Stanisicarion, Hyman & Ponder, 2010

Hyman, Isabel T. & Ponder, Winston F., 2010, A morphological phylogenetic analysis and generic revision of Australian Helicarionidae (Gastropoda: Pulmonata: Stylommatophora), and an assessment of the relationships of the family 2462, Zootaxa 2462 (1), pp. 1-148 : 49

Stanisicarion n. gen.

Type species Helixarion freycineti Férussac, 1821 .

Etymology. This genus is named for John Stanisic, both in thanks for helpful discussion and assistance over the course of this project and in acknowledgement of his extensive work on land snails in Australia, including Helicarionidae .

Description. External morphology: Shell reduced, 3–3.2 whorls, glossy, spire and apex flattened ( Stanisicarion freycineti ) to slightly raised ( S. virens ). Protoconch sculptured with incised spiral grooves; teleoconch with microscopic spiral grooves. Whorl profile rounded above and below evenly convex periphery. Internal walls of early whorls complete; umbilicus closed. Mantle laps wide at base, rounded, tapering to blunt point, not fused. Mantle laps uniform in colour. Mantle lobes large to very large, left and median lobes fused to form small lobe over head. Sole of foot and caudal apparatus as for family; caudal foss vertical slit in tail.

Mantle cavity: As for family. Mantle with visible minor blood vessels; pigmentation of black spots (not examined in S. virens ).

Digestive system: Oesophageal crop present.

Genital system: As for family. Carrefour embedded in albumen gland; talon embedded ( S. virens ) or free ( S. freycineti ). Free oviduct of medium length; capsular gland present; internal sculpture absent ( S. virens ) or longitudinal pilasters present ( S. freycineti ). Bursa copulatrix inserted on vagina, short, less than half spermoviduct length; duct of bursa copulatrix wide, distinguishable from bursa copulatrix, internally smooth. Vagina internally with longitudinal pilasters. Epiphallus enters penis through short verge; penis internally covered in pustules, longitudinal penis pilasters absent, diverticulum on penis absent. Penial sheath enclosing only base of penis; penis retractor muscle attached to tip ( S. freycineti ) or base ( S. virens ) of epiphallic caecum. Epiphallus internally with longitudinal pilasters. Epiphallic retractor caecum moderate in size, positioned in middle of epiphallus. Flagellum present; flagellum and distal part of epiphallus without internal cryptae and externally smooth and slender. Spermatophore not present in dissected specimens.

Radula (based only on freycineti ): Relatively long and narrow. Central tooth with small ectocones; mesocone lanceolate, longer than tooth base. Lateral and marginal tooth fields distinguishable. Lateral teeth with endocone smaller than central tooth ectocones; ectocone equal in size to those on central tooth; mesocone longer than tooth base. Marginal teeth with endocones absent; ectocones shorter and narrower than mesocone, not subdivided into extra teeth.

Remarks. Stanisicarion can be distinguished from Eungarion , Thularion and Parmacochlea by its less reduced shell, and from Fastosarion by its smaller size and smaller mantle laps and lobes. Anatomically, Stanisicarion differs from the other genera in this section by the presence of a short penial sheath covering only the bottom half of the penis, and by the presence of pustules and absence of pilasters in the penis interior.