Ribeira de Joao Gomes Amphorella Snail (Amphorella leacociana)

The Ribeira de Joao Gomes Amphorella Snail was described in 1852; it is known only from a few regions on the island of Madeira, Portugal, where it was found “under stones, very rare“. [1]

The shells reach sizes of about 3.7 in height; they were described as follows.:

“The shell is very small, oblong-turrite, widest near the base, very thin and fragile, subtransparent, yellowish-corneous, glossy, with a very narrow gray subsutural margin edged below with a light line. The spire has slightly convex outlines and obtuse summit. Whorls 5 1/2 slowly widening to the last which descends more rapidly. The aperture is small, piriform, very narrow above. Outer lip thin, strongly arched forward in the middle, deeply excised or retracted to the suture above. Columella rather wide, projecting into the aperture, truncate at base.” [1]

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syn. Achatina leacociana Lowe, Ferussacia leacociana (Lowe)

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This species can also be found named as Amphorella leacockiana (Lowe), which, of course, is wrong.

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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

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edited: 15.02.2024

Grabham’s Amphorella Snail (Amphorella grabhami)

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]

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syn. Ferussacia tornatellina var. grabhami Pilsbry

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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

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edited: 15.02.2024

Madeiran Cylichnidia Snail (Cylichnidia cylichna)

The Madeiran Cylichnidia Snail was described in 1852; it is only known from subfossil material that had been recovered from Middle Pleistocene to Holocene deposits at the Ponta de São Lourenço Peninsula as well as from Caniçal, both in the easternmost part of Madeira. [1]

The species must have survived into the 1950s as the youngest known specimens that were found could be dated to that age; the species thus died out without having ever been seen alive. [2] 

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syn. Achatina cylichna Lowe, Ferussacia cylichna (Lowe)

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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
[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

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edited: 15.02.2024