Marionina puntaalanensis, Felföldi & Nagy & Dózsa-Farkas, 2024

Felföldi, Tamás, Nagy, Hajnalka & Dózsa-Farkas, Klára, 2024, New data on the polyphyletic Marionina genus (Annelida, Enchytraeidae): description of three new species from European shore habitats, Zoosystematics and Evolution 100 (4), pp. 1269-1286 : 1269-1286

Marionina puntaalanensis sp. nov.

Fig. 1

Type material.

Holotype: Ma. 5, slide No. 3055. Type locality: (Loc. 3.) Italy, Punta Ala Grosseto, Castiglione della Pescaia , decaying seagrass detritus, 42 ° 46 ' 00.0 " N, 10 ° 51 ' 31.0 " E, Leg. András Dózsa-Farkas and Kinga Dózsa-Farkas, 24 Sep 2020.

Paratypes: in total, four specimens: P.146.1 slide No. 3022, P.146.2 slide No. 3056, P.146.3 slide No. 3077, P.146.4 slide No. 3192. Same data as for holotype, 24 Sep 2020 and 26 Nov 2020 .

Further material examined.

Four specimens for DNA analysis, five specimens only in vivo.

Diagnosis.

(1) Small size (body length 2–2.5 mm, 130–185 µm wide at clitellum, in vivo), segment number 19–30; (2) chaetae straight with ental hook, two chaetae in all bundles; (3) clitellum saddle-shaped; (4) first and second pharyngeal glands united dorsally, in V with ventral lobes; the third pair free dorsally with elongated ventral lobes; (5) dorsal vessel from clitellar region, blood colorless, anterior blood vessel bifurcation anteriorly behind the pharynx; (6) three pairs of preclitellar nephridia; (7) coelomocytes disc- or lemon-shaped with granules, 13–20 μm; (8) sperm funnels small, cylindrical, 100–140 μm long in vivo, 1.5–2.5 times longer than wide in vivo, collar high and narrower than funnel body; (9) spermatozoa 38–43 µm long, heads 15–22 µm in vivo; (10) male copulatory organs small and compact; (11) small subneural glands in XIII – XIV; (12) ectal duct of spermatheca surrounded along the length by glands and one larger, 15–27 µm long, sessile gland at orifice. Ampulla oval, 24–40 µm wide and 40–55 µm long in vivo.

Description.

Small species (Fig. 1 A ), holotype 1.9 mm long, 80 µm wide at VIII and 107 µm at clitellum (fixed), segment number 21. Body length of paratypes 2.0– 2.5 mm, width 120–180 µm at VIII and 130–185 µm at clitellum, in vivo, length of fixed specimens 1.5–2.7 mm, width 80–165 µm at VIII and 105–165 at clitellum, segment number 19–30. Chaetae straight with ental hook. Chaetal formula: 2 - 2: 2 - 2 (in one specimen from Castiglione della Pescaia, three chaetae were in one ventral bundle). The chaetae equal in size within the bundles; in the ventral bundles a little longer than in the lateral ones. 15–20 μm in preclitellar segments and 19–20 μm at the posterior end of the body. Clitellum saddle-shaped in XII- 1 / 2 XIII, gland cells squarish, arranged in transverse rows, midventrally absent. Head pore at 0 / I, no dorsal pores. Epidermal gland cells inconspicuous in vivo. Thickness of body wall about 18–20 µm, and cuticle thin <1 µm.

Brain (Fig. 1 B ) ca. 50–60 μm long (fixed), slightly longer than wide, incised posteriorly. Pharynx and postpharyngeal bulbs well developed. Prostomial ganglia absent. In the ventral nerve cord, perikarya continuous. First and second pharyngeal glands compact and united dorsally, in V with ventral lobes; the third pair free dorsally with elongate but stout ventral lobes (Fig. 1 C ). Chloragocytes from IV forming a denser layer from VI, about 15–20 μm long in vivo, filled with refractive globules. Transition between oesophagus and intestine gradual; oesophageal appendage and intestinal diverticula absent. Midgut pars tumida not seen. Dorsal vessel from clitellar region, blood colorless. The dorsal anterior blood vessel bifurcation in III (Fig. 1 D ). All coelomocytes nucleated oval, disc-shaped (Fig. 1 E ) or lemon-shaped (Fig. 1 F ) with granules, 13–20 μm long in vivo and 10–18 μm, fixed. Three pairs of preclitellar nephridia in 6 / 7–8 / 9, preseptal part consisting of funnel and coils of canals, postseptal part elongate, about two times as long as preseptal part, efferent duct terminal (Fig. 1 G ); the first postclitellar pair at 13 / 14 (mostly seven postclitellar pairs). Seminal vesicle absent or small, paired. Sperm funnels small, cylindrical, 100–140 μm long in vivo, 40–75 μm when fixed, and about 1.5–2.5 times longer than wide in vivo (1.5–2 times, when fixed), collar high and narrower than funnel body (Fig. 1 , I). Spermatozoa 38–43 µm long, heads 15–22 µm in vivo and 20–32 µm long and heads 10–13 µm, when fixed. Sperm ducts short, about four times longer than the funnel, coiled into a loose spiral, diameter 7–10 µm in vivo and 4–5 µm, when fixed. Male copulatory organs small and compact, 25–36 µm long, 23–40 µm wide, and 15–30 μm high in vivo (22–30 µm long, 20–27 µm wide, and 25–30 µm high, when fixed). Small subneural glands in XIII – XIV (in one specimen absent). Ectal duct of spermatheca 24–38 µm long, surrounded along the length by glands and one larger, 15–27 µm long, sessile gland at orifice. Ampulla oval, 24–40 µm wide and 40–55 µm long in vivo (20–30 µm wide, 25–35 µm long, fixed), in the lumen with some sperm (Fig. 1 J, K ). Ampulla attached with a short ental duct to the oesophagus. One or two mature eggs at a time.

Etymology.

The new species is named after the Punta Ala beach, where it was found.

Distribution and habitat.

Known from Loc. 3 and Loc. 2., the intertidal zone is near Punta Ala (Grosseto) and Castiglione della Pescaia, Italy, in the decaying seagrass detritus.

Differential diagnosis.

Among the mostly intertidal small Marionina species with two chaetae in all chaetal bundles and without sperm rings in spermathecae, eight species are similar to the new species: M. istriae Giere, 1974 ; M. miniampullacea Shurova, 1978 ; M. magnifica Shurova, 1978 ; M. mica Finogenova, 1972 ; M. aberrans Finogenova, 1973 ; M. elgonensis Černosvitov, 1938 ; M. neroutsensis Coates, 1980 ; and M. mesopsamma Lasserre, 1964 . The main differences are as follows: M. istriae is larger (body length 7–10 mm, segment number 38–43 vs. body length 2–2.5 mm, segment number 19–30), the chaetae are larger (65 µm long vs. 15–20 µm long), and a larger ectal gland is absent. M. miniampullacea is also larger (body length 4–5 mm), the chaetae are also larger (50 µm long), the dorsal vessel origin is in VII, and there is a rosette of glands at the orifice of the spermathecal duct. M. magnifica is larger (body length 4–5 mm), sometimes 3–4 chaetae occur, the chaetae are larger (40–50 µm long), and a larger ectal gland absent. M. mica has three ventral lobes of the pharyngeal glands in IV, V, and VI; the third pair is connected dorsally (vs. only in V; the third pair free); the dorsal vessel origin is in VIII; and the anterior blood vessel bifurcation is prostomial (also known as lumbricillinae-type). In M. aberrans , the cuticle is thick (2.5 µm vs. <1 µm), there is a large rosette of ectal glands, the preseptal part of the nephridia consists only of the funnel, and the sperm duct is long (vs. short). M. elgonensis is similarly small, but the ectal gland of the spermathecal ectal duct is absent. In M. neroutsensis , all pharyngeal glands are without ventral lobes; the ectal glands of spermathecae are absent, but a seminal vesicle is present (vs. absent). M. mesopsamma is larger (6 mm long), has a seminal vesicle, has only two pairs of preclitellar nephridia, and the spermathecae are free.

Figures

Figure 1. Micrograph of Marionina puntaalanensis sp. nov. A. Entire specimen; B. Brain; C. Pharyngeal glands (marked with white arrows; spermathecae marked with black arrows); D. Anterior bifurcation of the dorsal vessel in III; E. Rounded coelomocytes; F. Lemon-shaped coelomocytes; G. Preclitellar nephridium; H, I. Sperm funnels (e = egg); J, K. Spermathecae (ectal glands marked with black arrows, ampullae marked with white arrows). A, C – J. in vivo, B, K. fixed, stained. Scale bars: 500 μm (A); 50 μm (B – D, F, H – J); 20 μm (E, G, K).