HELICARIONIDAE BOURGUIGNAT, 1877

Hyman, Isabel T & Köhler, Frank, 2018, Reconciling comparative anatomy and mitochondrial phylogenetics in revising species limits in the Australian semislug Helicarion Férussac, 1821 (Gastropoda: Stylommatophora), Zoological Journal of the Linnean Society 184, pp. 933-968 : 947

FAMILY HELICARIONIDAE BOURGUIGNAT, 1877

Diagnosis: Shell present, complete or reduced, 5–35 mm in diameter; usually thin walled, glossy; spiral grooves present on protoconch and teleoconch. Mantle with accessory lobes lying over body and shell lappets of variable size lying over shell. Sole of foot tripartite; caudal apparatus present, formed from upcurled sole. Kidney unilobed; minor venation on roof of mantle cavity absent or present; mantle gland absent. Genital system oviparous; oviduct glandular. Bursa copulatrix variable in length; inserted on vagina or, if vagina absent, at junction of free oviduct and penis. Stimulator absent. Epiphallus enters penis through a simple pore, fleshy lips or verge; interior of penis variable. Penial tunica present, open at proximal end, attached by muscle fibres to epiphallus. Epiphallic retractor caecum absent or present; epiphallic flagellum absent or present; where present, flagellum contains an axial filament. Spermatophore a soft capsule with hard-walled tail-pipe.

Remarks: The Helicarionidae is distributed in Australia, islands of the Pacific, Southeast Asia, Madagascar and the Mascarene Islands. It is grouped in superfamily Helicarionoidea , along with the Asian Ariophantidae and the African Urocyclidae . The three families are unified by the presence of a flagellum with an axial filament, an epiphallic caecum, and mantle lobes ( Hausdorf, 1998; Hyman & Ponder, 2010); however, the flagellum and epiphallic caecum are absent in some members of all three groups. The only character that reliably distinguishes Helicarionidae from the other two families is the presence of a penial tunica that is open at the proximal end rather than being fused to the penis ( Hausdorf, 1998; Hyman & Ponder, 2010).