The Souapitia Snail was described in 1961; it was restricted to a single locality, a stretch of rapids in the Kountouré River in the Republic Guinea.
The habitat, rocks in swiftly running waters, does not exist anymore because China International Water & Electric Corporation, a Chinese construction and engineering consulting company, begun to build a dam, the Souapiti Hydropower Station, in 2015, a project that apparently was finished in 2019.
A survival of this highly rheophilic, i.e. adapted to live in fast-moving water, is rather unlikely, it is now extinct.
***
The species was said to have been found in Nigeria recently, however, this is report is erroneous and is based on a misinterpretation of specimens of another snail species, the African Gabbiella Snail (Gabbiella africana(Frauenfeld)). [1]
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References:
[1] S. O. Oladejo; O. A. Morenikeji: Spatial Distribution of Fresh Water Snails in Erinle Reservoir Dam, Olorunda Local Government Area, Osogbo, Osun State, Nigeria. Journal of Agriculture and Forest Meteorology Research 3(1): 246-254. 2020
This species was described in 2000 on the basis of a single subfossil specimen that had been found in 1996 in limestone scree in the Limekiln Cave on the Île aux Aigrettes, Mauritius.
The shell reaches a length of 2.8 cm; it differs from the shells of its close relative, the Two-colored Pachystyla Snail (Pachystyla bicolor (Lamarck)) (see photo below) by lacking a decussate sculpture and by its orange-colored last whorl with a white peripheral band.
The Straw-colored Laminella Snail was described in 1850; it was endemic to the island of O’ahu in the Hawaiian Islands, where it is known from several valleys, including the Makiki-, Nu’uanu-, Palolo-, Pauoa, and Waiala’e nui Valleys. The species was almost entirely found on the leaves of the endemic olonā (Touchardia latifolia Gaudich.). [1]
The shells reach sizes of about 2,2 to 2,4 cm in height; they are “acuminately oblong, sinistral, whorls convex, obliquely striated, columella strongly twist-plaited; straw-colored, unspotted.” [1]
We have a little information about the animal itself.:
“Animal of a uniform light flesh color, oral aperture margined with a line of orange.” [1]
***
This species is now considered most likely extinct.
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
The Beaverpond Marstonia was described in 1977, it is known exclusively from its type locality, Cedar Creek in the Flint River Drainage, Crisp County, Georgia, USA.
The species was not found during recetn surveys and was finally declared extinct in December 2017. [1]
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References:
[1] Georgia Snail Is First Species Declared Extinct Under Trump Administration. www.biologicaldiversity.org. Retrieved 2018-01-07
Walden’s Callina Snail was described in 2018 during a genus revision including many Madeiran land snail forms; it is known only from subfossil shells that were recovered from Holocene deposits near the southern coast of Porto Santo in the Madeiran archipelago in the Atlantic Ocean.
The shells reach sizes of around 1,57 cm in diameter; they are whitish (probably bleached) and have a closed umbilicus and a well-rounded rather than angulated or keeled last whorl.
The species disappeared before the island’s scientific exploration in the 19th century, maybe even due to natural causes like slight, local (non-human induced) climatical changes. [1]
*********************
References:
[1] Willy De Mattia; Marco T. Neiber; Klaus Groh: Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geometridae). ZooKeys 732: 1-125. 2018
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Photo from: ‘Willy De Mattia; Marco T. Neiber; Klaus Groh: Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geometridae). ZooKeys 732: 1-125. 2018’
Kondo’s Libera Snail was described in 2018; it is known only from subfossil remains that were recovered from at least two areas on the island of Mo’orea in the Society Islands.
The shells are ‘extremely’ large for a member of its family, reaching a size of up to 0.97 cm in diameter.
Kondo’s Libera Snail is quite similar to Jacquinot’s Libera Snail (Libera jacquinoti (Pfeiffer)) in its large size, its overall shape and apertural barriers but can be distinguished from that species by having consistently much finer and more numerous riblets on the apical surface of the shell and by the absence of a strong basal sculpture. [1]
Like so many snail species endemic to Polynesia, also this one is now sadly extinct.
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References:
[1] C. C. Christensen; J. G. Kahn; P. V. Kirch: Nonmarine Mollusks from Archaeological Sites on Mo‘orea, Society Islands, French Polynesia, with Descriptions of Four New Species of Recently Extinct Land Snails (Gastropoda: Pulmonata: Endodontidae). Pacific Science 72(1): 95-123. 2018
The Crowned Neohoratia Snail was described in 1870; I could not find out much about it except for a brief account of its former type locality.:
“in Madrid’s surroundings or, at least, in some springs or streams of the New Castille Province” [1]
The species is now considered most likely extinct. [1]
*********************
References:
[1] Beatriz Arconada; Maria-Angeles Ramos: Revision of the genus Islamia Radoman, 1973 (Gastropoda, Caenogastropoda, Hydrobiidae), on the Iberian Peninsula and description of two new genera and three new species. Malacologia 48(1-2): 77-132. 2006
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Depiction from: ‘Jules René Bourguignat: Mollusques nouveaux, litigieux, ou peu connus. Fasc. 1. Paris: cneohoratiahez F. Savy 1865’
The Inflated Samoana Snail was described in 1842, it was endemic to the island of Tahuata in the Marquesas.
This arboreal species inhabited the native forests at elevations of about 400 to 500 m above sea level, where it was commonly found on trees. [1]
***
The Inflated Samoana Snail is now considered extinct.
*********************
References:
[1] Justin Gerlach: Icons of Evolution: Pacific Island Tree-Snails of the Family Partulidae. Phelsuma Press 2016
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second Series: Pulmonata Vol. 20, Caecilioides, Clessula and Partulidae. Index to Vols. 16-20. 1909-1910’
The Small Amastra Snail was described in 1895; it inhabited the floors of the forests of Makawao in the northern part of eastern Maui, Hawaiian Islands, where it was once considered common, but very local in its distribution.
The animal was described when it was alive.:
“Animal when extended in motion as long as the shell. Mantle light brown. Foot above and below brown with spots of deeper shade on the sides. Tentacles and front above almost black.” [1]
The shells reach sizes of about 1,1 to 1,2 cm in height; their coloration was quite variable.
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
Grabham’s Amphorella Snail was described in 1908; it is only known from subfossil material that was recovered from deposits at the Ponta de São Lourenço Peninsula in the east of Madeira which were dated to the Middle Pleistocene; however, the species survived well into the Late Holocene and the youngest known specimens can be dated to an age of around 50 years, meaning this species disappeared around the 1950s without having ever been found alive. [1][2]
The shells reached sizes of about 0.6 cm; they were described as follows.:
“The shell resembles the small form of tornatellina in shape; but the very thick outer lip is inflexed, with an inwardly projecting lobe below the middle; supraparietal plait short and narrow; parietal nodule low but distinct.” [1]
***
syn. Ferussacia tornatellina var. grabhami Pilsbry
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Volume 19. Oleacinidae, Ferussacidae 1907-1908’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Volume 19. Oleacinidae, Ferussacidae 1907-1908 [2] Glenn A. Goodfriend; R. A. D. Cameron; L. M. Cook: Fossil evidence of recent human impact on the land snail fauna of Madeira. Journal of Biogeography 21: 309-320. 1994
The Dubious Libera Snail was described in 1889; it inhabited some of the valleys on the eastern- and northern sides of the island of Mo’orea in the Society Islands.
The shells reach sizes of 0.48 to 0.58 cm. [1]
The species was apparently never recorded alive subsequently. [2]
*********************
References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976 [2] C. C. Christensen; J. G. Kahn; P. V. Kirch: Nonmarine Mollusks from Archaeological Sites on Mo‘orea, Society Islands, French Polynesia, with Descriptions of Four New Species of Recently Extinct Land Snails (Gastropoda: Pulmonata: Endodontidae). Pacific Science 72(1): 95-123. 2018
The Hachijojima Snail was described in 1945; it is, or maybe was, restricted to the island of Hachijojima in the Izu Islands group, Japan.
The species is considered extinct since 2016. [1]
*********************
References:
[1] Robert H. Cowie; Claire Régnier; Benoît Fontaine; Philippe Bouchet. Measuring the Sixth Extinction: what do mollusks tell us? The Nautilus 131(1): 3-41. 2017
This species was described in 1849, it was endemic to the island of Java, Indonesia, an exact locality, however, appears to be unknown.
The shells reach sizes of about 2,3 cm in heigth, they are yellowish to olive with brown vertical flames and are sculptured with spiral lirae that are more prominent at the base of the body whorl. [1][2]
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References:
[1] Frank Kühler; Matthias Glaubrecht: Fallen into oblivion – the systematic affinities of the enigmatic Sulcospira Troschel, 1858 (Cerithioidea: Pachychilidae), a genus of viviparous freshwater gastropods from Java. The Nautilus 119: 15-26. 2005 [2] Ristiyanti M. Marwoto; Nur R. Isnaningsih: The freshwater snail genus Sulcospira Troschel, 1857 from Java, with description of a new species from Tasikmalaya, west Java, Indonesia (Mollusca: Gastropoda: Pachychilidae). The Raffles Bulletin of Zoology 60(1): 1-10. 2012
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Photo from: ‘Frank Kühler; Matthias Glaubrecht: Fallen into oblivion – the systematic affinities of the enigmatic Sulcospira Troschel, 1858 (Cerithioidea: Pachychilidae), a genus of viviparous freshwater gastropods from Java. The Nautilus 119: 15-26. 2005’
The Mare Landsnail was described in 1879; it was endemic to the island of Maré in the Loyalty Islands, New Caledonia.
The shells reach sizes of about 2.9 to 3.2 cm in height; they are fusiform, thin, greyish white with sparsely scattered translucent grey dots, spots or streaks, bordered on the left with opaque white, the surface is shining, lightly striate and inconspicuously grooved spirally; the aperture is oblong-ovate, white within, the peristome is expanded and white, the columella is dilated above and has a weak entering fold.
The species appears to be extinct now.
***
syn. Bulimus loyaltyensis Souverbie
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 13: Australasian Bulimulidae: Bothriembryon, Placostylus. Helicidae: Amphidromus. 1900′
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 13: Australasian Bulimulidae: Bothriembryon, Placostylus. Helicidae: Amphidromus. 1900
This species was described in 1856; it was apparently restricted to the Ka’a’awa Valley near the north-eastern shore of O’ahu, Hawaiian Island, where it was found “under stones in places not shaded by trees.” [1]
The shells reached heights of only about 0.6 cm; they were very thin, glassy transparent, shining, and scarcely striated.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
The Glowing Red Amastra Snail was found at a place named Kahuku, probably in the northeastern part of O’ahu, Hawaiian Islands, where it was found on the ground in the forest. [1]
… from the original description.:
“It is allied to Am. elliptica Gk., but differs in being more elongate in form, thicker iin structure, and for the most part destitute of epidermis. It is always dextral.“
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911′
This species was described in 2014 based on at least 405 subfossil shell specimens that were collected from a cave south of the village of Temao near the eastern coast of Makatea in the Tuamotu Archipelago.
The shells are less than 0,5 cm in diameter; they are depressed, white and do not bear any markings. [1]
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References:
[1] André F. Sartori; Olivier Gargominy; Benoît Fontaine: Radiation and decline of endodontid land snails in Makatea, French Polynesia. Zootaxa 3771(1): 1-68. 2014
The shells reach sizes of about 1,6 cm in height; they are glossy white or ivory yellow with a white sutural line, or either of these tints with a burnt sienna band immediately above a wider and darker band. [1]
***
The species was last found in 1980 in the forest along the Aiea Ridge Trail in the Ko’olau Mountains; it is now most likely extinct. [1]
*********************
References:
[1] Recovery Plan for the O’ahu Tree Snails of the genus Achatinella. U.S. Department of the Interior Fish and Wildlife Service. Region One, Portland, Oregon. April 1993
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Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’
The Straight Hirasea Snail was described in 1907; it is, or maybe was, restricted to the island of Hahajima in the Ogasawara Islands, Japan.
The shells reach sizes of about 0,2 cm in height and about 0,3 cm in diameter; the spire is low-conic and the base very convex.
The species is now likely extinct. [1]
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References:
[1] Robert H. Cowie; Claire Régnier; Benoît Fontaine; Philippe Bouchet. Measuring the Sixth Extinction: what do mollusks tell us? The Nautilus 131(1): 3-41. 2017
The Boulder Snail was described in 1842; it inhabited the Clinch- and the Powell rivers which are a part of a river system that spans over parts of Georgia, Iowa and Tennessee, USA.
The species is now extinct, the last remaining population of this species disappeared when the Tellico River was dammed in 1979 to create Lake Tellico.
***
The Boulder Snail is sometimes considered rediscovered, however, these accounts must be assigned to a closely related species, Anthony’s Boulder Snail (Athearnia anthonyi (Redfield)).
Forbe’s Amastra Snail was described in 1917; it is known only from (sub)fossil remains found in Late Pleistocene/Early Holocene deposits near the Makua beach at the foot of the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands.
“The material on which this species is based consists of two whole adult specimens and the lower portion of two additional specimens. all the specimens were taken by Mr. Forbes in a single pocket in sand deposits along the railroad track north of Makua. On a later visit by Mr. Forbes and the author, no additional specimens were found though all the exposed surfaces of the sand pockets along the track were carefully gone over. These pockets consist of beach sand covered by talus.” [1]
The shells of this species reach sizes of about 1,3 to 1,4 cm in height.
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References:
[1] C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917
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Photo from: ‘C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917’
Worthy’s Flax Snail was described in 1947; it is known from subfossil remains only.
“Cape Maria van Diemen (Mainland), on north-eastern side of headland, formerly an island but now linked to the mainland by a tombolo of consolidated and drifting sand (type); on a small island, accessible by wading at low tide, half a mile south of type locality …; in loose sandy humus, with Austrosuccinea remains; on a former islet 3/4 mile south of type locality and just off the western escarpment of the “priscus block,” in coarse cemented shell sand.” [1]
Worthy’s Flax Snail is one of several flax snail populations separated from each other by geographical barriers that have developed into distinct forms over time; it disappeared sometimes during the Late Pleistocene/Early Holocene due to climatic changes.
***
syn. Placostylus ambagiosus ssp. worthyi Powell
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References:
[1] A. W. B. Powell: On further colonies of Placostylus land snails from northernmost New Zealand. Records of the Auckland Institute and Museum 4(2): 134-140. 1951
The Mo’omomi beach at the northwestern coast of Moloka’i, Hawaiian Islands, is one of the last remaining dune sides found on these islands; thousands of shells poke out of the sandstone cliffs near the beach, some bleached completely, some still bearing hints of their former coloration; these are the shells of land snails that formerly inhabited this now quite desert-like place.
In the Pleistocene, the climate of the Hawaiian Islands was much wetter than it is today and the area that is now covered by sand dunes was forested back then. When the climate became dryer at the beginning of the Holocene about 10000 BP., these forests disappeared, leading to the extinction of the local snail populations.
In fact, the shells can be dated to ages from 42000 to about 3000 years, which means that this form died out during the Holocene, and, that this is a case of a natural extinction.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 23: Appendix to Amastridae. Tornatellinidae. Index, vols. XXI-XXIII. 1915-1916
The Globule Mercuria Snail was described in 1887, it is or was restricted to the central- and eastern parts of the Tell Atlas of Algeria and Tunisia.
The shells reach sizes of about 0,25 to 0,3 cm in length. [1]
***
I personally do not know now if it is indeed extinct, however, the species apparently has not been seen since the 19th century, was not found during recent surveys, and its name appears in lists of extinct molluscs.
********************
References:
[1] Peter Glöer; Slimane Bouzid; Hans D. Boeters: Revision of the genera Pseudamnicola Paulucci 1878 and Mercuria Boeters 1971 from Algeria with particular emphasis on museum collections. Archiv für Molluskenkunde 139(1): 1-22. 2010
The Oheatora Australdonta Snail was described in 2013; it is known from about 35 specimens that were recovered from the island of Rurutu, Austral Islands.
The shells are small, thin, relatively high, subdepressed, opaque to pellucid, white to light fawn-colored and show no traces of markings. [1]
[1] André F. Sartori; Olivier Gargominy; Benoît Fontaine: Anthropogenic extinction of Pacific and snails: A case study of Rurutu, French Polynesia, with description of eight new species of endodontids (Pulmonata). Zootaxa 3640(3): 343-372. 2013
This species was described in 2018, it is known only from the southeastern coast of Porto Santo.
The shells reach a size of about 0,5 to 0,56 cm in diameter.
The species appears to have already been extinct before the scientific exploration of the island in the 19th century. [1]
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References:
[1] Willy De Mattia; Marco T. Neiber; Klaus Groh: Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geometridae). ZooKeys 732: 1-125. 2018
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Photo from: ‘ Willy De Mattia; Marco T. Neiber; Klaus Groh: Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geometridae). ZooKeys 732: 1-125. 2018’
The Ancient Leptaxis Snail is a species that is known exclusively from fossil and subfossil shells that were recovered from Late Pleistocene and Holocene deposits on the island of Santa Maria, Azores.
The species disappeared due to several reasons.:
“Why became extinct this helicid? The explanation for the decline and extinction of this species is surely associated to environmental changes occurred inside its area of habitat, during last centuries. Evidences include (1) the destruction of the original laurel cover of Santa Maria, and the anthropic introduction of new botanic species; (2) a colonization by the introduced and opportunistic Otala lactea (Muller, 1774), one of the commonest and widespread land snails of the island.” [1]
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References:
[1] Pedro Callapez; A. Ferreira Soares; J. Marques: Rediscovery of Leptaxis vetusta (Morelet & Drouet, 1857), a subfossil land snail from the Quaternary of Santa Maria (Azores). Ciências da Terra (UNL) 15: 209-218. 2003
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Depiction from: ‘Arthur Morelet: Iles Açores. Notice sur l’histoire naturelle des Açores suivie d’une description des mollusques terrestres de cet archipel. Paris, Baillière 1860’
Yoshi’s Australdonta Snail was described in 1976 on the basis of subfossil specimens that were found on the foot of the Matonaa plateau on the island of Rurutu, Austral Islands.
The shells reach sizes of 0.29 to 0.35 cm in diameter; they are light yellowish white with prominent somewhat irregular, zigzag-shaped, reddish flammulations, becoming narrower and more sharply angled on the shell’s base, merging near or in the umbilicus. [1]
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References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
Remy’s Laminella Snail was described in 1855; it was endemic to the island of Lana’i in the Hawaiian Islands.
The shells reach sizes of about 1,4 cm in height; they are “… very pale buff, with some pink suffusion on the last whorl and the embryonic whorls. The first half-whorl is smooth, convex and uniform pinkish-brown; next whorl streaked, flattened ad unevenly, rather weakly costate; on part of the third whorl the costation or corrugation is stronger, more or less irregular, after that weakening. The last whorl is very finely striatulate. There are reddish streaks between the ribs on the embryonic whorls; near the end of the third whorl these give place to a few widely-spaced oblique blackish stripes; after which the angular, zigzag or netted pattern begins. This pattern is essentially like that of L. tetrao. The interior of the aperture and the columella are pink; columellar lamella simple, steeply ascending.” [1]
***
The species is now considered extinct.
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
This somewhat enigmatic species was described in 2006, apparently based on fossil shells that were collected from deposits that date back well into the Late Pleistocene era while some might well be younger in age.
The species has not yet been discovered alive and it might well be extinct, the question remains if this is a recent or an prehistoric extinction.
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References:
[1] Emilio Fabián Garcia: Conus sauros, a new Conus species (Gastropoda: Conidae) from the Gulf of Mexico. Novapex 7(2-3): 71-76. 2006
Cooke’s Leptachatina Snail was described in 1914, it is known only from subfossil specimens that had been found at a few scattered locations in western O’ahu, Hawaiian Islands. [1]
This was apparently a coastal, respectively lowland species and thus disappeared shortly after the arrival of the first Polynesian settlers.
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References:
[1] Patrick V. Kirch; Carl C. Christensen: Nonemarine molluscs and paleoecology at Barber’s Point, O’ahu. Prepared for Archaeological Research Center Hawaii, Inc.. Department of Anthropology; Bernice P. Bishop Museum 1-40. 1980
This species inhabited the forests of the Mt. Ka’ala and parts of the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands.
… from the species’ description.:
“Shell irregularely, acutely conical, the apex ponted; last whorl inflated; thin, corneous, with minute longitudinal striae; whorls 7, rounded; aperture subovate; lip thin, translucent; columella straight, white, and armed with a transverse plaited tooth. Color uniform dark horn, columella and tooth white.” [1]
The shells reach sizes of 1,1 to 1,75 in heigth and up to 0,85 cm in diameter.
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911′
This species was described in 1884; it is, or rather was, endemic to the island of Huahine in the Society archipelago.
The shells reach sizes of about 0,29 to 0,34 cm in diameter; they are light yellowish horn-colored with evenly spaced, wide, slightly zigzag-shaped, reddish flammulations which fade out on the base of the shell. [1]
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References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
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Depiction from: ‘G. W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second Series: Pulmonata Vol. 3, Helicidae Vol. 1. 1887’
The Silhouette Glabrennea Snail was described in 1994, it restricted to a very small area on Mt. Dauban on the island of Silhouette, Seychelles Islands, when it was discovered in 1990.
The species apparently was an inhabitant of leaf litter.
The Silhouette Glabrennea Snail was only ever found at its type locality, once in 1990, and a for second time one year later in 1991, when its population was already declining. All subsequent searches (2000, 2009, 2010) at the type locality and other suitable areas failed to find the species again which thus is considered extinct. [1]
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References:
[1] Justin Gerlach: Red List ing reveals the true state of biodiversity: a comprehensive assessment of Seychelles biodiversity. Phesluma 20: 9-22. 2012 [2] Justin Gerlach: Changes in non-marine mollusc populations in the Seychelles islands 1986-2012. Phelsuma 20: 23-38-2012
This species was described in 1976, originally on the basis of a single, quite worn specimen that was found in 1955 on the island of Makatea in the Tuamotu Archipelago.
The shells reach sizes of less than 0.7 cm in diameter; they are robust, opaque, subdepressed and white bearing regularly spaced, amber-colored flammulations which are usually stronger apically than on the body whorl, fading out on the shell’s base.
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976 [2] André F Sartori; Olivier Gargominy; Benoît Fontaine: radiation and decline of endodontid land snails in Makatea, French Polynesia. Zootaxa 3772: 1-68. 2014
This species was described in 2013; it is known by 24 subfossil specimens that were collected on the island of Rurutu in the Austral archipelago.
The shells are very large, much wider than high, discoidal, white with reddish-brown flammulations on the apical surface, often faintly visible peripherally on the shell’s base through the subpellucid shell wall.
[1] André F. Sartori; Olivier Gargominy; Benoît Fontaine: Anthropogenic extinction of Pacific and snails: A case study of Rurutu, French Polynesia, with description of eight new species of endodontids (Pulmonata). Zootaxa 3640(3): 343-372. 2013
Ancey’s Taipidon Snail was endemic to the island of Hiva Oa, Marquesas, it was described in 1887 when the species apparently was still alive, the author gives some slight information about it.:
“Sa grande taille, son large ombilic, ses grandes lamelles aperturales blanches et bien visibles, empêcheront de confondre cette Espèce avec ses congénerès.“
translation:
“Its large size, its large umbilicus, and its large, white apertural lamellae, well visible, will prevent this species from being confused with its congeners.“
***
Ancey’s Taipidon Snail was apparently a lowland species and might already have been extinct at the time of its discovery.
As far as I know, only three specimens of the species remain today with the holotype reaching a heigth of 0,23 cm and 0,5 cm in diameter, it is furthermore light yellow-brown and decorated with irregular, reddish flammulations.
*********************
References:
[1] Andrew Garrett: Mollusques terrestres des Iles Marquises (Polynésie). Bulletins de la Société malacologique de France 4: 1-48. 1887 [2] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
The Desirable Leptachatina Snail was described in 1911; it is known from two subfossil shells that were found at Lē’ahi (Diamond Head) in the south-eastern part of O’ahu, Hawaiian Islands.
This shells reach a height of about 0.78 cm.
“The description is based on two specimens one of which is not adult and is slightly broken. it is most closely related to L. exilis Gul. from the same island. L. exoptabilis is, however, larger, with less convex outlines and is narrower in proportion to its length.” [1]
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
This species was described in 1908, it was endemic to the Kohala Volcano in the northern part of Hawai’i, Hawaiian Islands.
The shells were very distinct, they were covered with transverse striae that were strongly developed, with cuticular margins which could very easily be broken, they reached sizes of about 0,26 cm in length.
***
According to a study from 2018, sadly all Hawaiian species of the genus Lyropupa are now extinct. [2]
*********************
References:
[1] C. Montague Cooke Jr.: A new species of Lyropupa. Bishop Museum Occasional Papers 3(2): 211-212. 1908 [2] Norine W. Yeung; Kenneth A. Hayes: Biodiversity and extinction of Hawaiian land snails: how many are left now and what must we do to conserve them – a reply to. Integrative and Comparative Biology 58(6): 1157-1169. 2018
*********************
Depiction from: ‘C. Montague Cooke Jr.: A new species of Lyropupa. Bishop Museum Occasional Papers 3(2): 211-212. 1908’
The Small-ribboned Oahu Tree Snail was described in 1846; like all members of its genus, it was endemic to the island of O’ahu in the Hawaiian Islands.
The shells reach sizes of about 1,8 to 2 cm in height; they are dextral, ovate-oblong, spiro-conic, solid, striatulate, more obsolete toward the apex and with slightly convex whorls; glossy white, ornamented with varying brown bands; the white columella is strongly toothed above and the margin is dilated, reflexed and appressed; the white aperture is irregularly semioval; the peristome is narrowly thickened outside and strongly lipped within. [1]
***
The Small-ribboned Oahu Tree Snail was last seen in 1966 at the Hawai’iloa- and the Kuliouou Ridges in the Ko’olau Mountains; it is now most like exinct. [1]
***
According to some authors, this species is actually a subspecies of the Green Oahu Tree Snail (Achatinella viridans Mighels), as there seems to be a complete integration between them. [1]
************************
References:
[1] Recovery Plan for the O’ahu Tree Snails of the genus Achatinella. U.S. Department of the Interior Fish and Wildlife Service. Region One, Portland, Oregon. April 1993
*********************
Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’
This very interesting species was described in 1968 based on about 30 specimens that were collected on Clipperton Island in the Pacific Ocean apparently 10 years earlier, when the species appeared to be very abundant on the atoll.
The rather unusal shell (for a member of that genus) reaches a length of about 1,1 cm, it is elongately ovate, thin, andr tanslucent, the upper whorls are light amber-colored, the last whorl is grayish-yellow with iregularely spaced brown lines which parallel the growth lines. [1]
***
The Atoll Amber Snail was not found alive since 1958 and it is obviously extinct. [2]
*********************
References:
[1] L. G. Hertlein; E. C. Allison: Descriptions of new species of gastropods from Clipperton Island. Occasional Papers of the California Academy of Science 66: 1-33. 1968
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Photo from: ‘Kirstie L. Kaiser: The recent molluscan fauna of Île Clipperton (Tropical Eastern Pacific). The Festivus 39. 2007’
This species was described in 1917; it was found at a place named Waiahole at the crest of the Ko’olau Mountains along the eastern coast of O’ahu, Hawaiian Islands.
The shells of this species reach sizes of about 1 to 1,2 cm in height.
*********************
References:
[1] C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917
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Photo from: ‘C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917’
This species was described in 1985, its species epithet, however, is now considered a nomen nudum, the reasons therefore are not known to me.
Kramer’s Galapagos Snail appears to have been quite common when it was discovered and described, it was found in all wetlands and in the Scalesia forests north of Cerro Puntudo on the island of Santa Cruz, Galápagos Islands. [1]
The species seems to have not been found alive during the most recent field searches and might be extinct.
*********************
References:
[1] Guy Coppois: Etude de la spéciation chez les Bulimulidae endémiques de l’archipel des Galápagos (Mollusques, Gastéropodes, Pulmonés). Thèse de Doctorat, Libre de Bruxelles 1-283. 1985
The Rock-dwelling Leptachatina Snail was described in 1856; it is known from Mokulē’ia near the north-western shore of O’ahu, Hawaiian Islands, where it was found under stones in open places.
The shells are only about 0.6 cm heigh; they are glass-like transparent, shining, and very finely striated.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
The Oromana Tubuaia Snail was described in 1962; it was only ever known from its type locality, the Oromana Hills on the island of Rimatara in the Austral archipelago, a place that today is completely degraded and transformed into agricultural fields (like actually most of the island).
This snail is now clearly extinct. [1]
*********************
References:
[1] Olivier Gargominy; Benoît Fontaine: A Global Overview of the Terrestrial and Freshwater Molluscs. In: Jean-Yves Meyer; Elin. M. Claridge: Biodiversity of the Austral Islands, French Polynesia. Muséum national d´Histoire naturelle, Paris. 55-91. 2014
St. John’s Mautodontha Snail (Mautodontha saintjohni)
This species was described in 1976; it was endemic to the island of Bora Bora in the Society archipelago.
The shells reach about 0,26 to 0,3 cm in diameter; they are white and bear prominent zigzag-shaped, reddish flammulations.
*********************
References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
The Aged Amastra Snail is one of many forms of its genus that are actually known only based on (sub)fossil material; this one was found in deposits of the Hanama’ulu plains near the eastern coast of Kaua’i, Hawaiian Islands.
“This extremely variable form is abundant in road cuttings on the coastal plain south of the Wailua river. There are several distinct forms found associated in the different deposits. The typical form described above might be considered a distinct species if it did not occur with numerous intergrades of other forms which closely approach A. rugulosa normalis. A constant differentiating character between all these specimens of annosa and normalis is the very weak, oblique, deeply situated columellar fold of the former. Some of the specimens of annosa at first glance seem to belong to the subgenus Cyclamastra but the embryonic whorls are less convex than those of any species of this subgenus.” [1]
*********************
References:
[1] C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917
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Photo from: ‘C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917’
The Channeled Newcombia Snail was described in 1905, it was restricted to the easternmost part of Moloka’i, Hawaiian Islands.
The author gave some information about the live animal.:
“Animal when extended in motion as long as the shell. Mantle slate color, margined with brown. Foot light slate, studded on the sides and head above with spots of deeper shade. Tentacles short and slender, dark slate.” [1]
***
The species is now considered extinct.
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 22: Achatinellidae. 1912-1914
*********************
Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 22: Achatinellidae. 1912-1914′
The Keeled Lantzia Snail was described in 1872; it is (or probably was) restricted to a single locality on the island of Réunion in the Indian Ocean.
The species inhabited wet moss that grew along a waterfall in the interior of the island at an elevation of 1200 to 1300 m above sea level.
The Keeled Lantzia Snail was thought to have gone extinct sometimes during the early 19th century but was rediscovered in 199; however, it seems to have disappeared again and is now most likely indeed extinct.
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Depiction from: ‘F. P. Jousseaume: Description de quatre mollusques nouveaux. Revue et magasin de zoologie pure et appliquée, series 2(23): 5-15. 1872’
The Achatinella-like Galapagos Snail was described in 1850.
“There is no doubt that N. achatellinus is one of the rarer Galápagos land snails. It is of special interest because of its superficial resemblance to certain species of Hawaiian tree snails of the genus Achatinella. Also, its straight-sided, conical shape, its non-impressed, nodulose sutures, and its relatively bright color pattern set it apart from any other known species of Naesiotus from the Galápagos Islands or from the South American mainland.” [2]
The species was found first on Island San Cristóbal in the early 1830s and in 1846; in 1868, it was apparently also found on Isla Española.
The shells reach sizes of about 1,2 to 1,6 cm in height, they are: “perforated, ovate-pyramidal with long, conic spire, rather thin; variously colored, being banded with chestnut on an olivaceous or whitish ground, or chestnut below, white above, always with a white line below the suture; surface smooth and glossy, like an Achatinella with slight growth-wrinkles and an impressed band below the suture, pinched up into tubercles at irregular intervals.” [1]
***
The Achatinella-like Galapagos Snail disappeared from Isla Española at an unknown date and was last seen on Isla San Cristóbal in the 1980s; it is now most likely extinct.
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 11: American Bulimulidae: Bulimulus, Neopetraeus, Oxychona, and South American Drymaeus. 1897-1898 [2] Allyn G. Smith: New record for a rare Galápagos land snail. Nautilus 85(1): 5-8. 1971
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 11: American Bulimulidae: Bulimulus, Neopetraeus, Oxychona, and South American Drymaeus. 1897-1898’
The shells reach sizes of about 1,75 cm in length; they are subperforate, subfusiform, slender, smooth, glossy coffee-colored and bear a white band at their suture. [1]
The species was not found during recent searches and might well be extinct. [2]
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 16: Urocoptidae, Achatinidae. 1904 [2] Gary Rosenberg; Igor Muratov: Status Report on the Terrestrial Mollusca of Jamaica. Proceedings of the Academy of Natural Sciences of Philadelphia 155: 117-161. 2006
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 16: Urocoptidae, Achatinidae. 1904’
This snail is known from a single specimen that was collected in 1991 during excavations at Anakena at the north coast of Rapa Nui. [1]
The Rapa Nui taxon was certainly an endemic species that is now extinct.
*********************
References:
[1] Patrick V. Kirch; Carl C. Christensen; David W. Steadman: Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae). Pacific Science, 63: 105–122. 2009
The Julimes Tryonia was discovered in 1991 and subsequently described in 2011.
The species was endemic to its type locality, a warm spring complex along the east side of the Río Conchos, where it formerly was very abundantly found in water with a temperature of about 44°C on hard substrate and in detritus which it apparently also fed upon.
The shells eached sizes of about 0,2 cm.
The only known habitat of the Julimes Tryonia was found excavated and draglined in 2001, no individual could be detected and the species is presumed extinct. [1]
*********************
References:
[1] Robert Hershler; Hsiu-Ping Liu; J. Jerry Landeye: New species and records of springsnails (Caenogastropoda: Cochliopidae: Tryonia) from the Chihuahuan Desert (Mexico and United States), an imperiled biodiversity hotspot. Zootaxa 3001: 1-32. 2011
The Concealed Helicostyla Snail was described in 1841.:
“Imperforate, ovate-oblong, solid; yellowish, ornamented with two bands and a basal area of chestnut, veiled with a whitish hydrophanous cuticle. Spire conic, apex obtuse. Whorls 6, scarcely convex, the last about equal to three-sevenths the entire length. Columella nearly straight, slightly dilated, rose-white; aperture oval, milk-white within; peristome somewhat thickened, narrowly reflexed, brown-edged.” [1]
This species is apparently restricted to the Camotes Islands east of Cebu Island, Philippines; it is possibly extinct now.
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second series: Pulmonata. Vol 8: Helicidae – Volume VI. 1892
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second series: Pulmonata. Vol 8: Helicidae – Volume VI. 1892’
The Kaipaupau Amastra Snail was described in 1911, as far as I understand, it is known from a single specimen that was collected at a place named Kaipaupau, which may actually be the area around the Kaipapa’u Waterfall near the northeastern coast of O’ahu, Hawaiian Islands.
***
… from the description.:
“The shell is short, subperforate, thin, with straightly conic spire and convex whorls, the last quite rotund; dull purplish-brown, the thin cuticle yellowish on theearly whorls. Embryo finely striate; later whorls with fine, irregular sculpture of growth-wrinkles. Aperture purplish within, the lip very narrowly thickened. Columnellar lamella thin, its lower edge subhorizontal. …. Near The above, yet with narrower, straightly conic spire and more convex whorls. ….” [1]
The shell has a length of 1,1 cm and reaches 0,7 cm in diameter.
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
*********************
Depiction from: ‘ George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
This species was described in 1942, it apparently was restricted to the Congo River, where it inhabited crevices among rocks in swiftly flowing water near the town of Matadi in the Democratic Republic of the Congo.
The shells reach sizes of about 1,2 cm in height.
***
The species is considered extinct, however, I didn’t find any additional information about thus assumption.
The Lake Prespa Mudsnail was described in 1973, it was apparently endemic to Lake Prespa, an quite ancient lake that is located between Albania, Greece, and Macedonia.
There are no recent records of this species and it is believed to be possibly extinct.
***
Another species of that genus, which was also presumed extinct, was rediscovered in 2013. [1]
*********************
References:
[1] Magdalena Szarowska; Sebastian Hofman; Andrzej Falinokski: Vinodolia fiumana Radoman, 1973 (Caenogastropoda: Rissoidea): rediscovery and relationships of a species presumed extinct. Folia Malacologica 21(3): 135-142. 2013
The Radiate Anoma Snail was described in 1853, originally as a subspecies of another species, Mauger’s Anoma Snail (Anoma maugeri Wood); it occurred near Bog Walk, a small town in the Saint Catherine Parish in southeast Jamaica.
The species was well distinguishable from related species by its fusiform shape, the finely plicate surface, the strong basal angle, the absense of bands or streaks, and the small, oblique, angular aperture. [1]
The Radiate Anoma Snail is now likely extinct.
*********************
References:
[1] Gary Rosenberg; Igor Muratov: Status Report on the Terrestrial Mollusca of Jamaica. Proceedings of the Academy of Natural Sciences of Philadelphia 155: 117-161. 2006
*********************
Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 16: Urocoptidae, Achatinidae. 1904’
The Giant Paua Snail is known only from subfossil shells that had been found in the Waikato region in the northern part of the North Island of New Zealand.
The shells could grow to a size of about 5 cm, that means the snails body might have reached lengths of about 15 cm.
The species very likely was among the first that were extirpated by the rats that had been imported by the first Polynesian settlers in the 13th century.
This form, described in 1920, was restricted to the island of Lana’i, Hawaiian Islands.
“Specimens from Lanai differ slightly from the Molokai form. The shells are slightly smaller, more conical in outline, tapering more gradually towards a somewhat acute summit; they are darker colored and with the pale zone only indicated near the aperture. There are 16 to 18 ribs on the last whorl; the embryonic whorls, under a strong lens, are distinctly, spirally striate; the columellar fold enters obliquely, is short, almost nodule-like when viewed above, and there is usually a minute basal fold, situated deep within. Length 2.5, diam. 1.5, apert. 0.92 mm.; 5 1/2 whorls.” [1]
***
According to a study from the year 2018, all Hawaiian species of this genus are now sadly extinct. [2]
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second Series: Vol.25, Pupillidae (Gastrocoptinae, Vertigininae) 1918-1920’
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second Series: Vol.25, Pupillidae (Gastrocoptinae, Vertigininae) 1918-1920 [2] Norine W. Yeung; Kenneth A. Hayes: Biodiversity and extinction of Hawaiian land snails: how many are left now and what must we do to conserve them – a reply to. Integrative and Comparative Biology 58(6): 1157-1169. 2018
The Towered Leptachatina Snail was described in 1856; it was apparently restricted to a small area named Lihue near the southern foots of the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands.
The shells reach sizes of about 0.9 cm; they are translucent dark corneous and finely striated. [1]
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
This species was described in 1931; it is known from at least two specimens that were found along the so-called Olokeke trail (a place that I cannot trace) on the island of Kaua’i, Hawaiian Islands; the specimens, when found, had only been dead for a short time.
The shells must have reached heights of up to 3.8 cm, maybe more. [1]
*********************
References:
[1] C. Montague Cooke Jr.: The land snail genus Carelia. Bishop Museum Bulletin 85: 1-97. 1931
The Temao Mautodontha Snail was described in 2014, it is known only from subfossil material that was found near the port of Temao on the island of Makatea in the Tuamotu Archipelago.
The shells are less than 0,3 cm in diameter; they are depressed, white and bear no markings at all. [1]
*********************
References:
[1] André F. Sartori; Olivier Gargominy; Benoît Fontaine: Radiation and decline of endodontid land snails in Makatea, French Polynesia. Zootaxa 3771(1): 1-68. 2014
The shells reach sizes of about 1,9 cm in height; they are glossy yellow, green, olive or chestnut, often banded with green or chestnut; the extremely color patterns were already mentioned by the species’ author.:
“The colouring of this species is extremely variable; there is, however, but one prevailing idea in its manner of distribution. The columella is of a livid purple-rose in all the varieties.” [1]
“This is one of the most common shells met with on Oahu, and passes through numerous slight variations, which have led to their description as distinct species.” [1]
***
The species was last found in 1965 along the slopes of the Pu’u ‘ohi’a (Mt. Tantalus); it is now considered extinct. [2]
************************
References:
[1] E. W. Thwing: Reprint of the original descriptions of the genus Achatinella. Bishop Museum Occasional Papers 3(1): 1-196. 1907 [2] Recovery Plan for the O’ahu Tree Snails of the genus Achatinella. U.S. Department of the Interior Fish and Wildlife Service. Region One, Portland, Oregon. April 1993
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Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914′
The Rimatara Australdonta Snail was described in 1976; it is known from about 12 specimens that were collected near Anapoto, a village in western Rurutu on the Austral Islands.
The shells reach sizes of 0.29 to 0.32 cm; they are light yellow horn-colored with rather broad, irregular, reddish flammulations that fade out on the shell’s base.
*********************
References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
Pilsbry’s Samoana Snail was described in 2016, it is known from several specimens that were collected in 1923 on the island of Fatu Hiva in the Marquesas.
The species lived an arboreal life and was usually found on the leaves of puarata (Metrosideros collina (J. R. Forst. & G. Forst.) A. Gray).
The shells are: “Light brown with some streaking, sometimes a faint narrow brown peripheral band, usually with a white subsutural band caused by decortications. A few bicolorous: light brown with wide supraperipheral white band but this is due to decortication, not pigmentation. A very uniform species.” [1]
We also have some information about the appearance of the animals themselves.:
“Mantle in juveniles is blackish with white maculae, becoming white with black threads and finally fully white in adults ….” [1]
***
Pilsbry’s Samoana Snail is now considered extinct.
*********************
References:
[1] Justin Gerlach: Icons of Evolution: Pacific Island Tree-Snails of the Family Partulidae. Phelsuma Press 2016
This species, described in 1845, was restricted to the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands.
The type specimens appear to have been destroyed and C. Montague Cooke, while assigning some specimens to Jesse Wedgwood Mighels’ description, writes the following statement.:
“It is with some hesitation that I refer shells to this species. Mighel’s description is incomplete and the types were probably lost in the fire which destroyed part of his collection as no trace can be found of this species. … My specimens are slightly larger than Mighel’s measurements and have an additional whorl. The measurements of an average specimen are: Length 7.0, diam. 2.3, alt. of ap. 2.3 mm.” [1]
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
Linear Truncatellina Snail (Truncatellina linearis)
This species was endemic to the island of Madeira, where it is known already from Middle Pleistocene deposits, it survived until the 1950s. [1]
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References:
[1] Glenn A. Goodfriend; R. A. D. Cameron; L. M. Cook: Fossil evidence of recent human impact on the land snail fauna of Madeira. Journal of Biogeography 21: 309-320. 1994
Yellow-tipped Oahu Tree Snail (Achatinella apexfulva)
The tree snails of the genus Achatinella are only found on the island of O’ahu in the Hawaiian archipelago; 41 species are currently accepted, of which about 20 may still survive.
All species inhabit trees and shrubs where they feed on fungi by scraping them from the surfaces of leaves or trunks; the snails are hermaphroditic and give birth to live young, however, only to a few each year. The snails can live to about ten years or even more, the growth rate is very low, and they reach maturity only with about six years.
The tree snails are very vulnerable to loss of individuals through over-collecting, but also to habitat destruction and especially to the introduction of predators like rats, or more recently the snail-eating Rosy Wolfsnail (Euglandina rosea (Férussac)). [1]
***
The Yellow-tipped Oahu Tree Snail was indeed the first member of its genus to reach Europe – as part of a shell lei, given by native Hawaiians to George Dixon, a British ship captain in 1786, and to be scientifically described – in 1789.
The species was restricted to some of the ridges of the Ko’olau Mountains, where it was last found in 1985. [1]
The shells reach sizes of about 1,9 cm in height; they are dextral or sinistral and are quite variably colored; the embryonic whorl might be yellow, the following whorls are blackish brown to chestnut-colored, sometimes with some whitish streaks and spiral lines; the narrow suture is light-edged; the moderately thickened lip is flesh- to salmon-colored while the columellar fold is nearly white; the aperture is bluish white within. [1]
***
The species was last seen in the wild at the Poamoho Trail and was considered extinct in the wild since then; a little captive population (brought into captivity in 1997) was all that was left of this species. This population, however, did not breed and finally was down to a last surviving individual.
This individual, named George (see photo below), died today (1. January 2019) at the age of 14 years, an exceptional age for an invertebrate species. [2]
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References:
[1] Recovery Plan for the O’ahu Tree Snails of the genus Achatinella. U.S. Department of the Interior Fish and Wildlife Service. Region One, Portland, Oregon. April 1993 [2] Jacina Bowler: Lonely George – A Hawaiian Tree Snail – Has Died, Taking His Species With Him. Science Alert January 9, 2019
Hatai’s Boninea Snail was described in 1973 on the basis of (sub)fossil shells that were recovered from deposits on the island of Minaijima in the Ogasawara archipelago, Japan.
The shells reach heights of about 1.3 cm; they are light brown, fusiform in shape with a highly conical spire of seven whorls and differ from those of their living relatives by being solid with a conical elevated spire and a large blunt apex. [1]
The species very likely disappeared before any humans set foot on the island caused by naturally occurring climatic changes.
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References:
[1] Tadashige Habe: Fossil land snails from Minami-jima, Bonin Islands. Science Reports of the Tohoku University, Special Volume 6 (Hatai Memorial Volume): 51-53. 1973
This species was described in 1939; it was found near the city of Ra’s al-‘Ain in a series of karst springs in northern Syria that form the main spring of the Khabour River, which again is a tributary of the Euphrates River. [1]
The water situation in the region is dramatic and the type locality has fallen dry; in fact, the snail species was never found again since its description and is quite certainly extinct.
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References:
[1] Joseph Heller; Peter Mordan; Frida Ben-Ami; Naomi Sivan: Conchometrics, systematics and distribution of Melanopsis (Mollusca: Gastropoda) in the Levant. Zoological Journal of the Linnean Society 144: 229-260. 2005
The Girded Leptachatina Snail was described in 1845; it is known to have inhabited parts of the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands.
The shells reach heights of about 0.6 to 0.7 cm; they are “dextral, conical, horn color, smooth, polished, imperforate; whorls six, convex, with an impressed revolving line just below the suture; aperture semiovate; lip simple acute.” [1]
***
Note: This species is very often found under the name Leptachatina accineta (Mighels), which is a writing error.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
The Thyreus Snail was described in 1852; it was known from several places in the Nilgiri Mountains in southern India.
The shells on average reach sizes of about 3,5 cm in diameter; they are of a horny brown color and often have a narrow dark rufous band below the subangulate periphery.
The species is now considered possibly extinct. [1]
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References:
[1] Robert H. Cowie; Claire Régnier; Benoît Fontaine; Philippe Bouchet. Measuring the Sixth Extinction: what do mollusks tell us? The Nautilus 131(1): 3-41. 2017
The Woven Amastra Snail was described in 1824, it appears to have been quite widespread around the center of southern O’ahu, Hawaiian Islands and indeed has repeatedly been described independently by several authors under a bunch of different names.
The shells are quite variable and reach sizes of 1,25 to 1,8 cm in heigth and 0,8 to 0,95 cm in diameter. [1]
At least three distinct subspecies have been described.
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘ George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
The Duncan Island Snail was described in 1893, it is restricted to the Isla Pinzón (aka. Duncan Island) in the Galapágos archipelago.
“Except the largest specimens of B. nux, these shells are the largest Bulimuli described from the islands.” [1]
The shells reach sizes of about 1,8 cm in height and about 1,1 cm in diameter. [1]
***
The species was never observed alive and is known exclusively from empty shells, thus it certainly was already extinct before it was scientifically described; it probably fell victim to a severe drought. [2]
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 11: American Bulimulidae: Bulimulus, Neopetraeus, Oxychona, and South American Drymaeus. 1897-1898’ [2] Guy Coppois; Sue Wells: Threatened Galápagos snails. Oryx 21(4): 236-241. 1987
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 11: American Bulimulidae: Bulimulus, Neopetraeus, Oxychona, and South American Drymaeus. 1897-1898’
Jacquinot’s Libera Snail was described in 1850; its actual place of origin was not known until 2018, when subfossil shells were recovered from archaeological sites on the island of Mo’orea, Society Islands.
The shells reach sizes of 0.75 to 0.92 cm, making it very large for a member of its family; they ae faint yellowish white, with irregular, zigzag, reddish flammulations above, absent from the base of the shells; the umbilicus is small and strongly constricted by the diagonal inward growth of the last whorls.
Jacquinot’s Libera Snail is now extinct.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second series: Pulmonata. Vol 3: Helicidae – Volume I. 1887’
(public domain)
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References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976 [2] C. C. Christensen; J. G. Kahn; P. V. Kirch: Nonmarine Mollusks from Archaeological Sites on Mo‘orea, Society Islands, French Polynesia, with Descriptions of Four New Species of Recently Extinct Land Snails (Gastropoda: Pulmonata: Endodontidae). Pacific Science 72(1): 95-123. 2018
This species was described in 2014 on the basis of subfossil specimens that were recovered from a large, shaded fault in the limestone cliff at the eastern shore of Makatea, Tuamotu Archipelago.
The shells reach sizes of less than 0.5 cm in diameter; they are depressed, white to fawn-colored and usually worn and thus without markings, however, some specimens show traces of faint, regularly spaced, amber-colored flammulations; the umbilicus is U-shaped.
The species, like so many other Polynesian gastropods, is now extinct.
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References:
[1] André F Sartori; Olivier Gargominy; Benoît Fontaine: radiation and decline of endodontid land snails in Makatea, French Polynesia. Zootaxa 3772: 1-68. 2014
The Gracile Anoma Snail was described in 1851, apparently based on empty shells; it seems that the species was already extinct at that time.
The species is endemic to the island of Jamaica, an exact locality, however, seems not to be known.
The shells are quite slender; they are pearl-white with a pure white keel and lip, they are coarsely striated at the end of the last whorl and bear excessively minute stirae otherwise. [1]
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 16: Urocoptidae, Achatinidae. 1904
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Depiction from: ‘Louis Pfeiffer: Die Gattung Cylindrella Pfr.: in Abbildungen nach der Natur. Nürnberg: Verlag von Bauer und Raspe, Julius Merz 1862’
Thaanum’s Amastra Snail was described in 1911, it was restricted to a place named Ka’a’awa in the Koʻolauloa District on the northeastern coast of O’ahu, Hawaiian Islands.
The species was described on the basis of a single living specimen and several dead shells.
… from the description.:
“The shell is sinistral, imperforate, moderately solid, oblong, having a somewhat silky luster. Spire widely conic with somewhat convex outlines and rather obtuse summit. Embryonic whorls marked with faint, very fine growth-striae only; later whorls distinctly striate obliquely, the striae fine and somewhat thread-like. Upper whorls purplish-brown ith irregular whitish streaks, the last two whorls covered with a rich dark chestnut cuticle, yellowish next the suture, and deciduous in front of the aperture, showing a glossy light green under layer. Aperture rather oblique, livid or bluish white whithin, with a whitish callous rim within the dark-edged lip. Columella short, bearing a strong, triangular, downward-bent lamella. Parietal callus thin.“
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘ George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
This species was described in 1872; it was endemic to a single (unknown) valley on the island of Rarotonga, Cook Islands and was described by its author as: “A somewhat rare species, easily known by its wide open umbilicus, few whorls, deep uniform brown color, and plicate striae. On the ground in damp woods, and only noticed in a single valley.“. [1]
The shells reach sizes of about 0,49 cm in diameter; they are: “Widely, perspectively umbilicated, thin, shining, subpellucid, uniform dark brown, closely, obliquely, arcuately, plicately striate, more slightly below, suture channeled; whorls 4 1/2, convex, rapidly increasing, the last deflected above, convex below.” [2]
The species is now extinct.
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References:
[1] Andrew J. Garrett: Descriptions of new species of land and fresh-water shells. American Journal of Conchology 7: 219-230. 1872
[2] G. W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second Series: Pulmonata Vol. 3, Helicidae Vol. 1. 1887
[3] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part II, Families Punctidae and Charopidae, Zoogeography. Field Museum of Natural History Chicago, Illinois 1983
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Depiction from: ‘G. W. Tryon; Henry A. Pilsbry; a. o.: Manual of Conchology. Second Series: Pulmonata Vol. 3, Helicidae Vol. 1. 1887’
The Graceful Laminella Snail was described in 1845, it was found in the Mapulehu Valley near the southeastern coast of Moloka’i, Hawaiian Islands.
This species differs from the congeneric Alexander’s Laminella Snail (Laminella alexandri (Newcomb)) and the Depicted Laminella Snail (Laminella depicta (Baldwin)) by its more swollen last whorl and the sunken black markings, which are generally coarser than in L. depicta and which do not form the characteristic patterns.
The shells reach sizes of about 1,35 cm in heigth and 0,62 to 0,73 in diameter.
The animal itself is also mentioned in the description.:
“The animal … is slender, body flesh-color with black puncta down the sides; tentacles very black. When extended, two-thirds as long as the shell.” [1]
***
The Graceful Laminella Snail has three additional color morphs assigned to it, orginally described as varieties, which in fact may well be distinct subspecies: var. muscaria Hyatt & Pilsbry, var. orientalis Hyatt & Pilsbry, var. semivestita Hyatt & Pilsbry. [1]
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
in which we can trace the exact course of their extinction.
***
The species was described in 1847, it was restricted to a single relict site, Lake Pețea, a thermal lake with a water temperature of around 42 °C near the town of Oradea in north-western Romania.
The lake is situated above a rich geothermal aquifer, which is known since ancient times, the thermal water has been used to heat a public bath and several houses in the area. It is home to several endemic plant- and animal forms and was declared a nature reserve in 1932. With the beginning of the 2000s the site was found to be heavily polluted with litter; in 2011, the thermal underwater spring suddenly ceased its activity, resulting in an abrupt reduction of the water level and the surface area and in 2015, the lake was reduced to a small pond due to the overexploitation of the thermal aquifer.
In an effort to save the Lake Petea Snail from extinction, several individuals were brought into captivity; in the beginning these individuals reproduced but after some time they began to suffer from a high mortality, and the last surviving snails were finally sent to specialists, but without any success – the species is now extinct. [1]
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References:
[1] Ioan Sîrbu; Adrian Gagiu; Ana Maria Benedek: On the brink of extinction: Fate of the Pețea thermal lake (Romania) and its endemic species. Tentacle 21: 34-37. 2013
[2] Thomas A. Neubauer; Mathias Harzhauser; Elisavet Georgopoulou; Claudia Wrozyna: Population bottleneck triggering millenial-scale morphospace shifts in endemic thermal-spring melanopsis. Paleogeography, Paleoclimatology, Paleoecology 414: 116-128. 2014
[3] Ioan Sîrbu; Ana Maria Benedek: Requiem for Melanopsis parreyssii or the anatomy of a new extinction in Romania. Tentacle 24: 26-28. 2016
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Photo from: ‘Thomas A. Neubauer; Mathias Harzhauser; Elisavet Georgopoulou; Claudia Wrozyna: Population bottleneck triggering millenial-scale morphospace shifts in endemic thermal-spring melanopsis. Paleogeography, Paleoclimatology, Paleoecology 414: 116-128. 2014’
Rice’s Amastra Snail was described in 1917, apparently based on only five recently dead specimens, it was restricted to a small part of the Miloli’i Valley near the northwestern coast of Kaua’i.
The shells reached sizes of about 2,4 cm in heigth and 1,2 to 1,3 cm in diameter.
***
The author of the species also described a variety, named as var. armillata, from the same locality, based on two dead specimens (empty shells) which may be of Pleistocene age or may just have been old surface shells.
This variety differs from the normal form in the following way …:
“… the fourth and fifth whorls are slightly swollen, and the surface is more coarsely but not as closely sculptured with growth-wrinkles. The periphery is distinctly carinated on the last whorl; the carina is margined along its upper edge by a deep narrow sinus. The lower halff of the last whorl descends rather rapidly, with the carina appearing slightly above the suture. The outer margin of the aperture is distinctly modified by the carina. The upper portion being flattened, the lower evenly arched. The columellar fold is weak, thread-like, very oblique and deeply situated.” [1]
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References:
[1] C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917
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Depiction from: ‘ C. Montague Cooke: Some new species of Amastra. Bishop Museum Occasional Papers 3(3): 1-34. 1917’
The Ribbed Slitshell was described in 1860, like all members of this genus, it was endemic to the Coosa River in Alabama, USA, it died out after the impoundment of the river system in the early 20th century.
The Minute Samoana Snail was described in 1857, it was endemic to the island of Fatu Hiva in the Marquesas.
The species was originally considered very abundant and widespread but was found to be restricted to the Teavapuhia Valley in 1995; it was not found subsequently and is now considered extinct. [1] *********************
References:
[1] Justin Gerlach: Icons of Evolution: Pacific Island Tree-Snails of the Family Partulidae. Phelsuma Press 2016
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second Series: Pulmonata Vol. 20, Caecilioides, Clessula and Partulidae. Index to Vols. 16-20. 1909-1910’
The Beautiful Leptachatina Snail was described in 1911; it was inhabiting the slopes of the Wai’anae Mountains on the island of O’ahu, Hawaiian Islands where it was found in open country at the base of small ferns.
The shells reach heights of about 0.83 cm; they are somewhat glossy, the spire and the upper part of the last whorl are light brown, the base is darker brown with a dark brown band accompanying the sutures.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
Rapa Nui Helicinid Land Snail (Helicinidae gen. & sp.)
This taxon is known so far only from a single apical fragment of a shell that was found during excavations at Anakena at the north coast of Rapa Nui in 1991.
Despite its fragmented character it could at least be assigned to the family Helicinidae which is widely distributed in the Pacific region, occuring on all higher islands. [1]
The Rapa Nui Helicinid Land Snail was certainly endemic to the island.
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References:
[1] Patrick V. Kirch; Carl C. Christensen; David W. Steadman: Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae). Pacific Science, 63: 105–122. 2009
This species was described in 1872, known only by subfossil shells that look quite fresh, however, so it might have become extinct quite recently or might turn out to be still alive.
This species was endemic to the island of Hawai’i, Hawaiian Islands.
The shells reach heights of about 0.5 cm; since they are only known based on subfossil remains, the original color is not known.
“A small species unlike anything from Hawaii. … The surface is minutely and very closely striate with lines of growth. This species is rather abundant in the fossil deposits explored by Dr. Henshaw in Mana.“
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
This species was described in 1907; it is restricted to the Ogasawara Islands, Japan.
I could not yet find any additional information, and the species is mentioned here only because of the fact that its name appears in listings of extinct life forms.
The Fleece Landsnail was endemic to the island of Mahé in the Seychelles; it was specialized to the moist forests on the summits of the north-western part of the island.
The species disappeared sometimes around 1994 after invasive plants began altering its habitat, especially Cinnamon Trees (Cinnamomum verum J. Presl) and Vanilla Orchids (Vanilla planifolia Andrews) which now cover large areas of former native forest.
Predation by the introduced and invasive Tailless Tenrec (Tenrec ecaudatus (Schreber)) very likely also plays a role – many snail shells are found with conspicuous bite marks caused by this small mammal.
***
The reason for this species’ extinction is often said to be due to hybridization with a congeneric species from lower elevations, the Black Landsnail (Pachnodus niger (Dufo)); however, this assumption turned out to be wrong and the putative hybrids were found to be a completely distinct species.
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Depiction from: ‘Christian R. Altaba: Extinction through Climate Change: Review of Evidence and Analysis of Two Land Snails from the Seychelles Islands. Preprints 2022, 2022100315. https://doi.org/10.20944/preprints202210.0315.v1’
[1] Justin Gerlach: Red Listing reveals the true state of biodiversity: a comprehensive assessment of Seychelles biodiversity. Phesluma 20: 9-22. 2012 [2] Christian R. Altaba: Extinction through Climate Change: Review of Evidence and Analysis of Two Land Snails from the Seychelles Islands. Preprints 2022, 2022100315. https://doi.org/10.20944/preprints202210.0315.v1
This species was described in 1900; it is known from the slopes of Mt. Ka’ala, the highest mountain of the island of O’ahu, Hawaiian Islands.
The shells reach heights of about 0.78 cm; According to the species’ author it is “a brownish horny, pyramidal shell which has no striking characters.“.
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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911’
(public domain)
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References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911
This species was described in 2009, it was described based on subfossil shells that were collected from the Waipoli Dune fossil deposit on the island of Kaua’i, Hawaiian Islands. The age of these deposit is not known but is most likely Late Pleistocene/Early Holocene.
The shells of this species reached sizes of 2,49 cm, making it one of the largest species in its genus. [1]
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References:
[1] Mike Severns: A new species of newcombia from the Pleistocene of Kaua’i, Hawaiian Islands, USA (Gastropoda, Pulmonata, Achatinellidae). Basteria 73: 57-60. 2009
