Marionina clavata Nielsen & Christensen, 1961

Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, Zootaxa 4896 (1), pp. 1-45 : 31-32

Marionina clavata Nielsen & Christensen, 1961

( Figure 18 )

Material examined. 5 specimens (three were deposited in the National Institute of Biological Resources , Korea; NIBRIV0000866133, NIBRIV0000866134, NIBRIV0000837805, in 70 % ethanol) .

Our observations mostly agree with the description of Nielsen & Christensen (1961). Small worms (4–7 mm long, 280–330 μm wide at XII in vivo), segments 22–27. Chaetae straight, maximum 2 per bundle, absent laterally in VIII–XII (but in the original description in IX–XII). Clitellum saddle-shaped, gland cells pattern irregular ( Fig. 18A ), glands absent midventrally ( Fig. 18B ). Brain incised posteriorly. A pair of short, club-shaped, hollow oesophageal appendages present dorso-laterally in IV ( Figs 18 C–E). All pharyngeal glands connected dorsally ( Fig. 18C ). Dorsal blood vessel origin in XII, anterior bifurcation in I. Coelomocytes oval, 25–28 μm long, finely granulated. Two pairs of preclitellar nephridia at 7/8–8/9, with considerable anteseptale, postseptale with gradual transition into terminal efferent duct ( Fig. 18F ). Sperm funnels ( Fig. 18G ) and penial bulbs small ( Fig. 18B ). Spermathecae possess long ental ducts covered with small glands all along. Ampullae pear-shaped, ental ducts united dorsally and communicating with oesophagus ( Figs 18H, I ).

Distribution and habitat in Korea. Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, Abies holophylla forest, N 37°47’09.03”, E 128°33’42.75”, 969 m asl; Mt. Jumbong, near to Hangyeryong, Inje-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 38°05’17.33”, E 128°23’12.49”, 659 m asl.

Figures

FIGURE 18. Micrographs of Marionina clavata Nielsen & Christensen, 1961. A. Clitellar glands, dorsal view. B. Clitellar glands absent midventrally, latero-ventral view (penial bulbs marked with arrows). C–E. Club-shaped, hollow oesophageal appendages (ph=pharyngeal glands). F. Nephridia. G. Sperm funnel. H–I. Spermathecae. All in vivo. Scale bars 50 μm.