Westracystis lissus ( Smith, 1894 ), 1982

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 : 70-71

Westracystis lissus ( Smith, 1894)

Figures 24B , 25D–F , 26A–B , 27A–B , 28A–B

Lamprocystis lissa Smith, 1894: 86–7 , pl. vii, figs 22–23; Cox, 1909: 2.

Microcystis lissa: Hedley, 1916: 71 .

Westracystis lissus: Iredale, 1933: 56 ; Iredale, 1937c: 6; Iredale, 1939: 44; Solem, 1982: 178–83, figs 1–5, 12–14, 16, 18; Solem, 1988: 554–555.

Westracystis tentus Iredale, 1939: 44 , pl. iii, fig. 14.

Synonymy follows Solem (1982).

Material examined. Western Australia, Australia: Syntypes: BMNH 90.12.30.80–4 (one shell measured, photographed), Queen’s Islet, NW Australia .

Other material: FMNH 211717 (two specimens dissected), N of Kununurra , Shakespeare Hill, Ord River Delta, S slopes (14º49'28'' S, 128º25'23'' E), 23 May 1984, A. Solem, L. Price, K. Emberton ; AM C64901 ( W. tentus syntypes; one shell measured, photographed), Napier (Barrier) Ranges (17º23' S, 124º52' E), Jun. 1887, W.W. Froggatt ; AM C438434 (one radula examined), Point Spring Nature Reserve , N of Kununurra (15º24' S, 128º53' E), under wood in damp vine thicket areas, 13 Jun. 2003, W.F. Ponder, J.C. Walker, L. Puslednik .

Northern Territory, Australia: AM C205297 (one specimen dissected, radula examined), Dudlock Falls , 15 km NE of Barayili on Dook Creek, E of Katherine, in leaf litter, 25 Dec. 1978 , V. Kessner .

Description. External morphology: Shell ( Figures 26A–B , 27A–B , 28A–B ) 4.8 whorls, orange-brown; shape and sculpture as for genus. Animal grey. Mantle laps and lobes as for genus. Caudal horn small; caudal foss vertical slit in tail.

Mantle cavity and digestive system: As for genus.

Genital system ( Figure 24B ): As for genus. Penis moderately long, very thin; epiphallus enters penis through simple pore; penis internally covered in transverse ridges, two longitudinal penis pilasters present. Penial sheath present, very thick, enclosing only penis. Epiphallus slightly longer than penis; internally with longitudinal pilasters.

Radula ( Figure 25D–F ): As for genus. Radular formula (27.8.1.8.27) × 75 rows.

Range and habitat. Westracystis lissus is widely distributed in the Kimberly region, from Fitzroy Crossing (Western Australia) to Kulumburu in the north and eastwards to the Northern Territory border. It is found in leaf litter, usually associated with limestone ( Solem 1982).

Remarks. Two morphs have been observed in populations of Westracystis lissus ( Solem 1982) . The smaller morph was around 3.75–4.25 whorls and usually showed a thick ridge on the outer edge of the parietal callus and a noticeable sinuation of the upper palatal lip. The larger morph was around 4.5–5.25 whorls and usually had no parietal callus ridge and no palatal lip sinuation; in addition, these specimens showed evidence of a growth pause ( Solem 1982). Solem (1982) interpreted this dichotomy as indicating that W. lissus lives through at least two wet seasons, aestivating at the end of each one. The morphs cannot be separated anatomically. Solem (1982) also pointed out that W. tentus was described based on the smaller morph, so W. lissus and W. tentus should be synonymised, a decision followed here.

Figures

FIGURE 24. Reproductive systems. A. Malandena suturalis, AM C425085. B. Westracystis lissus, FMNH 211717. C. Echonitor cyrtochila, SAM D16557. D. Echonitor albumenoidea, SAM D16567. E. Periclocystis ardeni, SAM D16562. F. Tarocystis responsivus, AM C425327. G. New Caledonian species NC3, MNHN no registration number. H. New Caledonian species NC5, MNHN no registration number. Scale bars 1 mm (C, G), 2 mm (A–B, D–F, H). Abbreviations: alb, albumen gland; bc, bursa copulatrix; c, caecum; ep, epiphallus; fl, flagellum; fov, free oviduct; her, hermaphrodite duct; m, muscle attaching penial sheath to epiphallus (only shown in D & G); ov, ovotestis; p, penis; pr, prostate; prm, penis retractor muscle; pt, penial sheath; t, talon; ut, uterus; v, vagina; vd, vas deferens.

FIGURE 25. Radulae. SEM. A–C. Malandena suturalis, AM C425085. D–F Westracystis lissus, AM C205297. G–I. Echonitor albumenoidea, SAM D16567. J–L. Tarocystis responsivus, AM C425327. M–O. New Caledonian species NC3, MNHN no registration number. P–R. New Caledonian species NC5, MNHN no registration number. Scale bars 20 mm (A–R).

FIGURE 26. Shells, dorsal view. A. Westracystis lissus, BMNH 90.12.30.80–4 (S). B. Westracystis lissus, AM C64901 (S of W. tentus). C. Echonitor cyrtochila, BMNH 1922.8.29.16 (H). D. Echonitor albumenoidea, AM C60533 (H). E. Periclocystis ardeni, AM C60541 (H). F. Tarocystis responsivus, AM C104308 (S). G. Conueplecta (Durgellina) calculosa, AM C374873. H. Coneuplecta (Nevelasta) pampini, AM C126763. Scale bars 2 mm (B, G–H), 3 mm (A, C–F). Photographs by M. Allan (F), H. Barlow (B, G–H), D. Beechey (D–E), W. Ponder (A, C). Abbreviations: H, holotype; S, syntype.

FIGURE 27. Shells, lateral view. A. Westracystis lissus, BMNH 90.12.30.80–4 (S). B. Westracystis lissus, AM C64901 (S of W. tentus). C. Echonitor cyrtochila, BMNH 1922.8.29.16 (H). D. Echonitor albumenoidea, AM C60533 (H). E. Periclocystis ardeni, AM C60541 (H). F. Tarocystis responsivus, AM C104308 (S). G. Conueplecta (Durgellina) calculosa, AM C374873. H. Coneuplecta (Nevelasta) pampini, AM C126763. Scale bars 2 mm (B, G–H), 3 mm (A, C–F). Photographs by H. Barlow (B, F–H), D. Beechey (D–E), W. Ponder (A, C). Abbreviations: H, holotype; S, syntype.

FIGURE 28. Shells, ventral view. A. Westracystis lissus, BMNH90.12.30.80–4 (S). B. Westracystis lissus, AM C64901 (S of W. tentus). C. Echonitor cyrtochila, BMNH 1922.8.29.16 (H). D. Echonitor albumenoidea, AM C60533 (H). E. Periclocystis ardeni, AM C60541 (H). F. Tarocystis responsivus, AM C104308 (S). G. Conueplecta (Durgellina) calculosa, AM C374873. H. Coneuplecta (Nevelasta) pampini, AM C126763. Scale bars 2 mm (B, G–H), 3 mm (A, C–F). Photographs by H. Barlow (B, F–H), D. Beechey (D–E), W. Ponder (A, C). Abbreviations: H, holotype; S, syntype.