Helicarionidae, Bourguignat, 1877

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 : 8-10

Australian Helicarionidae

There are 61 described species and 28 genera of Helicarionidae currently recognised from mainland Australia and Tasmania ( Smith et al. 2002; Hyman 2007) (Appendix 1). Most are known only from shells and external morphology. The relationships among the taxa are poorly understood, and there are over 100 undescribed species (J. Stanisic pers. comm., M. Shea pers. comm.; pers. observ.). More than half of the genera are monotypic.

Most of the currently recognised species were described before 1920 (see Appendix 1), primarily by Cox (1864, 1865, 1866, 1868, 1871, 1873), Brazier (1875a,b, 1876a,b), and Pfeiffer (1849, 1850, 1852, 1853). Nineteen of the 26 currently recognised genera were described by Tom Iredale in a series of papers on the land Mollusca of Australia (1933, 1937b,c, 1941, 1942). Iredale assigned all the semislugs to Helicarionidae , but stated that the genus name Helicarion was too widely used ( Iredale 1933, p. 37). Consequently, for these taxa he created seven new generic names ending in ‘-arion’ (e.g., Fastosarion Iredale, 1933 ) or ‘-vitrina’ (e.g., Parmavitrina Iredale, 1937 ). Similarly, most of the snails were assigned to Microcystidae (his genus names ending in ‘-cystis’, e.g., Expocystis Iredale, 1937 , or ‘-nitor’, e.g., Echonitor Iredale, 1937 ), with some placed in Macrochlamydidae , Durgellidae or his new family Nitoridae ( Iredale 1937c) . However, he split the taxa to such a great extent and created so many briefly described new genus names (many of them monotypic) that some subsequent authors (e.g., Zilch 1959) were unable to deal with them, let alone determine their subfamilial placement. Iredale also created a number of new family and subfamily names based on the Australian taxa (e.g, Nitoridae , Iredale 1937c), again with little or no justification.

Burch (1976) produced an outline of the classification of Australian terrestrial molluscs, in which he attempted to adjust Iredale’s system to a more usable form. He divided the Australian native limacoid taxa into three families: Ariophantidae , Euconulidae and Helicarionidae ( Table 3). Smith (1992), in his catalogue of Australian non-marine Mollusca, excluded Ariophantidae and treated Euconulidae as a subfamily of Helicarionidae .

Early anatomical studies of Australian taxa were carried out by Semper (1870) [ Helicarion cuvieri , Fastosarion freycineti ( Férussac, 1821) , Advena campbellii ( Gray, 1834) ], Godwin-Austen (1883b) [ Peloparion helenae (Godwin-Austen, 1883) ], Hedley (1890, 1891a) [ Parmellops etheridgei (Brazier, 1889) , Epiglypta howeinsulae ( Cox, 1873) ], Simroth (1898) ( Parmacochlea smithi Simroth, 1898 ) and Odhner (1917) [ Tarocystis fulva ( Odhner, 1917) , Expocystis rustica ( Pfeiffer, 1852) , Malandena suturalis ( Odhner, 1917) , Sodaleta umbraculorum ( Cox, 1864) ]. However, as pointed out by Solem (1982), the minimum standard for anatomical investigations in this group was set by Baker (1941a) in his pivotal work on the Zonitidae of the Pacific Islands; most anatomical studies that predate this work (and some subsequent ones) do not provide sufficient detail.

There have been some recent anatomical studies of Australian genera Helicarion ( Dartnall & Kershaw 1978; Kershaw 1979, 1981), Westracystis ( Solem 1982) , Queridomus ( Solem 1988) , Thularion ( Stanisic 1993b) , Eungarion ( Stanisic 1993a) , Cucullarion ( Stanisic 1998) , Fastosarion ( Scott 1995) , Nitor , Peloparion , Brevisentis Hyman, 2007 , Sheaia Hyman, 2007 and Levidens Hyman, 2007 (all in Hyman 2007), but there has not been an attempt to provide an overview of the anatomical data. Ron C. Kershaw worked on a review of the group for many years (B. Smith, pers. comm.), but unfortunately most of his work was never published. The most recent revision was carried out by Kershaw as part of Smith’s overview of Australian non-marine molluscs ( Smith 1992; Smith et al. 2002). However, this work did not include subfamilies and so showed all the Australian taxa as belonging to the family Helicarionidae , with no further divisions.