De Ridder’s Galapagos Snail (Naesiotus sp. ‘deridderi’)
This species was described in 1985, its species epithet, however, is a nomen nudum.
De Ridder’s Galapagos Snail occurred in the moister regions of the island of Santa Cruz; the animals apparently had a certain preference for the Arrow-leaved Sida (Sida rhombifolia L.) or the Prickly Sida (Sida spinosa L.), on whose branches they were often found. 
The species was not found alive during the last recent field studies and is feared to be extinct.
One of the few natural enemies of this species was the Woodpecker Finch (Camarhynchus pallidus (Sclater & Salvin)), which is known to occasionally pick up snails from the plants, which it subsequently beats against a twig or the like until the snail’s body detaches from the shell.
The reason for the extinction of so many of the endemic snail species of the Galápagos Islands, however, is mainly due to the destruction of their habitats.
 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
 G. Coppois: Threatened Galapagos bulimulid land snails: an update. In: E. Alison Kay: The Conservation Biology of Molluscs. Occasional Paper of the IUCN Species Survival Commision 9: 8-11. 1995  C. E. Parent; R. P. Smith: Galápagos bulimulids: status report on a devastated fauna. Tentacle 14. 2006
 C. E. Parent; B. J. Crepsi: Sequential colonization and diversification of Galapágos endemic land snail genus Bulimulus (Gastropoda, Stylommatophora). Evolution 60(11): 2311-2328. 2006