Cenozoic extinction and recolonization in the New Zealand flora: The case of the fleshy-fruited epacrids (Styphelieae, Styphelioideae, Ericaceae)

• Published in: Molecular phylogenetics and evolution 2013-01, Vol.66 (1), p.203-214
• Main Authors: Puente-Lelièvre, Caroline, Harrington, Mark G., Brown, Elizabeth A., Kuzmina, Maria, Crayn, Darren M.
• Format: Article
• Language: English
• Subjects: Bayes Theorem; Bayesian relaxed-clock; biogeography; Biological Evolution; Cenozoic extinction; DNA, Chloroplast - genetics; DNA, Plant - genetics; Ericaceae; Ericaceae - classification; Ericaceae - genetics; extinction; Extinction, Biological; flora; Fossils; Likelihood Functions; new species; New Zealand; Phylogeny; sediments; sisters; Styphelieae
• ISSN: 1055-7903; 1095-9513
• DOI: 10.1016/j.ympev.2012.09.027

[Display omitted] ► New Zealand Styphelieae closely relate to Australian and Tasmanian taxa. ► Styphelieae have not been continuously present in New Zealand since the Miocene. ► C. novae-zelandiae lineage went extinct in New Zealand. ► The Styphelieae recolonised New Zealand during the Pliocene–Pleistocene. ► Recolonization could relate to the emergence of alpine and subarid environments. The origins and evolutionary history of the New Zealand flora has been the subject of much debate. The recent description of Cyathodophyllum novaezelandieae from early Miocene sediments in New Zealand provides possible evidence for the antiquity of the fleshy fruited epacrids (tribe Styphelieae, Ericaceae) in New Zealand. Yet the extant species in this tribe are thought to be very closely related to or conspecific with Australian taxa, suggesting recent trans-Tasman origins. In order to investigate the origins and evolution of the extant New Zealand Styphelieae we produced molecular phylogenetic trees based on sequences of three plastid regions that include representatives of all the genera of the tribe and eight of the ten New Zealand species. We estimated the range of minimum ages of the New Zealand lineages with Bayesian relaxed-clock analyses using different calibration methods and relative dating. We found strong support for each of the eight extant species of New Zealand Styphelieae being a distinct lineage that is nested within an Australian clade. In all except one case the sister is from Tasmania and/or the east coast of mainland Australia; for Acrothamnus colensoi the sister is in New Guinea. Estimated dates indicate that all of the New Zealand lineages diverged from their non-New Zealand sisters within the last 7Ma. Time discontinuity between the fossil C.novae-zelandiae (20–23Ma) and the origins of the extant New Zealand lineages (none older than 5Ma) indicates that the fossil and extant Styphelieae in New Zealand are not related. The relative dating analysis showed that to accept this relationship, it would be necessary to accept that the Styphelieae arose in the early-mid Mesozoic (210–120Ma), which is starkly at odds with multiple lines of evidence on the age of Ericales and indeed the angiosperms. Therefore, our results do not support the hypothesis that Styphelieae have been continuously present in New Zealand since the early Miocene. Instead they suggest a historical biogeographical scenario in which the lineage to which C. novae-zelandiae belongs went e