Data for: Plio-Pleistocene decline of mesic forest underpins diversification in a clade of Australian Panesthia cockroaches

The progressive aridification of the Australian continent and the
coincident decline of mesic forests have been a powerful driver of
allopatric and environmental speciation in native species. The relictual
mesic forests of the eastern seaboard now harbour a diverse group of
endemic fauna, including the wood-feeding cockroaches of the genus
Panesthia, which reached the continent via two separate invasions from
Melanesia. The more recent of these colonisation events gave rise to a
group of five recognised species, occurring in mainland woodlands,
sclerophylls, and rainforests, as well as the forests and grasslands of
the Lord Howe Island Group. Due to limited sampling in molecular studies
and doubt regarding the standing taxonomy, there is little certainty about
relationships among the species and a poor understanding of the effects of
ancient climatic change upon their evolution. We undertook a comprehensive
phylogenetic analysis of the clade, using complete mitogenomes and nuclear
ribosomal markers from nearly all known morphospecies and populations. Our
time-calibrated phylogenetic analyses reveal an additional six
unrecognized, highly divergent lineages and suggest that these have arisen
primarily through vicariance as rainforests fragmented during
Plio-Pleistocene glacial cycles (2–5 million years ago). Ancestral niche
estimations also evidence a tropical rainforest origin for the group,
followed by at least three niche transitions into drier forest, including
one associated with the singular colonisation of the Lord Howe Island
Group. Finally, we find evidence of frequent, parallel wing reduction in
potential association with the contraction of forest habitats into small
refugia. Our results reiterate the far-reaching role of ancient
aridification in driving speciation, niche expansion, and morphological
evolution in Australian fauna.