Enchytraeus albidus Henle, 1837

Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, European Journal of Taxonomy 870, pp. 107-145 : 22-24

Enchytraeus albidus Henle, 1837 s. str.

Figs 1F , 6 , Tables 1–2

Material examined

HUNGARY • 16 specs; Budapest; ID 1300 to 1301, 1461 to 1462 , slide 3012, 3013, 3016 to 3018, 3024, 3028, 3044 to 3048 ; ELTE .

Description of new material

We investigated a living population of E. albidus s. str. from the laboratory of Szent István University, Hungary, which was derived from the culture of ECT Oekotoxikologie GmbH, Flörsheim, Germany. From this culture the neotype of E. albidus has been selected ( Erséus et al. 2019). In this way our morphological characters substantially agree with those described in Erséus et al. (2019).

MEASUREMENTS. Segment number 58–65, body length 15.5–20.8 mm, 850–900 μm wide at clitellum in vivo (700–980 μm, when fixed).

CHAETAE. In ventral bundles mostly 3–5 ( Fig. 6A ).

BRAIN. 125–165 μm long, 1.2–1.8 × as long as wide (fixed). PHARYNGEAL GLANDS. Variable, all converging or connected dorsally, or not converging (in Erséus et al. 2019: all converging).

COELOMOCYTES. 17–32 μm long, mostly oval or spindle-shaped, granulated (in Erséus et al. 2019: 10– 20 μm). In the coelomocytes mostly shining, hyaline, round or tetragonal corpuscles (diameter 9–15 μm) are also present, similar to E. adrianensis sp. nov.

CLITELLUM. Hyalocytes and granulocytes of clitellum irregularly arranged dorsally ( Fig. 6B ). Ventral surface of XII with a recess between lip-like folds ( Fig. 6C–D, J ).

NEPHRIDIA. Four pairs of nephridia preclitellarly ( Fig. 6G ).

SPERM FUNNELS. 700–820 μm long in vivo, 5–6 × as long as wide, the collar as wide as funnel body ( Fig. 6H ). Head of spermatozoa 30–60 μm long. Sperm duct ciliated ( Fig. 6E–F ), elongate, about the same width throughout (30–44 μm wide, with 9–16 μm thick wall), coiled, extending into XIV–XVII.

MALE COPULATORY ORGANS. Male glands multiple: one larger rounded primary bulb (65–80 μm, fixed) and numerous smaller glands (40–50 μm, fixed) ( Fig. 6I ).

SPERMATHECAE. Ectal duct of spermatheca 105–200 μm long, diameter of glands around duct 90–130 μm in vivo. Diverticulum of ampulla 180–237 μm long and 70–125 μm wide in vivo ( Figs 1F , 6K–L ).

For similarities and differences of the species of Enchytraeus studied by us, see Table 2 .

Distribution and habitat

Laboratory culture. For additional references, including synonymies and further distributional data, see Erséus et al. (2019).

Figures

Fig. 1. Schematic drawing of spermathecaeof the specimens studied.A. Enchytraeus adrianensissp. nov. B. E. krumbachi (Čejka, 1913). C–D. E. andrasi sp. nov. E. E. andrasiformis sp. nov. F. E. albidus Henle, 1837. G. E. irregularis Nielsen & Christensen, 1961.

Fig. 6. Micrograph of Enchytraeus albidus Henle, 1837 s. str. A–C, E–H, K–L. In vivo. D, I. Fixed, stained. J. Fixed, not stained. A. Chaetae in ventral bundles preclitellarly. B. Clitellar glands, dorsal view. C–D. Ventral recess between the lip-like folds in XII. D. Slide 3047 (ELTE). E–F Sperm ducts (In F the ciliated canal marked with arrow). G. Nephridium. H. Sperm funnel. I. Multiple male glands (larger primary bulb marked with arrows) (slide 3048, ELTE). J. Lip-like fold (slide 3028, ELTE). K–L. Spermathecae (diverticula marked with black arrow, glands at ectal duct marked with white arrow). Scale bars = 50 μm.