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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Mysticarion insuetus Iredale, 1941

Figs 14A-B, 15A-C, 16A, 17

Mysticarion leucospira insuetus Iredale, 1941: 7.

Mysticarion insuetus: Stanisic et al., 2010: 308-309, 330.


Material examined. Syntype. AM C.113776 (Scone, 32° 03’ S, 150° 52’ E, pre-1912; Fig. 14A).

Non-type material. See Table S1. Additional specimens: AM C.164470, AM C.456541, AM C.204742, AM C.204744.


Diagnosis. Shell. Small, thin, transparent golden amber, 3.2-3.9 whorls, glossy, globose with a low spire, whorls rounded. Protoconch with slightly notched, deep spiral grooves, teleoconch with very fine, shallow spiral grooves (Table 3, Figs 14A-B, 15A-C).

Animal. Body white with pale brown speckling on sole, tail tip, neck and shell lappets; eye tentacles grey, grey stripe down each side of tail, black line along mantle edge. Caudal horn large. Right mantle lobe moderately large, other lobes small, none fused. Right shell lappet long, left lappet moderately long, both lappets wide at base, rapidly tapering, white with black markings on underside (Fig. 16A).

Genitalia. Bursa copulatrix moderately short, less than half spermoviduct length, duct uniform in diameter, sac tear-shaped. Penis moderately long, slender, slightly swollen proximally, enclosed in penial tunica. Penis interior with two main longitudinal pilasters and multiple longitudinal ridges. Epiphallus short, approx. penis length, containing internal cryptae near flagellum; entering penis through rounded verge with a pointed tip of about half penis length. Epiphallic flagellum with few internal cryptae and slender tail. Spermatophore with 7 branched spines in a spiraling pattern: three widely spaced, complex branched spines at base of capsule, followed by four closely spaced, increasingly short and simple spines on tail-pipe (Fig. 17).


Fig. 17. Reproductive anatomy of Mysticarion insuetus, AM C.483756. A. Genitalia. B. Penial complex. C. Penial interior. D. Spermatophore. 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 = 2 mm, B-D = 1 mm.

Remarks. Mysticarion insuetus has a wide, disjunct range that stretches over 400 km, from Razorback, south of Sydney to the Macleay Valley in northern NSW (Fig. 18). Throughout much of its range, M. insuetus is sympatric with both M. porrectus and M. obscurior sp. Nov. However, M. insuetus is generally found at lower altitudes, in drier habitats, such as vine thickets, while M. porrectus and M. obscurior are present in rainforest or wet sclerophyll forests, and in the case of M. porrectus, usually at higher altitudes.


Fig. 18. Occurrence records of Mysticarion species from the malacological collection of the Australian Museum, Sydney. Symbols: ● = M. porrectus, Δ = M. insuetus, + = M. hyalinus, ♠ = M. obscurior.

The type locality for M. insuetus was given simply as ‘Scone’ (Iredale, 1941). The material closest to this locality in the research collections of the AM and the QM comes from Barrington Tops National Park, where three Mysticarion species are present: M. insuetus, M. porrectus, and M. obscurior. Mysticarion porrectus can easily be distinguished from its congeners by its larger size and less globose shell with a flatter spire and fewer whorls. Mysticarion insuetus and M. obscurior have much more similar shells, but the shell of M. insuetus is slightly higher-spired and the last whorl descends more rapidly. The two species can be distinguished much more readily alive, since the body of M. obscurior is considerably darker with orange and brown pigmentation. The fourth species in the genus, M. hyalinus, is found further to the north, and while it is very similar in appearance to M. insuetus it can be distinguished by its larger size and paler body colour. M. insuetus has a unique genital anatomy consisting of a short epiphallus and moderately long, narrow penis with a long verge and numerous longitudinal pilasters.