Phylogeny and the evolutionary origins of myrmecophytism in the Neonauclea clade (Rubiaceae) revisited, with particular emphasis on the Philippine lineages

• The Australasian Neonauclea is the largest genus of the tribe Naucleeae (subfamily Cinchonoideae, Rubiaceae) and is well known for its extensive radiation of myrmecophytic species. The genus is paraphyletic with respect to the genera Ludekia and Myrmeconauclea, and these three genera constitute the Neonauclea clade sensu Löfstrand et al. The Philippines is a center of species diversity of Neonauclea; however, its members have yet to be included in any molecular studies. We produced a phylogeny of the Neonauclea clade based on sequence data from nuclear (ETS and ITS) and plastid (rbcL and trnT-F) markers and including a large sampling of Neonauclea species from the Philippines. The resulting phylogeny was used to assess the phylogenetic positions and relationships of the Philippine Neonauclea species within the Neonauclea clade. We also reassessed the origins of myrmecophytism in the Neonauclea clade using ancestral state reconstructions. The sampled Philippine Neonauclea were resolved in five morphologically and geographically distinct clades. Our ancestral state reconstructions inferred a non-myrmecophytic ancestor for the Neonauclea clade, as shown by Razafimandimbison et al., and suggested at least two independent origins of myrmecophytism, one in myrmecophytic Myrmeconauclea and another in the myrmecophytic Neonauclea species from core Neonauclea. Losses of myrmedomes through multiple evolutionary reversals back to the non-myrmedome condition were inferred within core Neonauclea. Unlike the Bornean myrmecophytic lineages, our results favored a single origin of the Philippine endemic myrmecophytic Neonauclea.

Subject headings

NATURVETENSKAP  -- Biologi -- Biologisk systematik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biological Systematics (hsv//eng)

Keyword

Ant-plant association

myrmedome

Philippine flora

Rubiaceae

Diversity of life

Livets mångfald

Publication and Content Type

ref (subject category)

art (subject category)