Australophiotaenia striata ( Johnston, 1914 ) Chambrier & Beveridge & Scholz, 2018

Chambrier, Alain De, Beveridge, Ian & Scholz, Tomáš, 2018, Tapeworms (Cestoda: Proteocephalidae) of Australian reptiles: hidden diversity of strictly host-specific parasites, Zootaxa 4461 (4), pp. 477-498 : 488-490

Australophiotaenia striata ( Johnston, 1914) n. comb.

( Figs. 18–20 )

Syns Acanthotaenia striata Johnston, 1914 ; Crepidobothrium striata ( Johnston, 1914) Meggitt, 1927 ; Proteocephalus striatus ( Johnston, 1914) Hughes, Baker & Dawson, 1941 ; Ophiotaenia striata ( Johnston, 1914) Wardle & McLeod, 1952

Type and only known host. Burton’s legless lizard, Lialis burtonis Gray, 1835 ( Squamata : Pygopodidae ).

Site of infection. Intestine.

Type locality. Townsville , Queensland, Australia (19°15'32''S 146°49'1''E).

Distribution. Queensland, Australia.

Reference. Johnston (1914).

Material studied. Syntypes (2 whole mounts with two complete worms—AHC 28406).

Redescription. Based on type material. Cestodes up to 33 mm long; maximum width 1,150. Strobila acraspedote, anapolytic. Immature proglottids wider than long to longer than wide (length: width ratio 0.65–1.34), mature, pregravid and gravid proglottids longer than wide (length: width ratio 1.29–2.33). Scolex 235–335 long and 330–465 wide, slightly wider than neck, 210–385 wide ( Fig. 18 ). Suckers uniloculate, opening anteriorly, spherical, slightly embedded, 115–120 in diameter, representing 50–52% of scolex width. Apical organ absent.

Internal longitudinal musculature composed by dense layer of anastomosed isolated muscle fibres. Ventral osmoregulatory canals 25–35 in diameter. Dorsal osmoregulatory canals not visible.

Testes medullary, in one or two layers, forming two narrow lateral bands (poral field separated by terminal genitalia into preporal and postporal groups); testes may reach anterior margin of proglottid. Testes 64–83 (x = 75, n = 5) in number, with 30–41 (x = 37) aporal testes, 14–20 (x = 17) preporal testes and 17–23 (x = 20) postporal testes. Testes ovoid to elongate, 65–85 × 45–75), present also in gravid proglottids.

Cirrus-sac ovoid to pyriform, thick-walled, 150–215 long and 85–105 wide; length: width ratio 1.80–2.35; length of cirrus-sac represents 13–17 % (x = 15%, n = 6) of width of proglottid. Cirrus wide, its length representing up to 55% of cirrus–sac length. Sperm duct strongly coiled. Vas deferens coiled, occupying a rather narrow region, situated between proximal part of cirrus-sac and midline of proglottid, often crossing it.

Genital atrium present; genital pores alternating irregularly, equatorial, at 48–51% of proglottid length from anterior margin ( Figs. 19, 20 ). Genital ducts passing between osmoregulatory canals. Ovary medullary, bilobed, with narrow lateral wings, 435–695 wide; width of ovary represents 63–74 % (x = 69%, n = 6) of proglottid width; relative size of ovary 1.5%. Mehlis’ gland 45–55 wide, representing about 8% of proglottid width.

Vitelline follicles medullary, with some follicles paramuscular, i.e. penetrating between inner longitudinal musculature, on dorsal side, arranged in two narrow lateral fields near margins of proglottids, occupying porally 84–93% and aporally 88–91% of proglottid length, interrupted at level of cirrus-sac. Vaginal canal forming small seminal receptacle dorsal to ovarian isthmus. Canal slightly sinuous just anterior to seminal receptacle. Terminal part of vaginal canal (pars copulatrix vaginae) surrounded by tiny vaginal sphincter and chromophilic cells ( Figs. 19, 20 ). Vagina anterior (35%) or posterior (65%, n = 20) to cirrus-sac.

Primordium of uterine stem medullary, present in immature proglottids. Development of uterus type 1 according to de Chambrier et al., 2004, 2015; (see redescription of A. amphiboluri for detailed description of uterine development). In pregravid proglottids, uterus occupying up to 25% of proglottid width, with 18–27 (x = 23, n = 8) thin-walled lateral diverticula on each side. In gravid proglottids, diverticula occupying up to 40% of proglottid width.

Eggs (observed in whole mounts) with collapsed hyaline outer envelope, not in clusters. Embryophore deformed, 27–30 in diameter. Other layers and oncosphere not observable.

Remarks. This species, which has never been found since its original description, was described as Acanthotaenia striata by Johnston (1914). This author reported incorrect measurements of the scolex (as many as 3 mm wide). According to his drawing ( Fig. 3 on plate VI), the scolex is 330 µm wide, which corresponds to our measurements of this scolex in the type material. No molecular data are available for this rare species specific to Burton’s legless lizard. In 2001 and 2003, five Lialis burtonis from Queensland, Victoria and South Australia were examined by one of the present authors (A. C.), but no proteocephalidean cestodes were found.

Figures

FIGURE 18. Australophiotaenia striata (Johnston, 1914) n. comb., syntype from Townsville, Queensland, Australia [Coll. No. AHC 28406.], scolex.

FIGURES 19, 20. Australophiotaenia striata (Johnston, 1914) n. comb., syntype from Townsville, Queensland, Australia [Coll. No. AHC 28406.] 19. Mature proglottid, ventral view. 20. Pregravid proglottid, dorsal view.

FIGURES 1–4. Australophiotaenia amphiboluri (Nybelin, 1917) n. comb., syntype from Mount Tamborine, Queensland, Australia [Coll. No. SMNH 3279]. 1. Mature proglottid, ventral. 2. Cross sections at level of testes. 3. Cross sections at level of uterus with forming eggs. 4. Cross sections at level of eggs in capsules. Abbreviations (Figs. 1–20): cc—chromophilic cells; ci—cirrus; cs—cirrus-sac; doc—dorsal osmoregulatory canal; ec—egg capsule; em—bi-layered embryophore; ga—genital atrium; gc—gland cells; lm—internal longitudinal musculature; gm—Mehlis’ glands; mf—muscle fibres; mi—microtriches; oe—outer envelope; od—oviduct; on—oncosphere; ov—ovary; st—subtegumental muscle fibres; su—subtegumental cells; te—testes; tg—tegument; ud—uterine diverticula; us—uterine stem; va—vas deferens; vc—vaginal canal; vd—vitelloduct; vf—vitelline follicles; voc—ventral osmoregulatory canal; vs—vaginal sphincter.