Data from: Phylogenomics and continental biogeographic disjunctions – insight from the Australian starflowers (Calytrix: Myrtaceae)

PREMISE OF THE STUDY: Continental-scale disjunctions and
associated drivers is a core research interest in biogeographic studies.
Here, we selected a species-rich Australian plant genus
(Calytrix; Myrtaceae) as a case study to investigate
these patterns in an Australian context. The endemic Australian starflower
genus has a disjunct distribution across the mesic fringes of the
continent and is absent from the arid centre. METHODS: We used
high-throughput sequencing to generate unprecedented resolution and near
complete species-level nuclear and plastid phylogenies
for Calytrix. BioGeoBEARS and biogeographic stochastic
mapping (BSM) were used to infer ancestral areas, the relative
contributions of vicariance and dispersal events, and directionality of
dispersal. KEY RESULTS: Present-day disjunctions
in Calytrix are explained by a combination of scenarios:
(1) retreat of multiple lineages from the continental centre to
the more mesic fringes as Australia became progressively more arid, with
subsequent extinction in the centre, and also (2) origination of ancestral
lineages in southwestern Australia (SWA) for species-rich
clades. The SWA biodiversity hotspot is a major diversification
centre and the most common source area of dispersals, with multiple
lineages originating in SWA and subsequently spreading to the adjacent
arid Eremaean region.  CONCLUSIONS: Our results suggest
major extinction as a result of cooling and drying of the Australian
continent in the Eocene–Miocene shaped the present-day biogeography
of Calytrix. We hypothesise that this peripheral
vicariance pattern, which is similar to the African Rand flora, may
explain the disjunctions of many other Australian plant groups. Further
studies with densely sampled phylogenies are required to test this
hypothesis.