Molecular phylogeny of the tribe Danaideae (Rubiaceae: Rubioideae): Another example of out–of–Madagascar dispersal

Abstract

Extensive efforts have been made to resolve the phylogeny of the large coffee family (Rubiaceae) based on molecular data. As a result, several small tribes have been described, but the phylogenies and generic delimitations for many of these groups remain unclear. This study focuses on the small tribe Danaideae that belongs to subfamily Rubioideae and whose generic limits have not previously been addressed with molecular data. It is the sole rubiaceous tribe distributed almost entirely in the Western Indian Ocean region, with the exception of the East African Danais xanthorrhoea. The tribe consists of three genera: Danais, Payera (including the monotypic genus Coursiana), and Schismatoclada. We present the first molecular phylogenetic study of Danaideae including representatives from all three genera and using Bayesian and maximum parsimony methods and sequence data from nuclear DNA (nrITS) and chloroplast DNA (petD, psbA-trnH, rpl32-trnLUAG, rpsl6). Our main objectives were to rigorously test the monophyly of Danaideae as currently circumscribed and assess phylogenetic relationships within the tribe. The findings of this study shed light on the colonization history of the tribe. Our analyses reaffirm the monophyly of Danaideae and Danais but reveal the paraphyly of Payera and Schismatoclada. The close relationship between the three Danaideae genera and Coursiana is supported. However, we found very little support for the inclusion of the latter genus in Payera as proposed earlier. The tribe is resolved in two morphologically distinct major lineages, the highly supported Danais clade with lianescent habit (= Danais sensu Buchner & Puff) and the Payera-Schismatoclada clade with arborescent habit. The Malagasy and Mauritian specimens of Danais fragrans are not closely related, and we restrict D. fragrans to the Mauritian taxa and resurrect Danais lyallii Baker to accommodate the Malagasy D. fragrans. According to our analysis, Madagascar is the origin of all species of Danaideae occurring in the Comoro archipelago, East Africa, and Mauritius. The Mauritian and East African Danais each is the result of a single colonization event, while there were at least two independent colonization events to the Comoros.

From the Namib around the world: biogeography of the Inuleae–Plucheinae (Asteraceae)

“…The pattern is, however, not consistent with the commonly reported patterns of a Malagasy origin of Mascarene plants (e.g. Le Péchon et al ., ; Krüger et al ., ). On the other hand, a similar pattern has recently been reported from the tribe Octotropideae of the coffee family (Rubiaceae) with a Mascarene clade being nested inside an African one, which in turn is sister to an eastern‐southern African genus (Kainulainen et al ., submitted).…”

Madagascar sheds new light on the molecular systematics and biogeography of grammitid ferns: New unexpected lineages and numerous long-distance dispersal events

“…Therefore, Africa does not seem to be a source region for grammitid species in the WIO, contrary to what could be expected based on the Theory of Island Biogeography (MacArthur and Wilson, 1967) and empirical evidence for most of the angiosperms studied (Bacon et al, 2016;Buerki et al, 2013;Janssens et al, 2016;Yoder and Nowak, 2006). Actually, there is a growing body of evidence against the paradigm postulating that continents and islands respectively act as sources and sinks of species diversity (Heaney, 2007), and an increasing awareness of the importance of islands as cradles of diversity themselves: it has been documented for the WIO islands (Agnarsson and Kuntner, 2012;Krüger et al, 2012) and for the Macaronesian islands (Patiño et al, 2015). Although the observed patterns may be overestimated due to missing African species in our study (we included 14 out of 26 African species), grammitid ferns corroborate the latter scenario, and provide another example contradicting the traditional view.…”

In or Out-of-Madagascar?—Colonization Patterns for Large-Bodied Diving Beetles (Coleoptera: Dytiscidae)

“…Out-of-Madagascar dispersal events have been inferred for a number of other groups as well. Especially, the surrounding Mascarene and Comoros islands have been the recipients of flora and fauna from Madagascar [ 7 , 69 – 74 ] but also a number of cases to mainland Africa [ 71 , 72 , 75 , 76 ]. Similar “out of island” dispersal patterns were inferred also from other insular biodiversity hotspots.…”