Radiation of the Australian Salicornioideae (Chenopodiaceae)—based on evidence from nuclear and chloroplast DNA sequences

Shepherd, K.A., Waycott, M., and Calladine, A. (2004) Radiation of the Australian Salicornioideae (Chenopodiaceae)—based on evidence from nuclear and chloroplast DNA sequences. American Journal of Botany, 91 (9). pp. 1387-1397.

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In phylogenetic analyses of nuclear ITS and chloroplast trnL DNA sequences, the mostly endemic Australian genera; Halosarcia, Pachycornia, Sclerostegia, Tecticornia, and Tegicornia of the subfamily Salicornioideae (Chenopodiaceae) together form a monophyletic group, congruent with the hypothesis that they evolved from a common ancestor. However, limited genetic differentiation evident in both nrDNA and cpDNA sequences among these taxa suggests a possible rapid radiation. Based on fossil pollen records and climatic models of other authors, it is hypothesized that the expansion of the Australian endemic Salicornioideae most likely occurred during the Late Miocene to Pliocene, when increasing aridity caused the formation of extensive salt lakes along endorheic paleodrainage channels. Moreover, Australian Sarcocornia representatives were supported as monophyletic, nested within a paraphyletic Sarcocornia clade that also comprised European Salicornia in the ITS analysis. This suggests that Sarcocornia arrived in Australia subsequent to the ancestor of the Australian endemic genera most likely via long-distance dispersal.

Item ID: 5717
Item Type: Article (Research - C1)
ISSN: 1537-2197
Keywords: Chenopodiaceae; Halosarcia; ITS; phylogeny; rapid radiation; Salicornioideae; trnL
Date Deposited: 22 Dec 2009 23:38
FoR Codes: 06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060399 Evolutionary Biology not elsewhere classified @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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