Are the liverworts really that old? Cretaceous origins and Cenozoic diversifications in Lepidoziaceae reflect a recurrent theme in liverwort evolution

Abstract

Estimating the temporal origins of lineage diversity adds an important dimension to understanding diversity generating processes. In lineages with a sparse fossil record, molecular phylogenetic methods provide a means for estimating divergence times. In the present study, we use publicly available sequence data from the chloroplast genome of liverworts to simultaneously estimate significant divergence dates across all classes and orders of liverworts (Marchantiophyta). We show that, although there is great potential in synthetic dating analyses of sequence data, missing sequences can reduce the reliability of estimates, and that calibration priors should be interpreted with caution. Using the liverwort dataset as a broad outgroup, we obtain the first divergence time estimates for a large family of leafy liverworts; the Lepidoziaceae (Jungermanniidae). The Lepidoziaceae originated in the early Cretaceous with subsequent establishment of main lineages in the late Cretaceous. Divergence time estimates are consistent with Cenozoic diversification in Lepidozia, Telaranea, and Bazzania. Evidence was found for similar patterns of ancient origins followed by Cenozoic diversification in Ricciaceae (Marchantiopsida), Pelliaceae and Fossombroniaceae (Pelliidae), and Metzgeriaceae (Metzgeriidae), and adds to reports of similar patterns in Lejeuneaceae (Jungermanniidae, Porellales), and Plagiochilaceae (Jungermaniidae, Jungermanniales). The liverworts might be the living relatives of one of the earliest groups of land plants, but much of the extant diversity has evolved in the Cenozoic. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

Extant diversity of bryophytes emerged from successive post-Mesozoic diversification bursts

“…Consequently, species diversification events were not taken into account, leading the analysis to infer a decrease in diversification rates, which corresponds to a purely methodological phenomenon known as the 'pull of the present' 31,32 . Nevertheless, analyses incorporating species richness identified another eight, fifteen and one increases in species diversification rate in the course of the last 80 Ma in liverworts, mosses and hornworts, respectively, in agreement with previous species-level phylogenetic evidence of Cenozoic diversification in selected liverwort genera 33 . Our results therefore indicate that, as opposed to the predictions of the sequential replacement hypothesis but in keeping with other lineages of ancient origin 1,2 , bryophytes are still actively diversifying.…”

A Burmese amber fossil of <i>Radula</i> (Porellales, Jungermanniopsida) provides insights into the Cretaceous evolution of epiphytic lineages of leafy liverworts

“…This approach considered the distribution of the fossil's character states suggesting R. subgenus Odontoradula. Published divergence time estimates of Radula were gathered from the literature (Heinrichs et al, 2007;Fiz-Palacios et al, 2011;Cooper et al, 2012;Feldberg et al, 2014;Laenen et al, 2014;see Supplement) and compared with the results of the present analyses.…”

Exploring the impact of fossil constraints on the divergence time estimates of derived liverworts

“…Previous studies on the divergence times of liverworts addressed the age of the main lineages (e.g., Heinrichs et al 2007;Cooper et al 2012), biogeographic hypotheses such as pseudo-Gondwana distributions (Hartmann et al 2006;Heinrichs et al 2009b), and the pattern of divergences of liverworts. The latter studies reported evidence for the conservation of diversification rates in liverworts for the most of the Mesozoic and the Cenozoic.…”