Liardetia (Belopygmeus) doliolum ( Pfeiffer, 1846 )

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 : 113-114

Liardetia (Belopygmeus) doliolum ( Pfeiffer, 1846)

Figures 39G , 40G–I

Helix doliolum Pfeiffer, 1846: 41 .

Liardetia (Belopygmeus) doliolum: Baker, 1938: 27 , pl. 3, figs 6–8, pl. 9, fig. 9, pl. 14, fig. 9; Smith, 1992: 236. Liardetia doliolum: Benthem-Jutting, 1950: 410–411 , fig 28; Benthem-Jutting, 1964: 26.

Liardetia (Belopygmaeus) doliolum: Solem, 1988: 549–550 , figs 175, 181–182.

Material examined. Hawaii: BPBM 253684 (one specimen dissected, radula examined), Manoa, Honolulu, Oahu , R. Helling.

Description. External morphology: Shell 5.2 whorls, orange-brown, spire and apex raised. Protoconch sculptured with spiral ribs; teleoconch with radial lirae. Whorl profile flattened above and below evenly convex periphery. Internal walls of early whorls complete; umbilicus closed. Animal white. Mantle laps and lobes absent. Sole of foot undivided (possibly due to preservation condition of specimen); caudal apparatus as for family; caudal horn small; caudal foss horizontal slit in tail.

Mantle cavity: As for family. Pigmentation absent, mantle gland absent.

Digestive system: Oesophageal crop absent.

Genital system ( Figure 39G ): As for family. Oviduct non-glandular, containing 5–6 embryos. Post-uterine oviduct of medium length, internal longitudinal pilasters absent. Bursa copulatrix inserted at junction of penis and free oviduct, short, less than half spermoviduct length; duct of bursa copulatrix narrow, distinguishable from bursa copulatrix, internally smooth. Vagina absent. Penis short; epiphallus enters penis through simple pore; penis internally smooth, one circular penis pilaster present, penial diverticulum absent. Penial sheath present, enclosing coiled penis and epiphallus; penis retractor muscle attached to base of epiphallic caecum. Epiphallus longer than penis, simple internally. Epiphallic retractor caecum present; very long; positioned in middle of epiphallus. Flagellum and lime-sac absent. Spermatophore very short, soft-walled, smooth, peanutshaped tube with short tail.

Radula ( Figure 40G–I ): Relatively long and narrow. Central tooth with moderately small ectocones; mesocone lanceolate, similar in length to tooth base. Lateral and marginal tooth fields distinguishable. Lateral teeth with endocone equal in size to central tooth ectocones; ectocone equal in size to those on central tooth; mesocone similar in length to tooth base. Marginal teeth with endocones absent; ectocones approximately same length and breadth as mesocone, subdivided into two extra teeth. Radular formula (30–35.6.1.6.30–35) (number of rows not known).

Remarks. The taxonomic arrangement of Baker (1938) is followed here. Further details about this species and its distribution in Australia are found in Solem (1988).

In the phylogenetic analysis, Liardetia doliolum consistently grouped with Cystopelta sp. (Cystopeltidae) , instead of with other members of Microcystinae ( Figures 1–3 ). As mentioned earlier, Liardetia differs from the other Microcystinae in some key characters (e.g. position of the bursa copulatrix; presence of an epiphallic caecum), but other characters place it in this group (e.g. ovoviviparity; penis sheath enclosing coiled penis and epiphallus). When Dyakiidae and Cystopeltidae were excluded, L. doliolum grouped with the other Microcystinae (tree not shown).

Figures

FIGURE 1. Majority-rule consensus tree (1,743 trees, length 117 steps) from the morphological analysis containing representatives of all groups. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 2. Majority-rule consensus tree (646 trees, length 106 steps) from the morphological analysis with Dyakiidae and Urocyclidae excluded. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 3. Majority-rule consensus tree (770 trees, length 117 steps) resulting from the morphological analysis with two additional mantle lobe characters. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 39. Reproductive systems. A. Everettia sp., BMNH 20020188. B. Lamarckiella lamarckiana sibuyanensis, FMNH 201967. C. Coneuplecta pampini, AM C438751. D. Coneuplecta calculosa, AM C377891. E. Coneuplecta dahli, MNHN no registration number. F. Hiona pilsbryi, BPBM 206801. G. Liardetia doliolum, BPBM 253684. Scale bars 1 mm (C–E, G), 2 mm (F), 5 mm (A–B). Abbreviations: alb, albumen gland; bc, bursa copulatrix; ca, carrefour; e, eggs / embryos; ep, epiphallus; fov, free oviduct; her, hermaphrodite duct; m, muscle attaching penial sheath to epiphallus; ov, ovotestis; p, penis; pd, penial diverticulum; pr, prostate; prm, penis retractor muscle; pt, penial sheath; pv, penial verge; st, stimulator; ut, uterus; v, vagina; vd, vas deferens.

FIGURE 40. Radulae. SEM. A–C. Coneuplecta pampini, AM C438751. D–F. Coneuplecta calculosa, AM C377891. G–I. Liardetia doliolum, BPBM 253684. J–L. Lamprocystis guttula, FMNH 174940. Scale bars 10 mm (A–I), 20 mm (J–L).