Phytogeographic implications of fossil endocarps of Menispermaceae from the Paleocene of Colombia

Abstract

The new fossils from Colombia reveal a complex paleobiogeographic history of the recognized clades within Menispermaceae, suggesting a more active exchange among neotropical, paleotropical, North American, and European paleoforests than previously recognized. In addition, the new fossils indicate that neotropical forests were an important biome for the radiation and dispersal of derived lineages in Menispermaceae after the Cretaceous-Paleogene boundary.

Endocarps of menispermaceous plants in Taiwan

“…In Cissampelos and Cyclea , there are always two lateral crests (ridges) per side, usually two dorsal crests, and their endocarps are often imperforated. According to published results (Jacques 2009; Liu and Jacques 2010; Herrera et al 2011), endocarps of Cissampelos pareira L. are covered by conspicuous spines with two dorsal and lateral ridges (crests). They also have a distinctly longer distal limb that slightly comes closer, and the outer lateral ridge partly overlaps the inner one (all ridges bear outgrowths).…”

“…The three genera, Cissampelos, Cyclea, and Stephania , form a clade ( S – C – C clade, or pantropical clade in Herrera et al 2011) that is strongly supported as monophyletic, which has female flowers with a single carpel as a morphological synapomorphy (Wefferling et al 2013). Furthermore, the endocarps of the three genera are variously ornamented with spines, tubercles, wings, or ridges; distal limb is longer (rarely equal), and sometimes has two (to four) lateral chambers.…”

“…We prepared the endocarp material after Forman (1986), Tiffney (1991), Jacques (2009b), and Herrera et al (2011). First, the fruits were hydrated in boiling water for about 10 min, and subsequently left in water overnight to soften the pericarp.…”

“…The endocarp dimensions were measured using Image-J software (Ferreira and Rasband 2011), and if multiple specimens were examined, the average size was recorded. Furthermore, data were supplemented with available images and descriptions from other published studies (Thanikaimoni 1986; Ortiz et al 2007; Jacques 2009a; Liu Jacques 2010; Herrera et al 2011; Wefferling et al 2013; Ortiz and Nee 2014). The terminology for the description of the endocarps partly follows Jacques (2009a), and a complete definition of endocarp characters can be found in Appendix 2.…”

“…Most members of this family are distributed throughout the tropics, although some are found in temperate regions. Their endocarps appear often in fossil records, and they indicate the presence of a wet forest ecosystem (Herrera et al 2011). About 116 species in this family were surveyed for their endocarp traits by Jacques (2009).…”