Cernosvitoviella farkasi, Dózsa-Farkas, Klára, Csitári, Bianka & Felföldi, Tamás, 2017

Dózsa-Farkas, Klára, Csitári, Bianka & Felföldi, Tamás, 2017, A new Cernosvitoviella species (Clitellata: Enchytraeidae) and its comparison with other Cernosvitoviella species from Sphagnum mires in Hungary, Zootaxa 4254 (3), pp. 322-338 : 324-326

Cernosvitoviella farkasi sp. n.

( Figures 1 A, 2–4)

Holotype. C4 slide No.1064, adult, stained whole mounted specimen.

Type locality. Kȏszeg Mts. , near to the Sphagnum mire, 47o24.180N 16o33.531E, 349 m asl, in a young Scots pine forest with Molinia , mud, leg. K. Dózsa-Farkas, J. Farkas, Z. Tóth, 21.05.2014.

Paratypes (in total 59 specimens). P.89.1–89.13 slides No 1037, 1039–1042, 1044–1045, 1062–1063, 1065, 2150–2151, 2220, 19 stained specimens from type locality, 21.05.2014. P.89.14, 19 specimens from type locality, in 70 % ethanol, 21.05.2014. P.89.15, 11 specimens from type locality, 13.10.2014. P.89.16, 10 specimens from type locality, in 70 % ethanol, 24.10.2016.

Further material examined. 22 living specimens, not fixed, from the type locality.

Etymology. Named in honour of our colleague, Dr. János Farkas, who assisted many times in recent sampling campaigns.

Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (body length 3–5 mm, in vivo), segments 22–26; (2) maximum 6–8 sigmoid and nodulate chaetae per bundle; (3) clitellum developed only laterally; (4) two or three unpaired nephridia preclitellarly; (5) coelomocytes spindleshaped, with refractile granules, black under transmittent light; (6) 2 + 2 pharyngeal glands; (7) sperm funnel cylindrical, large, approximately 2/3 as long as body diameter, collar conspicuous, slightly narrower than the funnel body; (8) sperm ducts considerably widened in the middle; (9) male copulatory organs large, pores surrounded by gland cells; (10) spermathecae free, reaching VII–IX segments, consisting of ectal ducts, hemispherical parts with sperm and long wide ampullae; the distal part of ectal ducts with conspicuous widenings.

Description. Holotype 3.0 mm long, 160 µm wide at VIII and 205 µm at clitellum (fixed), 25 segments. Length of paratypes 3–5 mm, width 140–230 µm at VIII and 200–310 µm at clitellum in vivo, length of fixed specimens 1.8–3.8 mm, width 130–160 µm at VIII and 170–220 µm at clitellum, segments 22–26. Chaetae slender, sigmoid, with nodulus; number of chaetae per bundle variable, up to 6–8 in ventral preclitellar bundles, length 28– 35 µm. Chaetae in XII absent. Head pore at 0. Clitellum only laterally in XII–1 /2XIII, gland cells in dense rows or irregularly distributed (granulocytes about 10–13 µm long and 7–8 µm wide (fixed), the hyalocytes slightly smaller and fewer). Thickness of body wall about 12 µm in vivo, (9 µm when fixed), cuticle very thin. Brain deeply cleft posteriorly, about 100 µm long and two times longer than wide when fixed ( Fig. 2 A). In prostomium, about 12 inner papillae ( Figs. 2 A,B) similar to those found in Xetadrilus ( Schmelz et al. 2011) . This trait of Cernosvitoviella species is mentioned for the first time here. Oesophageal appendages and intestinal diverticula absent. Two pairs of primary pharyngeal glands in 4/5 and 5/6, dorsally without or with narrow connection, two secondary glands free in V and VI. ( Fig. 4 D). Chloragocytes from V and forming a dense layer from VI, individual cells relatively large (22–55 µm long) and containing refractile oil droplets in vivo ( Fig. 2 G). Midgut pars tumida in XV–XIX, occupying 2–3 segments ( Fig. 2 E). Dorsal vessel from XII or in front of XIII, blood slightly pink, the anterior bifurcation in peristomium. 2–3 mostly unpaired preclitellar nephridia from 6/7 or 7/8, anteseptale small with funnel only, postseptale with conspicuous canals, efferent duct terminal ( Fig. 2 F). Coelomocytes spindle-shaped with dark refractile granules, 36–60 µm long, 7–8 µm wide in the middle in vivo ( Figs. 2 C,D). In fixed specimens they are only 20–22 µm long, the granules are not visible but the nucleus is large. Seminal vesicle large in X–XI ( Fig. 3 A). Sperm funnels cylindrical, large ( Figs. 2 I, 3A,C), about 90–180 µm long in vivo (80–155 µm, fixed) and 2–3 times longer than wide, about 3/4 of body diameter; collar distinct, tall and slightly narrower than the funnel body. Spermatozoa about 70 µm long, heads 25 µm, in vivo (40–60 µm and 10–20 µm, fixed, respectively). Sperm ducts considerably widened in the middle ( Figs. 2 I, 3B,C,D). This thick-walled dilation about 120–180 µm long, 30–50 µm wide and the canal is 17–26 µm wide in vivo (100–180 µm, 23–34 µm and 14–17 µm, fixed, respectively). Tracts of the sperm duct before and after the dilation of about the same length as the dilated part; just after the sperm funnel duct is slightly thinner, diameter about 8–13 µm until the dilation, while the part after the dilation is 13–19 µm wide, finally slightly dilated again in the male copulatory organ, up to 15–20 µm in vivo. Male copulatory organs large, the male pore surrounded by glands forming a round and compact mass ( Figs. 3 B,C,D,E), diameter 60–90 µm in vivo (60–70 µm, fixed). Subneural glands absent. Spermathecae free ( Figs. 1 A, 2H, 4A.B,D), ectal glands absent. Spermathecae consist of ectal ducts (about 170 µm long and 10 µm wide in vivo, and fixed alike) widened ectally to up to 25 µm in vivo (20 µm, fixed) ( Figs. 3 F,G, 4C). The ectal ducts in VI widens into almost hemispherical parts with sperm in them (25–32 µm wide in vivo and fixed alike) ( Figs. 3 G. 4A). These bulbiform parts continue in long ducts which expand into wide sack-like ampullae (30–50 µm wide, in vivo and fixed alike). Ampullae reaching VII–IX segments when fully developed ( Figs. 2 H, 4A,B). In the subadult specimens the hemispherical parts absent and the ampullae smaller, expanding only to VI or VII. One mature egg at a time. On the body wall surface, often epibiotic ciliates attached, similar to other Cernosvitoviella species ( Figs. 2 I, 3H).

Distribution and habitat. Known only from the type locality.

Differential diagnosis. The new species is clearly distinguished from the rest of hitherto described Cernosvitoviella species by the prominent dilatation in the middle part of the vas deferens. C. farkasi sp. n. is most similar to C. aggtelekiensis in size, the type of coelomocytes, and the remarkable dilatations of the vasa deferentia ( Figs. 3 B–D vs. Figs. 5 I,J). However, in the new species coelomocytes are narrower ( Figs. 2 C,D vs. Figs. 5 E,F), the dilatations of the vasa deferentia are located more proximally, and they are more conspicuous and refracting. The spermathecal ectal duct of C. aggtelekiensis has also a widening distally, but the ampullae reach only into V or VI ( Figs. 1 B, 6D–F). In five Cernosvitoviella species ( C. sphaerotheca Healy, 1975 , C. briganta Springett 1969 , C. palustris Healy, 1979 , C. estaragniensis Giani, 1979 and C. ampullax Klungland & Abrahamsen, 1981 ), the spermathecae also extend into VIII or IX, but in these species the dilatations of the vasa deferentia are absent or smaller, or they occur distally if present.

Figures

FIGURE 1. Spermathecae of Cernosvitoviella species. A. C. farkasi sp. n. B. C. aggtelekiensis. C. C. atrata. D. C. crassoductus. E. C. minor s. l. with small spermatheca. F. C. minor s. l. Scale bars 50 µm.

FIGURE 2. Micrographs of Cernosvitoviella farkasi sp. n. A. Brain and prostomial papillae (arrow). B. Prostomial papillae (arrows). C. Coelomocytes (arrows, e = egg). D. Coelomocytes in the coelom and outside the body (p = pygidium). E. Pars tumida in XVIII – XIX (arrows). F. Nephridium (arrow). G. Chloragogen cells behind the clitellum. H. Segments III – VII (ectal opening of spermathecae marked with black arrows, b = hemispherical bulb, long sack-like ampullae marked with white arrows). I. segments XI – XII (sperm funnels marked with white arrows, dilatation of sperm funnels marked with black arrows, m = male openings, epibionts on the body wall marked with short arrows). A fixed, stained, B – I in vivo. Scale bars 50 µm.

FIGURE 3. Micrographs of Cernosvitoviella farkasi sp. n. A. Large sperm funnels (arrows, sv = seminal vesicle, e = egg). B. The wide dilatation of the sperm duct (the male pore with glands marked with arrows). C. Sperm funnels (short arrows) and the sperm ducts. D. Sperm ducts (male opening marked with arrow), in C and D, clearly visible that the wide parts of the ducts are conspicuous, refractile. E. Male pores with glands surrounding (arrow). F. Ectal widenings of the spermathecal ducts (arrows). G. Ectal widenings of the spermathecal ducts (black arrows) and the sphaerical bulb with sperm in them (white arrow). H. Epibiont on the body wall. A – D, F in vivo, E, G – H fixed, stained. Scale bars in A – F 50 µm, in G – H 20 µm.

FIGURE 4. Micrographs of Cernosvitoviella farkasi sp. n. A. Spermathecae (ectal widenings marked with black arrows, b = hemispherical bulbs with sperm, ampullae marked with white arrow). B. Well-developed spermathecal ampullae (white arrow). C. Ectal widenings. D. Segments IV – VI (primary pharyngeal glands marked with black arrows, secondary pharyngeal glands marked with white arrows, s = spermathecae). A – B in vivo, C – D fixed, stained. Scale bars in A – B, D 50 µm, in C 20 µm.

FIGURE 5. Micrographs of Cernosvitoviella aggtelekiensis. A. Prostomial papillae (arrows). B. Prostomial papillae in 100 x magnification (black arrows, coelomocytes marked with white arrow). C. Chaetae. D. Chaetae in 100 x magnification. E. Coelomocytes outside the body. F. Coelomocytes in coelom. G. Chloragogen cells in 100 x magnification. H. The second pair of nephridia in 7 / 8 (arrow). I – J. Sperm funnels (white arrows), dilation of the sperm ducts (black arrows), e = eggs. All micrographs in vivo. Scale bars in A, C, E – F, H – J 50 µm, in B, D, G 20 µm.