Molecular Phylogenetic Analyses Reveal the Diversification and Dispersal Processes of the Tribe Shoreae (Dipterocarpaceae)

Aim

The tribe Shoreae, part of the family Dipterocarpaceae, encompasses about 330 species and ten genera, namely Anthoshorea, Doona, Hopea, Neobalanocarpus, Neohopea, Pentacma, Parashorea, Richetia, Rubroshorea and Shorea. It has been hypothesized that Shoreae ancestors likely migrated from the Indian subcontinent and underwent rapid diversification within Southeast Asian rainforests. However, the phylogenetic relationships among genera and the specific processes of dispersal and diversification within this tribe remain unclear. This research conducted molecular phylogenetic analyses of the tribe Shoreae, aiming to establish a comprehensive framework for the evolutionary past of this group.

Location

South and Southeast Asia.

Time Period

The Cretaceous to present.

Major Taxa Studies

Tribe Shoreae (Dipterocarpaceae).

Methods

We conducted Bayesian molecular phylogeny inference, ancestral area and distributable climate reconstruction, and divergence time estimation by utilising the molecular data sourced from GenBank. The molecular data included four partial chloroplast DNA regions (trnL–trnF, rbcL, trnH–psbA and matK) and the partial ITS region of nuclear DNA from a total of 186 ingroup and five outgroup species (Dryobalanops). Based on these results, we also evaluated temporal and in situ diversification.

Results

The Bayesian molecular phylogeny identified two major clades within the tribe Shoreae with high posterior probabilities and confirmed the monophyly of the genera Anthoshorea, Doona, Hopea, Parashorea, Richetia and Rubroshorea. Furthermore, our results supported the origin of the tribe prior to the collision of the Indian subcontinent with Asia, the migration of the Shoreae ancestors to Southeast Asia, and subsequently, diversification in tropical Southeast Asia after the Oligocene.

Main Conclusions

Molecular phylogenetic analyses suggest that the formation of the tropical climate in Southeast Asia may have played a role in the diversification of Shoreae species. This study proposes a novel hypothesis regarding the distribution and diversification processes of Shoreae, highlighting the mechanisms driving plant diversification in response to changing climatic conditions.