Phylogenetic position and generic differentiation of Epithemateae (Gesneriaceae) inferred from plastid DNA sequence data

Abstract

The systematic position and generic differentiation of the morphologically and geographically outstanding tribe Epithemateae (Gesneriaceae) was analyzed using the rbcL/atpB-spacer and trnL-F intron-spacer regions of chloroplast DNA. In our analysis Epithemateae forms a strongly supported monophyletic clade (bootstrap [BS] = 100%; jackknife [JK] = 100%; decay index [DI] = 12) and appears as sister to the rest of the paleotropical Gesneriaceae (= subfamily Cyrtandroideae). The paleotropical Gesneriaceae form a monophyletic group (BS = 88%; JK = 85%; DI = 3) that is sister to the neotropical Gesneriaceae (subfamily Gesnerioideae) plus Austral Gesneriaceae (subfamily Coronantheroideae) (BS = 99%; JK = 98%; DI = 10). Within Epithemateae Rhynchoglossum is sister to the remaining Epithemateae (BS = 97%; JK = 96%; DI = 12), in which Epithema is sister to a clade of two genera: Loxonia/Stauranthera (BS = 68%; JK = 64%; DI = 1), which form, together with Epithema, a sister clade (BS = 85%; JK = 83%; DI = 2) to Whytockia and Monophyllaea. While the support for Loxonia and Stauranthera is moderate, the relationship of Whytockia and Monophyllaea is very strongly supported (BS = 100%; JK = 100%; DI = 13). Apart from the somewhat surprising (but well-substantiated) isolated position of Rhynchoglossum, the results are in perfect accordance with the relationships worked out earlier on grounds of architectural and floral characters. Especially remarkable is the predicted coherence between the morphologically and geographically different genera Whytockia and Monophyllaea.

New World Origins of Southwest Pacific Gesneriaceae: Multiple Movements Across and Within the South Pacific

“…Molecular studies have clarified the phylogenetic relationships of many genera and tribes, providing evidence that supports (1) the monophyly of Gesneriaceae as one of three families sister to ''core'' Lamiales (Oxelman et al 1999Backlund et al 2000;Olmstead et al 2001;Bremer et al 2002;Wortley et al 2005; APG III 2009); (2) the monophyly of the New World subfamily Gesnerioideae and the presence within it of at least six or seven tribes Zimmer et al 2002;Roalson et al 2005a); (3) the presence of a distinct, perhaps relictual, tribe, Epithemateae, sister to the rest of the tribes within Cyrtandroideae (Mayer et al 2003); (4) the incongruence between traditional classification and tribal relationships suggested by molecular data within subfam. Cyrtandroideae excluding Epithemateae (Mö ller et al 2009); and (5) the internal relationships and monophyly of several tribes (Episcieae: Smith 2000b;Clark et al 2006;Gloxinieae: Smith and Atkinson 1998;Roalson et al 2005aRoalson et al , 2005bRoalson et al , 2008Beslerieae and Napeantheae: Smith 2000a; Sinningieae: Perret et al 2003; Gloxinieae and Gesnerieae: Smith et al 2004aSmith et al , 2004b) and genera (Columnea: Smith andSytsma 1994a, 1994b;Saintpaulia: Mö ller and Cronk 1997; …”

“…Coronanthereae was raised to subfamily rank, as Coronantheroideae, by Wiehler (1983) and Burtt and Wiehler (1995), but this has not been accepted by all authors. Because of the inclusion of a few members of Coronanthereae in molecular studies, its placement at subfamily rank (as Coronantheroideae) has been questioned (Mayer et al 2003;Smith et al 2004b;Wang et al 2004). As the Coronanthereae have been little studied until now, are seldom collected, and are difficult to cultivate, questions about their relationships have not been definitively answered.…”

Patterns of diversification and ancestral range reconstruction in the southeast Asian–Pacific angiosperm lineage Cyrtandra (Gesneriaceae)

“…Crown group ages are estimated to be nearly as old (71 MYBP; Bremer et al, 2004) with Cyrtandra being one of the more recently derived genera in the family (Mayer et al, 2003). Dating of the split between Cyrtandra and its sister genus Aeschynanthus could not be performed in this study because outgroup taxa must be pruned as part of the r8s analysis protocol (Sanderson, 2002).…”

“…The Cyrtandroideae includes approximately half of all gesneriad species and is believed to be monophyletic based on developmental, morphological and genetic analyses (Burtt and Wiehler, 1995;Mayer et al, 2003). The Cyrtandroideae includes perhaps 80 or more recognized genera (Weber, 2004) and has been studied at the tribal and generic level (e.g., Wang et al, 2002;Mayer et al, 2003;Möller et al, 2009).…”

“…The Cyrtandroideae includes approximately half of all gesneriad species and is believed to be monophyletic based on developmental, morphological and genetic analyses (Burtt and Wiehler, 1995;Mayer et al, 2003). The Cyrtandroideae includes perhaps 80 or more recognized genera (Weber, 2004) and has been studied at the tribal and generic level (e.g., Wang et al, 2002;Mayer et al, 2003;Möller et al, 2009). The sister lineage to the Cyrtandroideae is the Gesnerioideae + Coronantherioideae (Weber, 2004); the Gesnerioideae are principally neotropical (Zimmer et al, 2002) whereas the Coronantherioideae are distributed minimally in South America and predominantly in Australia and northeast into the western South Pacific.…”