Plio‐Pleistocene decline of mesic forest underpins diversification in a clade of Australian Panesthia cockroaches

A comprehensive phylogenetic analysis reveals that the diversification of a clade of Australian Panesthia cockroaches was primarily driven by the fragmentation of mesic forests during Plio-Pleistocene glacial cycles (2–5 million years ago). The study identified six previously unrecognized, highly divergent lineages, suggesting that vicariance events played a significant role in their speciation. Ancestral niche estimations indicate an origin in tropical rainforests, followed by at least three transitions into drier forest habitats, including one associated with the colonization of Lord Howe Island Group. The research also provides evidence of frequent parallel wing reduction, potentially linked to habitat contraction into small refugia. This study underscores the profound impact of ancient aridification on speciation, niche expansion, and morphological evolution in Australian fauna.

Adams, M. W. D., Walker, J. A., Rose, H. A., Jones, B. R., Zwick, A., Yang, H., Nicholls, J., Hartley, D., Bent, S., Carlile, N., Hutton, I., Ho, S. Y. W., & Lo, N. (2024). Plio‐Pleistocene decline of mesic forest underpins diversification in a clade of Australian Panesthia cockroaches. Systematic Entomology, 50(2), 253–268. Portico. https://doi.org/10.1111/syen.12654