Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea)
Author
Páll-Gergely, Barna
Author
Hunyadi, András
0000-0003-3488-2817
hunand@freemail.hu
Author
Grego, Jozef
0000-0002-4977-0415
jozef.grego@gmail.com
Author
Reischütz, Alexander
0000-0002-8844-7004
alexander.reischuetz@gmx.at
Author
Auffenberg, Kurt
0000-0001-9660-6776
kurtauffenberg@gmail.com
text
Zootaxa
2021
2021-05-18
4973
1
1
61
journal article
6241
10.11646/zootaxa.4973.1.1
d0967b08-98d1-4ccd-b472-a678e0e57eda
1175-5326
4771958
42EB4BF2-A571-4894-9EEF-783649A27E4F
Dicharax ebrius
Páll-Gergely & Auffenberg
n. sp.
Fig. 21
Material examined.
Holotype
:
Thailand
,
Mae Hong Son Province
,
42 km
NW of Pai
,
Road
1095,
19°32’N
,
98°32’E
,
750 m
a.s.l.
,
20 Mar. 1988
,
K. Auffenberg
leg.,
UF
345577 (D:
2.89 mm
, H:
1.97 mm
)
.
Paratypes
:
22 shells, same data as holotype,
UF
551221
.
Other material:
9 juvenile
shells, same data as holotype,
UF
551222
.
Etymology.
The dorsal view of the shell of this new species looks like a face of a drunken (
ebrius
in Latin) man due to glossy R3 swelling.
Diagnosis.
A small
Dicharax
species
with a finely ribbed R1, glossy swelling on R3 situated far from peristome, thickened outer peristome and slightly fringed inner peristome.
Description.
Shell off-white to yellowish corneous, slightly translucent; shell outline slightly oval in dorsal view; spire slightly elevated, low conical, body whorl rounded; protoconch low, glossy, 1.25–1.5 whorls; R1 of 1.75–2 whorls, finely, regularly ribbed from beginning, ribs gradually become more widely-spaced toward R1 termination; boundary between R1 and R2 conspicuous due to dense R2 ribs; R2 ribs curved toward aperture, ca. 44–46 ribs present; R2 ribs almost adnate; R2+R3 slightly more than quarter whorl (ca. 100˚); R2 approximately as long as R3 or slightly shorter; boundary between R2 and R3 distinct due to change in sculpture and deep constriction; R3 with prominent, but rounded, glossy swelling situated close to constriction; between swelling and peristome with few fine ribs, in some specimens this area slightly swollen, seemingly forming secondary swelling; aperture strongly oblique to shell axis, rounded with basal incision; boundary between inner and outer peristomes indistinct; inner peristome strong, protruding, expanded, basal and palatal portions slightly fringed, outer peristome expanded, and reflected toward umbilicus; peristome edges merge to form a multi-layered, thickened apertural lip; umbilicus narrow, approximately one fourth of shell width.
Measurements.
D:
2.65–2.89 mm
, H:
1.85–1.97 mm
.
Operculum.
Outer surface concave, yellowish corneous, with some traces of a deciduous lamina; inner surface with a small, pointed, low central nipple.
Differential diagnosis.
The small shell size, blunt, but prominent, glossy swelling on R3 makes this new species easy to recognize.
Dicharax notus
(Godwin-Austen, 1914)
is similar in overall shell shape, but has blunter, less glossy R3 swelling situated closer to peristome and a rounded aperture.
Due to the weak traces of lower, secondary R3 swelling and overall shell shape, this new species is similar to
D. birugosus
(Godwin-Austen, 1893)
(syn.
Alycaeus canaliculus
Godwin-Austen, 1914
, see
Páll-Gergely
et al
. 2020
) from the Khasi Hills,
India
. However, the Indian species has shorter R2 and R3, the R2 ribs are more widely-spaced, and prominent secondary swelling.
Distribution.
This new species is known only from the
type
locality (
Fig. 17
).