Contributions of a small collection of terrestrial microsnails (Pupilloidea, Hypselostomatidae) from Myanmar with description of three new species
Author
Tongkerd, Piyoros
https://orcid.org/0000-0001-9221-9293
Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
Author
Lwin, Ngwe
https://orcid.org/0000-0002-4394-3741
Fauna and Flora International, No. 35, 3 rd Floor, Shan Gone Condo, Myay Ni Gone Market Street, Sanchaung Township, Yangon, Myanmar
Author
Pall-Gergely, Barna
https://orcid.org/0000-0002-6167-7221
Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman Otto ut 15, 1022 Budapest, Hungary
Author
Chanabun, Ratmanee
https://orcid.org/0000-0003-4584-2773
Program in Animal Science, Faculty of Agricultural Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon 47000, Thailand
Author
Pholyotha, Arthit
https://orcid.org/0000-0001-6677-1164
Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
Author
Prasankok, Pongpun
https://orcid.org/0000-0001-5967-223X
Biodiversity and Utilization Research Unit, Center of Excellence in Modern Agriculture, Sakon Nakhon Rajabhat University, Sakon Nakhon 47000, Thailand
Author
Seesamut, Teerapong
https://orcid.org/0009-0003-9589-8641
School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
Author
Siriwut, Warut
https://orcid.org/0000-0001-6760-9724
Department of Biology, Faculty of Science, Rangsit University, Pathum Thani 12000, Thailand
Author
Srisonchai, Ruttapon
https://orcid.org/0000-0002-7142-0999
Animal Systematics and Molecular Ecology Laboratory, Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
Author
Sutcharit, Chirasak
https://orcid.org/0000-0001-7670-9540
Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
jirasak4@yahoo.com
Author
Panha, Somsak
https://orcid.org/0000-0002-4431-2458
Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand & Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
somsak.pan@chula.ac.th
text
ZooKeys
2024
2024-03-14
1195
157
197
http://dx.doi.org/10.3897/zookeys.1195.112112
journal article
http://dx.doi.org/10.3897/zookeys.1195.112112
1313-2970-1195-157
7CFF082DDA924ECF8E7C0A9972F6CD08
E26F0ADE4B4C5BCB943E2FCC63E349C4
Bensonella lophiodera Tongkerd & Panha
sp. nov.
Figs 7C
, 9
, 13I
Type locality.
Myinmati Cave, Kalaw Township, Taunggyi District, Shan State, Myanmar (locality code SH4;
20°35'24.6"N
,
96°36'42.1"E
; 1312 m a.s.l.).
Type material.
Holotype
CUMZ 14378 (height 3.1 mm, width 1.8 mm; Fig.
7C
).
Paratypes
CUMZ 14379 (16 shells); CUMZ 14404 (12 shells; measured); CUMZ 14405 (3 shells; Figs
9
,
13I
), NHMUK 20230592 (3 shells), SMF 373020 (3 shells) all from the type locality.
Figure 9.
Bensonella lophiodera
sp. nov., from Taunggyi District, Shan State
A-C
paratypes CUMZ 14405. The white arrow indicates constriction. The yellow arrow indicates a cervical crest. Abbreviations:
a
: angular lamella,
b
: basal plica,
c
: columellar lamella,
ip
: infraparietal lamella,
lpl
: lower palatal plica,
p
: parietal lamella,
sbc
: subcolumellar lamella,
upl
: upper palatal plica.
Diagnosis.
Shell ovate-conical, high spired and pale yellowish brown colour. Cervical crest situated far from peristome. Lip not expanded. Aperture usually with seven barriers (parietal, infraparietal, angular, columellar, basal, and upper and lower palatals). Palatal tubercle is lacking.
Etymology.
The specific name
lophiodera
is a compound of the Greek words
lophia
meaning crest and
dere
meaning neck or throat. It refers to the prominent cervical crest on the palatal wall of the last whorl.
Description.
Shell ovate-conical, pale yellowish brown in colour, high spire and
51/2
-6 convex whorls. Shell height 2.7-3.2 mm and shell width 1.9-2.1 mm. Apex blunt; protoconch consisting of ~
11/2
whorls with wrinkles and weak spiral ridges. Teleoconch with somewhat strong and irregular growth lines; suture well impressed and deep. Last whorl large and rounded. Peristome slightly thickened and little expanded; constriction very weak; lip yellowish brown. Cervical crest sharp and situated close to peristome. Aperture subrectangular with seven or eight apertural barriers. Parietal lamella large, strongly developed, blunt, u-shaped from side view; infraparietal lamella small and knob shaped. Angular lamella weaker than parietal: outer part very low, weak and reaching peristome; inner part strong and tall. Palatal tubercle inconspicuous. Upper palatal plica small and low; lower palatal plica strong and tall, blunt. Basal plica small tubercle-like. Columellar lamella large and strong; sometimes an additional tiny subcolumellar lamella is present. Umbilicus narrowly perforate, ~ 1/5 of shell width, rounded and deep.
Distribution.
This species is currently known only from the type locality in Shan State. The living snails are found on limestone walls and under leaf litter in rock crevices.
Differential diagnosis.
This new species is similar to
B. salwiniana
in shell shape, number of apertural dentitions, and bears no palatal tubercle. However,
B. lophiodera
sp. nov. differs by having a strong cervical crest, and a very thin, fragile and unexpanded lip, while
B. salwiniana
shows no cervical crest, and has a thickened and expanded lip.
The new species is distinguishable from
Bensonella
reported from Thailand and Laos in having a weak palatal tubercle, a cervical crest, slightly expanded lip, no interpalatal plica, and apertural barriers are generally weak. Regarding the three species from Thailand,
B. nabhitabhatai
has one upper palatal plica, and lacks the basal plica and the infraparietal lamella;
B. tamphathai
possesses two interpalatal plicae, and its shell is sculptured with spiral striae;
B. pangmapaensis
has fine spiral striae and hooked palatal and basal plicae (
Panha and Burch 2000
,
2002b
,
2005
;
Panha et al. 2003
;
Inkhavilay et al. 2016
).
There are three
Bensonella
species known from Laos. Among them,
B. paralella
has an expanded lip and strongly prominent apertural dentitions;
B. anguloobtusa
has strong and sinuous apertural dentitions, and is sculptured with weak spiral striae;
B. wangviangensis
has a unique shell shape with small shell size (height 1-2 mm), a nearly closed sinulus, a shouldered last whorl, and lacks a basal plica and columellar lamella (
Panha and Burch 2000
,
2002b
,
2005
;
Panha et al. 2003
;
Inkhavilay et al. 2016
).
In addition,
B. lophiodera
sp. nov. differs from
B. taiyaiorum
sp. nov. in having eight apertural barriers, an inconspicuous palatal tubercle, one upper palatal plica, and lacking a supracolumellar lamella and interpalatal plica. In contrast,
B. taiyaiorum
sp. nov. possesses an expanded lip, has a strong palatal tubercle, two upper palatal plicae, and the inter- and lower- palatal plicae are connected and form a U-shaped plica.
Remarks.
The spiral striae on the protoconch are very faintly detectable under the SEM microscope. Among all the type series examined, no hooked-shaped dentitions were observed, while the apertural dentitions show minor variability in different degrees of thickness and sharpness. A clear constriction at the palatal wall near the aperture and a sharp cervical crest are present in all specimens.