Echonitor albumenoidea ( Cox, 1868 )

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 : 76

Echonitor albumenoidea ( Cox, 1868)

Figures 22G , 24D , 25G–I , 26D , 27D , 28D

Helix (Hyalina) albumenoidea Cox, 1868: 11 , pl. 12, fig. 2.

Zonites (Polita) albumenoidea: Cox, 1909: 7 .

Echonitor albumenoideus: Iredale, 1937a: 28 , pl. 1, fig. 17; Iredale, 1937b: 6.

Echonitor albumenoidea: Smith, 1992: 229 .

Material examined. South Australia: Holotype: AM C60533 (shell measured, photographed); Flinders Ranges (32º30' S, 138º30' E), pre 1868, G. Masters.

Other material: SAM D16567 (one specimen dissected, radula examined), Lower Brachina Gorge , ridge N side Rd. among archeocyathid limestone, Flinders Ranges, 26 Nov. 1983, J. Gehling, H. Anderson & B. Pierce .

Description. External morphology: Shell ( Figures 26D , 27D , 28D ) 4.6 whorls, golden brown; shape and sculpture as for genus. Animal cream. Mantle laps as for genus; mantle lobes not examined. Caudal apparatus as for genus; caudal horn moderately small; caudal foss vertical slit in tail.

Mantle cavity and digestive system: Not examined.

Genital system ( Figures 22G , 24D ): As for genus. Bursa copulatrix inserted on vagina, moderately short, about half spermoviduct length. Penis moderately long; epiphallus enters penis through simple pore; penis internally smooth, six bumpy longitudinal penis pilasters present. Epiphallus longer than penis, internally with longitudinal pilasters.

Radula ( Figure 25G–I ): As for genus. Radular formula (26.11.1.11.26) × 84 rows.

Range and habitat. This species appears to be restricted to the northern part of the Flinders Ranges in South Australia. No habitat data are available.

Remarks. The specimen examined in the current study was larger than the type specimen, although similar in shape and general appearance. The larger size is reflected in a higher whorl count (4.6 whorls compared to the holotype, 3.8 whorls). Echonitor albumenoidea did not group with E. cyrtochila in the phylogenetic analysis ( Figure 4 ) and differed anatomically, particularly in its lack of the distinctive penial complex (also present in Periclocystis ardeni ). Specimens of P. ardeni with shells of only 4.2 whorls showed the thickened penial sheath and distinctive internal sculpture of the penis, indicating that the specimen of E. albumenoidea was probably reproductively mature at 4.6 whorls. Nevertheless, anatomical data from a single (possibly immature) specimen does not provide sufficient evidence to move E. albumenoidea into a new genus.

Figures

FIGURE 4. Australian Helicarionidae. Majority-rule consensus tree of 13,839 trees, length 99. Where two or more species from a genus are included, the genera are shaded. Groups A and B are referred to in text.

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 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.