Expocystis rustica ( Pfeiffer, 1852 )

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 : 66-67

Expocystis rustica ( Pfeiffer, 1852)

Figures 17P–R , 18H , 19J , 20I , 21J , 22D , 23C

Helix inconspicua Forbes, 1851: 379 [non Helix inconspicua C. B. Adams, 1849 ].

Helix rustica Pfeiffer, 1852: 112 [nom. nov. for Helix inconspicua Forbes, 1851 ].

Helix impexa Reeve, 1852 : pl. 130, sp. 795 [nom. nov. for Helix inconspicua Forbes, 1851 ].

Helix villaris Reeve, 1854 : pl. 195, sp. 1375.

Helix crotali Cox, 1864: 13 [nom. nov. for Helix inconspicua Forbes, 1851 ].

Helix (Xesta) rustica: Cox, 1868: 2 , pl. 9, figs 3, 3a.

Helix (T halassia) rustica: Brazier, 1876b: 117–118 .

Helix (T halassia) villaris: Brazier, 1876b: 118 .

Nanina (Macrochlamys) villaris: Pfeiffer & Clessin, 1881: 44 .

Nanina (T halassia) rustica: Pfeiffer & Clessin, 1881: 46 .

Nanina (T halassia) impexa: Pfeiffer & Clessin, 1881: 46 .

Charopa (T halassia) rustica: Tryon, 1886: 212 , pl. 62, figs 44–45.

Nanina (Subg. Xesta Sect. Macrochlamys ) villaris: Tryon, 1886 : pl. 105, pl. 35, fig. 41.

Charopa (T halassia) rustica: Cox, 1909: 8 .

Microcystis rustica: Hedley, 1912: 260 , pl. viii, fig. 42; Odhner, 1917: 77, figs 29, 30c, 33.

Expocystis rustica: Iredale, 1937c: 4 ; Smith, 1992: 230.

Synonymy follows Iredale (1937c: 4) and Smith (1992: 230).

Material examined. Queensland, Australia: BMNH 1982243 ( H. villaris holotype) (one shell measured, photographed), Lizard Island ; AM C425540 (two specimens dissected, one radula examined), S of Cooktown , Mt. Cook National Park (15º30' S, 145º15' E), on ground, semi deciduous microphyll vine forest, 23 Oct. 1975, P.H. Colman .

Description. External morphology: Shell ( Figures 19J , 20L , 21J ) of about 5 whorls, very light pinkishbrown; shape and sculpture as for genus. Animal white. Mantle laps and lobes as for genus. Caudal horn large; caudal foss vertical slit in tail.

Mantle cavity and digestive system: As for genus.

Genital system ( Figures 18H , 22D , 23C ): As for genus. Penis moderately long; epiphallus enters penis through simple pore; penis internally covered in irregular ridges, four longitudinal penis pilasters present. Epiphallus longer than penis. Spermatophore soft capsule with firm tail pipe open at one end, tail pipe long, sculptured with longitudinal rows of tiny teeth.

Radula ( Figure 17P–R ): As for genus. Radular formula (30.14.1.14.30) × 100 rows.

Range and habitat. Expocystis rustica is found from Innisfail to Cape York Peninsula, N Queensland, on the mainland and also on many islands of the Great Barrier Reef. It is found in rainforest, microphyll vine forest and under trees on or behind beaches, in leaf litter, inside rotting logs and under stones.

Remarks. The synonymy of Helix inconspicua Forbes, 1851 , H. impexa Reeve, 1852 and H. crotali Cox, 1864 with Expocystis rustica was recognised by most early authors from Cox (1868) onwards. However, Cox (1868) incorrectly placed Pravonitor kreffti in synonymy with Helix villaris . Iredale (1937c) first recognised H. villaris as a synonym of Expocystis rustica and this was followed by Smith (1992) and Smith et al. (2002).

The anatomical details given here differ from those presented by Odhner (1917), who illustrated the penial complex. His figure and description indicate that the epiphallus is absent and that the flagellum and penis retractor muscle are both present at the junction of the penis and vas deferens. A dart sac is also described as being present. Some of these differences are, in part at least, due to misinterpretation. The structure referred to as the dart sac is actually the bursa copulatrix (see also remarks under Malandena suturalis below). It is possible that the structure referred to as the flagellum is actually the caecum, although this interpretation assumes that Odhner omitted the actual flagellum from the drawing.

The radula shown here also differs slightly from that figured by Odhner (1917), who shows his specimen as having unicuspid marginal teeth. However, in his written description of the radula, Odhner states that the secondary cusp of the marginal teeth is ‘rather reduced in size and rather remote from the tooth end’ ( Odhner 1917: 81), implying that there is a small secondary cusp present. A small secondary cusp was present in the radula examined in the current study.

It is possible that Odhner’s (1917) specimen was misidentified, but no shell was figured and Odhner’s material was not examined, so this cannot be confirmed.

Figures

FIGURE 17. Radulae. SEM. A–C. Fastosarion superba, AM C425248. D–F. Stanisicarion freycineti, AM C391188. G– I. Parmacochlea fischeri, AM C441743. J–L. Nitor circumcincta, AM C356607. M–O. Pravonitor kreffti, AM C425415. P–R. Expocystis rustica, AM C425540. Scale bars 20 mm (D–R), 50 mm (A–C).

FIGURE 18. Reproductive systems. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, QMMO19238. C. Eungarion mcdonaldi, AM C438760. D. Parmacochlea fischeri, AM C441743. E. Nitor circumcincta, AM C356607. F. Nitor subrugata, AM C334537. G. Pravonitor kreffti, AM C425415. H. Expocystis rustica, AM C425540. Scale bars 1 mm (E), 2 mm (A–D, G–H), 5 mm (F). 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 A); ov, ovotestis; p, penis; pr, prostate; prm, penis retractor muscle; pt, penial sheath; ut, uterus; v, vagina; vd, vas deferens.

FIGURE 19. Shells, dorsal view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Eungarion mcdonaldi, QMMO35628. D. Parmacochlea fischeri, AM C432179. E. Nitor circumcincta, AM C104161 (POS of Helix marmorata). F. Nitor subrugata, AM C333711. G.Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). H. Pravonitor kreffti, BMNH no number (POS). I. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). J. Expocystis rustica, BMNH 1982243 (POH of Helix villaris). K. Malandena suturalis, AM C425087. Scale bars 3 mm (E, J), 5 mm (A–D, F–I, K). Photographs by H. Barlow (A, D, F, I), D. Beechey (E, G), I. Hyman (K), W. Ponder (B, H, J), copyright Australian Museum; photographer unknown, copyright Queensland Museum (C). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 20. Shells, lateral view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Parmacochlea fischeri, AM C432179. D. Nitor circumcincta, AM C104161 (H). E. Nitor subrugata, AM C333711. F. Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). G. Pravonitor kreffti, BMNH no number (POS). H. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). I. Expocystis rustica, BMNH 1982243 (POH of Helix villaris). J. Malandena suturalis, AM C425087. Scale bars 3 mm (A, D, I), 5 mm (B–C, E–H, J). Photographs by H. Barlow (A, C, E, H), D. Beechey (D, F), W. Ponder (B, G, I), I. Hyman (J). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 21. Shells, ventral view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Eungarion mcdonaldi, QMMO35628 (H). D. Parmacochlea fischeri, AM C432179. E. Nitor circumcincta, AM C104161 (H). F. Nitor subrugata, AM C333711. G. Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). H. Pravonitor kreffti, BMNH no number (POS). I. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). J. Expocystis rustica, BMNH1982243 (POH of Helix villaris). K. Malandena suturalis, AM C425087. Scale bars 3 mm (A, E, J), 5 mm (B–D, F–I, K). Photographs by H. Barlow (A, D, F, I), D. Beechey (E, G), I. Hyman (K), W. Ponder (B, H, J), copyright Australian Museum; photographer unknown, copyright Queensland Museum (C). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 22. Penis interiors. A. Nitor circumcincta, AM C356607. B. Nitor subrugata, AM C334537. C. Pravonitor kreffti, AM C425415. D. Expocystis rustica, AM C425540. E. Malandena suturalis, AM C425085. F. Echonitor cyrtochila, SAM D16557. G. Echonitor albumenoidea, SAM D16567. H. Periclocystis ardeni, SAM D16562. I. New Caledonian NC3, MNHN no registration number. J. New Caledonian NC5, MNHN no registration number. K. Caldwellia angularis, AM C205299. L. Caldwellia imperfecta, AM C205300. Scale bars 1 mm (A–L). Abbreviations: ep, epiphallus; pd, penial diverticulum; pp, penial pilaster; ppd, diamond-shaped, ridged pustules; prm, penis retractor muscle; ppu, penial pustules; pv, penial verge.

FIGURE 23. Spermatophores. SEM. A, B. Nitor subrugata, AM C334537. C. Expocystis rustica, AM C425540. D. Ctenophila caldwelli, AM C205301. E, F. New Caledonian species NC5, MNHN no registration number. G,H. Kalidos balstoni, AM C205303. Scale bars 0.2 mm (B, F, H), 0.5 mm (C, E), 1 mm (A, D, G).