Epiphytic leafy liverworts diversified in angiosperm-dominated forests.

Kathrin Feldberg,Jochen Heinrichs,Alfons Schäfer-Verwimp,Alexander R Schmidt,Tanja Stadler,Harald Schneider

doi:10.1038/srep05974

Abstract

Recent studies have provided evidence for pulses in the diversification of angiosperms, ferns, gymnosperms, and mosses as well as various groups of animals during the Cretaceous revolution of terrestrial ecosystems. However, evidence for such pulses has not been reported so far for liverworts. Here we provide new insight into liverwort evolution by integrating a comprehensive molecular dataset with a set of 20 fossil age constraints. We found evidence for a relative constant diversification rate of generalistic liverworts (Jungermanniales) since the Palaeozoic, whereas epiphytic liverworts (Porellales) show a sudden increase of lineage accumulation in the Cretaceous. This difference is likely caused by the pronounced response of Porellales to the ecological opportunities provided by humid, megathermal forests, which were increasingly available as a result of the rise of the angiosperms.

Highlights

Recent studies have provided evidence for pulses in the diversification of angiosperms, ferns, gymnosperms, and mosses as well as various groups of animals during the Cretaceous revolution of terrestrial ecosystems
The orders Jungermanniales and Porellales show distinct patterns of biodiversity assembly through the Mesozoic and early Cenozoic (Figs 1A–1D, Supplementary 2.3–2.7). Jungermanniales accumulated their diversity with a relatively constant diversification rate until about 20–40 million years ago (Ma), whereas Porellales show a delay of the accumulation of lineages from the Permian-Triassic border onwards followed by a sudden increase in the Cretaceous (Fig. 1B, Supplementary 2.4)
Our analyses point to remarkable differences in the diversification rates of the predominantly epiphytic Porellales and the predominantly generalistic Jungermanniales

Summary

Introduction

Recent studies have provided evidence for pulses in the diversification of angiosperms, ferns, gymnosperms, and mosses as well as various groups of animals during the Cretaceous revolution of terrestrial ecosystems. Based on evidence provided in ecophysiological studies on early angiosperms, we expected the majority of epiphytic and epiphyllic liverworts to have diversified either during the KTR or after the Cretaceous-Palaeogene (K-Pg) boundary and, in contrast, generalists to have accumulated their diversity under a rather constant diversification rate as inferred in preceding studies[12,27] We explore this hypothesis by examining the evidence supporting two pertinent arguments: 1) that the two orders show distinct patterns of diversification during the Mesozoic and early Cenozoic; 2) that these differences coincide with the ecological preferences of the majority of species belonging to each order, in particular the strong preference in Porellales for epiphytic habitats

Methods

Results

Conclusion