Entomelas kazachstanica Sharpilo et Vakker, 1972

KUZMIN, YURIY, 2013, Review of Rhabdiasidae (Nematoda) from the Holarctic, Zootaxa 3639 (1), pp. 1-76 : 61

Entomelas kazachstanica Sharpilo et Vakker, 1972

( Fig. 32 )

Synonyms: Paraentomelas kazachstanica ( Sharpilo et Vakker, 1972) Sharpilo, 1976 ; Entomelas entomelas ( Dujardin, 1845) sensu Baker (1980) (part.).

Host: Pseudopus apodus ( Reptilia: Sauria : Anguidae ).

Site: lungs.

Distribution: Western and, partially, Central Palaearctic (south-eastern Europe, Caucasus, West of Central Asia).

Description. Adult hermaphrodites. Body slender. Head end rounded, tail end tapered. Body length 3.75 (3.01– 4.57) mm, maximum width 131 (110–188). Body cuticle inflated. Oral opening round. Buccal capsule almost hemispherical, with narrower basal part, 30 (28–32) deep and 36 (34–38) wide. Three of six teeth partially reduced. Oesophagus club-shaped, elongated, 561 (510–616) long (15.1 [12.9–18.3] % of body length). Width of posterior bulb 69 (60–80). Nerve ring at 192 (162–219) from anterior end of oesophagus (34.3 [29.7–41.4] % of oesophagus length). Excretory pore situated behind level of nerve ring. Excretory glands shorter than oesophagus. Intestine comparatively narrow, thick-walled. Proventriculus usually prominent. Vulva at 2.12 (1.87–2.35) mm from anterior end (52.7 [49.6–57.8] % of total length). Vulva lips distinct. Uteri tubular. Eggs numbering 3–15, with embryos on early cleavage stages. Ovaries almost straight, their proximal parts overlapping at vulva level. Tail conical, elongated, sharply pointed. Tail length 219 (186–243) (5.9 [4.7–8.1] % of body length).

Subadult hermaphrodites differing from adults by less developed muscular and hypodermal tissue on the anterior end, and by thin and smooth body cuticle. Body length 3.0 (2.05–3.40) mm, maximum width 73 (60–82). Buccal capsule barrel-shaped, 30 (28–34) deep and 35 (34–38) wide. Oesophagus 518 (429–567) long (17.5 [15.6– 24.1] % of body length). Bulb 57 (40–64) wide. Nerve ring at 184 (148–226) from anterior end of oesophagus (35.4 [32.3–45.7] % of oesophagus length). Vulva at 1.63 (1.12–1.85) mm from anterior end (54.2 [50.8–56.1] % of general length). Uteri short, tubular, empty. Proximal parts of syngonia overlapping at level of vulva. Tail 190 (130–222) long (6.4 [5.6–7.6] % of body length). Tail end sharpened.

Biology. Life cycle is of rhabdiasoid type. Free-living females have up to 18 eggs in uteri. Up to 8 larvae develop inside each female. Infective larvae were able to infect terrestrial snails Deroceras sp. and Arion sp. ( Kuzmin and Sharpilo 2000). Parasitic larvae were observed in lungs, body cavity and large blood vessels of experimentally infected host. Subadult hermaphrodites were found in body cavity.

Remarks. Baker (1980) considered this species to be a juvenile form of E. entomelas . Our experimental studies demonstrated differences in juvenile (subgravid) specimens of both species and thus supported the validity of E. kazachstanica . Molecular data ( Kuzmin and Tkach 2009) also supported the validity of the species.

Material studied: 34 adult and 25 subadult specimens ( SIZK) from naturally and experimentally infected hosts .

References: Sharpilo and Vakker (1972), Sharpilo (1976), Baker (1980), Kuzmin and Sharpilo (2000)

Figures

FIGURE 32. E. kazachstanica. Gravid: A—anterior part of body, lateral view; B—head end, lateral view; C—tail end, lateral view. Subgravid: D—head end, lateral view; E—anterior part of body, lateral view; F—tail end, lateral view; G—genital system, lateral view. Scale bars: A, E, G—0.2 mm; B, D—0.05 mm; C, F—0.1 mm.