Entomelas entomelas ( Dujardin, 1845 ) Travassos, 1930

KUZMIN, YURIY, 2013, Review of Rhabdiasidae (Nematoda) from the Holarctic, Zootaxa 3639 (1), pp. 1-76 : 60

Entomelas entomelas ( Dujardin, 1845) Travassos, 1930

( Fig. 31 A–D )

Synonyms: Angiostoma entomelas Dujardin, 1845 (part.); Angiostoma macrostoma Linstow, 1975 ; Rhabdias entomelas Seurat, 1916 .

Host: Anguis fragilis ( Reptilia: Sauria : Anguidae ).

Site: pharynx and anterior part of oesophagus, occasionally lungs.

Distribution: Western Palaearctic.

Description. Adult hermaphrodites. Body stout, head end truncated, tail end tapered. Body length 5.53 (4.87– 6.15) mm, maximum width 282 (220–340). Body cuticle thin, transversely striated. Oral opening large, round. Lips small. Circular cuticular fold present behind lips. Buccal capsule large, barrel-shaped, 76 (63–90) deep and 107 (89–116) wide. Six teeth small, equal in shape and size, situated close to entrance to oesophageal lumen. Anterior end of oesophagus dilated. Oesophagus 644 (570–714) long (11.7 [10.1–14.4] % of body length). Width of posterior bulb 116 (102–130). Nerve ring at 117 (100–147) from anterior end of oesophagus (18.3 [15.1–23.2] % of oesophagus length). Intestine reddish. Rectum prominently sclerotised. Vulva postequatorial, at 3.30 (2.80–3.66) mm from anterior end (59.6 [55.3–65.0] % of general length). Vulva lips small. Uteri containing numerous eggs with fully developed larvae. Genital tubes bending several times at oviducts. Proximal parts of ovaries overlapping at level of vulva. Tail conical, sharply pointed, 202 (132–257) long (3.7 [2.3–4.7] % of body length).

Subadult hermaphrodites. Differing from adults by the absence of cuticular ring on head end. Body length 4.10–4.71 mm, maximum width 181–194. Buccal capsule 63–80 deep and 197–105 wide. Dilation of oesophagus anterior end present. Oesophagus 619–631 long (13.4–15.1 % of body length). Bulb width 84–97. Nerve ring at 119–132 from anterior end of oesophagus (19.0–21.3 % of oesophagus length). Vulva at 2.51–3.08 mm from anterior end (61.4–65.4 % of general length). Uteri narrow, tubular, empty. Tail 137–169 long (3.0–3.7 % of body length).

Biology. Life cycle is of rhabdiasoid type. Free-living females have maximum 5 eggs in uteri. Matricidal hatching is obligate. Infective larvae were able to infect terrestrial snails Deroceras sp. and Arion sp. ( Kuzmin and Sharpilo 2000). Development in host is unknown. Parasitic larvae are presumed to develop in the body cavity and, thereafter, enter the pharynx, probably via migration from lungs. Subadult stages were observed in lungs and body cavity of experimentally infected slow-worms. Adults were also found in lungs of hosts investigated post-mortem and in the body cavity and lungs of experimentally hyperinfected host.

Material studied: over 200 specimens ( SIZK) from various localities. Twenty-nine adult and 5 subadult specimens were measured .

References: Dujardin (1845), Seurat (1916), Travassos (1930), Moravec (1974), Hartwich (1975), Sharpilo (1976), Kuzmin and Sharpilo (2000).

Figures

FIGURE 31. A—E. entomelas, head end, lateral view; B—E. entomelas, tail end, lateral view; C—E. entomelas, head end, apical view; D—E. entomelas, anterior part of body, lateral view; E—E. dujardini, anterior part of body, lateral view; F—E. dujardini, head end, lateral view; G—E. dujardini, head end, apical view; H—E. dujardini, tail end, lateral view. Scale bars: A...D, H—0.1 mm; E—0.2 mm; F—0.05 mm; G—0.025 mm.