Erhaia norbui: A new species of freshwater Snail from Bhutan.

Gastropods of the genus Erhaia are small aquatic Snails with ovoid shells less than 5 mm high, single gills and opercula, found in clear freshwater environments across a broad area of northern India, Nepal, Bhutan, and eastern China, with a total east-west distribution range of about 3500 km. These Snails are usually found in springs and brooklets, and show a high rate of endemism, with many species only known from a limited area or even single location. To date, three members of this genus have been described from Bhutan, two of which are found at single locations in Latipur and Kavre districts, with the third found at both of these locations, plus a further four localities.

In a paper published in the journal ZooKeys on 2 February 2022, Edmund Gittenberger of the Naturalis Biodiversity Center, and GiMaRIS, Choki Gyeltshen of the National Biodiversity Centre of Bhutan, and Björn Stelbrink of the Department of Animal Ecology & Systematics at Justus Liebig University Giessen, describe a new species of Erhaia from Haa District in Bhutan.

The new species is named Erhaia norbui in honour of Sangay Norbu, who discovered the population from which the species is described. The description is based upon six shells, collected from a spring at an altitude of 2700 m above sealevel, close to the village of Naychu. 

 

Erhaia norbui from the type locality, district Haa, Uesu, Naychu, roughly 2700 m above sealevel. (3) Holotype, NBCB 1239 (height 2.3 mm) and paratypes used for DNA analyses (4 UGSB 25956,height 1.5 mm 5 UGSB 25957, height 1.8 mm). Scale bar is 1 mm. Gittenberger et al. (2022).

Erhaia norbui has a ovoid to elongate ovoid or conical shell, smooth or with spiral microsculpture on the proto- and/or teleoconch (the protoconch is the embryonic shell of a Snail, which remains attached to the later shell, or teleoconch, and is often quite different in structure, making it a useful taxonomic tool). The apex of the shell is conspicuously and obliquely flattened. The aperture of the shell varies from ovoid-elliptical to circular; its palatal side is curved and gradually passes into the basal side. The peristome (layer of skin covering the shell is continuous, attached at the parietal side or slightly protruding. The umbilicus (gap inside the spirals of some Snail shells) is minute or closed. The parietal part of the aperture is smooth or with a lamella; columella smooth or with 2 spiral lamellae.

 

Habitat of Erhaia norbui at the type locality. Sangay Norbu in Gittenberger et al. (2022).

A DNA analysis based upon mitochondrial markers, plus the gened which code for the cytochrome c oxidase I protein and 16S rRNA, established that Erhaia norbui is a separate species, genetically differentiated from all other Erhaia species, but also that the three Erhaia species which are found in Bhutan and which were included in the study, form a distinct clade, all being more closely related to one another than any of them is to any species found outside the kingdom.

 

Maximum likelihood tree reconstructed with RAxML BlackBox (GTR+G substitution model for each partition and 100 bootstrap replicates), with new data in red. Numbers on branches denote bootstrap values of more than 50. Gittenberger et al. (2022).

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Lacustrine Gastropods from the Late Miocene Turiec Basin of Slovakia.

The Turiec Basin of the Slovakian Carpathian mountains was home to a closed freshwater lake for several million years during the Late Miocene, a lake that developed in a half-graben system (an area where tectonic movements are drawing rocks apart at the surface, causing thining of the crust and subsidence) and which developed a unique flora and fauna of endemic species (species not found elsewhere). This has been studied since the nineteenth century, with some groups from the lake (such as Ostracods) being very well understood, while others are less well known. Mollsuscs from Lake Turiec were first recorded in the 1860s, and have been intermittently described ever since; however the group has been the subject of few systematic reviews and the work on it is known to contian many imprecise descriptions and misidentifications.

In a paper published in the journal Geologica Carpathia in April 2015, Thomas Nuebauer and Mathias Harzhauser of the Department of Geology & Paleontology at the Vienna Natural History Museum and Radovan Pipík of the Geological Institute of the Slovak Academy of Sciences review the Gastropods of Lake Turiec, in which they describe four new species.

The first new species described is placed in the genus Viviparus, a widespread group of freshwater Snails with a fossil record dating back to the Jurassic, and given the specific name pipiki, in honour of Radovan Pipík of the Slovak Academy of Sciences for his work on the geology of Lake Turiec. Snails assigned to the genus Viviparus have been described from the Lake Turied deposits since the 1920s (and Snails described earlier are now assigned to this genus today), but oppinions have varied as to the specific assignment of these Snails, which have been placed in a number of fossil and extant species, but which Nuebauer et al. conclude should be described as a unique species found only in the Turiec deposits.

(D-E) Viviparus pipiki, first specimen; (F-G) Viviparus pipiki, second specimen; (H-I) Viviparus pipiki, protoconchs; (J) Viviparus pipiki, juvenile specimen. All specimens from Martin Brickyard. Scale bars correspond to 100 μm (H-I), 1 mm (A-C, J), and 10 mm (D-G). Nuebauer et al. (2015).

Viviparus pipiki is broad and conical with a thick shell and up to six whorls. The shape of the shell changed considerably as they grew, with early whorls being broadly conical, weakly convex and having a wide, ovoid, apature, while later whorls are conical to weakly ovoid and strongly convex, with a tear-shaped appature with a small posterior notch.

The second new species described is placed in the genus Melanopsis, which is today found in Europe, Anatolia, North Africa and parts of Austrelasia and which first appeared in the Cretaceous, and given the specific name glaubrechti, in honour of Matthias Glaubrecht of the Museum für Naturkunde Berlin, an expert on Melanopsid Snails. This species is described from 30 whole and fragmentary specimens from the Martin Brickyard, which were described by Czech palaeontologist Remeš as specimens of Melanoptychia pseudoscalaria, a species known from the Early Miocene of Moravia, a diagnisis rejected by Nuebauer et al. Melanopsis glaubrechti has a slender drop-shaped shell with distinct ribs and up to nine whorls.

 (A, D) Melanopsis glaubrechti, specimen digitally recombined from two separate images; (B) Melanopsis glaubrechti, juvenile shell; (C) Melanopsis glaubrechti, holotype. Scale bars correspond to 1 mm (D), and 5 mm (A-C). Nuebauer et al. (2015).

The third new species described is placed in the genus Tournouerina, which previously contains a single Mio-Pliocene species, and is given the specific name turiecensis, meaninf 'from Turiec'. This species is described from 35 specimens from Martin Brickyard, previously assigned to the species Lithoglyphus nannus in 2012 by Nadežda Krstić, Ljubinko Savić, and Gordana Jovanović, a diagnosis again rejected by Nuebauer et al. Tournouerina turiecensis is a small Snail shell with up to six convex whorls separated by deep sutures. The final whorl has a large drop-shaped apature with a thickened posterior tip.

 (E) Tournouerina turiecensis, paratype 1; (F) Tournouerina turiecensis, holotype; (G) Tournouerina turiecensis, paratype 2; (H) Tournouerina turiecensis, paratype 3; (I) Tournouerina turiecensis, protoconch. Scale bars correspond to 100 μm (I) and 1 mm (E-H).  Nuebauer et al. (2015).

The fourth species described is placed in the genus Radix, airbreathing freshwater Snails found throughout the Northern Hemisphere today and known to have been present by the Miocene, and given the specific name kovaci, in honour of Michal Kováč of Univerzita Komenského, for his work on the sedimentary evolution and stratigraphy of the Pannonian Basin. The species is described from a series of previously undescribed specimens from different locations in the Turiec Basin (many from drill cores). The majority of these specimens are fragmentary, making a full description difficult, but this is a small shell with four whorls, the last of which expands rapidly to the appature, which is eliptical with a small notch at the base, where it contacts the penultimate whorl.

Radix kovaci. (A) Holotype, Mošovce; (B) Juvenile specimen, Horná Štubňa; (C) Paratype 1, Horná Štubňa; (D) Paratype 3, Mošovce; (E) Paratype 2, Horná Štubňa; (F) Sediment infills of apertures of two specimens, Mošovce. Scale bars correspond to 10 mm. Nuebauer et al. (2015).

In addition to the newly described species Nuebauer et al. refur several Gastropod specimens to the species Theodoxus postcrenulatus, transfer the species Kosovia compressa to the new genus Popovicia and specimens assigned to the genera Radix and Planorbis but which cannot be assigned to species level.

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Tryonia infernalis: A new species of Cochliopid Snail from a hot spring in the southern Nevada Desert.

The deserts of southeast California and southwest Nevada have been shown to host a distinctive fauna of endemic (found nowhere else) Caenogastropod Snails, with many species with very limited distributions belonging to the families Assimineidae, Cochliopidae and Hydrobiidae found along tributaries to the Great Basin and lower Colorado Rivers and in the many hot springs found across the area.

In a paper published in the journal ZooKeys on 30 March 2015, RobertHershler of the Department of Invertebrate Zoology at the Smithsonian Institution and Hsiu-Ping Liu and Jeffrey Simpson of the Department of Biology at the Metropolitan State University of Denver describe a new species of Cochliopid Snail from Blue Point Spring, a hot spring close to Lake Mead in Clark County, southern Nevada.

The new Snail is placed in the genus Tryonia and given the specific name infernalis, meaning ‘hellish’, in reference to the proximity of Blue Point Spring to Nevada’s Valley of Fire. Tryonia infernalisis described from over 200 specimens ranging in length from 2.41 mm to 3.09 mm in shell height, with between 5 and 5¾ whorls. The males are on average slightly smaller than the females. The shells of the Snails are light brown, the bodies darker.

Tryonia infernalis, (A) female shell, (B) male shell, (C, D) opercula (outer, inner sides). Scale bars (A, B): 1.0 mm; (C, D): 200 μm. Hershler et al. (2015).

The species is known only from close to the source of Blue Point Springs, in waters within about 10 m of the spring from which the waters issue, which have a temperature of about 30˚C. The Snails were first observed in 1988, but appeared to have gone extinct in 2002. However they reappeared in 2007 and are now locally abundant.

Photographs of Blue Point Spring. (A) Outflow channel; spring originates below one of the mesquite trees in the upper right (photograph taken on 24 March 2009). (B) Ponded area where Tryonia infernalis occurs abundantly; the USGS gage house is in the lower left (15 May 2014). Hershler et al. (2015).

A genetic study of Tryonia infernalis suggests that it is most closely related to Tryonia clathrata, a species known from the White River Valley, which drains into Lake Mead, via the Muddy River, a few kilometres up-flow from Blue Point Spring. Two other Snail species present at the spring, Pyrgulopsis coloradensis and Assiminea sp., as well as a species of Amphipod Crustacean, Hyalella sp., appear to be more closely related to species from Death Valley in California, roughly 200 km to the west, and on the other side of the Spring Mountains.

Map showing the location of Blue Point Spring relative to other geographic areas. The collecting localities for specimens of Pyrgulopsis sanchezi and Tryonia clathrata (sister taxa of Blue Point Spring endemics) used in the molecular phylogenetic analyses are also shown. Hershler et al. (2015).

A molecular clock analysis of the three Snail species suggests that Assiminea sp. diverged from its closest known relative 1.42-1.60 million years ago, Tryonia infernalis from its nearest known relative 2.14-2.41 million years ago and Pyrgulopsis coloradensis from its closest relative 2.46-2.78 million years ago, suggesting that in all cases divergence occurred during the Pleistocene.The age of Blue Point Spring is not known, but the oldest spring deposits showing evidence of groundwater discharge associated with it are thought to be at least 2.6 million years old (Early to Middle Pleistocene). At no point during this time has Blue Point Spring or the surrounding area shared a common watershed with Death Valley, so Hershler et al. suggest that they may have been transferred to the site by Birds (which is thought to be common in for small invertebrates).

Hershler et al. suggest that Blue Point Spring represents a unique, if tiny, biodiversity hotspot with at least two (and possibly three) endemic Snail species. The site is currently administered by the National Park Service as part of the Lake Mead National Recreation Area, but Hershler et al. believe that it is in need of extra protective measures to ensure the survival of its unique fauna. The site is currently located close to a paved highway and small parking area, which makes it liable to disturbance by foot traffic and other activities. The Snail population might benefit from fencing off the spring, but the site is also home to one of the few known populations of the Relict Leopard Frog, Rana onca, which is known to be adversely affected by fencing, ruling this option out. Blue Point Spring was also used as an exotic-fish rearing site for the aquarium trade until the mid-1950s, and is known to host a population of the Convict Cichlid, Amatitlania nigrofasciata, which is omnivorous and may present a threat to the Snails, as well as the Red-rimmed Melania, Melanoides tuberculata, a highly invasive Gastropod species which has been shown to have an adverse effect on endemic Snail populations at other southwest American spring sites.

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A new subspecies of Polygyrid Snail from West Virginia.

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Three new species of Omalogyrid Snails from the southern West Coast of North America.

Omalogyrid Snails are among the smallest known Gastropods, with adult body sizes often comparable with larger Protozoans (single-celled ‘animals’). As such they tend only to be collected in surveys which directly target them, rather than general surveys of Mollusc...

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'Extinct' Gastropod rediscovered in Alabama.

The Mobile River Basin in Alabama and Georgia is considered to contain the most diverse Mollusc faunas of the entire North American continent. Unfortunately the area is also heavily urbanized and industrialized, with waterways channelized to allow shipping, blocked by hydroelectric projects and polluted by urban and mine runoff, leading to a large number of species being believed to be extinct; at last count 47 endemic Molluscs, including 37 Gastropods, were thought to have died out in the Basin.

In a paper published in the journal PLoS One on 8 August 2012, Nathan Whelan of the Department of Biological Sciences at the University of Alabama, Paul Johnson of the Alabama Aquatic Biodiversity Center at the Alabama Department of Conservation and Natural Resources, and Phil Harris also of the Department of Biological Sciences at the University of Alabama describe the rediscovery of Leptoxis compacta, an aquatic Snail endemic to the Cahaba River, which has not been alive for over 70 years, and which was declared extinct in 2000.

A specimen of Leptoxis compacta from the Cahaba River. Whelan et al. (2012).

The species was found at a single site on the Cahaba River, above the junction with Shades Creek, and established as being Leptoxis compacta by comparison with museum specimens. The site is considered highly vulnerable by Whelan et al., and believe the species should be classified as critically endangered under International Union for the Conservation of Nature criteria, and that the U.S. Fish and Wildlife Service should consider L. compacta for protection under the U.S. Endangered Species Act because of its highly restricted range and susceptibility to a single pollution or siltation event. They also suggest that, since the Snail proved willing to breed in captivity, it could be re-introduced to other parts of its former range.

Map showing known historical sites of Leptoxis compacta colonies and the site of the rediscovered colony. Whelan et al. (2012).

(A) Museum specimen of Leptoxis compacta. (B-F) Newly recovered specimens showing a growth series. Whelan et al. (2012).

Museum specimens of other species of Leptoxis and the related genera Elimia and Pleurocera used for comparison in the study. (A) L. ampla (B) E. ampla (C) E. annetae (D) E. cahawbensis (E) E. clara (F) E. showalteri (G) E. variata (F) P. prasinatum. Whelan et al. (2012).

(Top) The radula ('tongue') of a Leptoxis compacta specimen collected in 1881. (Bottom) The radula of a specimen collected in 2011. Whelan et al. (2012).

See also A new species of Pachychilid Snail from western Java, Deep-sea Gastropods from Miocene Cold Seeps and Whale-falls in Japan, Thirteen new species of interstitial Gastropods from New Zealand, The Snail that eats Crabs and Two new hydrothermal vent communities from the southern Central Indian Ridge.

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A new species of Pachychilid Snail from western Java.

Pachychilid Snails are freshwater Gastropods found throughout the tropics. They have thick shells and operculi (plates used to cover the entrance of the shell) enabling them to live in turbulent waters. Many species give birth to live young, rather than laying eggs. Their closest relatives are marine Gastropods not other freshwater forms.

In a paper published in The Raffles Bulletin of Zoology on 29 February 2012, Ristiyanti Marwoto and Nur Isnaningsih of the Museum Zoologicum Bogoriense at the Research Center for Biology in Cibinong, West Java, describe a new species of Pachychilid Snail from the River Cibangbay in Tasikmalaya, West Java.

Map of Java showing the site where the new species was found (star) as well as known sites where the closely related Sulcospira testudinaria occurs. Marwato & Isnaningsih (2012).

The new species is placed in the genus Sulcospira, which is found in fast moving streams and rivers throughout south China, Southeast Asia and western Indonesia. It is given the specific name kawaluensis, which refers to the Kawalu Subdistrict, where the snails were found. Sulcospira kawaluensis is a 10-28 mm dark-coloured Snail with a roughly oval shell, comprising four-to-six flattened whorls in the adults, though this is the result of earlier whorls being worn away rather than only this number being produced. The Snails were found living on stones at depths of ~40 cm in an area of the Cibangbay which also had sandy and gravely areas. The species was largely distinguished from its closest relative, Sulcospira testudinaria, on the basis of the teeth on its radula (the radula is the tongue of a Gastropod, it is covered in hooked teeth, used to scrape up food).

Sulcospira kawaluensis. (D) Is the operculum. Other pictures are the whole shell. Scale bar is 10 mm. Marwato & Isnaningsih (2012).

The raduli of Sulcospira kawaluensis (Top) and Sulcospira testudinaria (Bottom). Images on the left are taken from directly above, those on the right from behind at an angle of 45°.

See also Seismic activity beneath Mount Tangkubanparahu, Deep-sea Gastropods from Miocene Cold Seeps and Whale-falls in Japan, Thirteen new species of interstitial Gastropods from New Zealand and The Snail that eats Crabs.

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