comment on this calibration


Lineage (NCBI): root » Eukaryota » Embryophyta » magnoliids » Laurales
 node name
Laurales     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Massoni et al. 2015
  node minimum age
107.7 Ma
Cohongarootonia was collected from the Potomac Group at the same Puddledock locality, 9 km southwest of Hopewell, Virginia, as Virginianthus calycanthoides (Fossil 4). As discussed for that species, this locality has been correlated palynologically by R.A. Christopher (in Dischinger, 1987) with the lower part of Subzone II-B of Brenner (1963), which we argue is of middle Albian age. Therefore, we use the middle-late Albian boundary, 107.7 Ma (no uncertainty provided; Ogg and Hinnov, 2012), as a minimum age for Cohongarootonia.
  node maximum age
0 Ma
none specified
 primary fossil used to date this node 
FMNH PP53716
Cohongarootonia hispida, von Balthazar et al., 2011
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Puddledock locality
     Stratum: Potomac Group
     Geological age: Cretaceous, Mesozoic

  phylogenetic justification
A molecular scaffold analysis by von Balthazar et al. (2011), using the morphological data set from Doyle and Endress (2010) and one of the same backbone trees, in which Lauraceae and Hernandiaceae form a clade sister to Monimiaceae, placed Cohongarootonia hispida in a single most parsimonious position as the sister group of Lauraceae + Hernandiaceae. Synapomorphies of the three taxa were whorled tepals, whorled stamens, and one carpel. As a result, von Balthazar et al. (2011) unequivocally assigned the fossil to the order Laurales. However, although all recent analyses agree that Lauraceae, Hernandiaceae, and Monimiaceae form a well-supported clade within Laurales, the relationships among these three families are still debated. In analyses by Doyle and Endress (2000), a sister group relationship of Lauraceae and Hernandiaceae was strongly supported by morphological data and by combined morphological and molecular data, but analyses of molecular data alone have linked either Monimiaceae and Lauraceae or Monimiaceae and Hernandiaceae (Qiu et al., 1999, 2000, 2005, 2006, 2010; Renner, 1999; Doyle and Endress, 2000; Savolainen et al., 2000; Renner and Chanderbali, 2000; Hilu et al., 2003; Zanis et al., 2003; Soltis et al., 2011; Massoni et al., 2014). Until this conflict is resolved, we consider that Cohongarootonia hispida provides a minimum age for the stem node of the clade including Lauraceae, Monimiaceae, and Hernandiaceae, in other words the crown node of the clade of Laurales excluding Calycanthaceae (Figure 1).
  phylogenetic reference(s)
The linked fossil has no phylogentic references.
 tree image (click image for full size) 
tree image
Figure 1 from Massoni et al. (2015).