Corresponding author: Barna Páll-Gergely (
Academic editor: M. Haase
A review of the microgastropod genus
Jochum A, Slapnik R, Kampschulte M, Martels G, Heneka M, Páll-Gergely B (2014) A review of the microgastropod genus
Microgastropods are less than 5 mm in size and represent the majority of worldwide tropical land snail diversity. They are restricted to specific microhabitats such as limestone rock surfaces or caves, have limited active dispersal ability and thus, frequently demonstrate high local endemism. Due to their small size and high degree of endemicity, our knowledge of the taxonomy and ecology of microgastropod taxa such as the hypselstomatid genus
The microgastropod genus
The classification of
All
Royal Belgian Institute of Natural Sciences (Brussels, Belgium)
Senckenberg Forschungsinstitut und Naturmuseum (Frankfurt am Main, Germany)
Malacological collection of the Slovenian Museum of Natural History (Ljubljana, Slovenia)
Staatliches Museum für Naturkunde Stuttgart (Stuttgart, Germany)
The name derives from the combination of the Latin angustus (= narrow) and pila (= pillar, column). Gender: feminine.
The genus is known from Thailand and Malaysia. The Chinese
China, Hunan, Longshan (龙山县), Huoyan (火焰), Feihu Dong (飞虎洞), (
A tiny, thin-shelled conical snail with very deep and narrow umbilicus, 5 shouldered whorls and two apertural denticles (parietal and palatal).
Shell thin, greyish white, semi opaque; conical, widest at its base, with a homogeneous powdery superficial texture and regularly increasing, shouldered whorls separated by deep suture; smooth with no notable spiral or radial sculpture. It is characterized by very fine irregular axial lamellae and reticulating microgranules producing the powdery superficial texture; protoconch shows reticulating granules and recognisable radial lines only at the upper part of the first whorl; aperture semi-circular, slightly oblique from ventral view; peristome very slightly thickened and reflexed; parietal callus adnate (attached to the penultimate whorl); aperture with two well-developed but short denticles, one on the parietal and the other on the palatal side; umbilicus very deep and narrow.
Micro-CT Video of
See
Shell measurements (mm) for
SH | SW | AH | AW | SW/SH×100 | AW/AH×100 | specimen |
---|---|---|---|---|---|---|
1.09 | 0.87 | 0.33 | 0.43 | 80 | 133.33 | Holotype |
1.13 | 0.91 | 0.41 | 0.43 | 80.77 | 105.26 | Paratype |
1.09 | 0.89 | 0.35 | 0.41 | 82 | 118.75 | Paratype |
1.13 | 0.91 | 0.39 | 0.41 | 80.77 | 105.55 | Paratype |
1.20 | 0.96 | 0.43 | 0.43 | 80 | 100 | Paratype |
1.22 | 41641 | 0.39 | 0.46 | 83.93 | 116.66 | Paratype |
1.09 | 0.89 | 0.35 | 0.39 | 82 | 112.5 | Paratype |
1.09 | 0.91 | 0.33 | 0.39 | 84 | 120 | Paratype |
1.30 | 0.89 | 0.39 | 0.37 | 68.33 | 94.44 | Paratype |
Average. minimum value (min). maximum value (max). variance of values (var) and standard deviation of a set of values (stdev) for
SH | SW | AH | AW | SW/SH×100 | AW/AH×100 | |
---|---|---|---|---|---|---|
Average | 1.17 | 0.94 | 0.37 | 0.43 | 80.09 | 114.20 |
Min | 1.04 | 0.85 | 0.33 | 0.37 | 68.33 | 94.44 |
Max | 1.30 | 1.04 | 0.43 | 0.46 | 87.50 | 133.33 |
Var | 0.0058 | 0.0031 | 0.0008 | 0.0007 | 15.4080 | 79.0895 |
stdev | 0.0765 | 0.0560 | 0.0288 | 0.0288 | 3.9253 | 8.8932 |
The most important morphological traits and ecological information for
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greyish white | light gray | greyish white | white | white |
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spiral threads; weak growth wrinkles | spiral threads; weak growth wrinkles | very fine irregular axial lamellae, reticulating microgranules | spiral threads; growth wrinkles | spiral threads |
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spiral/ reticulated | reticulating granules | reticulating granules | not described | not decribed |
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kidney-shaped, oblique | ovate, oblique | semi-circular, oblique | ovate | semi-circular |
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angular, upper palatal, parietal | dentition lacking | parietal, palatal | angular, upper palatal, weak basal | parietal, palatal |
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narrow | narrow | very narrow | relatively wide | very narrow |
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4.6–5.3 | 4.2–4.3 | 5.3 | 4.5 | 4.75 |
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1.02–1.21 | 0.92–0.99 | 1.04–1.3 | 1.2–1.8 | 0.9–1.0 |
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leaf litter & limestone talus | leaf litter & limestone talus | cave | cave (?) | cave |
The new species is named after the Gorges of Huoyan, where the type locality is located.
The new species is known from the type locality only.
The new species is known only from the Feihu Dong (“Cave of the Wind Tiger”).
Our knowledge of the biogeography of the genus is very limited. However, we assume that most
Although the specimen on
The name
A genus of small, conical or depressed-conical species with regularly growing, rounded or angulated whorls. The sculpture is characterized by spiral lines on both the protoconch and the teleoconch, decussated by irregular radial lines resulting in a reticulated surface structure. The aperture is toothless, adnate or slightly adnate and shows a sharp peristome.
The new name is established by the fusion of Tonkin (northern Vietnam, the area of distribution) and the Latin spira (a coil, twist). Gender: feminine.
The systematic position of the genus is questionable. It most probably belongs to the family
So far, the genus is reported from Northern Vietnam only.
The whole shell, including the protoconch, is covered with regular, very fine spiral threads. The spiral lines are decussated with rather irregular radial lines, creating a reticulated surface.
SEM (
The whole shell, including the protoconch is covered with regular, extremely fine spiral threads. The number of threads increases from the apex towards the aperture. The spiral lines are decussated with irregular radial lines, resulting in in a reticulated surface.
SEM (
The teleoconch shows rather regular, very fine spiral threads. These spiral lines are more numerous than in the other two examined species. The spiral lines are decussated. Irregular, impressed varices occur at intervals across the whorls. At higher magnification, the shell shows a highly flocculent texture.
SEM (
Holotype (
SEM images of
Map showing the localities of
We are very grateful of Nguyen Duc Anh (Hanoi, Vietnam) for his help in clarifying old Vietnamese locality names and to Zoltán Fehér (HNHM) for his assistance in constructing the map. We thank Rose Sablon and Yves Samyn (RBINS) for providing valuable insights and collection material. Our gratitude also goes to Tomi Trilar (SMNH) for providing material of the new species. We additionally thank Ronald Janssen and Ira Richling (SMNS) for their kind help and use of their SEM facilities as well as Suzanne Leidenroth (SMNS) and Yaron Malkowsky (SMF) for their expert help with the SEM. Boris Sket provided valuable ecological data. Special gratitude also goes to Sigrid Hof (SMF) for her photographic patience imaging the minute