Rhabdias rubrovenosa Semenov 1929

Rhabdias rubrovenosa (Schneider, 1866) Semenov, 1929

(Fig. 26)

Synonyms: Leptodera rubrovenosa Schneider, 1866; Angiostomum rubrovenosum Linstow, 1885; Rhabdias bufonis (Schrank, 1788) (sensu Maguza, 1973).

Hosts: Bufo bufo, Pseudepidalea viridis (Amphibia: Anura: Bufonidae); Pelobates fuscus (Pelobatidae); Bombina bombina (Bombinatoridae).

Site: lungs.

Distribution: Western Palaearctic.

Description (after Kuzmin 2000 a). Head end rounded, tail end tapered. Body length 7.08 (4.0–11.9) mm, maximum width 265 (158–398). Body cuticle inflated, especially in anterior part, and covered with irregular folds. Oral opening round. Vestibulum reduced; small hemispherical buccal capsule situated close to the oral opening. Buccal capsule depth 8 (6–10), width 13 (10–14). Oesophageal tissue surrounding bottom of buccal capsule. Oesophagus club-shaped, 356 (307–423) long (5.4 [3.1–7.7] % of body length), lacking the anterior muscular bulb. Oesophagus width: 33 (30–40) at anterior end, 37 (32–44) at midlength; posterior bulb 62 (54–78) wide. Nerve ring at 174 (141–216) from anterior end of oesophagus (48.9 [41.5–54.8] % of oesophagus length). Excretory pore situated behind level of nerve ring. Excretory duct short and straight. Excretory glands narrow, elongated, slightly widened and rounded in posterior portion. Intestine wide, thick-walled in anterior part and thin-walled posteriorly. Rectum in gravid specimens thin, straight, sufficiently reduced. Posterior part of intestine sac-like, filled with black content and often stretched into tail region.

The last feature was present mainly in the largest (and probably the oldest) worms. In several cases, specimens with rupture of intestine were observed. The black filling of posterior gut was dispersed in the body cavity of such individuals.

Vulva pre-equatorial in gravid specimens, postequatorial in younger individuals, situated at 3.18 (2.05–5.6) mm from anterior end (45.3 [40.5–53.1] % of total length). Vulva lips reduced. Uteri large, thin-walled, filled with numerous eggs. Eggs located in region of vulva containing fully developed larvae. Egg size 106–121 × 53–71. Both genital tubes reflexed in zone of oocytes. Ovaries narrow, slightly twisted, their proximal ends overlapping at level of vulva. Tail conical, 315 (207–498) long (4.7 [3.3–7.4] % of body length).

Biology. Life cycle rhabdiasoid. Females of gonochoristic generation with maximum 2 eggs in uteri. One or 2 larvae developing in each female. Development in host unknown.

Material studied: over 200 specimens (SIZK), mainly from P. viridis from southeast of Europe; 33 specimens were measured.

References: Schneider (1866), Maguza (1973); Hartwich (1975), Kuzmin (2000 a).