, 3) Holotype. Fully mature, whole-mounted specimen, stained, JLO201412005. Type locality. Mt. Changbai, Jilin Province, hardwood forest, 42��180.607''N, 127��50.453''E, 1034 m asl, dark brown forest soil under Quercus mongolica, coll. Z. J. Piao, Dec. 2014. Paratypes. JLO201412003���JLO201412004, two whole mounted adult specimens from Korean pine broadleaved mixed forest, 42��20.150''N, 127��53.056''E, 1084 m asl, dark brown forest soil under Pinus koraiensis, 10 December 2014, coll. Z. J. Piao; JLO201412006, one whole mounted adult specimen from type locality, same data as holotype. JLO201503001���JLO201503002, two whole mounted specimens, fully mature, from secondary Betula platyphylla forest, 42��22.719''N, 128��01.020''E, 786 m asl, dark brown forest soil under Betula platyphylla, 2 April 2015, coll. Z. J. Piao. Etymology. Named after the shape of sperm bundles: "glomeratus" refers to "condensed into a ball". " spermatoglomeratus " refers to the sperm bundles of the new species, rolled into a round ball shape. Diagnosis. This new species is recognized by the following characters, diagnostic in combination: 1) enlarged ventral chaetae in segments V���VI and XI, 2 per bundle; 2) five pairs of preclitellar nephridia in VI/VII to X/XI; 3) sperm sacs asymmetrically paired from XI���XIV to XV���XXIV, containing curly ball-shaped sperm bundles; 4) spermathecae without diverticula, ental ducts connected with oesophagus in VI���VII; 5) atrium tubular, with 4���6 developed prostate glands, distinct from vas deferens; 6) vas deferens very long, extending backwards to XV��� XXII. Description. Small worms, active, twisting when submerged in water, pale in vivo, body wall thin, transparent. Body length 6.5���11.5 mm (holotype 8.0 mm), 7.0��� 12.5 mm in vivo; body width 270���355 ��m at V (330���450 ��m in vivo), 470���575 ��m at clitellum (320���625 ��m in vivo). Segments 28���46 (holotype 34). Head pore transverse slit near the apex of prostomium (Fig. 2A). Epidermal gland cells inconspicuous, almost absent. Chaetal formula: 2,3 - 3,4: 2���5(6) - 2���5(6), up to 6 per bundle in the last segments. Chaetae sigmoid, nodulated, distally thinner and single-pointed. Lateral chaetae 44���100 ��m in length and 3.5���5 ��m in maximal width, shortest in II (44���48 ��m), gradually increasing in size from III backwards, maximal size in IX (80���100 ��m) (Table 1). Ventral chaetae, except those in V, VI and XI, 63���120 ��m in length and 4���7.5 ��m in maximal width (Fig. 1A, D). Ventral chaetae in V, VI and XI reduced to 2 per bundle (occasionally 3) (Fig. 1B, C, E). Ventral chaetae in V and VI longer and stouter than the others even in immature specimens, 126���158 ��m in length and 7.5���11 ��m in maximal thickness (Fig. 1B, C). Ventral chaetae in XI shorter and thinner than in V and VI, but thicker than the ordinary ventral ones, 6���8.5 ��m in maximal thickness (Fig. 1E). Chaetae of XII lacking in fully mature specimens. Clitellum extending from 1/ 2 XI to XIII, elevated conspicuously. Hyalocytes (12���24 ��m in diameter) more abundant than granulocytes, irregularly arranged and in contact with each other. Granulocytes (13���22 ��m in diameter) irregular in shape, having some connection with each other and forming a loose net (Fig. 2B, F). Male pores distinct in the ventral middle of XII. Spermathecal pores paired, in the lateral line at IV/V (Fig. 2K). Length of lateral chaetae (��m) 71���90 71���85 71���80 71���80 65���75 Width of lateral chaetae (��m) 3.5���5 3.5���5 3.5���5 3.5���5 3.5���4.5 Number per bundle 3 3 3 3,4 3 Length of ventral chaetae (��m) 110���120 105���120 90���105 85���102 75���85 Width of ventral chaetae (��m) 6���8.5 6���7.5 5���6 5���6 5���6 Number per bundle 2 2,3 4 4 5 Brain in I-II (Figs. 1J, 2E), trapezoidal, deeply concave anteriorly and slightly incised posteriorly, 137���170 ��m long and 105���125 ��m in maximal width. Blood colourless or slightly yellowish. Dorsal vessel arising from XIV��� XVI. Two pairs of primary pharyngeal glands in IV and V, attached to septa of 4/5 and 5/6 respectively, and both not connected dorsally. Three pairs of secondary lobes ventrally in V���VII, largest in VI. No oesophageal appendages. Intestinal diverticula absent. Chloragogen cells developed, originating from VIII, 12���45 ��m high, absent in clitellum. Coelomocytes abundant, disc-shaped with conspicuous nuclei, 7.5���15.0 ��m in diameter, with uneven refractile granules (Fig. 2C). Five pairs of nephridia in preclitellar segments from VI/VII to X/XI. Anteseptale stalked, containing nephrostome only; postseptale bilobed and with fewer interstitial tissue. Efferent duct arising between the two lobes (Figs. 1F, 2G). Sperm funnels cylindrical, occupying 1/3���1/2 body cavity in XI, 390���440 ��m in length and 122���200 ��m in maximal width. Their ental openings much narrower than funnel body, 43���73 ��m wide. The heads of spermatozoa 17���20 ��m in length (Figs. 1I, 2I). Vasa deferentia with conspicuous cilia in the canal, wound in irregular spirals in coelom from XII and posteriorly into XV���XXII, 18���30 ��m in width, lumen of vasa deferentia 14���24 ��m wide (Fig. 2L). The transition between vas deferens and atrium gradual. Atria in XII���XIII, cylindrical, remarkably wider than vasa deferentia, 415���650 ��m long and 65���85 ��m in maximal width. No cilia observed in atrial canal. Each atrium possessing 4���6 tubular prostate-like glands (each 117���195 ��m in length and 50���68 ��m in width) (Figs. 1H, 2I,J). Each atrium divided into two distinct parts, an ental part (length: 217���400 ��m; width: 27.5���58 ��m) with thin muscle layer and thick epithelium, and an ectal part (length: 200���350 ��m; width: 25���44 ��m) with a muscular duct connecting with the penial bulb. Penial bulb large, compact in ventral of XII, consisting of muscle strands and surrounded by masses of accessory glands of different size (Figs. 1H, 2J). A pair of sperm sacs large from XI���XIV in different size, and backwards extending to XV���XXIV, each containing numerous ball-shaped sperm bundles (diameter: 50���110 ��m), a large number of spermatozoa coiled inside in vivo but much more loose in fixed condition (Fig. 2D,H). Egg sacs paired, large from XIV���XXII, continuing caudad to XVII���XXXIII, usually containing 2���11 mature eggs at a time. One pair of spermathecae in V���VII, without ectal glands. Ectal duct 215���385 ��m long and 37���50 ��m wide, projecting into ampulla. Ampulla spherical, 83���102 ��m in diameter. No diverticula visible. Ampulla filled with spermatozoa in fully mature specimens. Ental ducts stout, 195���244 ��m long and 62���67 ��m wide, connecting to the dorsal side of oesophagus separately in the posterior of VI or anterior of VII (Figs. 1G, 2K). Differential diagnosis (Table 3). This new species is morphologically most similar to the co-occurring species M. gigachaetus Xie, 2012, M. anisodiverticulus Shen et al., 2012 and M. monodiverticulus Shen et al., 2012 and to a further terrestrial species, M. longiductus Christensen & D��zsa-Farkas, 2012, collected in Korea, which also have enlarged ventral chaetae in V���VI, and atria, egg sacs, and spermathecae attached to oesophagus. However, Mesenchytraeus spermatoglomeratus sp. nov. possesses enlarged ventral chaetae in XI and ball-shaped sperm bundles in the sperm sacs, two characteristics absent in the latter four species. Besides, M. gigachaetus differs from M. spermatoglomeratus by a higher number per bundle of enlarged ventral chaetae (3���4), no sperm sac visible and no atrial prostate gland. Mesenchytraeus anisodiverticulus is distinct from this new species by its absence of atrial prostate glands and the presence of two asymmetrical spermathecal diverticula. Mesenchytraeus monodiverticulus is different from M. spermatoglomeratus by its higher number per bundle of enlarged ventral chaetae (4 or 5), absence of atrial prostate glands, and spermatheca with one diverticulum. In Mesenchytraeus longiductus, atrial prostate glands are less numerous (only 2) and fewer accessory glands surround the penial bulb (only 4���5). Five other species (M. crenobius Timm, 1994, M. kontrimavichusi Piper et al., 1982, M. tetrapodus Timm, 1978, M. monochaetus Bretscher, 1900 and M. calyx D��zsa-Farkas et al., 2015) differ from M. spermatoglomeratus in terms of location and number of enlarged chaetae, chaetae formula, spermatheca, origin of dorsal vessel and habitat requirement. Unlike the new species, M. crenobius, M. tetrapodus and M. monochaetus are aquatic enchytraids. They also have 1���2 spermathecal diverticula. The terrestrial M. kontrimavichusi differs from this new species in: spermatheca with one diverticulum, not attached to oesophagus, atria absent, dorsal vessel arising from XV���XVIII. The other terrestrial member, M. calyx, is different from M. spermatoglomeratus by its larger body size (20���39 mm), the location of enlarged chaetae (VII���IX) and spermatheca with 7���9 pointed diverticula., Published as part of Zhang, Junqian, Lu, Yajing & Xie, Zhicai, 2018, Two new Mesenchytraeus species (Annelida: Clitellata: Enchytraeidae) from Changbai Mountain, China, pp. 382-394 in Zootaxa 4496 (1) on pages 383-386, DOI: 10.11646/zootaxa.4496.1.28, http://zenodo.org/record/1446907, {"references":["Christensen, B. & Dozsa-Farkas, K. (2012) A new genus Globulidrilus and three new enchytraeid species (Oligochaeta: Enchytraeidae) from Seoraksan National Park (Korea). Journal of Natural History, 46, 2769 - 2785. https: // doi. org / 10.1080 / 00222933.2012.737038","Timm, T. (1994) Propappidae and aquatic Enchytraeidae (Oligochaeta) from the farthest southeast of Russia. Hydrobiologia, 278, 67 - 78. https: // doi. org / 10.1007 / BF 00142312","Piper, S. R., MacLean, S. F. & Christensen, B. (1982) Enchytraeidae (Oligochaeta) from taiga and tundra habitats of northeastern U. S. S. R. Canadian Journal of Zoology, 60 (11), 2594 - 2609 https: // doi. org / 10.1139 / z 82 - 334","Timm, T. & Popchenko, V. (1978) The aquatic Oligochaeta of the Murmansk Region. Hydrobiological Researches (Tartu), 7, 71 - 132. [in Russian with English abstract]","Bretscher, K. (1900) Mitteilungen uber die Oligochaeten fauna der Schweiz. Revue Suisse de Zoologie, 8, 1 - 44.","Dozsa-Farkas, K., Felfoldi, T. & Hong, Y. (2015) New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea. Zootaxa, 4006 (1), 171 - 197. https: // doi. org / 10.11646 / zootaxa. 4006.1.9"]}

Mesenchytraeus liberothecus sp. nov. (Figures 3, 4, Tables 2, 3) Holotype. Fully mature, whole-mounted specimen collected in April 2015, stained, JLO201504005. Type locality. Mt. Changbai, Jilin Province: Coniferous forest (42°08.177''N, 128°12.739''E; 1285 m asl), dark brown forest soil under Picea asperata, coll. Z. J. Piao. Paratypes. JLO201504006, JLO201504007, two whole-mounted fully mature specimens from type locality, same data as holotype. JLO201504015–JLO201504017, three whole mounted specimens, all fully mature, from Pure larch forest (42°06.391''N, 128°13.078''E; 1389 m asl), dark brown forest soil under Larix gmelinii, 2 April 2015, coll. Z. J. Piao. Etymology. From the Latin adjective "liber", meaning "free", referring to the spermathecae of the new species that are free and not connected via ental ducts with the oesophagus. Diagnosis. This new species is characterized by the following combination of diagnostic traits: 1) enlarged ventral chaetae in segments V–VI, 2–3 per bundle; 2) five pairs of nephridia from VI/VII to X/XI in preclitellar segments; 3) asymmetrical sperm sacs paired, from XIV to XX–XXXIV, containing flame-shaped sperm bundles; 4) spermatheca with two small diverticula and free from oesophagus; 5) atrium cylindrical, with 4–5 large prostate glands; 6) vasa deferentia short, only from XI to XII. Description. Medium sized, body wall thin and transparent, twisting when submerged in water. Body length 13.5–19.5 mm (holotype 17.2 mm) after fixation, 12.0–20.0 mm in vivo; body width 470–700 µm at V (430–550 µm in vivo), 520–750 µm at clitellum (490–625 µm in vivo). Segment number 59–77 (holotype 73). Head pore near the top of prostomium, transverse slit. Epidermal gland cells yellowish but inconspicuous, slightly increased in anterior segments, only one transverse row at level of chaetae in each segment. Chaetal formula: 2–4 - 3,4: 2–4 - 3–5(6), 6 per bundle in posterior segments (Table 2). Chaetae distinctly sigmoid and nodulated, distally thinner and single-pointed. Lateral chaetae 66–100 µm in length, 4.5–7 µm in maximal width, shortest in II and III (66–85 µm), gradually longer from III on, maximal length in V and VI (73–100 µm) (Fig. 3A–D, Table 2). Ventral chaetae, except those in V and VI, 90–166 µm in length and 4.5–9.5 µm in maximal width. Ventral chaetae in V and VI reduced to 2–3 per bundle, 155–190 µm in length and 12–13 µm in maximal thickness (Fig. 3B,C). Chaetae of XII absent in fully mature specimens. Clitellum in XI–XIII, elevated inconspicuously. Hyalocytes (11–17 µm in diameter) irregularly arranged, more abundant and larger than granulocytes (2–5 µm in diameter), often in contact with each other, interspersed with granulocytes (Fig. 4B). Paired male pore distinct and separate, located in the ventral middle of XII. Paired spermathecal pores in the lateral line of VI/V. Brain small, trapezoidal, incised anteriorly, truncate or weakly concave posteriorly, 150–180 µm long and 120– 170 µm in maximal width (Figs. 3F, 4A). Blood colourless. Dorsal vessel arising from XXII. Two pairs of primary pharyngeal glands in IV and V, both not connected dorsally and attached to respective posterior septa. Three pairs of secondary lobes ventrally in V–VII, in V smallest. No oesophageal appendages. Intestinal diverticula absent. Chloragogen cells developed, originating from VI, 26–47 µm high, absent in clitellar region. Coelomocytes elliptic with conspicuous nuclei, densely distributed in anterior body cavity, 15–17 µm in length and 20–24 µm in width, evenly granulated (Fig. 4F). Preclitellar nephridia 5 pairs from VI/VII to X/XI. Nephridial anteseptale containing nephrostome only, and postseptale bilobed with undeveloped interstitial tissue. Efferent duct arising between the two lobes. Sperm funnel small, trumpet-shaped, in segment XI, 150–200 µm in length and 60–100 µm in maximal width. Opening of sperm funnel much wider than funnel body, 150–250 µm wide. Heads of spermatozoa 32–61 µm long (Figs. 3E, 4C). Vasa deferentia short, with conspicuous cilia in the canal, wound in irregular spirals in coelom from XI to XII, 22–27 µm in width, lumen of vasa deferentia 15–19 µm wide, merging with atria gradually. Atria in XII, cylindrical, conspicuously wider than vasa deferentia, 220–320 µm long and 37–55 µm in maximal width, with 4– 5 prostate-like glands (length: 117–122 µm; width: 51–56 µm) (Figs. 3G, 4D). Atrium connected to penial bulb in XII. Penial bulb compact ventrally in XII, surrounded by several accessory glands. One pair of asymmetrical sperm sacs, large from XIV to XX–XXXIV, containing numerous flame-shaped sperm bundles (Fig. 4G). Each bundle 97–118 µm long, with spermatozoal heads clumped at one end (20–24 µm wide and wider than tails) (Fig. 4H). A pair of egg sacs present, extending into XXI–XXVIII, usually containing 3–13 mature eggs at a time. Spermathecae one pair in V, no ectal glands. Ectal duct 215–325 µm long and 37–64 µm wide, projecting into ampulla. Ampulla cup-shaped, maximal diameter 83–88 µm, carrying two oval-shaped diverticula (85–97 µm in length and 61–73 µm in width). Ampulla filled with spermatozoa in fully mature specimens. Spermathecae without ental duct, free in the body cavity of segment V (Fig. 4E). Differential diagnosis (Table 3). The terrestrial species M. kontrimavichusi, inhabiting the region nearby Chaun Bay in the Magadan Region, Russia, resembles M. liberothecus most by its spermathecae detached from oesophagus and the presence of both sperm sacs and egg sacs. However, M. kontrimavichusi differs from this new species by the location of enlarged chaetae (V–IX), spermathecae with one diverticulum and reaching backwards to VII and the absence of an atrium. All remaining species with enlarged ventral chaetae differ from this new species in the attachment of spermathecae to the oesophagus. In addition, the aquatic members of M. crenobius, M. tetrapodus and M. monochaetus are different from this new species by the location and number of enlarged chaetae, and by the origin of the dorsal vessel. The co-occurring species of M. gigachaetus, M. anisodiverticulus and M. monodiverticulus are distinct from this new species by their higher number of enlarged chaetae per bundle, the origin of the dorsal vessel, the structure of the spermathecae, and in details of the sperm sacs and atrial prostate glands. The main characters that discriminate M. longiductus from this new species are: spermatheca with no diverticula and atrium with lower number of prostate glands (only 2). The main differences of M. calyx from M. liberothecus are as follows: large body length (20–39 mm), location of enlarged chaetae and spermatheca with 7–9 pointed diverticula. The major differences between M. liberothecus and M. spermatoglomeratus sp. n. are the locations of enlarged chaetae, the origin of dorsal vessel and the structure of the spermatheca.

Enchytraeus sp. Examined material. TWO SPEcimENS iN 70% EThaNOl. Descriptions. Small SPEciES. BOdY lENgTh 1.9���2.4 mm (4���9 mm iN ViVO). BOdY WidTh 210���260 ��m aT V, 250��� 320 ��m aT XII. HEad PORE aT 0/I, lONgiTUdiNal. EPidERmal glaNd cEllS iNcONSPicUOUS, 3���4 TRaNSVERSE ROWS PER SEgmENT. ChaETaE FORmUla: 2,3 ��� 2,3: 2,3 ���2,3. CliTEllUm aT XII���XIII, SlighTlY ElEVaTEd, cEllS iN TRaNSVERSE PaTTERN, hYalOcYTES mORE ThaN gRaNUlOcYTES. BRaiN cONcaVE aNTERiORlY, TRUNcaTE POSTERiORlY, 100���110 ��m iN lENgTh, 55���64 ��m iN WidTh. ONE PaiR OF OESOPhagEal aPPENdagES aT IV���V, STOUT, WiThOUT bRaNchES. ThREE PaiRS OF PhaRYNgEal glaNdS aT IV/V���VI/VII, all SEPaRaTE dORSallY. ThE ThiRd PaiR WiTh VENTRal lObES. FiVE PaiRS OF PREcliTEllaR NEPhRidia iN VI/VII���X/XI. DORSal blOOd VESSEl RiSiNg FROm XII���XIII. BlOOd cOlORlESS. COElOmOcYTES 15���19 ��m iN diamETER. SPERm FUNNEl Small, 2���2.5 TimES aS lONg aS WidE, 68���76 ��m iN lENgTh, aNd 24���27 ��m iN WidTh. COllaR cONSPicUOUS, SlighTlY SmallER ThaN FUNNEl bOdY, 3���5 ��m high. VaS dEFERENS lONg aNd ThiN, iRREgUlaR WOUNd iN lOOPS iN XII. SEmiNal VESiclE iN XI, Small. SPERmaThEca WiTh EcTal glaNdS. EcTal dUcT 54���60 ��m lONg, 12���15 ��m WidE, gRadUallY WidENiNg. AmPUlla SPiNdlE-ShaPEd. ENTal dUcT 10���13 ��m lONg. 1���10 maTURE EggS aT a TimE. Remarks. IN ChiNa, Enchytraeus SP. WaS FOUNd iN ChaNgbai MOUNTaiN OF JiliN PROViNcE aNd TibET., Published as part of Lu, Yajing, Xie, Zhicai & Zhang, Junqian, 2018, Preliminary taxonomical investigation of soil enchytraeids (Clitellata, Enchytraeidae) from south region of Tibet, China, pp. 395-410 in Zootaxa 4496 (1) on pages 407-408, DOI: 10.11646/zootaxa.4496.1.29, http://zenodo.org/record/1446917

Mesenchytraeus liberothecus sp. nov. (Figures 3, 4, Tables 2, 3) Holotype. Fully mature, whole-mounted specimen collected in April 2015, stained, JLO201504005. Type locality. Mt. Changbai, Jilin Province: Coniferous forest (42��08.177''N, 128��12.739''E; 1285 m asl), dark brown forest soil under Picea asperata, coll. Z. J. Piao. Paratypes. JLO201504006, JLO201504007, two whole-mounted fully mature specimens from type locality, same data as holotype. JLO201504015���JLO201504017, three whole mounted specimens, all fully mature, from Pure larch forest (42��06.391''N, 128��13.078''E; 1389 m asl), dark brown forest soil under Larix gmelinii, 2 April 2015, coll. Z. J. Piao. Etymology. From the Latin adjective "liber", meaning "free", referring to the spermathecae of the new species that are free and not connected via ental ducts with the oesophagus. Diagnosis. This new species is characterized by the following combination of diagnostic traits: 1) enlarged ventral chaetae in segments V���VI, 2���3 per bundle; 2) five pairs of nephridia from VI/VII to X/XI in preclitellar segments; 3) asymmetrical sperm sacs paired, from XIV to XX���XXXIV, containing flame-shaped sperm bundles; 4) spermatheca with two small diverticula and free from oesophagus; 5) atrium cylindrical, with 4���5 large prostate glands; 6) vasa deferentia short, only from XI to XII. Description. Medium sized, body wall thin and transparent, twisting when submerged in water. Body length 13.5���19.5 mm (holotype 17.2 mm) after fixation, 12.0���20.0 mm in vivo; body width 470���700 ��m at V (430���550 ��m in vivo), 520���750 ��m at clitellum (490���625 ��m in vivo). Segment number 59���77 (holotype 73). Head pore near the top of prostomium, transverse slit. Epidermal gland cells yellowish but inconspicuous, slightly increased in anterior segments, only one transverse row at level of chaetae in each segment. Chaetal formula: 2���4 - 3,4: 2���4 - 3���5(6), 6 per bundle in posterior segments (Table 2). Chaetae distinctly sigmoid and nodulated, distally thinner and single-pointed. Lateral chaetae 66���100 ��m in length, 4.5���7 ��m in maximal width, shortest in II and III (66���85 ��m), gradually longer from III on, maximal length in V and VI (73���100 ��m) (Fig. 3A���D, Table 2). Ventral chaetae, except those in V and VI, 90���166 ��m in length and 4.5���9.5 ��m in maximal width. Ventral chaetae in V and VI reduced to 2���3 per bundle, 155���190 ��m in length and 12���13 ��m in maximal thickness (Fig. 3B,C). Chaetae of XII absent in fully mature specimens. Clitellum in XI���XIII, elevated inconspicuously. Hyalocytes (11���17 ��m in diameter) irregularly arranged, more abundant and larger than granulocytes (2���5 ��m in diameter), often in contact with each other, interspersed with granulocytes (Fig. 4B). Paired male pore distinct and separate, located in the ventral middle of XII. Paired spermathecal pores in the lateral line of VI/V. Brain small, trapezoidal, incised anteriorly, truncate or weakly concave posteriorly, 150���180 ��m long and 120��� 170 ��m in maximal width (Figs. 3F, 4A). Blood colourless. Dorsal vessel arising from XXII. Two pairs of primary pharyngeal glands in IV and V, both not connected dorsally and attached to respective posterior septa. Three pairs of secondary lobes ventrally in V���VII, in V smallest. No oesophageal appendages. Intestinal diverticula absent. Chloragogen cells developed, originating from VI, 26���47 ��m high, absent in clitellar region. Coelomocytes elliptic with conspicuous nuclei, densely distributed in anterior body cavity, 15���17 ��m in length and 20���24 ��m in width, evenly granulated (Fig. 4F). Preclitellar nephridia 5 pairs from VI/VII to X/XI. Nephridial anteseptale containing nephrostome only, and postseptale bilobed with undeveloped interstitial tissue. Efferent duct arising between the two lobes. Sperm funnel small, trumpet-shaped, in segment XI, 150���200 ��m in length and 60���100 ��m in maximal width. Opening of sperm funnel much wider than funnel body, 150���250 ��m wide. Heads of spermatozoa 32���61 ��m long (Figs. 3E, 4C). Vasa deferentia short, with conspicuous cilia in the canal, wound in irregular spirals in coelom from XI to XII, 22���27 ��m in width, lumen of vasa deferentia 15���19 ��m wide, merging with atria gradually. Atria in XII, cylindrical, conspicuously wider than vasa deferentia, 220���320 ��m long and 37���55 ��m in maximal width, with 4��� 5 prostate-like glands (length: 117���122 ��m; width: 51���56 ��m) (Figs. 3G, 4D). Atrium connected to penial bulb in XII. Penial bulb compact ventrally in XII, surrounded by several accessory glands. One pair of asymmetrical sperm sacs, large from XIV to XX���XXXIV, containing numerous flame-shaped sperm bundles (Fig. 4G). Each bundle 97���118 ��m long, with spermatozoal heads clumped at one end (20���24 ��m wide and wider than tails) (Fig. 4H). A pair of egg sacs present, extending into XXI���XXVIII, usually containing 3���13 mature eggs at a time. Spermathecae one pair in V, no ectal glands. Ectal duct 215���325 ��m long and 37���64 ��m wide, projecting into ampulla. Ampulla cup-shaped, maximal diameter 83���88 ��m, carrying two oval-shaped diverticula (85���97 ��m in length and 61���73 ��m in width). Ampulla filled with spermatozoa in fully mature specimens. Spermathecae without ental duct, free in the body cavity of segment V (Fig. 4E). Differential diagnosis (Table 3). The terrestrial species M. kontrimavichusi, inhabiting the region nearby Chaun Bay in the Magadan Region, Russia, resembles M. liberothecus most by its spermathecae detached from oesophagus and the presence of both sperm sacs and egg sacs. However, M. kontrimavichusi differs from this new species by the location of enlarged chaetae (V���IX), spermathecae with one diverticulum and reaching backwards to VII and the absence of an atrium. All remaining species with enlarged ventral chaetae differ from this new species in the attachment of spermathecae to the oesophagus. In addition, the aquatic members of M. crenobius, M. tetrapodus and M. monochaetus are different from this new species by the location and number of enlarged chaetae, and by the origin of the dorsal vessel. The co-occurring species of M. gigachaetus, M. anisodiverticulus and M. monodiverticulus are distinct from this new species by their higher number of enlarged chaetae per bundle, the origin of the dorsal vessel, the structure of the spermathecae, and in details of the sperm sacs and atrial prostate glands. The main characters that discriminate M. longiductus from this new species are: spermatheca with no diverticula and atrium with lower number of prostate glands (only 2). The main differences of M. calyx from M. liberothecus are as follows: large body length (20���39 mm), location of enlarged chaetae and spermatheca with 7���9 pointed diverticula. The major differences between M. liberothecus and M. spermatoglomeratus sp. n. are the locations of enlarged chaetae, the origin of dorsal vessel and the structure of the spermatheca., Published as part of Zhang, Junqian, Lu, Yajing & Xie, Zhicai, 2018, Two new Mesenchytraeus species (Annelida: Clitellata: Enchytraeidae) from Changbai Mountain, China, pp. 382-394 in Zootaxa 4496 (1) on pages 387-390, DOI: 10.11646/zootaxa.4496.1.28, http://zenodo.org/record/1446907

Buchholzia sp. (FigURES 7A–G) Examined material. XZO201510004, XZO201510008, XZO201510009, XZO201510010, FOUR immaTURE SPEcimEN, STaiNEd, WhOlE-mOUNTEd. MORE ThaN 20 SPEcimENS iN 70% EThaNOl, all immaTURE. Descriptions. MEdiUm SiZE. BOdY cOlOR WhiTE iN ViVO. BOdY lENgTh 3.6–4 mm. BOdY WidTh 140–175 Μm. SEgmENTS 32–36. A maXimUm OF 5 chaETaE PER bUNdlE. ChaETaE WEaklY SigmOid, WiThOUT NOdUlUS (Fig. 7A). ChaETaE 2–3 PER bUNdlE aT aNTERiOR SEgmENTS, 4–5 PER bUNdlE aT POSTERiOR SEgmENTS. EPidERmal glaNd cEllS PRESENT, iRREgUlaR aNd cONSPicUOUS, 2–4 TRaNSVERSE ROWS PER SEgmENT (Fig. 7F). BRaiN SlighTlY cONcaVE POSTERiORlY. ThREE PaiRS OF PhaRYNgEal glaNdS PRESENT iN IV–VI, all WiTh dORSal cONNEcTiON. PaiRS OF V aNd VI laRgER ThaN ThaT OF VII, WiTh WidE cONNEcTiON (Fig. 7C). ONE PaiR OF cONSPicUOUS OESOPhagEal aPPENdagES cONFiNEd TO IV, WiThOUT bRaNchES (Fig. 7D). INTESTiNal diVERTicUla aT VII/VIII, OccaSiONallY iN VI/VII (Fig. 7B). ANTESEPTalE WiTh FUNNEl aNd Small PaRTS OF NEPhRidial bOdY (Fig. 7G). TWO TYPES OF cOElOmOcYTES (Fig. 7E). MUcOcYTES laRgER aNd lESS NUmEROUS ThaN lENTicYTES. COElOmO-lENTicYTES abUNdaNT, SiZE aS 1/4–1/3 aS mUcOcYTES. DORSal blOOd VESSEl ORigiNaTiNg FROm ThE ENd OF VII. BlOOd cOlORlESS. Differential diagnosis. OUR SPEcimENS cORRESPONd WEll TO Buchholzia appendiculata (BUchhOlZ, 1862) (SchmElZ & COlladO 2010), iN haViNg UP TO 5 chaETaE PER bUNdlE, laRgER SiZE OF cOElOmO-lENTicYTES aNd ThE ShaPE OF ThE iNTESTiNal diVERTicUlUm. B. appendiculata REPROdUcES SEXUallY aNd aSEXUallY bY FRagmENTaTiON. AdUlT SPEcimENS OR SigNS OF aSEXUal REPROdUcTiON (FRagmENTS) WERE NOT FOUNd, ThEREFORE ThE SPEciES idENTiTY OF OUR SPEcimEN REmaiNS UNcERTaiN. ThiS gENUS iS NEW REcORd FOR ChiNa.

Chen, Jing, Jiang, Wanxiang, Xie, Zhicai (2016): First records of Enchytraeidae (Annelida, Clitellata) from the Three Parallel Rivers region. Zootaxa 4093 (2): 275-284, DOI: http://doi.org/10.11646/zootaxa.4093.2.8

Mesenchytraeus laojunensis sp. nov. (Figures 2, 3, Tables 1, 2) Type material. Holotype. Fully mature, whole-mounted specimen, stained, YNO 201400001. Coniferous forest, Mt. Laojun, Yunnan Province (99 �� 43.185 E, 26 �� 37.956 N, 3958 m above sea level), under snow, in dark, sandy soil, under roots of Abies and moss, coll. J. Chen and W. X. Jiang, 27 April 2014. Paratypes. YNO 201200002 ���10, 4 dissected and 5 whole-mounted adult specimens, type locality, collection data as for holotype. Other examined material. About 10 submature and 15 immature specimens, also from type locality, March 2012, October 2013 and 2014, coll. J. Chen and W.X. Jiang. Etymology. The new species is named after the type locality of Laojun Mountain in the Southwestern region of China. Description. Worms stout, grey or yellowish in vivo but intensely white in some preclitellar regions due to accumulations of coelomocytes. Body length 18���28 mm in vivo and 17.5���23 mm after fixation (holotype: 22 mm), body width 0.7���0.8 mm at V, 0.8 ���1.0 mm at clitellum (Fig. 3 A). Segment number 64���72 (holotype: 72). Head pore near the apex of prostomium, longitudinal slit (Fig. 3 B). Epidermal gland cells conspicuous in I���III (especially on peristomium, with irregular distribution and accumulation at level of chaetae) but underdeveloped in remaining segments. Chaetal formula: 3,4 ��� 3,4: 4���6 ��� 4,5. Chaetae sigmoid and nodulated, distally thinner and simplepointed. Chaetae shortest in II (Fig. 2 A), reaching maximum length in VII (Fig. 2 B���C), and gradually reducing posteriorly (Table 1). Lateral chaetae 90���120 ��m in length, 6���8 ��m in width. Ventral chaetae 95���152 ��m in length, 6���11 ��m in width, maximum width in VII (Table 1). Chaetae of XII lacking in mature specimens. Clitellum elevated conspicuously, in XII���XIII (1 / 3 XI ���XIII in some specimens). Granulocytes and hyalocytes irregularly arranged, the former often in contact with each other, and with larger proportional distribution region than the latter (Figs. 2 E, 3 E). Two separate male pores ventro-laterally in the middle of XII. Paired spermathecal pores at 4 / 5 of each lateral line. Brain (Fig. 3 B) in I���II, trapezoidal, deeply concave anteriorly and weakly incised posteriorly, 150���250 ��m wide and 200���300 ��m long. Dorsal vessel arising from intestinal blood sinus in XIII, anterior bifurcation beneath front of brain, circumesophageal connectives merging ventrally in IV. Two pairs of circumesophageal (lateral) commissures connecting dorsal and ventral vessel, one in III (above pharynx) and another in IV. Blood colorless. Two pairs of primary pharyngeal glands in 4 / 5 and 5 / 6, both without dorsal connection and attached to septa (Fig. 3 A). Four pairs of secondary pharyngeal glands in VI���IX (Fig. 3 A). Gradual transition between oesophagus and intestine. No esophageal appendage. No intestinal diverticula. Chloragogen cells brownish, dense, granulated, beginning from V backwards. Coelomocytes (Fig. 2 F) lemon-shaped, densely distributed, more concentrated in anterior segments, dark in transmitted light due to numerous refractile droplets. Its live size from 40 to 55 ��m in length by 19 to 25 ��m in width. Nephridia from 6 / 7 backwards, five pairs in preclitellar region. Anteseptale containing funnel only, about 50 ��m long, postseptale bilobed, with folded canal and little interstital tissue, 120��� 150 ��m long and 50 ��m wide, with efferent duct arising anteroventrally between the two lobes, close to septum. Sperm funnel much developed, long, cylindrical, occupying segments XI���XII; fixed dimensions: length 900��� 2250 ��m, width 200���300 ��m (Figs. 2 D, 3 C); collar as wide as or slightly wider than funnel body. Heads of spermatozoa ca. 22���33 ��m long. Vas deferens with ciliated canal, ca. 25���38 ��m wide, wound in irregular spirals in coelom of XII���XIV, and entering subterminally into the atrium. Atrium in XII, distinct, cylindrical (Fig. 2 I), ca. 100���130 ��m wide in vivo, length 300���400 ��m, connecting with penial bulbs centrally in XII. Atrial glands absent. Penial bulbs ventral, compact, consisting of masses of glandular cells and muscle strands, ca. 160���200 ��m in diameter. Several accessory copulatory glands extending in different directions around the male pore (Fig. 2 I). Testes in XI, compact. One pair of well-developed and asymmetrical sperm sacs originating from XII and extending backward into XVII���XXII, containing numerous flame-shaped sperm bundles (Figs. 2 G, 3 D). Spermatozoal heads in the wider part of the bundle and tails in the narrower one; length of a sperm bundle ca. 500��� 600 ��m, width ca. 50���70 ��m. Egg sac present, extending into XIX. One or two eggs mature at a time. Spermathecae confined to V, external openings at midline of 4 / 5 (Fig. 2 H). No ectal gland visible. Ectal duct short, 30���50 ��m in length and 60���80 ��m in maximal width, thick-walled, both epidermis and muscle layers welldeveloped. Ectal duct expanding abruptly into onion-shaped ampulla (ca. 200 ��m in diameter); ampulla continued into the narrowing ental duct. Each ampulla with one diverticulum. Ampullar diverticulum elongate and cylindrical, thick walled, 250���320 ��m in length and 130���180 ��m in width. Ental ducts ca. 70���90 ��m wide and 48��� 49 ��m long, thin-walled, connecting with oesophagus separately in posterior of V. DNA sequences. Fragments of the 16 S rDNA (Genbank Acc. No. KU 360271), 28 S rDNA (Acc. No. KU 360272) and 12 S rDNA (Acc. No. KU 360273) of three non-type specimens of M. laojunensis sp. nov. obtained from the type locality were sequenced and deposited in GenBank. Remarks. Mesenchytraeus laojunensis sp. nov. is differentiated from all its congeners by the combination of the following characters: 1) secondary pharyngeal glands extending to IX; 2) coelomocytes with distinct refractile vesicles; 3) much swollen spermathecal ampulla associated with one diverticulum, with ental duct communicating dorsally with oesophagus in V; 4) sperm funnel cylindrical and very long (up to 2000 ��m in length); 5) spermatozoa forming multiple flame-shaped sperm bundles in sperm sacs with spermatozoal heads clumped at one end; 6) vas deferens extending backwards to XIV and communicating subterminally with enlarged atrium; 7) sperm sacs extending backward into XVII���XXII; 8) well-developed accessory glands around the male pores (Table 2). Among these traits, both the extra long sperm funnel and the subterminal entering of vas deferens into the atrium are exceptional traits in Mesenchytraeus. The new species belongs morphologically to a group of Mesenchytraeus species that is characterized by the absence of enlarged chaetae, spermathecae communicating with oesophagus and each ampulla bearing one diverticulum (Christensen & D��zsa���Farkas 1999; Healy & Timm 2000; Schmelz & Collado 2010, 2012). Five species have thus far been reported in this group. Among them, M. celticus Southern 1909, described from moist soil in Ireland and Scotland, is most similar to the new species by its large body size, the origin of the dorsal vessel (XIII), the backward extension of the pharyngeal glands, and the presence of several accessory glands around the male pore. M. celticus differs from the new species by a higher number of chaetae per bundle (up to 13), a subcylindrical and thin-walled ampulla with smaller diverticulum, pear-shaped sperm funnel (length: width ratio ca. 2: 1) associated with a short sperm duct, and an indistinct atrium (Southern 1909; Schmelz & Collado 2010) (Table 2). Characters of the remaining four species that differ from those of the new species are as follows. Mesenchytraeus kuril Healy & Timm, 2000, described from a small river in Kamčatka, Russia, has three pairs of primary glands in 3 / 4���5 / 6, only one pair of preclitellar nephridia and 4���5 pairs in the postclitellar region at XIV��� XVIII���XX, an indistinct spermathecal ampulla, a sperm funnel 3���4 times as long as wide, and no atrium and accessory copulatory glands (Healy & Timm 2000). Mesenchytraeus ogloblini Černosvitov, 1928, another riverdwelling species described from the Eastern Carpathians in South-East Europe, has secondary pharyngeal glands in V���VII as large as or larger than the primary glands, smaller coelomocytes (length ca. 15 ��m), a shorter vas deferens entering terminally into a somewhat swollen atrium, penial bulb with only two large and stalked accessory glands, and a smaller and trumpet-shaped sperm funnel (length: width ratio ca. 1.5: 1) (Černosvitov 1928; Schmelz & Collado 2010). Mesenchytraeus viivi Timm, 1978, described from lake sediments of the Kola Peninsula, Russia, differs from M. laojunensis in a higher number of chaetae (up to 9 per bundle), a more posterior origin of the dorsal vessel (XVI���XVII), a lower number of secondary pharyngeal glands (V���VI/VII), a smaller sperm funnel (1.5: 1) associated with a shorter sperm duct, a slightly swollen spermathecal ampulla (twice as wide as ectal duct); it further has occasionally two ampullar diverticula and possibly one small ectal gland at the spermathecal orifice (Timm & Popchenko 1978; Schmelz & Collado 2010). Mesenchytraeus torbeni Christensen & D��zsa-Farkas, 1999 is a genuine terrestrial enchytraeid species collected in the North Yamal Peninsula of the Siberian tundra. It differs from the new species in: three lobed secondary pharyngeal glands in V���VII, sperm sacs absent or small (confined to XII or XIII), sperm funnel smaller, 1.2 times as long as wide, sperm duct shorter, only two large accessory glands around each male pore, an undeveloped spermathecal ampulla (ca. 1.4: 1 as wide as ectal duct), and a smaller ampullar diverticulum (Christensen & D��zsa���Farkas 1999) (Table 2). To date, only three species of Mesenchytraeus are known that possess the specific trait of regular sperm bundles in the sperm sacs, M. gigachaetus Xie, 2012 (= M. megachaetus Shen et al., 2011), M. anisodiverticulatus Shen et al., 2012 and M. monodiverticulus Shen et al., 2012 (Shen et al. 2011, 2012a,b; Xie 2012). All of them were described from China. They diifer from M. laojunensis sp. nov. in enlarged ventral chaetae in some preclitellar bundles (Shen et al. 2011, 2012a,b; Xie 2012). In particular, the new species otherwise resembles M. monodiverticulus by the single diverticulum in each spermatheca. However, the new species differs from M. monodiverticulus in many traits, such as larger body size, different patterns of clitellar granulocytes and hyalocytes and sperm bundles, and more developed sperm sacs. Geographic distribution and habitat requirements. The worms were only found at the snowpack of the top of Laojun Mountain (ca. 3800���4000 m asl) in Yunnan Province of southwestern China, where the dominant plants are Abies spp., Rhododendron lapponicum and mosses. These worms prefer to live beneath the moss and above the frozen soil, where the soil moisture is ca. 18.3 % and the soil temperature ca. - 2���4 ��C. Mesenchytraeus laojunensis sp. nov. was usually dominant in the enchytraeid assemblages and co-occurred with Ch. ozensis during the sampling seasons., Published as part of Chen, Jing, Jiang, Wanxiang & Xie, Zhicai, 2016, First records of Enchytraeidae (Annelida, Clitellata) from the Three Parallel Rivers region, pp. 275-284 in Zootaxa 4093 (2) on pages 277-282, DOI: 10.11646/zootaxa.4093.2.8, http://zenodo.org/record/261808

Mesenchytraeus laojunensis sp. nov. (Figures 2, 3, Tables 1, 2) Type material. Holotype. Fully mature, whole-mounted specimen, stained, YNO 201400001. Coniferous forest, Mt. Laojun, Yunnan Province (99 ° 43.185 E, 26 ° 37.956 N, 3958 m above sea level), under snow, in dark, sandy soil, under roots of Abies and moss, coll. J. Chen and W. X. Jiang, 27 April 2014. Paratypes. YNO 201200002 –10, 4 dissected and 5 whole-mounted adult specimens, type locality, collection data as for holotype. Other examined material. About 10 submature and 15 immature specimens, also from type locality, March 2012, October 2013 and 2014, coll. J. Chen and W.X. Jiang. Etymology. The new species is named after the type locality of Laojun Mountain in the Southwestern region of China. Description. Worms stout, grey or yellowish in vivo but intensely white in some preclitellar regions due to accumulations of coelomocytes. Body length 18–28 mm in vivo and 17.5–23 mm after fixation (holotype: 22 mm), body width 0.7–0.8 mm at V, 0.8 –1.0 mm at clitellum (Fig. 3 A). Segment number 64–72 (holotype: 72). Head pore near the apex of prostomium, longitudinal slit (Fig. 3 B). Epidermal gland cells conspicuous in I–III (especially on peristomium, with irregular distribution and accumulation at level of chaetae) but underdeveloped in remaining segments. Chaetal formula: 3,4 – 3,4: 4–6 – 4,5. Chaetae sigmoid and nodulated, distally thinner and simplepointed. Chaetae shortest in II (Fig. 2 A), reaching maximum length in VII (Fig. 2 B–C), and gradually reducing posteriorly (Table 1). Lateral chaetae 90–120 Μm in length, 6–8 Μm in width. Ventral chaetae 95–152 Μm in length, 6–11 Μm in width, maximum width in VII (Table 1). Chaetae of XII lacking in mature specimens. Clitellum elevated conspicuously, in XII–XIII (1 / 3 XI –XIII in some specimens). Granulocytes and hyalocytes irregularly arranged, the former often in contact with each other, and with larger proportional distribution region than the latter (Figs. 2 E, 3 E). Two separate male pores ventro-laterally in the middle of XII. Paired spermathecal pores at 4 / 5 of each lateral line. Brain (Fig. 3 B) in I–II, trapezoidal, deeply concave anteriorly and weakly incised posteriorly, 150–250 µm wide and 200–300 µm long. Dorsal vessel arising from intestinal blood sinus in XIII, anterior bifurcation beneath front of brain, circumesophageal connectives merging ventrally in IV. Two pairs of circumesophageal (lateral) commissures connecting dorsal and ventral vessel, one in III (above pharynx) and another in IV. Blood colorless. Two pairs of primary pharyngeal glands in 4 / 5 and 5 / 6, both without dorsal connection and attached to septa (Fig. 3 A). Four pairs of secondary pharyngeal glands in VI–IX (Fig. 3 A). Gradual transition between oesophagus and intestine. No esophageal appendage. No intestinal diverticula. Chloragogen cells brownish, dense, granulated, beginning from V backwards. Coelomocytes (Fig. 2 F) lemon-shaped, densely distributed, more concentrated in anterior segments, dark in transmitted light due to numerous refractile droplets. Its live size from 40 to 55 Μm in length by 19 to 25 Μm in width. Nephridia from 6 / 7 backwards, five pairs in preclitellar region. Anteseptale containing funnel only, about 50 µm long, postseptale bilobed, with folded canal and little interstital tissue, 120– 150 µm long and 50 µm wide, with efferent duct arising anteroventrally between the two lobes, close to septum. Sperm funnel much developed, long, cylindrical, occupying segments XI–XII; fixed dimensions: length 900– 2250 µm, width 200–300 µm (Figs. 2 D, 3 C); collar as wide as or slightly wider than funnel body. Heads of spermatozoa ca. 22–33 µm long. Vas deferens with ciliated canal, ca. 25–38 µm wide, wound in irregular spirals in coelom of XII–XIV, and entering subterminally into the atrium. Atrium in XII, distinct, cylindrical (Fig. 2 I), ca. 100–130 µm wide in vivo, length 300–400 µm, connecting with penial bulbs centrally in XII. Atrial glands absent. Penial bulbs ventral, compact, consisting of masses of glandular cells and muscle strands, ca. 160–200 µm in diameter. Several accessory copulatory glands extending in different directions around the male pore (Fig. 2 I). Testes in XI, compact. One pair of well-developed and asymmetrical sperm sacs originating from XII and extending backward into XVII–XXII, containing numerous flame-shaped sperm bundles (Figs. 2 G, 3 D). Spermatozoal heads in the wider part of the bundle and tails in the narrower one; length of a sperm bundle ca. 500– 600 µm, width ca. 50–70 µm. Egg sac present, extending into XIX. One or two eggs mature at a time. Spermathecae confined to V, external openings at midline of 4 / 5 (Fig. 2 H). No ectal gland visible. Ectal duct short, 30–50 µm in length and 60–80 µm in maximal width, thick-walled, both epidermis and muscle layers welldeveloped. Ectal duct expanding abruptly into onion-shaped ampulla (ca. 200 µm in diameter); ampulla continued into the narrowing ental duct. Each ampulla with one diverticulum. Ampullar diverticulum elongate and cylindrical, thick walled, 250–320 µm in length and 130–180 µm in width. Ental ducts ca. 70–90 µm wide and 48– 49 µm long, thin-walled, connecting with oesophagus separately in posterior of V. DNA sequences. Fragments of the 16 S rDNA (Genbank Acc. No. KU 360271), 28 S rDNA (Acc. No. KU 360272) and 12 S rDNA (Acc. No. KU 360273) of three non-type specimens of M. laojunensis sp. nov. obtained from the type locality were sequenced and deposited in GenBank. Remarks. Mesenchytraeus laojunensis sp. nov. is differentiated from all its congeners by the combination of the following characters: 1) secondary pharyngeal glands extending to IX; 2) coelomocytes with distinct refractile vesicles; 3) much swollen spermathecal ampulla associated with one diverticulum, with ental duct communicating dorsally with oesophagus in V; 4) sperm funnel cylindrical and very long (up to 2000 µm in length); 5) spermatozoa forming multiple flame-shaped sperm bundles in sperm sacs with spermatozoal heads clumped at one end; 6) vas deferens extending backwards to XIV and communicating subterminally with enlarged atrium; 7) sperm sacs extending backward into XVII–XXII; 8) well-developed accessory glands around the male pores (Table 2). Among these traits, both the extra long sperm funnel and the subterminal entering of vas deferens into the atrium are exceptional traits in Mesenchytraeus. The new species belongs morphologically to a group of Mesenchytraeus species that is characterized by the absence of enlarged chaetae, spermathecae communicating with oesophagus and each ampulla bearing one diverticulum (Christensen & Dózsa–Farkas 1999; Healy & Timm 2000; Schmelz & Collado 2010, 2012). Five species have thus far been reported in this group. Among them, M. celticus Southern 1909, described from moist soil in Ireland and Scotland, is most similar to the new species by its large body size, the origin of the dorsal vessel (XIII), the backward extension of the pharyngeal glands, and the presence of several accessory glands around the male pore. M. celticus differs from the new species by a higher number of chaetae per bundle (up to 13), a subcylindrical and thin-walled ampulla with smaller diverticulum, pear-shaped sperm funnel (length: width ratio ca. 2: 1) associated with a short sperm duct, and an indistinct atrium (Southern 1909; Schmelz & Collado 2010) (Table 2). Characters of the remaining four species that differ from those of the new species are as follows. Mesenchytraeus kuril Healy & Timm, 2000, described from a small river in Kamčatka, Russia, has three pairs of primary glands in 3 / 4–5 / 6, only one pair of preclitellar nephridia and 4–5 pairs in the postclitellar region at XIV– XVIII–XX, an indistinct spermathecal ampulla, a sperm funnel 3–4 times as long as wide, and no atrium and accessory copulatory glands (Healy & Timm 2000). Mesenchytraeus ogloblini Černosvitov, 1928, another riverdwelling species described from the Eastern Carpathians in South-East Europe, has secondary pharyngeal glands in V–VII as large as or larger than the primary glands, smaller coelomocytes (length ca. 15 µm), a shorter vas deferens entering terminally into a somewhat swollen atrium, penial bulb with only two large and stalked accessory glands, and a smaller and trumpet-shaped sperm funnel (length: width ratio ca. 1.5: 1) (Černosvitov 1928; Schmelz & Collado 2010). Mesenchytraeus viivi Timm, 1978, described from lake sediments of the Kola Peninsula, Russia, differs from M. laojunensis in a higher number of chaetae (up to 9 per bundle), a more posterior origin of the dorsal vessel (XVI–XVII), a lower number of secondary pharyngeal glands (V–VI/VII), a smaller sperm funnel (1.5: 1) associated with a shorter sperm duct, a slightly swollen spermathecal ampulla (twice as wide as ectal duct); it further has occasionally two ampullar diverticula and possibly one small ectal gland at the spermathecal orifice (Timm & Popchenko 1978; Schmelz & Collado 2010). Mesenchytraeus torbeni Christensen & Dózsa-Farkas, 1999 is a genuine terrestrial enchytraeid species collected in the North Yamal Peninsula of the Siberian tundra. It differs from the new species in: three lobed secondary pharyngeal glands in V–VII, sperm sacs absent or small (confined to XII or XIII), sperm funnel smaller, 1.2 times as long as wide, sperm duct shorter, only two large accessory glands around each male pore, an undeveloped spermathecal ampulla (ca. 1.4: 1 as wide as ectal duct), and a smaller ampullar diverticulum (Christensen & Dózsa–Farkas 1999) (Table 2). To date, only three species of Mesenchytraeus are known that possess the specific trait of regular sperm bundles in the sperm sacs, M. gigachaetus Xie, 2012 (= M. megachaetus Shen et al., 2011), M. anisodiverticulatus Shen et al., 2012 and M. monodiverticulus Shen et al., 2012 (Shen et al. 2011, 2012a,b; Xie 2012). All of them were described from China. They diifer from M. laojunensis sp. nov. in enlarged ventral chaetae in some preclitellar bundles (Shen et al. 2011, 2012a,b; Xie 2012). In particular, the new species otherwise resembles M. monodiverticulus by the single diverticulum in each spermatheca. However, the new species differs from M. monodiverticulus in many traits, such as larger body size, different patterns of clitellar granulocytes and hyalocytes and sperm bundles, and more developed sperm sacs. Geographic distribution and habitat requirements. The worms were only found at the snowpack of the top of Laojun Mountain (ca. 3800–4000 m asl) in Yunnan Province of southwestern China, where the dominant plants are Abies spp., Rhododendron lapponicum and mosses. These worms prefer to live beneath the moss and above the frozen soil, where the soil moisture is ca. 18.3 % and the soil temperature ca. - 2–4 °C. Mesenchytraeus laojunensis sp. nov. was usually dominant in the enchytraeid assemblages and co-occurred with Ch. ozensis during the sampling seasons.

Xie, Zhicai, Rota, Emilia (2001): from China and re-examination of M. hoVbaueri Möller. Journal of Natural History 35 (10): 1417-1431, DOI: 10.1080/002229301317067610, URL: http://www.tandfonline.com/doi/abs/10.1080/002229301317067610