Fleece Landsnail (Pachnodus velutinus)

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.

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

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

References:

[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

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

edited: 29.01.2024