Historical biogeography of Loranthaceae (Santalales): Diversification agrees with emergence of tropical forests and radiation of songbirds

Abstract

Coadaptation between mistletoes and birds captured the attention of Charles Darwin over 150 years ago, stimulating considerable scientific research. Here we used Loranthaceae, a speciose and ecologically important mistletoe family, to obtain new insights into the interrelationships among its hosts and dispersers. Phylogenetic analyses of Loranthaceae were based on a dataset of nuclear and chloroplast DNA sequences. Divergence time estimation, ancestral area reconstruction, and diversification rate analyses were employed to examine historical biogeography. The crown group of Loranthaceae was estimated to originate in Australasian Gondwana during the Paleocene to early Eocene (59 Ma, 95% HPD: 53-66 Ma), and rapidly diversified, converting from root parasitic to aerial parasitic trophic mode ca. 50 Ma during the Eocene climatic optimum. Subsequently, Loranthaceae were inferred to be widespread in Australasia and South America but absent in Africa. The African and European members were derived from Asiatic lineages. The burst of diversification of Loranthaceae occurred during a climatic optimum period that coincides with the dominance of tropical forests in the world. This also corresponds to the trophic mode conversion of Loranthaceae and rapid radiation of many bird families - important agents for long-distance dispersal in the Cenozoic.

Morphology, geographic distribution, and host preferences are poor predictors of phylogenetic relatedness in the mistletoe genus Viscum L

“…For example, with 81–68 mya, the origin of Viscaceae was inferred as much younger by Vidal-Russell and Nickrent (2008), who included only two species of Viscum and one of Arceuthobium . In contrast, our estimation of the crown group age of Loranthaceae (68.24–42.31 my) are close to or even congruent with earlier studies (e.g., Grímsson et al 2017; Liu et al 2018). The focus and, thus, sampling strategies and tree topologies differ largely between earlier works and ours, and so did the preferred molecular dating approaches regarding the employed methods, software programs, models, type and number of genetic markers, fossil information, calibration and constraint strategies.…”

“…Thus, vicariance from direct land mass connections seems unlikely. Stepping stone dispersal via the Kerguelen Plateau, Crozet Plateau, and Ninetyeast ridge represents an alternative explanation, one that has also been proposed for some palms and birds, the latter of which important seed dispersers of Viscum (Carpenter et al 2010; Liu et al 2018). With some certainty, continental Asia was colonized by Viscum at least three times independently from Australasia.…”

Widespread morphological parallelism in Korthalsella (Santalaceae, tribe Visceae): A molecular phylogenetic perspective

“…Most of these events correlate with known migratory bird patterns, although some (e.g., to Australia) do not. Similarly, Liu & al. (2018) showed recently that long-distance dispersal of Loranthaceae mistletoes was facilitated by birds (between Australasia and Asia, Africa and Asia, and Africa and Madagascar).…”

Morphometric, phylogenetic and biogeographic analyses ofPyrularia(Santalales), a parasitic disjunct lineage between eastern Asia and eastern North America

“…(), mainly referring to B. Liu & al. (). The minimum crown age of the subtribe Psittacanthinae was constrained to 47.8 Ma (95% CI: 48.2–67.1 Ma) according to the fossil pollen Miller Clay Pit MT2 identified as aff.…”