Echonitor cyrtochila ( Gude, 1905 )

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 : 74-75

Echonitor cyrtochila ( Gude, 1905)

Figures 22F , 24C , 26C , 27C , 28C

Thalassia cyrtochila Gude, 1905: 12 .

Echonitor cyrtochilus: Iredale, 1937a: 27 ; Iredale, 1937c: 5.

Echonitor cyrtochila: Smith, 1992: 229 .

Material examined. South Australia, Australia: Holotype: BMNH 1922.8 .29.16 (shell measured, photographed), Long Reef.

Other material: SAM D16557 (two specimens dissected), Buckeringa Gorge, Flinders Ranges, under rocks, 15 Aug. 1984, H. Anderson, A. Gackle, K. Gowlett .

Description. External morphology: Shell ( Figures 26C , 27C , 28C ) about 4.3 whorls, orange-brown, glossy, spire and apex slightly raised; otherwise shell shape and sculpture as for genus. Animal dark brown. Mantle laps and lobes as for genus; right mantle lap moderately small, left mantle lap small; caudal apparatus as for genus; caudal horn medium, caudal foss diamond-shaped slit in tail.

Mantle cavity and digestive system: As for genus.

Genital system ( Figures 22F , 24C ): As for genus. Bursa copulatrix inserted on vagina, moderately long, more than half spermoviduct length; vagina very short. Penis moderately long, internally covered in eight to ten longitudinal rows of flat, ridged, diamond-shaped pustules. Short apical diverticulum on penis in one specimen. Penial sheath very thick, enclosing only penis; penis retractor muscle attached to epiphallus or penis. Epiphallus much shorter than penis, internally with longitudinal pilasters. Flagellum and lime-sac absent.

Radula: Not examined.

Range and habitat. This species was first described from Long Reef in South Australia and is also known from Little Gorge, south of Adelaide, the Mt. Lofty Ranges, the Flinders Ranges and Farina. Little habitat data are known, but specimens have been found under rocks.

Remarks. Externally this species is very dissimilar to Periclocystis ardeni , particularly in the shape and sculpture of the shell. Anatomically it is very similar, however, sharing the distinctive internal sculpture of the penis seen in no other helicarionids to date, and the highly thickened penial sheath. However, as well as the differences in shell shape, there are a number of features of the reproductive system that differ between the two species (including the length of the free oviduct, vagina and bursa copulatrix and the presence or absence of a lime-sac). For these reasons the genera have been retained as separate taxa until further data are available.

Figures

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 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 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.