Rhabdias incerta Wilkie, 1930

KUZMIN, YURIY, 2013, Review of Rhabdiasidae (Nematoda) from the Holarctic, Zootaxa 3639 (1), pp. 1-76 : 41-44

Rhabdias incerta Wilkie, 1930

( Fig. 21 )

Hosts: Bufo gargarizans , B. japonicus , Pseudepidalea raddei ( Amphibia: Anura : Bufonidae ).

Site: lungs.

Distribution: Eastern Palaearctic (mainland part and Japanese Isles).

Description. Body length 11.27 (9.05–14.95) mm, maximum width 328 (183–465). Body cuticle swollen. Globular swelling of cuticle observed on the cephalic end in some studied specimens. Six lips prominent, lateral lips situated farther from oral opening than submedian ones. Oral opening wide, round. Vestibulum reduced.

Buccal capsule wide, cup-like, 17 (14–20) deep, 32 (24–38) wide. Oesophagus elongated, with prominent dilation at middle of muscular part. Oesophagus length 0.92 (0.69–1.27) mm (8.2 [6.0–10.1] % of body length). Width of oesophagus: 59 (36–72) at anterior end, 71 (48–100) at middle of muscular part, 62 (36–84) at middle of glandular part; bulb 114 (64–176) wide. Nerve ring at 227 (174–290) from anterior end of oesophagus (24.9 [20.8–34.9] % of oesophagus length). Intestine wide, thick-walled. Rectum short, weakly sclerotised. Vulva at 6.10 (5.0–8.17) mm from anterior end (54.3 [49.6–58.2] % of total length). Uteri long, straight, tubular, filled with numerous eggs, most eggs containing larvae. Egg size 94 × 49 (after Wilkie 1930), 105-135 × 48-63 (after Yamaguti 1941). Tail conical, wide at base, narrow in posterior half. Tail length 388 (315–481), or 3.5 (2.7–4.1) % of body length.

Remarks. In the material studied, specimens from mainland populations had wider buccal capsule and larger (longer and wider) oesophagus than those from island populations ( Table 9). Narrower buccal capsule (21 - 31) was reported also for R. incerta from B. japonicus (Siga Prefecture, Japan) by Yamaguti (1941). The type specimen described by Wilkie (1930), however, had buccal capsule 37 wide. The variability of morphological characters in the species apparently needs separate investigation.

Material studied: 30 specimens ( SIZK, including specimens collected by Dr. Hasegawa) from B. gargarizans (15 from Okinawa Island, Japan, 15 from Primorye region , Russia) and 3 specimens from P. raddei (Primorye region, Russia) .

References: Yamaguti (1935, 1941), Hasegawa (1989 b).

Figures

FIGURE 21. R. incerta. A—anterior part of body, lateral view; B—general view; C—head end, lateral view; D—head end, apical view; E—tail end, lateral view. Scale bars: A—0.5 mm; B—1 mm; C, D—0.1 mm; E—0.25 mm.