The discovery of historically extinct, but hitherto undescribed, species: An under-appreciated element in extinction-rate assessments

Abstract

Estimates of the numbers of species that have become extinct during historic times may need to be reconsidered in view of issues that may not factor highly in academic consciousness. For example, there are (a) species that may have gone extinct since their collection, yet were never described, (b) species now extinct of which there are extant durable remains but that have not yet been collected or described, and (c) organisms that may have been dependent on species that are now extinct. The case of overlooked species that have become extinct in historic times is exemplified by the paper of Richling and Bouchet in this issue of Biodiversity and Conservation. This paper also emphasizes the need for detailed taxonomic study as a foundation for biodiversity conservation. However, as a matter of policy, the journal does not currently include articles with descriptions of novel taxa, but an exception is made here because of the importance of the phenomenon of extinction before description and to stress the role of taxonomy in biodiversity conservation, both being issues not always widely appreciated by conservation biologists and biodiversity scientists. Based on preserved shells, Richling and Bouchet report a radiation of helicinid land snails (nine new species and one previously described), from a group of Pacific islands, with eight of the nine new species and the single previously described species appearing to be extinct. © 2013 Springer Science+Business Media Dordrecht.