Phylogeny and Systematics of the Rauvolfioideae
PHYLOGENY AND SYSTEMATICS Andre´ O. Simo˜es,2 Tatyana Livshultz,3 Elena OF THE RAUVOLFIOIDEAE Conti,2 and Mary E. Endress2 (APOCYNACEAE) BASED ON MOLECULAR AND MORPHOLOGICAL EVIDENCE1 ABSTRACT To elucidate deeper relationships within Rauvolfioideae (Apocynaceae), a phylogenetic analysis was conducted using sequences from five DNA regions of the chloroplast genome (matK, rbcL, rpl16 intron, rps16 intron, and 39 trnK intron), as well as morphology. Bayesian and parsimony analyses were performed on sequences from 50 taxa of Rauvolfioideae and 16 taxa from Apocynoideae. Neither subfamily is monophyletic, Rauvolfioideae because it is a grade and Apocynoideae because the subfamilies Periplocoideae, Secamonoideae, and Asclepiadoideae nest within it. In addition, three of the nine currently recognized tribes of Rauvolfioideae (Alstonieae, Melodineae, and Vinceae) are polyphyletic. We discuss morphological characters and identify pervasive homoplasy, particularly among fruit and seed characters previously used to delimit tribes in Rauvolfioideae, as the major source of incongruence between traditional classifications and our phylogenetic results. Based on our phylogeny, simple style-heads, syncarpous ovaries, indehiscent fruits, and winged seeds have evolved in parallel numerous times. A revised classification is offered for the subfamily, its tribes, and inclusive genera. Key words: Apocynaceae, classification, homoplasy, molecular phylogenetics, morphology, Rauvolfioideae, system- atics. During the past decade, phylogenetic studies, (Civeyrel et al., 1998; Civeyrel & Rowe, 2001; Liede especially those employing molecular data, have et al., 2002a, b; Rapini et al., 2003; Meve & Liede, significantly improved our understanding of higher- 2002, 2004; Verhoeven et al., 2003; Liede & Meve, level relationships within Apocynaceae s.l., leading to 2004; Liede-Schumann et al., 2005). the recognition of this family as a strongly supported Despite significant insights gained from studies clade composed of the traditional Apocynaceae s.
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