Fridericia cf. sohlenii Rota, Healy & Erséus, 1998

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 : 30-31

Fridericia cf. sohlenii Rota, Healy & Erséus, 1998

( Figure 16 )

Material examined. Five specimens (three were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000860938, in 70 % ethanol).

Our observations substantially agree with the description of Rota, Healy & Erséus (1998), except for a few traits (see details in discussion). Middle-large worms, 10–14 mm long, 390–430 μm wide at clitellum in vivo, segments 40–49 (in the original description the number of segments is slightly higher: 45–56). Body covered with debris and soil particles. Chaetae 2 in all bundles, several parcels of detached chaetae in the coelom ( Fig. 16F ). Clitellum girdle-shaped, gland cells form an irregular pattern ( Figs 16B, C ), between the penial bulbs mostly granular cells, but some hyaline cells can occur ( Fig. 16D ). Brain about twice as long as wide ( Fig. 16A ). Oesophageal appendages a-type. Dorsal blood vessel from XV–XVI, chylus cells in X–XI, occupying 2 segments. Mucocytes 27–36 μm long with refractile granules at periphery (b-type) ( Figs 16 F–G). Lenticytes large, 9–12 μm long. Five pairs of preclitellar nephridia at 6/7–10/11. Seminal vesicle absent. Sperm funnels cylindrical, 135–157 μm long, 1.8–3 times longer than wide in vivo ( Fig. 16H ), uniformly granular. Penial bulbs about 160 μm long and 90 μm wide in vivo ( Fig. 16D ). Bursal slit not T-shaped as in the original description, but longitudinal. Spermathecal ampulla carrying two rounded sessile diverticula. Ectal duct long, about 190–250 μm long and 15 μm wide, with one or two ectal glands at orifice. Diverticula mostly empty; sperm, when present, not rotating ( Figs 16I, J ).

Distribution and habitat in Korea. Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Quercus mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers, mixed forest, N 37°47’03.63”, E 128°33’44.06”, 906 m asl.

Figures

FIGURE 16. Micrographs of Fridericia cf. sohlenii Rota, Healy & Erséus, 1998. A. Brain. B. Clitellar glands, dorsal view. C. Clitellar region, lateral view (upside down). D. Clitellar glands, ventral view of the gland-free surface around the bursal slits (marked with arrows). E. Pharyngeal glands (marked with black arrows); spermathecae (marked with white arrow). F. Detached chaetae in coelom. G. Nucleated coelomocytes (b-type). H. Sperm funnel. I, J. Spermathecae. All in vivo. Scale bars 50 μm, C 100 μm.