Stomion is one of three speciose and taxonomically difficult genera of flightless Darwin's darkling beetles of the Galápagos Islands. The previously named species and subspecies of Stomion are analysed by morphometric and cladistic methods. Eleven species are here recognized, which probably descended from colonization by a single ancestral species. Cladistic analysis yielded two weakly supported clades that are different from previously published morphological and allozyme genotype groups. Phenotypic and genotypic characters may be evolving independently. There is much within-species variation, but there is no compelling evidence of adaptive radiation in Stomion, in contrast to that in the famous Darwin's finches. The analyses show the need for changes in morpho-species taxonomy: S. punctipennis Van Dyke (syn. nov.) is elevated to full species from a subspecies of S. galapagoensis Waterhouse. There is no evidence to support the validity of: S. laevigatum santacruzensi Franz (syn. nov.), synonomized here under S. l. laevigatum Waterhouse; S. galapagoensis leleupi Kaszab (syn. nov.), synonomized here under S. linelli Blair; S. galapagoensis pinzoni Franz (syn. nov.), synonomized here under S. obesum Van Dyke. S. genovesa sp. nov. is described from Genovesa Island. Lectotypes are designated for S. galapagoensis Waterhouse, S. laevigatum Waterhouse and S. helopoides Waterhouse.

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Zoological Journal of the Linnean Society
Department of Biology

Finston, T.L. (Terrie L.), & Peck, S. (2004). Speciation in Darwin's darklings: Taxonomy and evolution of Stomion beetles in the Galápagos Islands, Ecuador (Insecta: Coleoptera: Tenebrionidae). Zoological Journal of the Linnean Society, 141(1), 135–152. doi:10.1111/j.1096-3642.2004.00115.x