Species limits and diversification in the Madagascar olive (Noronhia, Oleaceae)

Abstract

Studies of ecological and phenotypic diversity in adaptive radiations have greatly contributed to our understanding of the patterns and processes of species diversification, whilst also challenging our assessment of the nature of species. Here, analyses of bioclimatic, molecular and morphological data, interpreted in phylogenetic and geographical contexts, were carried out to understand species limits in the Madagascar olive (Noronhia, Oleaceae). Most species hypotheses exhibit clear boundaries and are supported by at least one line of evidence, but a contrasting pattern of high morphological and ecological variation with relatively low nucleotide sequence divergence characterizes the diversification of Noronhia. This diversification was probably driven by fine‐scale ecological and evolutionary processes, as suggested by the poor fit with four models of species diversification of the biota of Madagascar and the apparent lack of differentiation detected from large‐scale bioclimatic data. Overall, this study offers useful insights into the patterns of plant diversification in Madagascar, the understanding of which requires good circumscription of species, improved knowledge of their distribution and operational models of diversification that take into account the particular biology of plants. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 141–161.

Multivariate morphometric analysis and species delimitation in the endemic New Caledonian genusStorthocalyx(Sapindaceae)

“…Traditionally in taxonomy, and especially in efforts to delimit species, discriminant methods such as canonical discriminant analysis or discriminant function analysis are used, in addition to PCA, to identify and evaluate those characters (or variables) that best distinguish recognized groups (De La Estrella, Aedo & Velayos, ; Slovak et al ., ; Hong‐Wa & Besnard, ). This approach, however, was not well suited to the present study because we did not conserve information on the membership of each individual (specimen) to a particular group (Legendre & Legendre, ).…”

<p><strong>Two new <em>Noronhia </em>species (Oleaceae) from the Guineo-Congolian forests in Africa</strong></p>

“…As a result of molecular research all African Chionanthus species were recently transferred to the genus Noronhia (Hong-Wa & Besnard 2013). For the phylogenetic tree published by Hong-Wa & Besnard (2013, 2014 three different specimens were sampled that were identified at that time as Chionanthus mannii. After re-identification, Schmidt 3487 from Ghana [in the phylogenetic tree as C. mannii subsp.…”

The evolutionary history of sedges (Cyperaceae) in Madagascar

“…As a biodiversity hotspot (Myers et al., 2000), Madagascar is renowned for its biodiversity (Ganzhorn et al., 2001), endemism (Goyder et al., 2017) and role as model system for species diversification (Vences et al., 2009). From lemurs and vangas to mayflies and dung beetles, and from tree ferns and olives to orchids and grasses, the exceptional faunistic and floristic diversity and endemism in Madagascar has made the region a natural laboratory for understanding geographical and ecological drivers of diversity (Martin, 1972; Renner, 2004; Janssen et al., 2008; Wirta et al., 2008; Jønsson et al., 2012; Reddy et al., 2012; Strijk et al., 2012; Andriananjamanantsoa et al, 2016; Hong‐Wa & Besnard, 2013; Ganzhorn et al., 2014; Herrera, 2017). Dispersal to Madagascar, followed by phenotypic shifts allowing novel ecological invasions (i.e.…”