Innesoconcha delecta, (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 : 59-60

INNESOCONCHA DELECTA ( IREDALE, 1944)

( FIGS 5D , 6C , 14 , 15 , 16A–C )

Melloconcha delecta Iredale, 1944: 323 , pl. 20, fig. 8; Smith, 1992: 237; Stanisic et al., 2010: 334–335; Hyman & Köhler, 2020: 106.

Type material: Holotype, AM C.63478 ( Fig. 5D ), North Bay (31°31.14′S, 159°2.7′E), 1912, R.Bell.

Material examined: See Table 1 .

Description

External morphology: Shell ( Fig. 5D ) small ( SW 5.3– 5.9 mm, SH 3.0– 4.3 mm), 4.6–5.8 whorls, glossy, light yellow-brown, domed in shape with a raised spire. Microsculpture of fine, incised spiral grooves. Whorl profile rounded above and below a rounded periphery; sutures slightly impressed. Animal ( Fig. 6C ) grey to black in life, faded to white in alcohol. Right shell lappet long, narrow, finger-shaped, left shell lappet absent; caudal horn small.

Pallial caƲity: Mantle with pigmentation of white spots.

ReproductiƲe system ( Fig. 14 ): Oviduct with one to two eggs, one to two embryos. Penis short; penis not fully coiled but twisted only once at epiphallus end; epiphallus enters penis through a simple pore; penis internally flat, three to four longitudinal penis pilasters present, penial diverticulum absent. Penial tunica enclosing coiled penis and epiphallus; penis retractor muscle attached to junction of penis and epiphallus and to parts of epiphallus. Epiphallus approximately equal in length to penis, internally with longitudinal pilasters. Spermatophore a short, soft-walled, smooth, peanut-shaped tube, closed at both ends.

Radula ( Fig. 16A–C ): Marginal teeth with ectocones approximately same length and breadth as mesocone, multicuspidate. Radular formula (54.7.1.7.54) × ~120, (46.7.1.7.46) × ~120, (45.7.1.7.45) × ~120 (all AM C.391383); (~70.7.1.7.~70) × ~100 ( AM C.391761).

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 14. Reproductive system of Innesoconcha delecta, AM C.583081, lower slopes of Mount Eliza. A, reproductive system. B, penis with tunica opened. C, penis interior. Scale bars: 1 mm.

Figure 15. Map showing the known range of Innesoconcha delecta, based on the Australian Museum collections data. No specimens were collected in the period 1931–1960.

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.