New Caledonian Araucaria

[2] New Caledonia, considered as the smallest of the most significant biodiversity hotspots in the world,[3] hosts a unique flora of which 75.1% is endemic.

[13] Among Eutacta section, New Caledonian species formed a monophyletic group where A. cunninghamii (Papua New Guinea) was derived first, then A. heterophylla (Norfolk Island).

[13] This strong homology and A. heterophylla as a sister group of New Caledonian species (the Norfolk Island being relatively young, less than 3 million years old) are first elements suggesting a recent differentiation of Araucaria trees in New Caledonia.

Gaudeul et al. attempted in 2012 to better describe the evolutionary relationships and diversification of New Caledonian species by using AFLP markers and by performing Bayesian, genetic distances and cladistics analyses.

[14] Ecological, morphological and geographical parameters were also considered in the study, which ended supporting a recent diversification of the genus in New Caledonia.

[15] For the first time in the family Araucariaceae, genetic (19 plastid, 2 nuclear and 2 mitochondrial genomic regions) and morphologic data (52 discrete and 10 continuous characters) were combined, confirming a strong monophyly for the 4 sections existing.

However, relationships among New Caledonian species remain difficult to elucidate even if their relatively recent origin is confirmed by phylogeny based on combination of plastid and nuclear data, and the use of molecular clock.

Distinctions with the latter hold in larger leaves, microsporophylls without a shouldered base and shorter female cone bracts.