Orpiella (Kalendyma) concavum (Clapp, 1923)

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 : 121

Orpiella (Kalendyma) concavum (Clapp, 1923)

Figures 33L , 37E–F , 41D , 42J–L

Material examined. Solomon Islands: BMNH no number (Acc no. 2181, no. JP104 ) (two specimens dissected, radulae examined) , near Ribi Caves, Auki, Malaita, foliage.

Description. External morphology: Shell 5 whorls, pale golden brown, glossy, spire and apex slightly raised. Protoconch smooth; teleoconch sculptured with broad, flat, moderately widely spaced radial ribs. Whorl profile rounded above and flattened below a slightly angular periphery. Internal walls of early whorls complete; umbilicus closed. Animal beige with multiple black spots on sides of foot and black stripes leading to eyestalks. Mantle laps absent; mantle lobes very small. Sole of foot tripartite; caudal apparatus formed from curled up foot ( Muratov’s 1999 helicarionid type). Caudal horn of medium size; caudal foss vertical slit in tail.

Mantle cavity: As for family. Mantle pigmentation of black and white spots, mantle gland absent.

Digestive system: Oesophageal crop absent.

Genital system ( Figures 33L , 37E–F , 41D ): As for family. Carrefour free of albumen gland, carrefour embedded. Free oviduct long; capsular gland present; internal longitudinal pilasters absent. Bursa copulatrix inserted on vagina, moderately short, about half spermoviduct length; duct of bursa copulatrix wide, distinguishable from bursa copulatrix, internally with longitudinal pilasters. Vagina very short; internally with longitudinal pilasters. Penis short; epiphallus enters penis through simple pore; penis internally smooth, six to seven longitudinal penis pilasters present, penial diverticulum absent. Penial sheath present, thin, enclosing only penis; penis retractor muscle attached to epiphallus, wrapping once around vas deferens but not attaching to it. Epiphallus longer than penis, internally with longitudinal pilasters. Epiphallic retractor caecum absent; Lime-sac present. Spermatophore long soft-walled tube closed at both ends, sculptured with two longitudinal ridges, one with a row of tiny teeth.

Radula ( Figure 42J–L ): Relatively long and narrow. Central tooth with small ectocones; mesocone lanceolate, similar in length to tooth base. Lateral and marginal tooth fields distinguishable. Lateral teeth with endocone much smaller than central tooth ectocones; ectocone equal in size to those on central tooth; mesocone slightly longer than tooth base. Marginal teeth with endocones absent; ectocones approximately same length and breadth as mesocone, not subdivided into extra teeth. Radular formula (43.10.1.10.43) × 91 rows.

Remarks. Baker (1941a) included a number of groups as subgenera within Orpiella , but stated that a proper revision could not take place without the study of more material. Schileyko (2002b) raised most of these subgenera to generic level, including Owaraha and Kalendyma, both of which are restricted to the Solomon Islands. In the current study, Baker’s (1941a) more conservative approach is followed.

The species dissected in the current study has strong similarities to the type species of Kalendyma, Orpiella (K.) compluviata ( Cox, 1871) , particularly in the form of the spermatophore with two ridges, one toothed and one smooth ( Rensch & Rensch 1936). The other reproductive characters are also similar, as is the shell ( Schileyko 2002b). However, the two species differ in the presence of a fine filiform keel on the shell of Orpiella (K.) compluviata and the presence of flat radial ribs on the shell of O. (K.) concavum .

The varying taxonomic placement of this genus is outlined above (Family Trochomorphidae : Remarks).

In the phylogenetic analysis, Orpiella concavum was the sister taxon to Helicarionoidea and did not group with Trochomorphidae ( Figures 1–3 ). However, in the molecular phylogenetic analysis of Hyman et al. (2007), O. concavum grouped with Videna planorbis (Trochomorphidae) ( Figure 44A ).

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 33. Penis interiors. A. Erepta odontina, AM C205302. B. Kalidos balstoni, AM C205303. C. Madagascan species MA1, AM C205304. D. Sheldonia poeppigii, NMSA L5563. E. Elisolimax flavescens, NMSA V9710. F. Parmarion martensi, BPBM 252738. G. Coneuplecta pampini, AM C438751. H. Hiona pilsbryi, BPBM 206801 & 20701. I. Trochomorpha rubens, FMNH 175247. J. Videna planorbis, FMNH 160957. K. Dendrotrochus eva eva, FMNH 175196. L. Orpiella concavum, BMNH no registration number. Scale bars 1 mm (A, C–D, F–H, J, M), 2 mm (B, E, I, K). Abbreviations: bc, bursa copulatrix; c, caecum; ep, epiphallus; fov, free oviduct; ovi, ovipositer; p, penis; pp, penial pilaster; prm, penis retractor muscle; ppu, penial pustules; pv, penial verge.

FIGURE 37. Spermatophores. SEM. A, B. Elisolimax flavescens, NMSA L5563. C, D. Macrochlamys petrosa, AM C205305. E, F. Orpiella concavum, BMNH no registration number. Scale bars 0.2 mm (D, F), 0.5 mm (B), 1 mm (A, C, E).

FIGURE 41. Reproductive systems. A. Lamprocystis guttula, FMNH 174940. B. Trochomorpha rubens, FMNH 175247. C. Videna planorbis, FMNH 160957. D. Orpiella concavum, BMNH no registration number. E. Dendrotrochus eva eva, FMNH 175196. Scale bars 1 mm (A), 2 mm (B–D, F), 5 mm (E). Abbreviations: alb, albumen gland; bc, bursa copulatrix; ca, carrefour; e, eggs / embryos; ep, epiphallus; fov, free oviduct; her, hermaphrodite duct; ov, ovotestis; p, penis; pr, prostate; prm, penis retractor muscle; puo, post-uterine oviduct; t, talon; ut, uterus; vd, vas deferens.

FIGURE 42. Radulae. A–C. Trochomorpha rubens, FMNH 175247. D–F. Videna planorbis, FMNH 160957. G–I. Dendrotrochus eva eva, FMNH 15719. J–L. Orpiella concavum, BMNH no registration number. Scale bars 20 mm (A–L).

FIGURE 44. Trees resulting from the phylogenetic analysis of two molecular datasets. Families and subfamilies are shaded. A. Mitochondrial gene cytochrome c oxidase subunit I [after Hyman et al. (2007)]. B. Nuclear gene 28S rRNA [after Wade et al. (2006)].