Tag Archives: Achatinella

Achatinella pupukanioe Pilsbry & Cooke

Oahu Tree Snail (Achatinella pupukanioe)

This species was described in 1914.

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

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’ 

(public domain) 

*********************

edited: 08.06.2021

Achatinella taeniolata Pfeiffer

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’ 

(public domain) 

*********************

edited: 08.06.2021

Achatinella vulpina (Férussac)

Foxy Oahu Tree Snail (Achatinella vulpina)

The Foxy Oahu Tree Snail was described in 1824.

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

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914′

(public domain)

*********************

edited: 06.06.2021

Achatinella apexfulva (Dixon)

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]

*********************

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

*********************

Photo: Brenden Holland
http://portugal.inaturalist.org/people/bholland

(under creative commons license (4.0))
http://creativecommons.org/licenses/by-nc/4.0/

*********************  

edited: 08.06.2021

Achatinella caesia Gulick

Cutted Oahu Tree Snail (Achatinella caesia)

This species was described in 1858.

The shells reach sizes of about 1,8 cm in height; the shining shell is so streaked with white and fawn brown as to have a gray appearance. [1]

The species was already rare in the 1900s and is now considered extinct.

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’

*********************

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

*********************

edited: 07.06.2021

Achatinella rosea Swainson

Rosy Oahu Tree Snail (Achatinella rosea)

The Rosy Oahu Tree Snail was described in 1828, the species inhabited the Helemano- and Poamoho Ridges and adjacent places at the western slopes of the Ko’olau Mountains in eastern O’ahu, Hawaiian Islands.  

The shells reached heights of about 1,9 to 2,2 cm, they are white or pale rosy to strong pink or sometimes brown, unicolored or multicolored striped; many, but yet not all individuals of this species have a strong pink colored shell aperture (mouth).  

We also have some information about the appearance of the actual animal.:

Animal, when young, of a bright straw yellow, with ocular appendages tinged with brown. In the adult, the color is a uniform light gray, with mantle and tentacles dark brown.” [1]

This is also considered some kind of variety or maybe subspecies of the Bulimus-like Oahu Tree Snail (Achatinella bulimoides Swainson).

***

The last record for this species was the sighting of a single individual at the Helemano Ridge in 1949, since then the species is considered extinct. [2]

***

Parts of the former range of the Rosy Oahu Tree Snail are still inhabited today by another tree snail species, Sowerby’s Oahu Tree Snail (Achatinella sowerbyana Pfeiffer) that somehow still manages to survive in the wild.  

*********************

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

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’

(public domain) 

*********************  

edited: 08.06.2021

Achatinella stewartii (Green)

Stewart’s Oahu Tree-Snail (Achatinella stewartii)

Stewart’s Oahu Tree Snail was described in 1827.

The shells reach sizes of about 2,2 to 2,7 cm in height; they are usually very variably colored.:

„… the ground colour is usually greenish or some shade of yellow, sometimes a single blackish coloured band accompanies the suture, sometimes this band is doubled and of different shades, and on many specimens there are two bands, one at the suture and one in the middle of the whorls. In some varieties the base of the body whorl is dark brown, the rest of the shell being of a dark form, and not unfrequently the whole shell is without any markings whatever; in which case the colour is yellow, the aperture, when inverted is ear-shaped, the truncation of the columella is rounded and thickened in a remarkable manner at its edge; along the inner margin of the outer lip there is a strong callous ridge, as in most of the species of this genus, which gradually attenuates towards the edge of the lip, which is this and sharp inside, white and pinkish round the columella.“ [1]

***

The species was last found in 1961 somewhere on the slopes of the Pu’u ‘ohi’a (Mt. Tantalus); it is now 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

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914′

(public domain)

*********************

edited: 09.06.2021

Achatinella phaeozona Gulick

Gray-banded Oahu Tree Snail (Achatinella phaeozona)

The Gray-banded Oahu Tree Snail was described in 1856.

The shells reach sizes of about 2,2 cm in height; They are sinistral and scarcely perforate, oblong-ovate and solid; the apex is subacute and the spire convexly conical; the suture is marginate and moderately impressed; they are glossy white with one to six black or chestnut bands varying in width; the whorls are moderately convex; the strong central columellar fold is white with a dilated, adnate or sometimes slightly detached margin; the aperture is slightly oblique and lunately rounded; the peristome is acute and well thickened within. [1]

***

The species was originally widespread on the island, as is proven by subfossil shells that were recovered from the soil of a coconut plantation near the shore; it was last seen in 1974 in the Ka’alakei Valley near the southeastern coast of O’ahu; it is now considered 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

*********************

Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’

(public domain)

*********************

edited: 08.06.2021

Achatinella casta (Newcomb)

Casta Oahu Tree Snail (Achatinella casta)

The Casta Oahu Tree Snail was described in 1853; it was found in the forests along he ridges north of Pearl Harbor on the island of O’ahu, Hawaiian Islands.

The shells reach sizes of about 1,67 cm in height; they have six whorls, which are rounded and margined above; the simple lip is thickened within and the short columella has a strong plaited brownish tooth; they are glossy white or yellowish with extremely variable transverse bands of brown, pink or white, variously arranged. [1]

***

The species is now considered extinct.

*********************

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′

(public domain)

*********************

edited: 09.06.2021

Achatinella buddii Newcomb

Budd’s Oahu Tree-Snail (Achatinella buddii)

Budd’s Oahu Tree-Snail was described in 1853; it was apparently restricted to the Palolo Valley on the island of O’ahu, Hawaiian Islands.

The shells reach a size of about 2 cm in height; they are yellowish or cinnamon-colored, slate or fawn, the columella and aperture are white. [1]

***

This species appears to have gone extinct shortly after 1900, however, an exact extinction date is not known. [1]

*********************

[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: ‘G. W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914’ 

(public domain)

*********************

edited: 09.06.2021

Achatinella pulcherrima Swainson

Beautiful Oahu Tree Snail (Achatinella pulcherrima)

The Beautiful Oahu Tree Snail was described in 1828.

The shells reached heights of about 1,8 to 2 cm, they are generally deep chestnut and orange colored and was decorated with one to three fulvous, orange, white or yellow bands; the margin of the lip is brown. [1]

***

The Beautiful Oahu Tree Snail was last seen alive in 1974 at a place named Helemano somewhere in the center of O’ahu, Hawaiian Islands. [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′ 

(public domain)

*********************

edited: 08.06.2021