Innesoconcha aberrans, (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 : 57

INNESOCONCHA ABERRANS ( IREDALE, 1944)

( FIGS 5C , 6B , 10G–I , 12 , 13 ; TABLE 1 )

Innesoconcha aberrans Iredale, 1944: 326 , pl. 20, fig. 15; Smith, 1992: 234; Hyman & Köhler, 2020: 100.

Type material: Holotype, AM C.63475 ( Fig. 5C ), Mount Gower (31°35.4′S, 159°4.35′E), 1912, R.Bell.

Material examined: See Table 1 .

Description

External morphology: Shell ( Fig. 5C ) small ( SW 5.2– 7.8 mm, SH 4.3–4.9 mm), 4.5–5.5 whorls, not glossy, golden brown (appearing darker in live specimens), trochoidal with an elevated spire. Protoconch with fine, incised spiral grooves, teleoconch smooth. Whorl profile flattened above and below an angulate periphery. Animal ( Fig. 6B ) black (faded to white in old spirit-preserved specimens). Right shell lappet long, narrow, finger-shaped; left shell lappet absent. Caudal horn moderately long.

ReproductiƲe system ( Fig. 12 ): Oviduct with no more than one egg, two embryos. Penis moderately long, coiled once or twice in tunica; epiphallus enters penis through a simple pore; penial wall internally with v-shaped ridges; two major longitudinal penis pilasters present; three or four short minor pilasters apically; one moderately short minor longitudinal pilaster basally, reaching the middle of the penis. 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. 10G–I ): Lateral teeth with broad, rounded mesocones slightly longer than tooth base, and relatively small ectocones. Marginal teeth primarily bicuspidate, with reduced extra cusps becoming more prominent towards outer edge. Radular formula (60.8.1.8.60) × 124 ( AM C.391773).

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 10. 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 catletti, AM C.399376, Blinky Beach. D–F, I. catletti, AM C.446502, Goat House. G–I, Innesoconcha aberrans, AM C.391773, Goat House. Scale bars: 20 µm.

Figure 12. Reproductive system of Innesoconcha aberrans. A, B, AM C.391773, Goat House, Mount Lidgbird.A, reproductive system. B, penis with tunica removed. C, AM C.583109, upper south face of Mount Lidgbird, penis interior. D, AM C.568520, Mount Lidgbird, penis interior. Scale bars: 1 mm.

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