Fridericia bulboides Nielsen and Christensen, 1959

Torii, Takaaki, Akagi, Tomohiro, Uchino, Toru & Kobayashi, Tohru, 2018, New descriptions of enchytraeid species (Clitellata: Enchytraeidae) from Korea, Journal of Species Research 7 (1), pp. 80-91 : 85-86

3. Fridericia bulboides Nielsen and Christensen, 1959

( Fig. 5 )

Fridericia bulboides Nielsen and Christensen, 1959: 72- 75 ; Dózsa-Farkas & Hong, 2010: 31, Table 1; Dózsa-Farkas, Felföldi and Hong, 2015: 173, Table 1, for complete synonym assign: Schmelz (2003).

New Korean name: Myohyang-cham-ae-jireongi (MȒ ḂOiNjffiḍ)

Material examined. Korea, Jeollabuk-do, Buan-gun, Dongjin-myeon , soil in a rice paddy field of agronomical fields (35°46′05.7″N, 126°43′14.7″E, 17 m asl.), 3 April 2014, Y. Hong coll. ; North Korea, Pyunganbuk-do, Mt. Myohyang, Hyangsan at the branch of Chongchon river , litter layers in deciduous forest, 7 July 1988, Csuzdi coll. ; North Korea, Pyunganbuk-do, Mt. Myohyang, litter layers in deciduous forest, Isonnam near to a waterfall, 8 July 1988, Csuzdi coll.

Diagnosis. White worms, 5-9 (12) mm long, 0.25 mm wide with 29-38 segments, chaetae straight and distinctly hooked entally, maximum length ca. 40-50 μm preclitellarly, 60-75 μm postclitellarly, inner chaetae in a bundle shorter than outer chaetae, formula: (1,3)4-4,2: 4,(5)-4,2. Clitellum girdle-shaped, cells mostly reticulate. Oesophageal appendage unbranched very long, much coiled in IV-V, extending to VII (type b) ( Fig. 5A ). Five pairs of preclitellar nephridia from 6/7 to 10/11. Coelomo-mucocytes ( Fig. 5C ) with hyaline matrix at periphery refractile vesicles, type b (according to Möller, 1971). Chylus cells between XI-XV, occupying 2 segments. Dorsal blood vessel originating in XIII-XVII, blood colorless. Seminal vesicle absent or small. Sperm funnels ( Fig. 5B ) about 1.5-2 times longer than wide, bursal slits longitudinal. Male copulatory organ small, often flat. Subneural glands absent. Spermathecal ectal glands globular and sessile, ectal duct long, ampullae onion-shaped without diverticula. Typically proximal ducts of spermathaecae fused at entrance into oesophagus ( Fig. 5D ). 1- 2 eggs mature at a time.

Remarks. Genus Fridericia Michaelsen, 1889 is currently composed of more than 100 valid species. F. bulboides differs from other small Fridericia species with onion-shaped spermathecal ampullae fused one common opening into oesophagus, 4 chaetae in preclitellar bundles, type b coelomo-mucocytes, and characteristic b type oesophageal appendages ( Cech and Dózsa-Farkas, 2005).

Habitat and distribution. Fridericia bulboides is one of the most common species in soil with, a cosmopolitan distribution. Found in limy to sandy, dry and moist, nutrient-rich and nutrient-poor soils. Also found in aquatic, salt marshes, and freshwater habitats ( Schmelz, 2003).

Deposition. NIBRIV0000544612.

Genus Hemifridericia Nielsen and Christensen, 1949 New Korean name: Aegi-ae-jireongi-sok (OinjOiNjffiḍẃ)

Figures

Fig. 5. Fridericia bulboides. A. Oesophageal appendage; B. Sperm funnel; C. Coelomocytes; D. Spermathecae. Scale bars: 50 μm.