Evaluating hypotheses on the origin and diversification of the ringneck snake Diadophis punctatus (Colubridae: Dipsadinae)
Article first published online: 30 OCT 2009
© 2009 The Linnean Society of London
Zoological Journal of the Linnean Society
Volume 158, Issue 3, pages 629–640, March 2010
How to Cite
FONTANELLA, F. and SIDDALL, M. E. (2010), Evaluating hypotheses on the origin and diversification of the ringneck snake Diadophis punctatus (Colubridae: Dipsadinae). Zoological Journal of the Linnean Society, 158: 629–640. doi: 10.1111/j.1096-3642.2009.00554.x
- Issue published online: 26 FEB 2010
- Article first published online: 30 OCT 2009
- Received 30 May 2008; accepted for publication 27 November 2008
Close affinities recognized between taxa in Mexico and the contiguous USA have led to a variety of biogeographical scenarios. One such hypothesis suggests that species that occur in both countries have an origin in central Mexico followed by dispersal into the USA. This study expands upon previous phylogeographical work of the ringneck snake Diadophis punctatus by incorporating new data from previously unsampled areas appropriate to critically assess hypotheses regarding a Mexican origin for this species. Maximum likelihood and maximum parsimony analyses inferred a derived position for the lineage from southern Mexico with constraint tests for alternate evolutionary hypotheses resulting in significantly worse likelihood values. Ancestral area reconstructions inferred an origin for D. punctatus in the south-eastern USA followed by a south-east to north-east then westward directionality of historical migration. The position within the phylogeny and date estimate for the south-western + Mexico clade suggests a recent invasion into central Mexico with expansion into the Nearctic/Neotropic transition zone. The extensive lineage diversity inferred from the mtDNA suggests that the genus is a complex of cryptic species whose conservational status should be re-evaluated on both the national and regional levels.
© 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 629–640.