A review of the family Clenchiellidae (Mollusca: Caenogastropoda: Truncatelloidea)
Author
Ponder, Winston F.
Author
Fukuda, Hiroshi
Author
Hallan, Anders
text
Zootaxa
2014
3872
2
101
153
journal article
10.11646/zootaxa.3872.2.1
e9b8d555-d661-4f1a-86e8-f2a0acc38798
1175-5326
253224
F9F81CC8-E033-46B7-B73B-9FB777DF4116
Coliracemata
?
innocens
(
Preston, 1915
)
Figure 27
Cyclostrema
(
Tubiola
)
innocens
Preston, 1915
: 296
, figs 9, 9a–b.
Types
and
type
locality.
Holotype
: Serua Nadi, Lake Chilka (=Chilika Lake) (eastern
India
),
5–9 ft
. (
1.5–2.7 m
) depth (Indian Museum, Calcutta,
Preston, 1915
: 289 (
type
material apparently lost).
Distribution.
Known only from the
type
locality, a large brackish-water lake.
Material examined.
None.
Description
(based on Preston 1914: 296, figs 9a–c).
Shell
. Minute (2.0 mm in diameter;
Table 3
), spire low (
Fig. 27
C–E). Protoconch not elevated above line of spire, details unknown. Teleoconch of about 3 convex whorls, surface smooth except for growth lines. Periphery evenly convex. Base evenly convex, umbilicus moderately wide (slightly more than half width of base). Sutures impressed. Aperture near circular, prosocline, with simple, slightly thickened peristome, no obvious external varix. Colour milk white.
Operculum, head-foot and anatomy unknown.
Remarks.
Preston’s
Cyclostrema
(
Tubiola
)
innocens
was compared with
Co
.
microscopica
by
Annandale and Kemp (1916: 347)
with the comment that it “clearly belongs to the same genus” and “appears to differ from that species in its smaller size, reddish colour and in the sculpture on its surface; but the
type
of Preston’s species is bleached and perhaps somewhat eroded.” Preston’s description stated that his specimen (from Serua Nadi, Lake Chilka, a brackish water locality) is smooth. He gives a size of 2.0 mm maximum diameter, whereas
microscopica
is, according to Nevill’s original description,
1.5 mm
in diameter. Annandale later (1924: 858) stated a slightly different opinion - “Dr Kemp and I were inclined to think [that
innocens
] is a small denuded shell of Nevill’s species”. These authors are the only ones who had access to the
type
material of both and that have published an opinion on these taxa.
Abbott (1949)
was uncertain regarding the synonymy of these two species. Because, on the available evidence,
Co.
?
innocens
differs from
Co.
?
microscopica
in its larger size, apparent lack of spiral sculpture and slightly wider umbilicus, we tentatively treat both as separate species pending the discovery of new topotypic material.
Co
.?
innocens
could also conceivably be a species of
Coleglabra
n. gen.