Systematics and phylogeography of <I>Cerion sensu stricto</I> (Pulmonata: Cerionidae) from Aruba, Curaçao and Bonaire

Abstract

The systematic relationships of the Cerion uva complex and its constituent taxa are reviewed based on partial sequences of the cytochrome c oxidase I and 16S rDNA genes from 19 populations spanning the geographic range of the species complex and including the type localities of 8 of the 9 subspecies and forms. Molecular data support the conclusion of prior morphometric studies that all living Cerion inhabiting Aruba, Curaçao and Bonaire are members of a single species, C. uva. Sequence variability among and within populations is not sufficiently discontinuous to segregate populations into discrete, species-level taxa. Three of four subspecies, proposed on the basis of geographic isolation during the Quaternary, C. uva uva (Linnaeus, 1758), the nominotypical subspecies from eastern Curaçao, C. uva knipensis Baker, 1924, from western Curaçao, and C. uva bonairensis Baker, 1924, from Bonaire, are all supported by distinctive haplotypes. Cerion uva arubanum Baker, 1924, a taxon based on living specimens from Aruba, is shown to be a synonym of C. uva uva, with which it shares a preponderance of haplotypes. It is conjectured that C. uva was widespread on Aruba during the Quaternary, but had become extinct on that island, and was reintroduced from a population near Willemstad in eastern Curaçao by humans (either by Caquetío Indians or by European settlers) within the past 800 years. Further investigation is needed to determine if Quaternary Aruban Cerion warrant subspecific recognition. On the island of Curaçao, molecular data lend support to the partition of the Cerion fauna into C. uva knipensis, which is confined to an isolated western region, as defined by Baker, and C. uva uva, which inhabits a broad, eastern region that is composed of Baker&#39;s central and eastern regions. A population at Ronde Klip in eastern Curaçao has remained genetically isolated, and retains subspecific status as C. uva diablensis Baker, 1924. A neotype is designated for Turbo uva Linnaeus, 1758, as is necessary to provide an objective standard of reference for this species-group taxon, and for the genus- and family-level taxa based upon it.