Dyakioidea, Gude & B.B.Woodward, 1921

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 : 100

Superfamily Dyakioidea

Remarks. Hausdorf (1998) removed Dyakiidae from Helicarionidae and placed it in the monotypic Dyakioidea . Schileyko (2003a) retained Dyakioidea as a superfamily, but included the family Staffordiidae in addition to Dyakiidae .

We tentatively follow this arrangement because we have insufficient material to make any further judgement. The superfamily Dyakioidea can be defined as follows:

Shell complete. Mantle usually with visible minor blood vessels. Stimulator present; stimulator section A 5 present, with two major gland lobes; section A 4 present; section A 3 absent; stimulator section A 2 with papilla and dart. Penial sheath open at distal end. Epiphallic retractor caecum and epiphallic flagellum absent. Bursa copulatrix inserted on base of stimulator. Spermatophore unknown.

Description. Shell complete. Mantle laps and lobes absent. Sole of foot tripartite or undivided; caudal apparatus present, formed from curled up sole ( Muratov’s 1999 helicarionid type). Kidney unilobed; mantle usually with visible minor blood vessels. Genital system oviparous. Bursa copulatrix inserted on base of stimulator. Stimulator present; inserted on atrium or vagina; stimulator section A 5 with acinose glands, two major lobes present; stimulator section A 2 with papilla and dart. Penial sheath absent or present; if present, open at distal end. Epiphallic retractor caecum absent; epiphallic flagellum absent. Spermatophore unknown.