Fridericia cf. loretensis Schmelz, 2003

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, pp. 1957-1996 : 1979-1982

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).

Figures

Figure 13. Fridericia loretensis Schmelz, 2003. a) Segment III to segment VIII, dorsal view. b) Brain. c) Sperm funnel. Scale bars: 50 µm. Abbreviations: oa, oesphageal appendage; st, spermatheca.

Figure 14. Micrographs of Fridericia loretensis Schmelz, 2003. a, c, f, g, i in vivo; b, d, e, h fixed. Scale bars: 50 µm. a) Brain. b) Spermathecae. c) Pharyngeal glands. d) Chaetae. e, f) Sperm funnel. g) Epidermal gland cells. h) Clitellum, ventral view. i) Clitellum, lateral view. Abbreviations: ad, spermathecal ampullae, distal part; ap, spermathecal ampullae, proximal part; bs, bursal slit; dl, dorsal lobes; ec, epidermal gland cell; ed, ectal duct; fp, female pore; gb, male glandular bulb; gr, granulocytes; hy, hyalocytes; sf, sperm funnel; sp, spermatozoa; vl, ventral lobes.