Everettia sp.

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 : 101-103

Everettia sp.

Figures 11J , 35C , 36P–R , 38A , 39A

Material examined. North Borneo: BMNH 20020188 (one specimen dissected, radula examined), Mesilau, Kinabalu S, alt. 1524 m, in leaf litter, 11 Aug. 1967, P . R. Williams.

Description. External morphology: Shell 6.2 whorls, light golden brown, spire and apex slightly raised. Protoconch highly eroded; teleoconch sculptured with strong radial growth lines and microscopic spiral grooves. Whorl profile rounded above and below evenly convex periphery. Internal walls of early whorls complete; umbilicus very narrowly open. Animal ( Figure 35C ) primarily dark grey, with cream colouration in middle part of sole and along top of tail. Mantle laps and lobes not visible. Sole of foot tripartite; caudal apparatus as for family; caudal horn quite small; caudal foss diamond-shaped slit in tail.

Mantle cavity ( Figure 38A ): As for family. Mantle with visible minor blood vessels, pigmentation of black and white spots, mantle gland absent.

Digestive system: Oesophageal crop absent.

Genital system ( Figure 39A ): As for family. Carrefour and talon both not embedded in albumen gland. Free oviduct of medium length; capsular gland absent; internal longitudinal pilasters present. Bursa copulatrix inserted on stimulator, very short, shorter than free oviduct; duct of bursa copulatrix wide, not distinguishable from bursa copulatrix, internally smooth. Vagina absent. Stimulator inserted at junction of penis and free oviduct; internally with papilla holding dart; multiple apical glands and ducts present. Penis short; epiphallus enters penis through simple pore; penis internally covered in transverse ridges, four longitudinal penis pilasters present, penial diverticulum absent. Penial sheath present, enclosing only base of penis; penis retractor muscle attached to penis. Epiphallus shorter than penis, internally with longitudinal pilasters. Epiphallic retractor caecum absent; Flagellum and lime-sac absent. Spermatophore not present in dissected specimen.

Radula ( Figure 36P–R ): Relatively long and narrow. Central tooth with small ectocones; mesocone long, narrow, straight-sided, considerably longer than tooth base. Lateral and marginal tooth fields distinguishable. Lateral teeth with endocone slightly smaller than central tooth ectocones; ectocone equal in size to those on central tooth; mesocone much longer than tooth base. Marginal teeth with endocones absent; ectocones reduced to a tiny stub, not subdivided into extra teeth. Radular formula (65.25.1.25.65) (number of rows not known).

Remarks. The exact identity of this species is unknown. However, it can be assigned to Everettia based on the multiple major gland lobes of the stimulator and the short bursa copulatrix inserted on the stimulator, synapomorphies of this genus ( Hausdorf 1995). In the phylogenetic analysis it grouped with Parmarion (Ariophantidae) ( Figure 1 ) or as the sister taxon to Microcystidae ( Figure 3 ), depending on the characters included in the analysis.

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 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 11. Nervous systems. Cerebral commissure cut (cut regions shaded with diagonal lines). A. Helicarion cuvieri, AM C424333. B. Brevisentis atratus, AM C205294. C. Stanisicarion freycineti, AM C391188. D. Nitor circumcincta, AM C365822. E. Tarocystis responsivus, AM C425327. F. New Caledonian species NC3, MNHN no registration number. G. Ctenophila caldwelli, AM C205301. H. Madagascan species MA1, AM C205304. I. Macrochlamys petrosa, AM C205305. J. Everettia sp., BMNH 20020188. K. Coneuplecta pampini, AM C438751. L. Lamprocystis guttula, FMNH 174940. M. Trochomorpha rubens, FMNH 175247. Scale bars 1 mm except for J (scale bar 2 mm). Abbreviations: ce, cerebral ganglion; pa, parietal ganglion; pe, pedal ganglion; pl, pleural ganglion; vg, visceral ganglion.

FIGURE 35. External morphology of caudal regions. A. Kalidos balstoni, AM C205303. B. Macrochlamys petrosa, AM C205303. C. Everettia sp., BMNH 20020188. D. Greenwoodoconcha nux, AM C433375. E. Videna planorbis, FMNH 160957. F. Dendrotrochus eva eva, FMNH 160957. Scale bars 1 mm (D), 2 mm (E–F), 5 mm (A–C).

FIGURE 36. Radulae. SEM. A–C. Sheldonia poeppigii, NMSA V9710. D–F. Elisolimax flavescens, NMSA L5563. G– I. Macrochlamys petrosa, AM C205305. J–L. Sesara infrendens, BMNH 1995067. M–O. Parmarion martensi, BPBM 252738. P–R. Everettia sp., BMNH 20020188. Scale bars 10 mm (G–I), 20 mm (A–F, J–R).

FIGURE 38. Mantle cavities. A. Everettia sp., BPBM 20020188. B. Coneuplecta pampini, AM C438751. C. Hiona pilsbryi, BPBM 20680 & 20701 (mixed). D. Trochomorpha rubens, FMNH 175247. Scale bars 2 mm (B–D), 5 mm (A). Abbreviations: i, intestine; k, kidney; mc, mantle collar; pc, pericardium; pv, pulmonary vein; ur1, primary ureter; ur2, secondary ureter.

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.