Research Article |
Corresponding author: Barna Páll-Gergely ( pallgergely2@gmail.com ) Academic editor: Martin Haase
© 2015 Barna Páll-Gergely, Prem B. Budha, Fred Naggs, Thierry Backeljau, Takahiro Asami.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Páll-Gergely B, Budha PB, Naggs F, Backeljau T, Asami T (2015) Review of the genus Endothyrella Zilch, 1960 with description of five new species (Gastropoda, Pulmonata, Plectopylidae). ZooKeys 529: 1-70. https://doi.org/10.3897/zookeys.529.6139
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All known taxa of the genus Endothyrella Zilch, 1960 (family Plectopylidae) are reviewed. Altogether 23 Endothyrella species are recognized. All species are illustrated and whenever possible, photographs of the available type specimens are provided. Five new species are described: E. angulata Budha & Páll-Gergely, sp. n., E. dolakhaensis Budha & Páll-Gergely, sp. n. and E. nepalica Budha & Páll-Gergely, sp. n. from Nepal, E. robustistriata Páll-Gergely, sp. n. from the Naga Hills, India, and E. inexpectata Páll-Gergely, sp. n. from Sichuan, China. Helix (Plectopylis) munipurensis Godwin-Austen, 1875 is synonymized with Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) gregorsoni Gude, 1915 is synonymized with Helix (Plectopylis) macromphalus W. Blanford, 1870. Plectopylis plectostoma var. exerta Gude, 1901 is a synonym of Plectopylis plectostoma var. tricarinata Gude, 1896, which is a species in its own right. Five species of the genus Chersaecia viz. Plectopylis (Chersaecia) bedfordi Gude, 1915, Helix (Plectopylis) brahma Godwin-Austen, 1879, Helix (Plectopylis) Oglei Godwin-Austen, 1879, Helix (Plectopylis) serica Godwin-Austen, 1875, and Plectopylis (Endothyra) williamsoni Gude, 1915 are moved to Endothyrella. The holotype of Plectopylis hanleyi Godwin-Austen, 1879 seems to be lost; therefore, P. hanleyi is considered to be a nomen dubium.
Taxonomy, anatomy, India, Nepal, China, Myanmar, sinistrality
The Plectopylidae Möllendorff, 1898 are a land snail family of the superfamily Plectopyloidea that ranges across large parts of southeast Asia from Nepal to southern Japan (
Gude revised every known taxon of Plectopylis Benson, 1860 at the end of the 19th century, and published drawings of their shells and armature (lamella complex) (see citations in
The aim of this paper is to review and diagnose all Endothyrella species, publish images of the type specimens where possible, provide a diagnosis of Endothyrella, and delimit it from other plectopylid genera. Ongoing revision of the genera Chersaecia and Plectopylis revealed that Chersaecia sensu
Endothyrella plectostoma was the first described species that is currently placed in the Plectopylidae. It was introduced as Helix plectostoma by
The helicid subgenus Plectopylis was erected by
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 (A, B, D) and palatal (C) plicae and lamellae. A shows a “Gudeodiscus-type” plication with two lamellae B shows a usual Endothyrella lamellation D shows a “Chersaecia-type” lamellation with long lower plica and middle plica not connected to the apertural fold (in most species however, they are connected forming a continuous plica). Small arrows under the letters show the direction of the aperture (A shows dextral, B and D sinistral specimen). Large arrow next to C shows the direction of counting of palatal plicae (first above, last below). Abbreviations: af: apertural fold; al: anterior lamella; am: apertural margin (peristome); ip: intermediate plica; l: lamella; lp: lower plica; mp: main plica; pl: posterior lamella; pd: posterior denticles; pl: posterior lamella; up: upper plica. Note that there are upper and lower plicae on both (palatal and parietal) walls.
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 Endothyrella Zilch, 1960 taxa. Asterisks indicate names with unknown exact localities.
Locality | Region | Taxon |
---|---|---|
Abor Hills | India, Arunachal Pradesh | williamsoni |
Arakan Hills (= Rakhine) | Myanmar, Rakhine district | plectostoma |
Bassein (= Pathein) | Myanmar, Ayeyarwady district: 16°47'N, 94°44'E | plectostoma |
Brahmakund | India, Assam: 27°51.4'N, 96°22'E | brahma |
Burrail (= Barail) Gorge | India, mountain range centered 70 km NE Silchar (Assam) | macromphalus, plectostoma |
Cachar (= Katchar) | India, District in Assam: 24°46'N, 92°50'E | affinis, blanda, plectostoma, serica |
Cherra Poonjee (= Cherrapunji) | India, Meghalaya, Khasi Hills: 25°18'N, 91°42'E | affinis, fultoni, plectostoma, tricarinata |
Chittagong | City in Bangladesh: 22°22'N 91°48'E; also name of a district | plectostoma |
Damsang Peak | India, Sikkim | blanda, pinacis |
Darjiling (= Darjeeling) | India, town in West Bengal: 27°2'N, 88°15.5'E | blanda, macromphalus, minor, pinacis, plectostoma |
Dihang (= Siang) River | India, Arunachal Pradesh: river flows to the Brahmaputra at 27°50'N, 95°27'E | bedfordi, oakesi |
Dunsiri (= Dhansiri) River | India, river flows to the Brahmaputra at 26°42'N, 93°35'E | plectostoma |
Durrang (= Darrang) | India, district in Assam: centered at 26°26'N, 92°1.5'E | plectostoma |
Garo Hills | India, Western Meghalaya: 25°28'N, 90°20'E | plectostoma |
Ghoramara | Bangladesh, town approx. 15 km NW from Chittagong, at 22°29'N 91°43'E | plectostoma |
Prov. Harenni* | Myanmar | plectostoma |
Hengdan* | India, mountain in northern Cachar Hills | serica |
Ihang River* | India, Manipur | robustistriata sp. n., serica |
Japvo Peak | India, highest mountain in Naga Hills: 25°36'N, 94°4'E | serica |
Karenni (= Kayah) State | state located south of Shan State, Myanmar | plectostoma |
Khasi (= Khasia) Hills | India, Meghalaya | affinis, fultoni, macromphalus, minor, pinacis (?), plectostoma, sowerbyi, tricarinata |
Khunho (= Khono) Mountain | India, Naga Hills: 25°31.3'N, 94°6.5'E | serica |
Kohima | India, town in SE Nagaland: 25°40'N, 94°6.5'E | serica |
Kopamedza ridge* | India, Dafla Hills, Barail Range | serica |
Laisen Peak* | India, Manipur | robustistriata sp. n. |
Lhota Naga* | India, Nagaland, Naga Hills | robustistriata sp. n. |
Lopchu | India, Sikkim 27°7.5'N, 88°25'E | pinacis |
Luyor Peak | India, Abor county, Arunachal Pradesh: 28°45'N, 95°45'E | babbagei |
Mairung (= Mairang) | India, village in Meghalaya, Khasi Hills: 25°34.2'N, 91°37.8'E | macromphalus |
Miri Hills | India, on the border between Assam and Arunachal Pradesh | miriensis |
Munipur (= Manipur) | India, Manipur | plectostoma, robustistriata sp. n., serica |
Naga Hills | on the border of Nagaland (India) and Myanmar | blanda, macromphalus (?), minor (?), plectostoma, plectostoma, serica |
Naraindher* | India, Assam, Cachar district | affinis |
Pankabari (= Pankhabari) | India, northern part of West Bengal: 26°50'N, 88°16'E | pinacis |
Pegu (= Bago) | Myanmar, Bago District: 17°20'N, 96°29'E | plectostoma |
Picholanulla* | India, probably Dafla Hills | plectostoma |
Pyema Khyoung | Myanmar, Ayeyarwady district | plectostoma |
Rarhichu (= Rungpo?)* | India, Sikkim | blanda, minor, pinacis |
Renging (= Rengging) | India, Abor county, Arunachal Pradesh: 28°9'N, 95°15.5'E | aborensis |
Richila (Rechila) Peak | India, Sikkim: 27°8'N, 88°45'E | blanda |
Rinkpo valley* | India, Sikkim | blanda |
Rissetchu* | India, Sikkim | blanda |
Riu* | India, Abor Hills | oakesi |
Rotung (= Rottung) | India, Abor county, Arunachal Pradesh: 28°8'N, 95°8.5'E | aborensis |
Rungmaval* | India, Sikkim | pinacis |
Rungun* | India, probably Sikkim | minor, pinacis |
Sadia (Sadiya) | India, Assam: 27°51.6'N, 95°37.6'E | oglei |
Salwen (= Salween) River | River in China and eastern Myanmar | plectostoma |
Shillong | India, city in Meghalaya, Khasi Hills | macromphalus |
Shiroifurar peak (probably Shirui Hills) | India, NE Manipur: 25°6.3'N 94°27.4'E | plectostoma |
Shweego (probably Shwegu) | probably Myanmar, Kachin District: 24°12'N, 96°48'E | plectostoma |
Sibbum (= Sibum) | India, Abor Hills: 28°19'N, 95°9'E | oakesi |
Sigon (= Siyom) River | India, river runs into the Siang River at 28°14'N, 95°E | bedfordi |
Singging* | India, Abor Hills | oakesi |
Sylhet | Bangladesh, Sylhet Division, Sylhet city: 24°54'N, 91°52'E | plectostoma, serica |
Teria Ghat | India, Khasi Hills | macromphalus, plectostoma |
Tongoop* | Myanmar, Rakhine district | plectostoma |
Torúpútú* | India, Dafla Hills | robustistriata sp. n. |
Tsanspu (= Tsangpo) River | India (Tibetan name of the Brahmaputra River) | bedfordi |
Yamne River | India, Abor Hills, river flows into the Siang River at 28°10.5'N, 95°13'E | gregorsoni, oakesi |
Ywathit (= Ywarthit) | Village (?) in Kayah State, Myanmar: 19°10'N 97°30'E | plectostoma |
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 Chersaecia taxon deposited in the
The following shell characters of species formerly classified in Chersaecia and Endothyrella were examined in order to revise the generic assignment and diagnose genera: (1) coiling direction; (2) sculpture of the protoconch; (3) presence or absence of the apertural fold; morphology of the parietal plicae and lamellae, namely (4) the presence/absence/length of a horizontal main plica, (5) the presence/absence/length of a the lower plica, and (6) the presence or absence of additional denticles behind the lamella; (7) morphology of middle palatal plicae (the first and last are straight in almost all cases); and the (8) presence/absence/morphology of hairs.
This taxonomic revision of Endothyrella species is based on morphology by examination of specimens and literature. The present species are defined based on unique combinations of morphological traits, some of which are discrete in nature (e.g. presence or absence of periostracal filaments) or continuous but with distinct gaps (e.g. height of the spire). No specimens were found that show transitional characters between probably sympatric morphospecies (Table
Co-occurrence of Endothyrella Zilch, 1960 species. Two stars indicate that the two species were collected at geographically close sites (nepalica-minor: 2680 m). One star indicates presence of the two species mixed within museum samples.
nepalica sp. n. | blanda | macromphalus | tricarinata | sowerbyi | affinis | |
---|---|---|---|---|---|---|
affinis | * | * | ||||
minor | ** | * | * | |||
pinacis | * | |||||
blanda | * | * | ||||
plectostoma | * | * | * | * |
CDZMTU
Central Department Zoology Museum of
D shell diameter
H shell height
HA Collection András Hunyadi (Budapest, Hungary)
JUO Collection Jamen Uiriamu Otani (Osaka, Japan)
MMGY Mátra Múzeum, Gyöngyös, Hungary
NHM
The
NHMSB
TH Collection Takashi Hosoda (Kofu, Japan)
UMZC
Wh number of whorls
WM Collection Wim J. M. Maassen (Echt, The Netherlands)
ZSI
1899c Chersaecia (section of the genus Plectopylis) Gude: Science Gossip, 6: 148.
1999 Chersaecia, — Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs, Part 4. (...): 2: 462.
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 Chersaecia species is known anatomically (Ch. simplex in the original description:
Chersaecia differs from Endothyrella, Gudeodiscus Páll-Gergely, 2013, Halongella Páll-Gergely, 2013, Sicradiscus Páll-Gergely, 2013 and Sinicola by the usually tuberculated (not regularly ribbed) protoconch. The presence of long parietal plicae (main and lower) distinguishes most Chersaecia species from most Endothyrella, Gudeodiscus, Halongella, Sicradiscus and Sinicola species. The delimitation of Chersaecia from Plectopylis and Endoplon needs further investigation. Among all plectopylids examined to date Chersaecia simplex is the only species found to lack an epiphallus. The anatomy of more Chersaecia species should be studied to check the taxonomic value of the lack of the epiphallus.
austeni, brachydiscus, degerbolae, dextrorsa, kengtungensis, leiophis (pseudophis is probably a synonym, see
The genus is known to inhabit northeastern India, eastern and southern Myanmar (Burma) and northern Thailand.
1899c Endothyra (section of the genus Plectopylis) Gude: Science Gossip, 6: 148., non Endothyra Phillips, 1845 (Foraminifera).
1960 Plectopylis (Endothyrella), — Zilch: Handbuch der Paläozoologie, 6 (2).
1999 Endothyrella, — Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs, Part 4.(...): 2: 460.
Helix plectostoma Benson, 1836, by original designation.
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 Sinicola, Gudeodiscus, Halongella and Sicradiscus are dextral. Regardless of the coiling direction, most Endothyrella species differ from Sinicola by the presence of usually hair-like periostracal folds standing in multiple lines. Deciduous periostracal folds in Sinicola are present only along the keel and the folds are always flat. Most Sinicola species (especially the large species) have a sharp keel, whereas Endothyrella species usually have a rounded or slightly keeled, shouldered body whorl. The palatal plicae of Sinicola are usually simple, horizontal, straight and parallel, but in Endothyrella they are often oblique to vertical, divided and ornamented with minute denticles at their posterior ends. In Sinicola the posterior lamella is present on the parietal wall, with two horizontal plicae anteriorly above and below, whereas in most Endothyrella species (probably except for E. aborensis) the anterior lamella is present and the posterior is missing or reduced to one or two short vertical plicae.
Some Gudeodiscus and Halongella species possess low, radial periostracal folds (e.g.
Some Gudeodiscus species possess a fold in the aperture, which is always missing in Endothyrella. The palatal plicae in Gudeodiscus are usually depressed Z- or L-shaped and posterior small denticles are very rare (except for one denticle above the posterior end of the last plica), whereas the palatal plicae of Endothyrella are frequently divided in the middle and posterior small denticles are usually present. In Endothyrella the anterior lamella is present, and often the upper horizontal plica is missing, whereas in Gudeodiscus both lamellae, or only the posterior one, are visible and the upper horizontal plica (above the lamella) is almost always present. Additionally, Gudeodiscus species have a rounded body whorl, while in many Endothyrella species the body whorl is angled or shouldered. Our limited knowledge on the anatomy of Endothyrella species shows that the entire inner penial wall of Endothyrella is covered by pits, whereas in Gudeodiscus these pocket-like structures are restricted to the a certain (usually apical) portion of the penis.
Sicradiscus is similar to Endothyrella in possessing a weak or reduced posterior lamella. Long periostracal folds standing in more than one row have also been found in one Sicradiscus species, namely in juveniles of Sicradiscus transitus Páll-Gergely, 2013. This species, however, has hairs standing in two spiral lines on the body whorl, whereas in Endothyrella the hairs are arranged in 3–7 spiral lines. This trait seems to be absent in adult S. transitus shells and all other species of Sicradiscus, but is common in fully grown Endothyrella shells (i.e. most species possess them). The two genera (i.e. Endothyrella and Sicradiscus) differ in the short, straight palatal plicae, which are usually connected in Sicradiscus vs. longer, more complex palatal plicae sometimes having additional denticles in Endothyrella. In both genera divided plicae may occur, but in the case of Sicradiscus the posterior fourth and fifth plicae seem to be always connected, whereas in Endothyrella all plicae are free. Moreover, western Sicradiscus species (feheri Páll-Gergely, 2013, invius [Heude, 1885], mansuyi [Gude, 1908b], securus [Heude, 1885] and transitus) differ from Endothyrella by the presence of a strong apertural fold.
Plectopylis and Endoplon species have a granulated or smooth protoconch, whereas it is usually finely ribbed in Endothyrella. Moreover, Plectopylis and Endoplon usually have a strong apertural fold which is often connected to a long main plica. In contrast, although some Endothyrella species have a main plica, they all lack an apertural fold. See also under Chersaecia and Table
Genus | Coiling direction | Apertural fold | Lower plica | Body whorl | Anterior lamella | Posterior lamella | Periostracal folds | Penial pockets |
---|---|---|---|---|---|---|---|---|
Endothyrella | sinistral or dextral | absent | short or long (reaching peristome) | rounded or keeled | present | present (?), absent or reduced | usually in multiple rows | whole penial wall |
Sinicola | dextral | absent (present in 1 species) | short | keeled | absent or reduced | present | present in a single row or absent | whole penial wall |
Gudeodiscus | dextral | absent or present | missing or short | rounded | present, reduced or absent | present | absent | apical part |
Halongella | dextral | present | short | rounded | present, reduced or absent | present | absent | whole penial wall |
eastern Sicradiscus | dextral | absent | missing or short | keeled | present | present or reduced | present in a single row or absent | whole penial wall |
western Sicradiscus | dextral | present | missing or short | rounded | present | present or reduced | absent | apical part |
aborensis, affinis, angulata sp. n., babbagei, bedfordi, blanda, brahma, dolakhaensis sp. n., fultoni, inexpectata sp. n., macromphalus (syn.: gregorsoni), minor, miriensis, nepalica sp. n., oakesi, oglei, pinacis, plectostoma, robustistriata sp. n., serica (syn: munipurensis), sowerbyi, tricarinata, williamsoni. See also Tables
(Sub)generic classification of Endothyrella Zilch, 1960 (formerly Endothyra Gude, 1899) species by previous authors. Species marked with a star were moved to Endothyrella by Páll-Gergely & Hunyadi (2013). Abbreviations: n. m.: not mentioned.
Name | Subgenus in |
Subgenus in |
---|---|---|
aborensis * | Endoplon | |
affinis | Endothyra | n. m. |
babbagei * | Sinicola | |
bedfordi | Chersaecia | |
blanda | Endothyra | n. m. |
brahma | Chersaecia | Chersaecia |
exerta (syn. of tricarinata) | Endothyra | n. m. |
fultoni | Endothyra | n. m. |
gregorsoni (syn. of macromphalus) | Endothyra | |
hanleyi | Endothyra | n. m. |
macromphalus | Endothyra | Endothyra |
minor | Endothyra | n. m. |
miriensis | Endothyra | |
munipurensis (syn. of serica) | Chersaecia | n. m. |
oakesi | Endothyra | |
oglei | Chersaecia | n. m. |
pinacis | Endothyra | Endothyra |
plectostoma | Endothyra | n. m. |
serica | Chersaecia | n. m. |
sowerbyi | Endothyra | n. m. |
tricarinata | Endothyra | n. m. |
williamsoni | Chersaecia |
Species | Diagnostic characters | Similar species (most similar species in bold) |
---|---|---|
aborensis | depressed Z-shaped palatal plicae; two parietal lamellae (?) | |
affinis | narrow umbilicus; four hair rows; horizontal parietal plica absent | plectostoma, sowerbyi, tricarinata |
angulata sp. n. | body whorl shouldered; four hair rows | dolakhaensis sp. n., pinacis, minor |
babbagei | dextral shell; flattened dorsal side; 14 mm | inexpectata sp. n., oglei, serica |
bedfordi | single parietal lamella with long lower plica; posterior ends of palatal plicae with several additional small denticles | |
blanda | conical dorsal side; 7 hair rows | macromphalus, minor, robustistriata sp. n., williamsoni |
brahma | three parallel, horizontal parietal plicae anterior to the lamella | |
dolakhaensis sp. n. | rather conical dorsal side; slightly angulated body whorl; 5 hair rows | angulata sp. n., sowerbyi |
fultoni | large size (19.9–20.3 mm); reversed trapezoid shell shape | |
inexpectata sp. n. | dextral shell; flattened dorsal side; 6.6–6.7 mm | babbagei, oglei, serica |
macromphalus | nearly flat dorsal side; smooth ventral side | blanda, minor, robustistriata sp. n., williamsoni |
minor | flat dorsal side; four hair rows | blanda, macromphalus, robustistriata sp. n., williamsoni |
miriensis | prominent spiral sculpture | |
nepalica sp. n. | hairless shell; domed dorsal side; rounded body whorl; simple palatal plicae | oakesi, pinacis |
oakesi | hairless shell; slightly domed dorsal side; rounded body whorl; complicated palatal plicae | nepalica sp. n., pinacis |
oglei | dextral shell; 16.8–16.9 mm; protoconch without groove | babbagei, inexpectata sp. n., serica |
pinacis | hairless shell; slightly elevated dorsal side; shouldered body whorl; simple palatal plicae | nepalica sp. n., oakesi |
plectostoma | very narrow umbilicus; five hair rows; horizontal parietal plica present | affinis, sowerbyi, tricarinata |
robustistriata sp. n. | elevated spire; smooth ventral side; strongly reticulated dorsal surface | blanda, macromphalus, minor, williamsoni |
serica | dextral shell; protoconch with groove | babbagei, inexpectata sp. n., oglei |
sowerbyi | narrow umbilicus; thin peristome; five hair rows; weak horizontal parietal plica | affinis, dolakhaensis sp. n., plectostoma, tricarinata |
tricarinata | very narrow umbilicus;, shouldered whorls; four hair rows | affinis, plectostoma, sowerbyi |
williamsoni | conical dorsal side; hairless shell; long horizontal parietal plica | blanda, macromphalus, minor, robustistriata sp. n. |
1915 Plectopylis (Sinicola) babbagei Gude: Records of the Indian Museum, 8: 512–513, Plate 42, figs 4a–d. [“Luyor Peak, Abor Hills, alt. 7200 ft. Lat. 28°45': Long. 95°45'].
1920 Plectopylis (Sinicola) babbagei, — Gude: Proceedings of the Malacological Society of London, 14 (2–3): 64.
2013 Endothyrella babbagei, — Páll-Gergely & Hunyadi: Archiv für Molluskenkunde, 142 (1): 5.
Peak Luyor, Abor Hills, 7,200 ft, leg. C.F.G. Oakes R.E.,
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): D: 14.4, H: 6.3 (n = 1).
For differences with E. oglei, and E. serica and E. inexpectata sp. n., see there. See also Table
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, 27°03.834'N, 101°23.611'E, leg. Hosoda, T., Ohara, K., Okubo, K., Otani, J. U., 12.09.2013,
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): D: 6.6–6.7, H: 3.0–3.1 (n = 2, from different localities).
Endothyrella babbagei is much larger than E. inexpectata sp. n., and it has flatter whorls and has a weaker callus than the new species. Sinicola species of the same size have a keeled or shouldered body whorl and have two parallel parietal plicae anterior to or above the lamella (one near the upper, the other near the lower suture). Sicradiscus invius also occurs in Sichuan, but it is smooth (glossy) and has a strong apertural fold. See also under Endothyrella oglei and E. serica and Table
The name inexpectata (meaning unexpected in Latin) refers to the surprizing new, especially dextral Endothyrella species in China.
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, 27°03.834'N, 101°23.611'E.
Endothyrella inexpectata sp. n. is known from two localities in western Sichuan province, China (Figure
1879a Helix (Plectopylis) Oglei Godwin-Austen: Journal of the Asiatic Society of Bengal, 48 (2): 3, Plate 1, figs 2, 2a–c. [“Near Sadiya, Assam”].
1887 Helix (Plectopylis) oglei, — Tryon: Manual of Conchology…, 2 (3): 159, Plate 36, figs 29–31.
1898 Plectopylis oglei, — Gude: Science Gossip, 4: 263, figs 68a–h.
1899c Plectopylis (Chersaecia) oglei, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Chersaecia) oglei, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Chersaecia) oglei, — Gude: The Fauna of British India…: 73, 92–93, figs 39a–h.
Sadia, E. Assam, leg. Ogle,
Shells of Endothyrella species. A Endothyrella oglei (Godwin-Austen, 1879),
Photos (A–C) and SEM images (D–F) of Endothyrella protoconchs. A Endothyrella oglei (Godwin-Austen, 1879), same data as in Fig.
Distribution of Endothyrella species. Empty circle: Endothyrella inexpectata sp. n.; Filled triangle, top up: type locality of Endothyrella babbagei. Letters indicate localities of Endothyrella plectostoma (Benson, 1836). Abbreviations: A Arakan HillsB Bassein (= Pathein)C Silchar (Cachar)Ch Chittagong (Ghoramara)D DarjeelingDu Dunsiri valleyG Garo HillsK Khasi HillsM ManipurN Naga HillsP Pegu (= Bago)S SylhetSw ShweguY Ywathit.
SEM images of Endothyrella shells. A Endothyrella nepalica Budha & Páll-Gergely, sp. n., 4th, 5th whorl, for locality see Fig.
Parietal (A, C, E, G, I, K) and palatal (B, D, F, H, J, L) lamellation of Endothyrella spp. A–B Endothyrella inexpectata sp. n. (holotype) C–D Endothyrella nepalica sp. n., for locality, see Fig.
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 Endothyrella species.
(in mm): D: 16.8–16.9, H: 7.7–8.1 (n = 2, type series).
Endothyrella babbagei and E. inexpectata sp. n. differ from the E. oglei by the flat dorsal surface of the shell and the presence of hairs arranged in three rows on the body whorl. See also under E. serica and Table
The information published by
The species is known from the type locality only (Figure
Distribution of Endothyrella species in Northeastern India. Abbreviations: A type locality of
1875 Helix (Plectopylis) serica Godwin-Austen: Proceedings of the Zoological Society of London: 608, 609, 612, Plate 73, figs 5a–c. [“on the peak of Henozdan, Burrail range” “above 5000 feet on the same range as far east as the Kopamedza ridge”] (1874, part IV, published in 1875; see
1875 Helix (Plectopylis) munipurensis Godwin-Austen new synonym: Proceedings of the Zoological Society of London: 610, 612, Plate 73, figs 6a–c. [“At the end of the Ihang valley, Munipúr, at about 3000–4000 feet”] (1874, part IV, published in 1875; see
1875 Helix sericata (sic.), — Hanley & Theobald: Conchologia Indica...: 53, Plate 132, figs 8, 9.
1878 Helix (Plectopylis) serica, — Nevill: Hand list of Mollusca in the Indian Museum, Calcutta...: 71. [“Hengdan Peak and Burrail”].
1879a Helix (Plectopylis) serica, — Godwin-Austen: Journal of the Asiatic Society of Bengal, 48 (2): 3.
1887 Helix (Plectopylis) serica, — Tryon: Manual of Conchology…, 2 (3): 159, Plate 34, figs 49–52.
1887 Helix (Plectopylis) Munipurensis, — Tryon: Manual of Conchology…, 2 (3): 160, Plate 34, figs 56–58.
1897a Plectopylis serica, — Gude: Science Gossip, 3: 205–206, figs 31a–c.
1897 Plectopylis serica, — Gude: Science Gossip, 3: 246.
1898 Plectopylis munipurensis, — Gude: Science Gossip, 4: 263–264, figs 69a–g.
1899c Plectopylis (Chersaecia) serica, — Gude: Science Gossip, 6: 148.
1899c Plectopylis (Chersaecia) munipurensis, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Chersaecia) serica, — Gude: Science Gossip, 6: 175, 177.
1899d Plectopylis (Chersaecia) munipurensis, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Chersaecia) serica, — Gude: The Fauna of British India…: 73, 93–94, figs 40a–c.
1914b Plectopylis (Chersaecia) munipurensis, — Gude: The Fauna of British India…: 73, 94–95, figs 41a–g.
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): D: 9.7–9.9, H: 4.4–4.8 (n = 3,
Endothyrella babbagei and E. inexpectata sp. n. differ from E. serica by the flat dorsal surface of the shell and the presence of three rows of hairs on the body whorl. Endothyrella oglei differs from the also dextral E. serica by the much larger size, the absence of the groove on the protoconch, which runs parallel with the suture in E. serica, and the morphology of the lamella which has only posteriorly elongated ends. See also Table
The species is recorded from the Naga Hills (see also remarks). “Plectopylis munipurensis” was described from “end of the Ihang valley” (Figure
Distribution of Endothyrella species in Northeastern India. Abbreviations: Dafla Dafla Hills (locality of
In the original description
1915 Plectopylis (Endoplon) aborensis Gude: Records of the Indian Museum, 8: 511–512, Plate 42, Fig.
2013 Endothyrella aborensis, — Páll-Gergely & Hunyadi: Archiv für Molluskenkunde, 142 (1): 5.
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 ZSI following foundation of the ZSI in 1916. The ZSI supplied us with two photos of an adult shell under the name of Plectopylis aborensis, which they considered as one of the type specimens. These photos, however, clearly showed a different specimen than the one figured in
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): D: 14, H: 6.5 (according to the original description).
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 28°10'N, 95°13'E) (Figure
So far, this is the only Endothyrella species with two well-developed lamellae. The parietal lamellae show a very unusual arrangement which has not been observed in any other species of Plectopylidae. The two parietal plicae can be the result of teratological duplication which has been reported for some species (
Shells of Endothyrella and Chersaecia species. A Endothyrella fultoni (Godwin-Austen, 1892),
1897b Plectopylis affinis Gude: Science Gossip, 3: 276, figs 41a–d. [“Khasia Hills, Assam”].
1897g Plectopylis affinis, — Gude: The Journal of Malacology, 6: 46–48, fig. 3.
1899c Plectopylis (Endothyra) affinis, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) affinis, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Endothyra) affinis, — Gude: The Fauna of British India…: 73, 84–85, figs 34a–d.
India, Khasia Hills, ex Fulton,
Shells of Endothyrella species. A Endothyrella plectostoma (Benson, 1836), UMZC 102155 (syntype, specimen figured by
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): D: 9.7–10.9, H: 5.4–5.7 (n = 4,
See under E. plectostoma, E. sowerbyi and E. tricarinata and Table
The species is recorded from the Khasi Hills only (Figure
Nepal, Taubas, Bhainse, Makwanpur District, 27°492521'N, 85°04839'E., leg. Budha, P., 30.03.2012., holotype (CDZMTU018, Figure
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): D: 8.5, H: 3.5 (holotype); D: 5.5, H: 2.5, Wh: 5 (paratype; subadult specimen).
See under Endothyrella dolakhaensis sp. n., E. minor, E. nepalica sp. n., E. pinacis and Table
The Latin angulatus (cornered, angular) refers to the shouldered/angulated body whorl of the new species.
Nepal, Taubas, Bhainse, Makwanpur District, 27°492521'N, 85°04839'E.
Endothyrella angulata sp. n. is known only from the type locality (Figure
1915 Plectopylis (Chersaecia) bedfordi Gude: Records of the Indian Museum, 8: 510–511, plate 42, fig. 2a–d. [“Abor country, Tsanspu Valley, on the Dihang, about 50 miles above the junction of the Sigon River, alt. 2800 ft.”].
Tsanspu Valley Abor Hills, 2800 ft, leg. C.F.G. Oakes R.E.,
Shells of Endothyrella species. A Endothyrella oakesi (Gude, 1915),
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): D: 9.1, H: 4.9 (n = 1, type series).
Endothyrella bedfordi has a single curved parietal lamella with a long lower plica (which reaches the peristome) attached to it, and at the posterior ends of palatal plicae there are several small denticles. These features distinguish E. bedfordi from all congeners. See also Table
The species is known from the type locality only (approximately 28°44'N, 94°56'E) (Figure
1898 Plectopylis blanda Gude: Science Gossip, 4: 264, figs 70 a–f. [“Naga Hills, Assam”]
1899c Plectopylis (Endothyra) blanda, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) blanda, — Gude: Science Gossip, 6: 175, 176.
1900 Plectopylis blanda, — Gude: The Journal of Malacology, 7: 34–35, figs 11a–f.
1914b Plectopylis (Endothyra) blanda, — Gude: The Fauna of British India…: 73, 77–78, figs 28a–f.
Naga Hills,
Shells of Endothyrella species. A Endothyrella williamsoni (Gude, 1915),
Richila Peak, Sikkim, India, coll. Ottó, L., MMGY 66425/2; Darjeeling, India, West Bengal, Darjeeling, North Point 900–1400 m asl., under stones in forest clearings, coll. Topál, 1967.
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): D: 4.9–5.7, H: 2.8–3.3 (n = 3,
See under E. macromphalus, E. minor, E. robustistriata sp. n. and E. williamsoni and Table
(Figure
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 Endothyrella species. A, C, E central and adjacent lateral teeth B, D, F marginal teeth A–B Endothyrella blanda (Gude, 1898) (For locality see Fig.
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
1879a Helix (Plectopylis) brahma Godwin-Austen: Journal of the Asiatic Society of Bengal, 48 (2): 3–4, plate 1, fig 3. [“near Brahmakund, eastern Assam, at 1,000 feet elevation”].
1887 Helix (Plectopylis) brahma, — Tryon: Manual of Conchology…, 2 (3): 164, Plate 36, figs 35–37.
1894 Plectopylis brahma, — Pilsbry: Manual of Conchology, 2 (9): 145.
1897d Plectopylis brahma, — Gude: Science Gossip, 4: 170–171, figs 63a–c.
1899c Plectopylis (Chersaecia) brahma, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Chersaecia) brahma, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Chersaecia) brahma, — Gude: The Fauna of British India…: 74, 113–114, 54a–c.
1915 Plectopylis (Chersaecia) brahma, — Gude: Records of the Indian Museum, 8: 509, 511.
1920 Plectopylis (Chersaecia) brahma, — Gude: Proceedings of the Malacological Society of London, 14 (2–3): 63.
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): D: 8.1–8.2, H: 4.6 (n = 2, type series).
Endothyrella brahma can be distinguished from all other Endothyrella species by the presence of three parallel, horizontal parietal plicae anterior to the lamella. See also Table
The species is known from the type locality only (Figure
Nepal, Suridobhan, Dolakha, 1023 m, 27.758852°N, 86.197894°E, leg. Budha, P., 03.02.2009., holotype (CDZMTU001, Figure
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): D: 6.5–9.0, H: 4.0–5.0., Wh: 5.5–6.0 (n = 5).
The most similar species are E. affinis and E. plectostoma, which are larger, have a higher spire, and a deeper, narrower umbilicus. Endothyrella dolakhaensis sp. n. has a more elevated spire and more rounded body whorl than E. angulata sp. n. Moreover, E. dolakhaensis sp. n. has five rows of periostracal folds, whereas E. angulata sp. n. has four. See also under E. macromphalus, E. minor and E. nepalica sp. n. and Table
The new species is named after the district name (Dolakha).
Nepal, Suridobhan, Dolakha, 1023 m, 27.758852°N, 86.197894°E.
Endothyrella dolakhaensis sp. n. is known from two localities in the valley of the Tamakoshi River, Dolakha district, Central Nepal (Figure
1892 Helix (Plectopylis) fultoni Godwin-Austen: The Annals and Magazine of Natural History, 6 (10): 300–301. [“Exact locality unknown. Khasi Hills?”; detailed description on the exactness of the locality on page 301].
1893 Plectopylis fultoni, — Pilsbry: Manual of Conchology..., 2 (8): 296, 297.
1894 Plectopylis fultoni, — Pilsbry: Manual of Conchology..., 2 (9): 144, 146, Plate 40, figs 13–15.
1896 Plectopylis fultoni, — Gude: Science Gossip, 3: 178–179, figs 23a–b.
1899c Plectopylis (Endothyra) fultoni, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) fultoni, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Endothyra) fultoni, — Gude: The Fauna of British India…: 72, 87–89, figs 36a–b.
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): D: 19.9–20.3, H: 9.5–10.4 (n = 2,
Endothyrella fultoni is much larger than any other Endothyrella species and has a characteristic reversed trapezoid shell shape. See also Table
(Figures
Mantle pattern (A) and inner wall of the penis (C–F) and the penial caecum (B) of Endothyrella species. A Endothyrella plectostoma (Benson, 1836), For locality, see Fig.
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 Gudeodiscus species, see
(Figure
The species is assumed to occur in the Khasi hills (
1870 Helix (Plectopylis) macromphalus W. Blanford: Journal of the Asiatic Society of Bengal, 39 (2): 17–18, Plate 3, fig. 14. [“ad Mairung in montibus Khasi”].
1870–1876 Helix macromphalus, — Hanley & Theobald: Conchologia Indica…: Plate 83, figs 8–10.
1875 Plectopylis macromphalus, — Godwin-Austen: Proceedings of the Zoological Society of London: 612, 613, Plate 73, figs 1, 1a. [“Darjeeling and N. E. frontier, Bengal. Khási”] (1874, part IV, published in 1875; see
1878 Helix (Plectopylis) macromphalus>, — Nevill: Hand list of Mollusca in the Indian Museum, Calcutta...: 71.
1879b Helix (Plectopylis) macromphalus, — Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 163–164.
1887 Helix (Plectopylis) macromphalus, — Tryon: Manual of Conchology…, 2 (3): 160, Plate 34, figs 65–68.
1892 Plectopylis macromphalus, — Godwin-Austen: The Annals and Magazine of Natural History, 6 (10): 301.
1893 Plectopylis macromphalus, — Pilsbry: Manual of Conchology..., 2 (8): 297.
1894 Plectopylis macromphalus, — Pilsbry: Manual of Conchology..., 2 (9): 146.
1897c Plectopylis macromphalus, — Gude: Science Gossip, 4: 10–11, figs 46a–b. [“Khasia, Dafla and Naga Hills, in Assam”].
1899c Plectopylis (Endothyra) macromphalus, — Gude: Science Gossip, 6: 147, 148.
1899d Plectopylis (Endothyra) macromphalus, — Gude: Science Gossip, 6: 175, 177.
1914b Plectopylis (Endothyra) macromphalus, — Gude: The Fauna of British India…: 72, 79, figs 29a–b.
1915 Plectopylis (Endothyra) macromphalus, — Gude: Records of the Indian Museum, 8: 507.
1915 Plectopylis (Endothyra) gregorsoni Gude new synonym: Records of the Indian Museum, 8: 506–507, Plate 41, figs 2a–d. [“Yamne Valley, Abor Hills”].
Darjiling, coll. W. Blanford,
Shells of Endothyrella species. A Endothyrella macromphalus (W. Blanford, 1870),
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): D: 5.5–8.2.2, H: 2.7–4.2 (n = 13, shells from different samples); the holotype of Plectopylis gregorsoni is 7.5 × 3.7 mm.
Endothyrella macromphalus has more depressed shells than E. blanda. Moreover, E. macromphalus shells are smooth on the ventral side, whereas most blanda shells have hairs, or in case of corroded E. blanda specimens, holes which indicate the hairs’ positions. Endothyrella dolakhaensis sp. n. is hairy, has weaker sculpture, and its spire is more elevated than in E. macromphalus. Endothyrella robustistriata sp. n. is smaller, has a narrower umbilicus and stronger dorsal sculpture. See also under E. williamsoni and Table
Endothyrella macromphalus seems to have a wide range including Assam and the Dafla and Khasi Hills. It has been reported from the Naga Hills, but those samples are probably misidentified. Plectopylis gregorsoni (treated here as a synonym of E. macromphalus) is recorded from the type locality only (approximately: 28°13.4'N, 95°13.3'E) (Figure
The type specimen of Plectopylis gregorsoni is very similar to typical E. macromphalus specimens. The main difference is that the palatal plicae are not divided in gregorsoni, and the base is less glossy (rather weakly ribbed). In our view these minor difference are not sufficient for species level distinction, especially because E. macromphalus is a relatively variable species inhabiting wide geographical range. Very little is known about the distribution of specimens having divided or undivided palatal plicae. Therefore, until more information becomes available, Plectopylis gregorsoni is synonymised with Endothyrella macromphalus.
1870 Helix (Plectopylis) macromphalus var. minor, — W. Blanford, Journal of the Asiatic Society of Bengal, 39 (2): 18. (no formal description presented) [“in valle Rungnu prope Darjiling in Sikkim”].
1879b Helix (Plectopylis) minor Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 164.
1895 Helix (Plectopylis) minor, — Godwin-Austen: Journal of the Asiatic Society of Bengal, 64: 154, Plate 7, figs 3, 3a.
1897c Plectopylis minor, — Gude: Science gossip, 4: 11, figs 47a–k.
1899c Plectopylis (Endothyra) minor, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) minor, — Gude: Science Gossip, 6: 175, 177.
1914b Plectopylis (Endothyra) minor (partim), — Gude: The Fauna of British India…: 73, 75–77, figs 27a–l. [“Sikkim: Darjeeling”, “Rungun Valley”, “India: Naga Hills”, “Laisen Peak, Munipur” (this is the locality of E. robustistriata sp. n.)].
2015 Endothyrella minor, — Budha et al., ZooKeys, 492: 18–19.
Darjiling, leg. Stoliczka, coll. Godwin-Austen,
Nepal, Lalitpur, Phulchowki Hill, 2308 m, 27.574557°N, 85.400842°E, leg. Budha, P., 04.05.2007., 21 shells (Figure
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): D: 4.9–5.3, H: 2.4–2.6 (n = 3, type series); D: 5–5.1, H: 2.4 (n = 3,
Endothyrella minor is smaller and has weaker keeled body whorl than E. angulata sp. n. Moreover, the first and second rows of the periostracal folds are comparatively at larger distance from each other in E. minor than in E. angulata sp. n. Endothyrella blanda has more elevated spire and more hair rows than E. minor. Endothyrella robustistriata sp. n. has more elevate spire than E. minor and lacks the hairs on its ventral surface. Endothyrella macromphalus is hairless and larger than E. minor, it has a comparatively larger protoconch and a lower (or missing) parietal callus. Endothyrella minor is smaller and flatter than E. dolakhaensis sp. n. Moreover, it has a more elevated parietal callus, and has only four rows of hairs (E. dolakhaensis sp. n. has five). See also under E. williamsoni and Table
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 E. minor. “Typical” specimens of E. minor and Nepalese shells are very similar in terms of size, shell and aperture shape and the morphology of the plicae and lamellae. The only notable difference between these shells is the position of the hair rows on the body whorl. The first row is situated more upper in position (on the upper angle of the body whorl) in the Nepalese shells, whereas in typical shells the first row runs under the angle. Additionally, the distance between the third and fourth rows is smaller in the Nepalese populations.
1915 Plectopylis (Endothyra) miriensis Gude: Records of the Indian Museum, 8: 507–508, Plate 41, figs 3a–d. [“Miri Hills, Upper Assam”].
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): D: 12.1–12.3, H: 5.3–5.4 (n = 2, type series).
The unique spiral sculpture, which is very prominent on the ventral side as well, distinguishes E. miriensis from all congeners. See also Table
The species is known from the type locality only (Figure
2015 Endothyrella affinis, — Budha et al., ZooKeys, 492: 18.
Champadevi, Kirtipur, Kathmandu District, 1326–1500 m, 27.654868°N, 85.244084°E, leg. Budha, P., 02.10.2010., holotype (CDZMTU005.1), paratypes CDZMTU005.2–16 (15 shells), CDZMTU005P (2 paratypes = specimens dissected and preserved, 3 dry shells = paratypes, 2 juvenile shells = not paratype); W-Nepal, Dhaulagiri Zone, Myagdi District, Annapurna Conservation Area, right side of Kali Gandaki valley, 300 m NNW of Suke Bagar village along “Tatopani-Dana” track, 1430 m alt., 14.05.1996., leg. A. Kuznetsov, WM/10 paratypes; Nepal, Kathmandu Valley, NW end of Kathmandu, middle part of S slope of Swoyambhunath Hill, in dry oak forest, 1500 m, 25.04.1995, leg A. Kuznetsov, WM/4 sinistral and 1 dextral paratypes; W Nepal, Daulagiri zone, Hyagdi distr., Annapurna NP., right side of Kali Gandaki v., NNW od Suke Bagar, Tatop, leg. A. Kuznetsov, 14.05.1996., ex coll. W. Maassen,
Shells of Endothyrella species. A Endothyrella nepalica Budha & Páll-Gergely, sp. n., paratype, same data as on Fig.
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): D: 8.2–14.9, H: 4.0–6.0, Wh: 5.5–7.5 (n = 35, different populations).
Endothyrella nepalica sp. n. is usually larger than E. angulata sp. n., it has a domed dorsal surface, rounded body whorl and lacks hairs standing in spiral rows, whereas E. angulata sp. n. has a flat dorsal surface, shouldered body whorl and has hairs which are arranged in spiral rows. Endothyrella dolakhaensis sp. n. differs from E. nepalica sp. n. by the usually smaller size, fewer whorls, stronger sculpture, comparatively larger protoconch, conical dorsal surface, slightly angulated body whorl and the presence of hairs standing in five spiral lines. For comparison with E. oakesi and E. pinacis, see under those species. See also Table
(Figures
The name nepalica refers to the country (Nepal) where the new species lives.
Champadevi, Kirtipur, Kathmandu District, Nepal, 1326–1500 m, 27.654868°N, 85.244084°E.
Endothyrella nepalica sp. n. inhabits a relatively large area in western and central Nepal (Figure
1915 Plectopylis (Endothyra) oakesi Gude: Records of the Indian Museum, 8: 505–506, Plate 41, Figs
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): D: 11.7–12.5, H: 4.7–5.5 (n = 3, type series).
Endothyrella nepalica sp. n. also has simpler palatal plicae than those of E. oakesi. Moreover, E. nepalica sp. n. has a flatter shell and a less descending aperture. See also under E. pinacis and Table
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 E. oakesi were opened (probably by Gude). The long lower parietal plica, described as characteristic feature of this species, is present only in one specimen. In face of this, Endothyrella oakesi seems to be a distinct species on the basis of the palatal plicae and shell shape.
1859 Helix pinacis Benson: The Annals and Magazine of Natural History, 3 (3): 268–269. [“Habitat raro in regione Sikkim in valle Rungun (4000 ped.), necnon prope Pankabari (1000 ped. alt.)”].
1860 Helix (Plectopylis) pinacis, — Benson: The Annals and Magazine of Natural History, 3 (5): 243–247. [“Darjiling and the Khasia Hills”].
1868 Helix pinacis, — Pfeiffer: Monographia Heliceorum Viventium…, 5: 417.
1868 Helix (Corilla) pettos Martens: Malakozoologische Blätter, 15: 158.
1869 Helix pettos, — Pfeiffer: Novitates conchologicae…: 462–463.
1872 Helix pinacis, — Hanley & Theobald: Conchologia Indica…: 7, 36, Plate 13, fig. 5, Plate 84, figs 1–4. [“Sikkim (Rungun, and near Pankabari)”].
1875 Plectopylis pettos, — Godwin-Austen: Proceedings of the Zoological Society of London, 612. [“Himalaya?”].
1875 Helix (Plectopylis) pinacis, — Godwin-Austen: Proceedings of the Zoological Society of London: 612, 613, plate 74, fig. 1. (1874, part IV, published in 1875; see
1878 Helix (Plectopylis) pinacis, — Nevill: Hand list of Mollusca in the Indian Museum…: 71.
1879b Helix (Plectopylis) pinacis, — Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 163.
1887 Helix (Atopa) pettos, — Tryon: Manual of Conchology…, 2 (3): 156, Plate 34, figs 36–38.
1887 Helix (Plectopylis) pinacis, — Tryon: Manual of Conchology…2(3)159–160, Plate 34, figs 53–55.
1894 Plectopylis pinacis, — Pilsbry: Manual of Conchology..., 2 (9): 144, 146.
1894 Plectopylis pettos, — Pilsbry: Manual of Conchology..., 2 (9): 146.
1895 Plectopylis pinacis, — Godwin-Austen: Journal of the Asiatic Society of Bengal, 64: 154, Plate 7, figs 2, 2a.
1897a Plectopylis pinacis, — Gude: Science Gossip, 3: 206, figs 32a–d.
1897a Helix (Corilla) pettos = Plectopylis pinacis, — Gude: Science Gossip, 3: 206.
1899c Plectopylis (Endothyra) pinacis, — Gude: Science Gossip, 6: 147, 148.
1899c Plectopylis (Endothyra) pettos (under pinacis), — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) pinacis, — Gude: Science Gossip, 6: 175, 177.
1899d pettos, — Gude: Science Gossip, 6: 177.
1907 Plectopylis pinacis, — Godwin-Austen: Land and freshwater Mollusca of India…: 203–204.
1914b Plectopylis (Endothyra) pinacis, — Gude: The Fauna of British India…, 72, 86–87, figs 35a–d. [“Sikkim : Darjeeling”, “Rungun, Pankabari”, “Rungmaval”, “Damsang”].
1914b Plectopylis (Endothyra) pinacis, — Gude: The Fauna of British India…: 72, 86.
1915 Plectopylis (Endothyra) pinacis, — Gude: Records of the Indian Museum, 8: 506, 508.
Sikkim, coll. Benson, UMZC 102755 (holotype of Helix pinacis, Figure
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): D: 13.6–14.1, H: 5.9–6.1 (n = 3,
Endothyrella angulata sp. n. is usually smaller than E. pinacis, it has a stronger keel and has weaker spiral lines on the ventral side of the shell, which are clearly visible in E. pinacis. The most similar species is Endothyrella nepalica sp. n., which nevertheless has a higher spire and rounded whorls, whereas E. pinacis has shouldered whorls and nearly flat dorsal surface. The ventral surface of the two species is similar, but E. pinacis has slender hairs standing in 3 lines, which is missing in E. nepalica sp. n. According to previous studies (
The anatomy of Endothyrella pinacis was described by
All museum samples examined were collected from Sikkim.
1836 Helix (Helicodonta) plectostoma Benson: Journal of the Asiatic Society of Bengal, 5: 351. [not specified. “North-East Frontier of Bengal” (in the title)].
1848 Helix plectostoma, — Pfeiffer, Martini & Chemnitz, 1(12): 367, Plate 64, figs 19–21.
1854 Helix plectostoma, — Reeve: Conchologia Iconica 7, species 782.
1860 Helix plectostoma, — Benson: The Annals and Magazine of Natural History, 3 (5): 247.
1865 Helix plectostoma, — W. Blanford: Journal of the Asiatic Society of Bengal 34 (2): 94. [“...the Himalayan and Khasi H. plectostoma, Bens. abounded south of the town of Bassein in several places, Pyema Khyoung, Long Island, &c. It was also found by Captain Ingram in Arakan, near Tongoop.”].
1872 Helix (Plectopylis) plectostoma, — Hanley & Theobald: Conchologia Indica…: 7, Plate 13, fig. 2. [“Darjiling and Khasia Hills”].
1875 Plectopylis plectostoma, — Godwin-Austen: Proceedings of the Zoological Society of London: 612–613, Plate 73, figs 2–2a. (1874, part IV, published in 1875; see
1878 Helix (Plectopylis) plectostoma, — Nevill: Hand list of Mollusca in the Indian Museum…: 1: 71. [“Nágá Hills”, “Bassein, &c., Pegu”, “Sylhet”, “Arakan Hills”, “Khasi Hills”, “Darjeeling”].
1887 Helix (Plectopylis) plectostoma, — Tryon: Manual of Conchology…, 2 (3): 160–161, Plate 34, figs 69–70.
1894 Plectopylis plectostoma, — Pilsbry: Manual of Conchology..., 2 (9): 146.
1897b Plectopylis plectostoma, — Gude: Science Gossip, 3: 274–275, figs 39a–7c. [“Darjeeling”, “Burma— Bassein and Arakan; Assam — Sylhet, Khasia and Naga Hills”, “Dafla Hills in Assam”].
1899c Plectopylis (Endothyra) plectostoma, — Gude: Science Gossip, 6: 148, 149.
1899d Plectopylis (Endothyra) plectostoma, — Gude: Science Gossip, 6: 175, 177.
1914b Plectopylis (Endothyra) plectostoma, — Gude: The Fauna of British India…: 72, 73, 75, 81–83, figs 31a–c. [“Naga Hills”, “Dafla Hills, Khasi Hills”, “Burma: Arakan Hills”, “Tongoop”, “Bassein: Pegu”, “Sylhet”, “Sikkim : Darjeeling”].
1922 Plectopylis (Endothyra) plectostoma, — Ehrmann: Sitzungsberichte der Naturforschender Gesellschaft zu Leipzig, 45–48: 8–10.
1960 Plectopylis (Endothyrella) plectostoma, — Zilch: Handbuch der Paläozoologie, 6 (2): fig. 2092.
Darjeeling, coll. MacAndrew ex coll. Benson, UMZC 102160 (7 syntypes of plectostoma); Darjeeling, coll. MacAndrew ex coll. Benson, UMZC 102155 (1 syntype of plectostoma, Figure
Indien, Khasi Hills, ex coll. Oberwimmer, NHMSB 122805–122810/5; India, Meghalaya, Khasi Hills, Altonaer Museum,
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): D: 8.1–9, H: 4.6–5.1 (n = 3,
Endothyrella plectostoma is similar to E. affinis and E. tricarinata in the narrow umbilicus. All other Endothyrella species of similar size have wider umbilicus. Endothyrella plectostoma is usually smaller, darker than E. affinis, it has a horizontal, relatively long plica anterior to the lamella, and has the periostracal folds arranged on five spiral line. In contrast, E. affinis lacks the horizontal parietal plica and has four hair rows. Moreover, E. plectostoma has a narrower umbilicus and more elevated spire than E. affinis. See also under E. sowerbyi and E. tricarinata and Table
(Figures
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 “prodigium Benson” probably refers to Endothyrella plectostoma. It is a manuscript name, which was mentioned several times in the literature (
1914b Plectopylis (Endothyra) minor (partim), — Gude: The Fauna of British India…: 76.
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): D: 4.1–4.6, H: 2.3–3.5 (n = 2
Endothyrella blanda is similar in shell shape to E. robustistriata sp. n., but is larger, has hairy ventral surface (or if hairs are missing, than hollows are visible indicating the hairs’ positions), and on its dorsal surface the radial lines are dominant. See also under E. macromphalus and E. williamsoni and Table
The word robustistriata means strongly striated (Latin) which refers to the prominent spiral striae of the new species on the dorsal side of its shell.
Munipur, Laisen Peak.
The new species is known only from the Naga Hills and Manipur (Figure
1899a Plectopylis sowerbyi Gude: Science Gossip, 5: 239, figs 93a–f. [“Khasi Hills: Assam”].
1899c Plectopylis (Endothyra) sowerbyi, — Gude: Science Gossip, 6: 148, 149.
1899d Plectopylis (Endothyra) sowerbyi, — Gude: Science Gossip, 6: 175, 177.
1914b Plectopylis (Endothyra) sowerbyi, — Gude: The Fauna of British India…: 72, 80–81, figs 30a–f.
1915 Plectopylis (Endothyra) sowerbyi, — Gude: Records of the Indian Museum, 8: 507, 509.
Khasia Hills, India,
Indien, leg. Stoliczka, coll. Oberwimmer,
A very small, sinistral species with narrow umbilicus (but wider than in the three similar species; affinis, plectostoma, tricarinata), rather domed dorsal surface, and hairs standing in five rows on the body whorl; the hairs are usually missing and the ventral side is with relatively strong radial lines; plication similar to E. plectostoma, but the main anterior parietal plica is missing or weak.
(in mm): D: 7.8–8.6, H: 4.3–5.0 (n = 3,
Endothyrella affinis is larger, has lighter shell with narrower umbilicus and a weaker sculpture. Endothyrella sowerbyi has a wider umbilicus and a thinner peristome than E. plectostoma. Moreover, the spire is lower and the dorsal side is rather domed in E. sowerbyi (conical in plectostoma), and the main parietal plica is weaker or missing. See also under E. tricarinata and Table
Museum specimens are collected from the Khasi Hills, Darjeeling, and Burma.
During the preparation of this revision, Endothyrella sowerbyi was handled as the synonym of E. plectostoma, because the only known specimen (the holotype) looked like a juvenile shell of E. plectostoma. The first author recognized that E. sowerbyi is a valid species in the Senckenberg Museum in August, 2015, because of several mixed samples deposited there. Thus, the Endothyrella plectostoma/sowerbyi sample of the
1897b Plectopylis plectostoma var. tricarinata Gude: Science Gossip, 3: 275, figs 40a–b. [“Bengal”].
1897g Plectopylis plectostoma var. tricarinata, — Gude: The Journal of Malacology, 6: 45, fig. 2.
1899c Plectopylis (Endothyra) plectostoma var. tricarinata, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) plectostoma var. tricarinata, — Gude: Science Gossip, 6: 176, 177.
1901 Plectopylis plectostoma var. exerta Gude new synonym: The Journal of Malacology, 8: 49, figs 5a–d. [“Khasi Hills: Assam”].
1914b Plectopylis (Endothyra) plectostoma var. tricarinata, — Gude: The Fauna of British India…: 83, figs 32a–b. [“Bengal”, “Khasi Hills”].
1914b Plectopylis (Endothyra) plectostoma var. exerta, Gude, The Fauna of British India…: 83–84, figs 33a–d.
Bengal, coll. MacAndrew ex coll. Benson, UMZC 102170 (2 syntypes of Plectopylis plectostoma var. tricarinata, Figure
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): D: 10.1–10.4, H: 6.3–6.7 (n = 2,
Endothyrella affinis has less shouldered whorls, wider umbilicus, weaker sculpture and it lacks the long horizontal plica anterior to the lamella. Endothyrella tricarinata differs from E. plectostoma by the larger size, more conical dorsal surface, narrower umbilicus, the shouldered whorls, the presence of only four rows of hairs, and the stronger sculpture. Endothyrella sowerbyi has much weaker dorsal sculpture and has wider umbilicus. See also Table
All museum samples were collected from the Khasi Hills and Assam (Figure
Two varieties of Plectopylis plectostoma have been described under the names Plectopylis plectostoma var. tricarinata and P. plectostoma var. exerta. Both of them differ from typical Endothyrella plectostoma specimens by the more shouldered whorls, and the more conical dorsal side of the shell having stronger spiral lines. No difference between the type specimens of these forms have been found except for the presence (exerta) and the absence (tricarinata) of hairs. The absence of hairs might be due to the corroded state of the syntypes of tricarinata. Although the difference between typical E. plectostoma and typical tricarinata/exerta shells seem to be minor, we found no intermediate forms, and in some cases we found mixed museum samples which indicate that the shells might have been collected from the same site. This suggest that Endothyrella plectostoma and E. tricarinata are distinct species.
1915 Plectopylis (Endothyra) williamsoni Gude: Records of the Indian Museum, 8: 509, Plate 42, figs 1a–d. [“Abor Hills, exact part not indicated”].
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): D: 6, H: 3.6–3.7 (n = 2, type series).
Endothyrella williamsoni has a more elevated spire than E. macromphalus and E. minor, and has two horizontal parietal plicae anterior to the lamella which are missing in the other two species. The most similar species in terms of shell shape and size to E. williamsoni is E. blanda. The latter species, on the other hand, lacks the two horizontal parietal plicae anterior to the lamella which area characteristic for E. williamsoni. Moreover, E. blanda specimens have seven rows of hairs, whereas E. williamsoni is hairless. Endothyrella robustistriata sp. n. is smaller, has stronger dorsal sculpture and lack the main plica which is characteristic for E. williamsoni. See also Table
This species is known from the type locality only (Figure
1879b Plectopylis hanleyi Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 164. [“Sikkim?”].
1897c Plectopylis hanleyi, — Gude: Science Gossip, 4: 11.
1899a Plectopylis hanleyi, — Gude: Science Gossip, 5: 240.
1899c Plectopylis (Endothyra) hanleyi, — Gude: Science Gossip, 6: 148.
1899d Plectopylis (Endothyra) hanleyi, — Gude: Science Gossip, 6: 175, 176.
1914b Plectopylis (Endothyra) hanleyi, — Gude: The Fauna of British India…: 73, 77.
“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 P. plectostoma, but is not so angular on the periphery, while the internal plication is quite different, besides being so very much smaller in size.”
In the original description
Examining all species assigned to Chersaecia and Endothyrella by
The finely ribbed protoconch is considered to be one of the key characters allowing separation of Chersaecia and Endothyrella species. Dextral Endothyrella species however, have “no typical” protoconch: (1) E. babbagei has slightly waved ribs (Figure
Based on the ribbed protoconch Endothyrella seems to be closely related to Gudeodiscus, Halongella, Sicradiscus and Sinicola, and to “Plectopylis” laomontana and “Plectopylis” andersoni. Other plectopylid genera without ribs on the protoconch (Plectopylis, Endoplon, Chersaecia) are probably only distantly related. The radula morphology of Endothyrella (large central tooth and tricuspid, pointed marginals) are similar to Sinicola, Sicradiscus and Gudeodiscus (Gudeodiscus) species, whereas Gudeodiscus (Veludiscus) Páll-Gergely 2015 and Halongella are characterized by small central teeth and bicuspid or bluntly tricuspid marginals.
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 (