Dissecting an island radiation: systematic revision of endemic land snails on Lord Howe Island (Gastropoda: Stylommatophora: Microcystidae)
Author
Hyman, Isabel T.
Author
Caiza, Jennifer
Author
Köhler, Frank
text
Zoological Journal of the Linnean Society
2023
2022-10-17
197
1
20
75
http://dx.doi.org/10.1093/zoolinnean/zlac075
journal article
10.1093/zoolinnean/zlac075
0024-4082
7499138
613C3FA2-CDF7-4BED-B852-340C3DE724F9
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).