Lythrum and Peplis from the Late Cretaceous and Cenozoic of North America and Eurasia: New evidence suggesting early diversification within the Lythraceae

Abstract

The appearance of Lythrum and Peplis in North America and Peplis in Asia at approximately the same interval in the mid Late Cretaceous points to an already wide geographical distribution by then. These findings add vital information for the time of origin of the Lythraceae and suggest a higher diversity within the family. They also indicate that the distribution of particular genera during the Cretaceous was wider than previously thought.

Evolution of pollen morphology in Loranthaceae

“…The general conservation of pollen morphologies over long periods of time and within phylogenetic lineages (e.g. Denk & Grimm 2009; Friis et al 2011; Grímsson et al 2011; this study) make them more valuable as taxonomic indicators than any other morphological feature at the supergeneric level. An example of the general high diagnostic value of pollen morphology in Santalales are the studies of Maguire et al (1974) and Feuer (1977), which document the diverse pollen of ‘Olacaceae’ now placed in distinct families/molecular-defined clades (Aptandraceae [ Aptandra and Anacolosa clades], Strombosiaceae, Ximeniaceae; [e.g.…”

“…Pollen features are generally conserved traits that can remain nearly unchanged for 40 or more million years, as e.g. documented for Aponogetaceae (Alismatales; Grímsson et al 2014), Fagaceae (Fagales; Denk & Grimm 2009; Bouchal et al 2014; Grímsson et al 2015), Lythraceae (Grímsson et al 2011, 2012), and several Santalales lineages (next section). However, this does not explain the disparity between pollen diversity and genetic diversity in the Lorantheae in comparison to the Psittacantheae.…”

Eocene Loranthaceae pollen pushes back divergence ages for major splits in the family

“…Diagnostic (lineage-specific) pollen hence allow for the tracing of modern lineages deep into the past (e.g. Zetter, Hesse & Huber, 2002; Grímsson, Zetter & Hofmann, 2011; Grímsson et al, 2016). …”

Tiny pollen grains: first evidence of Saururaceae from the Late Cretaceous of western North America

“…Hence, the lack of Saururaceae pollen all over the Northern Hemisphere may be in part a sieving artefact. The single grain method using a combination of LM and SEM imaging (e.g., Zetter, 1989) is a time-consuming approach, but as demonstrated here the information obtained can be highly beneficial to other botanical disciplines such as (i) molecular dating by providing new/alternative age priors (e.g., Hubert et al, 2014) and (ii) the study of historical biogeography by providing actual evidence for the occurrence of a certain lineage at a certain time in a certain place (e.g., Denk, Grímsson & Zetter, 2010; Grímsson, Zetter & Hofmann, 2011; Grímsson et al, 2015; Grímsson et al, 2016a). A main advantage of pollen for assessing past distribution is its high evolutionary conservatism across long periods of time.…”