Innesoconcha grata, (IREDALE, 1944)

Hyman, Isabel T., Caiza, Jennifer & Köhler, Frank, 2023, Dissecting an island radiation: systematic revision of endemic land snails on Lord Howe Island (Gastropoda: Stylommatophora: Microcystidae), Zoological Journal of the Linnean Society 197 (1), pp. 20-75 : 64

INNESOCONCHA GRATA ( IREDALE, 1944)

( FIGS 5G , 6F , 13 , 16G–I , 20 ; TABLE 1 )

Melloconcha grata Iredale, 1944: 323 , pl. 20, fig, 13; Smith, 1992: 238; Hyman & Köhler, 2020: 109.

Type material: Lectotype (herein designated), AM C.63475 ( Fig. 5G ), Mount Gower (31°35′23″S, 159°4′20″E), 1912, R. Bell.

Material examined: See Table 1 .

Description

External morphology: Shell ( Fig. 5G ) small ( SW 5.6– 6.6 mm, SH 3.6–4.5 mm), 4.9–5.5 whorls, not glossy, amber, depressed trochoidal. Protoconch and teleoconch with fine, incised spiral grooves. Whorl profile rounded above and below a weakly angulate periphery. Animal ( Fig. 6F ) grey, head and eyestalks dark grey, sole pale (faded to white in old spirit-preserved specimens). Right shell lappet long, narrow, finger-shaped; left shell lappet absent; caudal horn small.

ReproductiƲe system ( Fig. 20 ): Oviduct with one to two eggs, one to two embryos. Penis moderately long, coiled twice in tunica; epiphallus enters penis through a simple pore; penial wall with irregular longitudinal ridges, including ridges radiating out from basal region of penis; one major longitudinal penis pilaster present; two short minor pilasters apically, one short minor pilaster medially. Penial tunica enclosing coiled penis and epiphallus; penis retractor muscle attached to epiphallus. Epiphallus approximately equal to penis length, internally with longitudinal pilasters.

Radula ( Fig. 16G–I ): Lateral teeth with mesocones slightly longer than tooth base. Marginal teeth multicuspidate. Radular formula (62.6.1.6.62) × 105 ( AM C.91365).

Figures

Figure 5. Shells of Innesoconcha.A,B,Innesoconcha catletti.A,AM C.101187 (syntype).B, AM C.101188 (syntype of I.catletti major). C, Innesoconcha aberrans, AM C.63475 (holotype). D, Innesoconcha delecta, AM C.63478 (holotype). E, Innesoconcha doppelganger sp. nov., AM C.592779 (holotype). F, Innesoconcha flaƲescens, AM C.40600 (syntype). G, Innesoconcha grata, AM C.63479 (lectotype). H, Innesoconcha miranda, AM C.39175 (holotype). I, Innesoconcha prensa, AM C.63476 (holotype). J, Innesoconcha princeps, AM C.38958 (syntype). K, L, Innesoconcha rosacea. K, AM C.38940 (holotype). L, AM C.63477 (holotype of Melloconcha alma). M, Innesoconcha segna, AM C.114789 (possible holotype).

Figure 6. Live individuals of Innesoconcha. A, Innesoconcha catletti, AM C.532582, Research Station. B, Innesoconcha aberrans, AM C.593857, Mount Lidgbird mid-south-western slopes. C, Innesoconcha delecta, AM C.574679, Mount Gower summit. D, Innesoconcha flaƲescens, AM C.532623, Boat Harbour. E, I. flaƲescens, AM C.574741, Mount Lidgbird lower northern slopes. F, Innesoconcha grata juvenile, AM C.593.893, Mount Lidgbird mid-south-western slopes. G, Innesoconcha prensa, AM C.583114, Mount Gower summit. H, Innesoconcha princeps, AM C.574711, Mount Gower summit. I, I. princeps juvenile, AM C.574683, Mount Gower summit. J, Innesoconcha rosacea, AM C.583117, Dinner Run. Images by A. Moussalli (A, D), C. Stehn (B, C, E, F, H, I) and F. Köhler (G, J).

Figure 13. Map showing the known range of Innesoconcha aberrans and Innesoconcha grata, based on collections data from the Australian Museum.

Figure 16. Radulae. Column one shows central tooth and adjacent laterals, column two shows the transition between lateral and marginal teeth, and column three shows the outer marginal teeth. A–C, Innesoconcha delecta, AM C.391383, Smoking Tree Ridge. D–F, Innesoconcha flaƲescens, AM C.391761, Goat House. G–I, Innesoconcha grata, AM C.91365, Mount Gower. Scale bars: 20 µm.

Figure 20. Reproductive system of Innesoconcha grata. A–C, AM C.91365, north edge of Mount Gower, on track. A, reproductive system. B, penis with tunica removed. C, penis interior. D, AM C.409419, Mount Gower walking track, penis interior. E, AM C.583124, Mount Gower summit, penis interior. Scale bars: 1 mm.