Review of Rhabdiasidae (Nematoda) from the Holarctic Author KUZMIN, YURIY text Zootaxa 2013 2013-04-16 3639 1 1 76 http://dx.doi.org/10.11646/zootaxa.3639.1.1 journal article 10.11646/zootaxa.3639.1.1 1175-5326 5262629 32584FBD-212B-4042-BCEF-04C698D71117 Rhabdias agkistrodonis Sharpilo, 1976 ( Fig. 12 ) Syn.: Rhabdias sp . (in Hasegawa, 1985 ); Rhabdias annulosa Hsu, 1933 ( sensu Bogdanov et al. , 1969 ) Hosts: Gloydius blomhoffi , G. halys , Protobothrops elegans , P. flavoviridis ( Reptilia : Serpentes: Viperidae : Crotalinae ). Site: posterior part of lung. Distribution: Eastern Palaearctic (mainland part and Okinawa Island, Japan ). Occurrence in Central Palaearctic ( Kazakhstan ) is presumed but needs confirmation. FIGURE 12. R. agkistrodonis : A—general view; B—head end, apical view; C—anterior part of body, lateral view; D—tail end, lateral view. Scale bars: A—0.5 mm; B—0.05 mm; C, D—0.2 mm. Description (after Kuzmin, 1999). Body length 5.24 (4.07–6.44) mm, body width 220 (133–307). Head end rounded, tail end tapered. Body cuticle slightly swollen and transversely striated in anterior and posterior parts of body. Surface of cuticle finely longitudinally striated. Mouth opening round. Six lips in two lateral groups present. Papillae prominent. Vestibulum short. Buccal capsule wide, cup-shaped, 13 (10–18) deep, 20 (16–23) in outer diameter. Oesophagus relatively short, club-shaped, 266 (208–300) long; posterior bulb 59 (40–72) wide. Nerve ring encircling mid-region of oesophagus. Distance from anterior end of oesophagus to nerve ring 136 (91–170), or 51.7 (44–63.6) % of oesophagus length. Excretory glands slightly longer than oesophagus. Intestine wide, thickwalled. Rectum funnel-shaped, with thick walls and narrow lumen. Vulva pre-equatorial, 2.40 (1.96–3.15) mm from anterior end (45.6 [41.5–49.9] % of body length). Lips of vulva distinct. Uteri wide, sac-like, filled with numerous eggs (about 100 in largest specimens), most eggs containing fully developed larvae. Egg size 82–89 × 45–49 (after Sharpilo, 1976 ). Ovaries narrow, slightly twisted. Tail short, with awl-like end formed by a short cuticular needle on the tip. Tail length 167 (91–224), or 3.2 (2.0–4.1) % of body length. Biology. Life cycle is of strongyloid type , heterogony predominates. Females are much more numerous than males in the gonochoristic generation; male:female ratio was about 30: 1 in laboratory cultures. At least the presence of males was observed to be necessary for reproduction. Up to 15 eggs were present in uteri of females (Kuzmin, 1999). Homo- and heterogonic infective larvae are similar in morphology, the former possess more prominent rhabditoid structure of oesophagus. Development in host is unknown. Material studied: 15 specimens from G. blomhoffi ( Primorye region , Russia ), 10 specimens from G. halys (Altaiskiy Krai, Russia ), 2 specimens from P. elegans , 4 specimens from P. flavoviridis ( Okinawa Island , Japan ). Material is stored in SIZK . References: Bogdanov et al. (1969) , Sharpilo (1976) , Hasegawa (1985) , Kuzmin (1999).