Corresponding author: Barna Páll-Gergely (
Academic editor: M. Haase
All known taxa of the genus
Páll-Gergely B, Budha PB, Naggs F, Backeljau T, Asami T (2015) Review of the genus
The
Gude revised every known taxon of
The aim of this paper is to review and diagnose all
The helicid subgenus
Simultaneously,
From the shells collected during the Abor Expedition (Abor Country, north-eastern India),
Shell whorls were counted according to
For the nomenclature of lamellae (vertical parietal folds) and plicae (horizontal parietal folds and palatal folds) see Figure
Nomenclature of parietal ( : apertural fold : anterior lamella : apertural margin (peristome) : intermediate plica : lamella : lower plica : main plica : posterior lamella : posterior denticles : posterior lamella : upper plica
For each taxon, the specimens studied are listed separately as types, museum material and new material. Geographic names mentioned in the literature and on labels (Table
Geographic names mentioned in the literature and on labels of
Locality | Region | Taxon |
---|---|---|
Abor Hills | India, Arunachal Pradesh |
|
Arakan Hills (= Rakhine) | Myanmar, Rakhine district |
|
Bassein (= Pathein) | Myanmar, Ayeyarwady district: |
|
Brahmakund | India, Assam: |
|
Burrail (= Barail) Gorge | India, mountain range centered 70 km NE Silchar (Assam) | |
Cachar (= Katchar) | India, District in Assam: |
|
Cherra Poonjee (= Cherrapunji) | India, Meghalaya, Khasi Hills: |
|
Chittagong | City in Bangladesh: |
|
Damsang Peak | India, Sikkim | |
Darjiling (= Darjeeling) | India, town in West Bengal: |
|
Dihang (= Siang) River | India, Arunachal Pradesh: river flows to the Brahmaputra at |
|
Dunsiri (= Dhansiri) River | India, river flows to the Brahmaputra at |
|
Durrang (= Darrang) | India, district in Assam: centered at |
|
Garo Hills | India, Western Meghalaya: |
|
Ghoramara | Bangladesh, town approx. 15 km NW from Chittagong, at |
|
Prov. Harenni* | Myanmar |
|
Hengdan* | India, mountain in northern Cachar Hills |
|
Ihang River* | India, Manipur | |
Japvo Peak | India, highest mountain in Naga Hills: |
|
Karenni (= Kayah) State | state located south of Shan State, Myanmar |
|
Khasi (= Khasia) Hills | India, Meghalaya | |
Khunho (= Khono) Mountain | India, Naga Hills: |
|
Kohima | India, town in SE Nagaland: |
|
Kopamedza ridge* | India, Dafla Hills, Barail Range |
|
Laisen Peak* | India, Manipur | |
Lhota Naga* | India, Nagaland, Naga Hills | |
Lopchu | India, Sikkim |
|
Luyor Peak | India, Abor county, Arunachal Pradesh: |
|
Mairung (= Mairang) | India, village in Meghalaya, Khasi Hills: |
|
Miri Hills | India, on the border between Assam and Arunachal Pradesh |
|
Munipur (= Manipur) | India, Manipur | |
Naga Hills | on the border of Nagaland (India) and Myanmar | |
Naraindher* | India, Assam, Cachar district |
|
Pankabari (= Pankhabari) | India, northern part of West Bengal: |
|
Pegu (= Bago) | Myanmar, Bago District: |
|
Picholanulla* | India, probably Dafla Hills |
|
Pyema Khyoung | Myanmar, Ayeyarwady district |
|
Rarhichu (= Rungpo?)* | India, Sikkim | |
Renging (= Rengging) | India, Abor county, Arunachal Pradesh: |
|
Richila (Rechila) Peak | India, Sikkim: |
|
Rinkpo valley* | India, Sikkim |
|
Rissetchu* | India, Sikkim |
|
Riu* | India, Abor Hills |
|
Rotung (= Rottung) | India, Abor county, Arunachal Pradesh: |
|
Rungmaval* | India, Sikkim |
|
Rungun* | India, probably Sikkim | |
Sadia (Sadiya) | India, Assam: |
|
Salwen (= Salween) River | River in China and eastern Myanmar |
|
Shillong | India, city in Meghalaya, Khasi Hills |
|
Shiroifurar peak (probably Shirui Hills) | India, NE Manipur: |
|
Shweego (probably Shwegu) | probably Myanmar, Kachin District: |
|
Sibbum (= Sibum) | India, Abor Hills: |
|
Sigon (= Siyom) River | India, river runs into the Siang River at |
|
Singging* | India, Abor Hills |
|
Sylhet | Bangladesh, Sylhet Division, Sylhet city: |
|
Teria Ghat | India, Khasi Hills | |
Tongoop* | Myanmar, Rakhine district |
|
Torúpútú* | India, Dafla Hills | |
Tsanspu (= Tsangpo) River | India (Tibetan name of the Brahmaputra River) |
|
Yamne River | India, Abor Hills, river flows into the Siang River at |
|
Ywathit (= Ywarthit) | Village (?) in Kayah State, Myanmar: |
|
Ethanol-preserved specimens were dissected under a Leica stereomicroscope, equipped with a photographic camera. In description of the reproductive system, we used the terms “proximal” and “distal” relative to the centre of the body.
Individual buccal masses was removed and soaked in 2 M KOH solution for 5 h before extracting the radula, which was preserved in 70% ethanol. Radulae and shells were directly observed without coating under a low vacuum SEM (Miniscope TM-1000, Hitachi High-Technologies, Tokyo).
The dates of publication of the Proceedings of the Zoological Society of London follows
All available type material of each
The following shell characters of species formerly classified in
This taxonomic revision of
Co-occurrence of
|
|
|
|
|
||
---|---|---|---|---|---|---|
|
* | * | ||||
|
** | * | * | |||
|
* | |||||
|
* | * | ||||
|
* | * | * | * |
Central Department Zoology Museum of Tribhuvan University (Kathmandu, Nepal)
shell diameter
shell height
Collection András Hunyadi (Budapest, Hungary)
Hungarian Natural History Museum (Budapest, Hungary)
Collection Jamen Uiriamu Otani (Osaka, Japan)
Museum of Comparative Zoology (Massachusetts, USA)
Mátra Múzeum, Gyöngyös, Hungary
The Natural History Museum (London, UK)
Natural History Museum, Sibiu (Romania), Bielz collection
When citing NHM registered specimens
Naturhistorisches Museum Wien (Vienna, Austria)
Natural History Museum, Bern, Switzerland
Senckenberg Forschungsinstitut und Naturmuseum (Frankfurt am Main, Germany)
Collection Takashi Hosoda (Kofu, Japan)
UniversityMuseum of Zoology (Cambridge, UK)
number of whorls
Collection Wim J. M. Maassen (Echt, The Netherlands)
Museum für Naturkunde (Berlin, Germany)
University of Hamburg (Hamburg, Germany)
Zoological Museum, University of Copenhagen (Denmark)
Zoological Survey of India
Shell (
Shell sinistral or dextral, flat, widely umbilicated; in most cases protoconch seemingly “smooth” to the naked eye, but not glossy, rather matt; under the microscope usually tubercles of various size are visible (Figure
Only one
The genus is known to inhabit northeastern India, eastern and southern Myanmar (Burma) and northern Thailand.
Shell sinistral or dextral; protoconch usually finely, regularly ribbed (see also discussion and Figures
Genitalia (see Figures
Radula (see Figures
All known species of the genera
Some
Some
Characters of the plectopylid genera possessing ribbed protoconchs.
Genus | Coiling direction | Apertural fold | Lower plica | Body whorl | Anterior lamella | Posterior lamella | Periostracal folds | Penial pockets |
---|---|---|---|---|---|---|---|---|
|
sinistral or dextral | absent | short or long (reaching peristome) | rounded or keeled | present | present (?), absent or reduced | usually in multiple rows | whole penial wall |
|
dextral | absent (present in 1 species) | short | keeled | absent or reduced | present | present in a single row or absent | whole penial wall |
|
dextral | absent or present | missing or short | rounded | present, reduced or absent | present | absent | apical part |
|
dextral | present | short | rounded | present, reduced or absent | present | absent | whole penial wall |
eastern |
dextral | absent | missing or short | keeled | present | present or reduced | present in a single row or absent | whole penial wall |
western |
dextral | present | missing or short | rounded | present | present or reduced | absent | apical part |
(Sub)generic classification of : not mentioned
Name | Subgenus in |
Subgenus in |
---|---|---|
|
||
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Main diagnostic characters of
Species | Diagnostic characters | Similar species (most similar species in bold) |
---|---|---|
|
depressed Z-shaped palatal plicae; two parietal lamellae (?) | |
|
narrow umbilicus; four hair rows; horizontal parietal plica absent | |
body whorl shouldered; four hair rows | ||
|
dextral shell; flattened dorsal side; 14 mm | |
|
single parietal lamella with long lower plica; posterior ends of palatal plicae with several additional small denticles | |
|
conical dorsal side; 7 hair rows | |
|
three parallel, horizontal parietal plicae anterior to the lamella | |
rather conical dorsal side; slightly angulated body whorl; 5 hair rows | ||
|
large size (19.9–20.3 mm); reversed trapezoid shell shape | |
dextral shell; flattened dorsal side; 6.6–6.7 mm | ||
|
nearly flat dorsal side; smooth ventral side | |
|
flat dorsal side; four hair rows | |
|
prominent spiral sculpture | |
hairless shell; domed dorsal side; rounded body whorl; simple palatal plicae | ||
|
hairless shell; slightly domed dorsal side; rounded body whorl; complicated palatal plicae | |
|
dextral shell; 16.8–16.9 mm; protoconch without groove | |
|
hairless shell; slightly elevated dorsal side; shouldered body whorl; simple palatal plicae | |
|
very narrow umbilicus; five hair rows; horizontal parietal plica present | |
elevated spire; smooth ventral side; strongly reticulated dorsal surface | ||
|
dextral shell; protoconch with groove | |
|
narrow umbilicus; thin peristome; five hair rows; weak horizontal parietal plica | |
|
very narrow umbilicus;, shouldered whorls; four hair rows | |
|
conical dorsal side; hairless shell; long horizontal parietal plica |
The distribution of this genus is restricted to Nepal, northeastern India and the province Sichuan in China. One species (
Known distribution of the genus
Peak Luyor, Abor Hills, 7,200 ft, leg. C.F.G. Oakes R.E.,
Shells of
Shell small, dextral, slightly concave above; widely umbilicated; hairs arranged in three spiral lines on the body whorl; callus strong, palatal plicae short, simple, parietal wall with a single curved lamella.
(in mm):
For differences with
Only known from the type locality (Figure
China, Sichuan Sheng (四川省), Panzhihua Shi (攀枝花市), Yanbian Xian (盐边县), Qinghe Xiang (箐河乡), Qinghepubu (箐河瀑布), Xianrendong (仙人洞), 1410 m,
Shell very small, dextral, almost flat, relatively widely umbilicated with elevated callus; hairs standing in three lines on the body whorl; parietal wall with a single, curved lamella; palatal wall with six short plicae.
Shell dextral, with almost flat, very slightly domed dorsal side (protoconch slightly elevates from the dorsal surface); brownish or slightly reddish in colour; protoconch consists of 1.5–1.75 whorls, first whorls rather smooth, last 0.25–0.5 whorl regularly ribbed (Figure
One specimen (the holotype) was opened. The armature is situated very close to the aperture, palatal plicae visible from oblique view through the aperture. Parietal wall with a single curved lamella without additional denticles; arms of the lamella pointing posteriorly; palatal wall with six very short plicae becoming narrower posteriorly; the last one with an additional denticle posteriorly (Figures
(in mm):
The name inexpectata (meaning unexpected in Latin) refers to the surprizing new, especially dextral
Sichuan Sheng (四川省), Panzhihuashi (攀枝花市), Yanbian Xian (盐边县), Qinghe Xiang (箐河乡), Qinghepubu (箐河瀑布), Xianrendong (仙人洞), 1410 m,
Sadia, E. Assam, leg. Ogle,
Shells of
Photos (
Distribution of Arakan Hills Bassein (= Pathein) Silchar (Cachar) Chittagong (Ghoramara) Darjeeling Dunsiri valley Garo Hills Khasi Hills Manipur Naga Hills Pegu (= Bago) Sylhet Shwegu Ywathit
SEM images of
Parietal (
Shell middle sized, dextral, yellowish-reddish striped with moderately wide umbilicus and somewhat domed dorsal surface; callus strong, palatal plicae divided at their middle and the posterior fragments are connected by a ridge; parietal wall with a single curved lamella with posteriorly elongated upper and lower ends. Probably at least the upper elongation is homologous with the posterior denticle of other
(in mm):
The information published by
The species is known from the type locality only (Figure
Distribution of type locality of Abor Hills (type locality of type locality of Type locality of Miri Hills (type locality of Type locality of Type locality of
Khunho, H.S. Naga Hills, leg. Godwin-Austen,
Naga Hills, coll. Godwin-Austen,
Shell very small to small, dextral, yellowish-reddish striped with moderately wide umbilicus and depressed conical dorsal surface; callus strong, palatal plicae more or less straight, simple or have dichotomously divided posterior ends; parietal wall with a single curved lamella with denticles near the upper and lower ends posteriorly, which occasionally fuse with the lamella.
(in mm):
The species is recorded from the Naga Hills (see also remarks). “
Distribution of Dafla Hills (locality of Khasi Hills (locality of Lhota Naga (locality of Nepalese localities of Silchar (locality of
In the original description
According to the original description, two shells, an adult and a juvenile were collected and finally deposited in the Indian Museum (inventory numbers: 5998 and 6135). Specimen reference collections in the Indian Museum were transferred to the
Shell small, sinistral, almost flat, widely umbilicated; callus strong; palatal plicae Z or L-shaped; there are two parietal lamellae, a short upper plica which is in contact with the posterior lamella, and a long lower plica which reaches the peristome.
(in mm):
The species was not examined by us, but according to the original description the species differs from all congeners by the short and uniquely shaped palatal plicae, which are depressed Z-shaped, or the lower branch of the “Z” is elongated. See also Table
Known from the type locality only (approximately
So far, this is the only
Shells of
India, Khasia Hills, ex Fulton,
Shells of
India, Khasi Hills,
Shell small, sinistral, yellowish, with narrow umbilicus, conical dorsal surface and shouldered body whorl; hairs are arranged in four rows on the body whorl; callus strong, middle palatal plicae usually divided in the middle; the posterior fragments are oblique, the anterior ones are rather straight; parietal wall with a single, slightly curved lamella with short denticles posteriorly, one above and one below, and a horizontal lower plica which may be divided in the middle.
(in mm):
See under
The species is recorded from the Khasi Hills only (Figure
Nepal, Taubas, Bhainse, Makwanpur District,
Shells of
Shell small, sinisttral, with flat dorsal surface and shouldered (keeled) body whorl; hairs are arranged in four rows; parietal lamella simple with a short free horizontal plica below it, and two denticles posterior to the lamella which are in contact with the lamella; middle palatal plicae divided.
Shell sinistral, semi-transparent; protoconch elevated from the flat dorsal surface; colour brownish or greyish; protoconch conspicuously large, consists of 2.5, 2.75 whorls, very finely, regularly ribbed; teleoconch with clearly visible reticulated sculpture dominated by radial growth lines; sculpture somewhat weaker on the ventral surface; very slender, long periostracal folds (hairs) standing in four spiral lines along the body whorl; two closely adjacent rows running with the keel above, one row on the ventral side around the umbilicus, and one row approximately in the middle line of the body whorl; whorls 6.25 (holotype) moderately bulging, separated by relatively deep suture; umbilicus wide and deep; peristome thin, slightly reflexed; callus moderate; no fold in the aperture.
One specimen was opened. Palatal wall with a single, straight lamella, with two short denticles on the posterior side of the lamella, both are in contact with the lamella; a short, free horizontal plica is visible under the lamella; palatal wall with six plicae, first straight, last slightly curved, the middle plicae are divided in the middle, the fragments are horizontal, oblique or Z-shaped (Figure
(in mm):
See under
The Latin angulatus (cornered, angular) refers to the shouldered/angulated body whorl of the new species.
Nepal, Taubas, Bhainse, Makwanpur District,
Distribution of
Tsanspu Valley Abor Hills, 2800 ft, leg. C.F.G. Oakes R.E.,
Shells of
Shell very small, sinistral, brownish, with moderately wide umbilicus, almost flat dorsal surface (only the apex is elevated slightly), and rounded body whorl; callus strong, palatal plicae long, more or less straight horizontal, with dichotomously divided posterior ends and many small denticles at their posterior ends; lamella single, curved, in contact with a lower plica, which runs until the peristome.
(in mm):
The species is known from the type locality only (approximately
Naga Hills,
Shells of
Richila Peak, Sikkim, India, coll. Ottó, L.,
Shell tiny to very small, sinistral, with narrow umbilicus, conical dorsal surface and 7 rows of hairs; callus weak but present; palatal plicae divided, posterior fractions denticle-like; anterior fractions horizontal, straight; lamella straight or very slightly S-shaped, with posterior denticles above and below, and with a lower and an upper plica close to the sutures; lower plica sometimes short, sometimes very long, and reaches the peristome.
(in mm):
See under
(Figure
Genital anatomy of atrium albumen gland diverticulum epiphallus embryos gametolytic sac penis retractor muscle vagina vas deferens
The left ommatophoral retractor passes between penis and vagina. Atrium short, penis long, rather cylindrical, but slowly tapers towards the proximal end; opening the penis was very difficult, not only because of its size, but also due to the age of the specimen; the internal morphology could hardly be seen, although parallel folds forming “pockets” were visible; a little thickening was found near the posterior end of the penis, this could be interpreted as a penial caecum. The slender and relatively long retractor muscle inserts on the proximal end of the penis, slightly in proximal direction from the caecum; epiphallus also slender, slightly longer than the penis; vas deferens long and slim; vagina shorter than the penis and epiphallus combined, it is very thick, with a well-developed vaginal bulb; several short muscle fibres attach the vagina to the body wall and diaphragm; both the gametolytic sac and the diverticulum are very long and slim, although the gametolytic sac is somewhat thickened.
(Figures
SEM images of the radula of
Most museum samples have been collected in the Sikkim area. Gude received the holotype from Godwin-Austen, and it was said to be collected in the Naga Hills, approximately 600 km from Sikkim. The anatomically examined specimens have been collected from Silchar Cachar, which is located at least 500 km from Sikkim, but not far from the Naga Hills. If the samples from the Naga Hills and from Silchar are correctly labelled, we may expect that the species is widely distributed throughout north-eastern India (see also Figure
Brahamakund, E. Assam,
Assam, leg. Hungerford,
Shell very small, sinistral, with narrow umbilicus, depressed conical dorsally, conspicuous radial sculpture without hairs; callus very strong; palatal plicae short, straight, with many small denticles at their posterior ends, standing along a vertical line; lamella oblique, with three horizontal plicae anteriorly, the lowermost is in contact with the lower end of the lamella; besides these anterior plicae, there is a short upper plica above the lamella, and long lower plica close to the lower suture, which runs until the aperture.
(in mm):
The species is known from the type locality only (Figure
Nepal, Suridobhan, Dolakha, 1023 m,
Shell small with rather conical dorsal surface; body whorl slightly angulated with five rows of hairs; parietal lamella simple with one or two denticles posteriorly and a plica below; middle palatal plicae divided or almost divided.
Shell very small, sinistral, with somewhat elevated spire and rather conical apex; protoconch elevated from the dorsal surface; colour brownish or greyish; protoconch conspicuously large, consists of 2.25–2.5 whorls (n = 2), very finely, regularly ribbed; teleoconch with clearly visible reticulated sculpture dominated by radial growth lines; sculpture somewhat weaker on the ventral surface; very slender, long periostracal folds (hairs) standing in five spiral lines along the body whorl; whorls 5.25–5.5 (n = 3) moderately bulging, separated by relatively deep suture; umbilicus wide and deep; apertural lip whitish, thin, slightly reflexed; callus also very weak, slightly S-shaped; no fold in the aperture.
One specimen from the type locality was opened. Parietal wall with one rather straight lamella with slight lower arms pointing in both directions; small denticle near the upper end posteriorly, connected to the lamella; two short horizontal plicae under the lamella; palatal wall with six plicae; first slim and short, the second-fifth plicae are divided in the middle and are of the same length; last plica also short, rather straight (Figures
(in mm):
The most similar species are
The new species is named after the district name (Dolakha).
Nepal, Suridobhan, Dolakha, 1023 m,
Khasi Hills (?) from Fulton,
Ost-Ind., coll. Gerstenbrandt,
Shell middle sized to large, sinistral, with reversed trapezoid shape, narrow umbilicus, angled body whorl, an apex which is elevated from the dorsal surface, and four rows of hairs on the body whorls; callus very strong; 3rd, 4th and 5th palatal plicae are divided in the middle, the others are more or less straight and horizontal; lamella vertical or oblique, with short lower and upper plicae above and below.
(in mm):
(Figures
SEM images of
Genital anatomy of atrium diverticulum epiphallus gametolytic sac penis penial caecum retractor muscle spermoviduct vagina vas deferens
Mantle pattern (
The left ommatophoral retractor passes between penis and vagina. Atrium relatively long; penis long, consists of a longer, slimmer distal and a shorter, more thickened proximal part; at the proximal end of the penis there is a rounded bulb-like thickening (similar to that of some
(Figure
The species is assumed to occur in the Khasi hills (
Darjiling, coll. W. Blanford,
Shells of
Cherra, leg. Godwin-Austen,
Shell very small, sinistral with relatively wide umbilicus, reticulated, almost flat spire (only the apex is elevated) and smooth umbilical side; callus weak, only very slight whitish lime layer is visible; palatal plicae straight, divided or not, lamella with short upper and lower plicae and two posterior denticles, one above and one below; the lower plica might be long (see under Additional material examined).
(in mm):
The type specimen of
Darjiling, leg. Stoliczka, coll. Godwin-Austen,
Nepal, Lalitpur, Phulchowki Hill, 2308 m,
Shell tiny, sinistral, with relatively narrow umbilicus, flat dorsal surface and four rows of hairs; callus strong; palatal plicae divided; lamella straight or slightly curved, with two denticles posteriorly, one above and one below; lower plica can be short and in some specimens reaching the peristome.
(in mm):
Originally the species was recorded from Darjeeling, Sikkim area. Very similar specimens were found from Central Nepal in the surroundings of Kathmandu (Shivapuri-Nagarjun National Park and Phulchowki hill) and Langtang National Park. Some literature records (Laisen Peak, Naga Hills) are based on misidentified specimens (see Figure
W.
Recent fieldwork in Nepal yielded a few populations in the surroundings of Kathmandu which can be assigned to
Miri Hills, leg. C.F.G. Oakes, R.E.,
Shell small, sinistral, with very slightly elevated spire, relatively wide umbilicus, and conspicuous spiral sculpture; callus moderately strong, palatal plicae slightly oblique, connected by a vertical ridge; lamella almost straight, with anteriorly elongated upper and lower ends and small denticles on the posterior side, one above and one below.
(in mm):
The unique spiral sculpture, which is very prominent on the ventral side as well, distinguishes
The species is known from the type locality only (Figure
Champadevi, Kirtipur, Kathmandu District, 1326–1500 m,
Shells of
A small to middle-sized, hairless species with domed dorsal surface and rounded body whorl; parietal lamella simple with one or two denticles posteriorly and sometimes a plica below the lamella, middle palatal plicae divided or almost divided.
Shell very small to small, sinistral, with somewhat elevated spire and domed dorsal surface; protoconch slightly elevates from the dorsal surface; usually brownish but sometimes turns into yellowish; protoconch consists of 1.5–1.75 whorls, very finely, regularly ribbed; teleoconch with very weak, irregular growth lines on the ventral surface and fine reticulated sculpture on the dorsal surface; in high magnification the surface is covered by flat periostracal folds; no spirally arranged large deciduous folds found; whorls 5.5–6.25, moderately bulging, separated by relatively deep suture; umbilicus wide and deep, whorls almost flat inside, resulting in an funnel-like shape, apertural lip whitish, rather thin, slightly reflexed; callus inconspicuous, but present, slightly S-shaped; no fold in the aperture.
Ten specimens were opened from different populations. Parietal wall with one slightly curved lamella with arms pointing in the direction of the aperture; lower end on the lamella more conspicuously curved than the upper end; two small denticles above and below posteriorly of the lamella (exceptionally, the lower one is missing); in some populations (e.g. Majhbeni – Parbat District, Champadevi – Kathmandu District and Siddha Cave – Tanahu District) with short plica under the lamella; palatal wall with six plicae; first slim and short, parallel with the suture; second plica is the longest, it shows a tendency towards dividing in the middle, but the two parts always fused; third, fourth and fifth plicae usually divided (third one sometimes not); last plica short, slightly curved with arms pointing in the direction of the lower suture (Figures
(in mm):
(Figures
Genital anatomy of albumen gland diverticulum epiphallus gametolytic sac penis penial caecum retractor muscle spermoviduct vagina vas deferens
The name
Champadevi, Kirtipur, Kathmandu District, Nepal, 1326–1500 m,
Yamne Valley, Abor Hills, leg. C.F.G. Oakes, R.E.,
Sibbum, Abor,
Shell small, sinistral, with wide umbilicus, and slightly domed dorsal surface; callus strong, palatal plicae complicated, their anterior part is horizontal, but the posterior part vertical; there are several short horizontal plicae between posterior parts of the palatal plicae; lamella almost straight with posteriorly elongated upper end, and sometimes with a long lower plica which reaches the aperture.
(in mm):
This species was reported only from the localities mentioned in the original description (Yamne Valley, Abor Hills and Sibbum”, “between Riu and Singging, on the Dihang River”) (Figure
Three specimens (two adults and a juvenile) of the type lot of
Sikkim, coll. Benson,
India, West Bengal, Darjeeling District, Lopchu + Ghum, coll. Topál, 21–22.04.1967, locality code: 869,
Shell very small to small, sinistral, hairless, with wide umbilicus and slightly angulated body whorl; callus strong, palatal plicae short and oblique, lamella rather straight with anteriorly elongated upper and lower ends, and posteriorly elongated upper end; there are two denticles on the posterior side of the lamella, one above and one below, the lower one might be in contact with the lamella.
(in mm):
The anatomy of
All museum samples examined were collected from Sikkim.
Darjeeling, coll. MacAndrew ex coll. Benson,
Indien, Khasi Hills, ex coll. Oberwimmer,
A very small, sinistral species with very narrow umbilicus, conical dorsal surface, and hairs standing in five rows on the body whorl; palatal plicae more or less straight, the 4th and 5th divided; lamella slightly curved, with short lower and long upper elongation in anterior direction; there are two denticles posteriorly, one above and one below.
(in mm):
(Figures
Genital anatomy of atrium albumen gland diverticulum epiphallus embryos gametolytic sac penis penial caecum retractor muscle spermoviduct vagina vas deferens
The left ommatophoral retractor passes between penis and vagina. Atrium short; penis relatively short, internally with holes of various sizes; some tiny, rounded calcareous crystals were found in the penis lumen, not directly associated with the holes; this inner structure continued in the epiphallus; penial caecum short, with central thickening; retractor muscle short, it inserts on the proximal end of the penial caecum; epiphallus slightly longer than penis, it enters the proximal penial portion laterally; vas deferens long and slender; vagina approximately as long as the penis, but thicker, curved centrally; vagina with several thick and relatively long muscle fibres attaching it to the body wall and to the diaphragm, especially at its curved portion; vagina internally with longitudinal folds, which are rather sharp, elevated at the curved area of the vagina, and low elsewhere; the gametolytic sac and the diverticulum are aligned in parallel; the gametolytic sac is slightly thicker and shorter; a relatively long part of the spermoviduct was visible distal to the thickened uterus with the developing embryos; the embryo sac contained no visible calcareous granules, which were reported in other plectopylid species (
(Figure
Museum samples are labelled from several locations. This species is probably widely distributed in north-eastern India through south-eastern Bangladesh to Bago, the Arakan Hills and in the Kayah State in Burma (Myanmar) (Figure
The name “
Munipur, Laisen Peak, coll. Godwin-Austen,
A tiny species with elevated spire, smooth ventral side and strongly reticulated dorsal surface; parietal wall with a single lamella, an upper and a lower denticle posteriorly, and a long lower plica which reaches the peristome.
Shell tiny, sinistral, with slightly elevated spire and conical/domed dorsal surface; colour light brown, greenish or yellowish; protoconch consists of approx. 2 whorls, glossy, in some populations (
Two opened specimens were observed (
(in mm):
The word
Munipur, Laisen Peak.
The new species is known only from the Naga Hills and Manipur (Figure
Khasia Hills, India,
Indien, leg. Stoliczka, coll. Oberwimmer,
A very small, sinistral species with narrow umbilicus (but wider than in the three similar species;
(in mm):
Museum specimens are collected from the Khasi Hills, Darjeeling, and Burma.
During the preparation of this revision,
Bengal, coll. MacAndrew ex coll. Benson,
India, Khasia Hills, K4.30, coll. Rolle,
A small, sinistral species with narrow umbilicus, conical dorsal surface with strong spiral lines, strongly, densely ribbed surface, and hairs standing in four rows on the body whorl; palatal plicae more or less straight, they are more or less divided; lamella slightly curved, with small denticles on the posterior side (they might fuse to the lamella), and a long upper plica on the anterior side of the lamella.
(in mm):
All museum samples were collected from the Khasi Hills and Assam (Figure
Two varieties of
Abor Hills, leg. C.F.G. Oakes, R.E.,
Shell very small, sinistral with narrow umbilicus and conical dorsal surface; shell hairless but densely, finely ribbed and ornamented with low radial periostracal lamellae on the whole shell; callus strong; palatal plicae horizontal, almost straight and thin at their middle; lamella slightly curved; there is long, horizontal plica anteriorly to the lamella, and a short horizontal plica above the long one; additionally, there is a very short upper plica above the lamella, a small denticle posteriorly above, and a long lower plica near the suture which reaches the aperture.
(in mm):
This species is known from the type locality only (Figure
“Shell sinistral, depressedly conoid, openly umbilicated, probably hirsute when young. Sculpture coarse, irregular, transverse ridges. Colour uniform ochraceous. Spire conoidal; apex blunt, smooth. Suture well marked. Whorls six, close-wound, convex. Aperture semicircular, diagonal; peristome somewhat thickened, white, with a thin callus on the parietal margin, not to the extent of a ridge. Size — major diam. 5.5, minor diam. 5.0, alt. 3.0 millims. Parietal vertical lamina simple; palatal plicæ in two rows, four long in front, four short behind, and one basal long. The shell is very distinct; it has somewhat the form of
In the original description
Examining all species assigned to
The finely ribbed protoconch is considered to be one of the key characters allowing separation of
Based on the ribbed protoconch
We are very grateful to all colleagues, who in various ways contributed to our review. Colleagues who provided shell material for description: Takashi Hosoda, Wim J. M. Maassen, Jamen Uiriamu Otani; provided information, sent pictures: Eike Neubert (