Rhabdias bufonis ( Schrank, 1788 ) Stiles et Hassall, 1905

KUZMIN, YURIY, 2013, Review of Rhabdiasidae (Nematoda) from the Holarctic, Zootaxa 3639 (1), pp. 1-76 : 35-37

Rhabdias bufonis ( Schrank, 1788) Stiles et Hassall, 1905

( Fig. 17 )

Synonyms: Ascaris bufonis Schrank, 1788 ; Ascaris pulmonalis Gmelin, 1790; Fusaria nigrovenosa Zeder, 1800 ; Ascaris nigrovenosa Rudolphi, 1802 ; Leptodera nigrovenosa Schneider, 1866 ; Rhabdonema nigrovenosum Leukart, 1789 ; Angiostoma nigrovenosum Linstow, 1882 ; Rhabdias microoris Semenov, 1929 .

Hosts: Bombina bombina , B. variegata ( Amphibia: Anura : Bombinatoridae ); Bufo bufo , Epidalea calamita , Pseudepidalea viridis , Rhinella orientalis (Bufonidae) ; Hoplobatrachus rugulosus (Discoglossidae) ; Hyla arborea (Hylidae) ; Pelobates fuscus (Pelobatidae) ; Pelophylax lessonae (?), P. perezi , P. ridibundus (?), Rana amurensis , R. arvalis , R. dalmatina , R. macrocnemis , R. temporaria (Ranidae) .

Site: lungs.

Distribution: Palaearctic.

Description. Body cuticle inflated, the swelling more prominent in anterior part of body. Body length 8.09 (3.88–13.02) mm, width 246 (99–340). Six small lips present. Lateral lips situated farther from oral opening than submedian ones. Inner papillae small, outer papillae minute. Amphids pore-like. Oral opening round. Vestibulum elongated. Buccal capsule funnel-shaped, 10 (10–12) deep and 10 (8–12) wide. Anterior end of oesophagus surrounding buccal capsule. Oesophagus club-shaped, 458 (324–589) long (5.5 [4.1–9.9] %) of body length). Oesophagus width: 30 (22–42) at anterior end, 37 (28–45) at middle of muscular part, 36 (26–45) at middle of glandular part; width of posterior bulb 63 (45–77). Dilation of oesophagus at middle of muscular part prominent in subadult and young specimens, indistinct in gravid worms. Nerve ring encircling oesophagus at 196 (133–241) from its anterior end (43.0 [34.3–50.8] % of oesophagus length). Excretory glands approximately of the same length as oesophagus (observed in young specimens). Intestine wide, excepting the comparatively narrow anteriormost part, with prominent dilation of lumen posteriorly. Vulva situated at 4.79 (2.20–7.00) mm from anterior end (54 [50.7–58.7] % of body length). Vulva lips indistinct. Eggs numerous, most of eggs containing larvae. Egg size 100–119 × 47–64 (after Hartwich, 1972). Tail conical, 331 (192–498) long (3.9 [2.4–5.5] % of general length).

Biology. Life cycle is of rhabdiasoid type. Free-living females are with 1– 3 eggs in uteri. Up to 3 larvae develop inside each female. Hosts are infected cutaneously (oral infection possible). Parasitic larvae develop during the migration from subcutaneous and muscular tissues to body cavity. Subadult specimens were found arrested in lungs and body cavity of frogs in winter ( Kuzmin 2000 b).

Remarks. The species was reported from wide host range within vast distribution area. It is not unlikely that R. bufonis is actually a collective species. Recently, R. esculentarum was described from Pelophylax spp. previously known as hosts of R. bufonis in Europe ( Cipriani et al. 2012). Integrated studies including both morphological and molecular approaches may clarify the status of R. bufonis . In our opinion, the records of R. bufonis in Africa ( Moravec et al. 1987) and India ( Fotedar 1965) need confirmation.

Material studied: Several hundreds of specimens from various hosts ( SIZK) were investigated, of which 30 specimens from Rana temporaria and 30 specimens from R. arvalis ( Ukraine) were measured .

References (main): Hartwich (1972, 1975), Ryzhikov et al. (1980), Baker (1987b).

Figures

FIGURE 17. R. bufonis. A—anterior part of body of young specimen with prominent excretory glands; B—subgravid specimen, anterior part of body; C—region of vulva in young specimen with empty uteri; D—tail end. Scale bars: A, B, D—0.2 mm; C—0.1 mm.