Contributions to Zoology, 86 (1) – 2017Isabel T Hyman; Irantzu de la Iglesia Lamborena; Frank Köhler: Molecular phylogenetics and systematic revision of the south-eastern Australian Helicarionidae (Gastropoda, Stylommatophora)

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Parmavitrina megastoma (Cox, 1868)

Figs 22D, 24C, 29

Vitrina megastoma Cox, 1868: 87.

Helicarion megastoma: Tryon, 1885: 170, pl. 38, figs 52-53.

Parmavitrina megastoma: Iredale, 1941: 8; Smith, 1992: 240; Stanisic et al., 2010: 312-313, 331.


Material examined. Holotype. AM C.101145 (Clarence River, NSW).

Non-type material. See Table S1.


Diagnosis. Shell. Amber, moderately large, 2.5-3.0 whorls, ear-shaped, flattened; last whorl very large and flared with membraneous base; shell glossy, protoconch with fine spiral grooves, teleoconch with very fine, indistinct spiral grooves (Table 3, Fig. 22D).

Animal. Brown with purple mucus, faintly spotted, yellow line along neck, foot border edged with orange, mid field of sole slightly darker than outer fields, slime network prominent, tail with a strong, reddish keel, caudal horn small. Mantle lobes moderately large, left and median lobes fused to form a large cephalic shield; shell lappets broad, moderate size, rounded, edged with black and with faint black markings (Fig. 24C).

Genitalia. Bursa copulatrix long, more than twice length of free oviduct, sac elongate. Penis relatively slender, cylindrical; penis and part of epipahllus enclosed in a thick penial tunica. Penis interior with one longitudinal pilaster and numerous weak longitudinal ridges. Epiphallus long, more than twice penis length; epiphallis enters penis through a moderately long, slender verge. Epiphallic flagellum with spiraling rows of internal cryptae and slender tail. Spermatophore not observed (Fig. 29).


Fig. 29. Reproductive anatomy of Parmavitrina megastoma, AM C.377461. A. Genitalia. B. Penial complex. C. Penial interior. Abbreviations: alb, albumen gland; bc, bursa copulatrix; cg, capsule gland; ep, epiphallus; fl, flagellum; her, hermaphroditic duct; ov, ovotestis; p, penis; pp, penial pilasters; pr, prostate; prm, penial retractor muscle; pt, penial tunica; pv, penial verge; ut, uterus; vd, vas deferens. Scale bars: A = 4 mm, B-C = 2 mm.

Remarks. This species is listed by Stanisic et al. (2010) as ranging from Coffs Harbour to Grafton (Fig. 26). Specimens confirmed as P. megastoma by dissection or sequencing range from just north of Coffs Harbour to the Gibraltar Range and the Grafton area, in dry woodland to rainforest habitats. Parmavitrina megastoma is intermediate in size between P. maculosa and P. flavocarinata and is the only species known to exude bright purple mucus when disturbed (mucus colour is not known for P. maculosa). It is sympatric with P. flavocarinata in the Gibraltar Range National Park and Washpool National Park. It may also be sympatric with P. maculosa since the two species occur very close together just north of Coffs Harbour, P. megastoma in Bagawa State Forest and P. maculosa in Bruxner Park Flora Reserve.