comment on this calibration

Pantherophis+Pituophis

Lineage (NCBI): This node has no ancestors.
 node name
Pantherophis+Pituophis     Look for this name in NCBI   Wikipedia   Animal Diversity Web
 
  recommended citations
http://palaeo-electronica.org/content/fc-9 Head et al. 2016
 
  node minimum age
11.93 Ma
USNM 125457 was encased in a local ash deposit that is geochemically matched with the Ibex Hollow Tuff, radiometrically dated to 11.93 Ma (Tucker et al., 2014).
 
  node maximum age
None specified
 
 primary fossil used to date this node 
 
USNM 125457
Pantherophis, NO REFERENCE
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Ibex Hollow Tuff
     Geological age: Miocene, Neogene, Cenozoic
 
 

 
  phylogenetic justification
Assignment to Pantherophis is based on a premaxilla with thin, dorsomedially angled maxillary processes, a blunt, rounded anterior margin, and laterally expanded ascending processes forming a keyhole shape in anterior view.
 
  phylogenetic reference(s)
Head, J.J., K. Mahlow, and J. Müller. 2016. Fossil calibration dates for molecular phylogenetic analysis of snakes 2: Caenophidia, Colubroidea, Elapoidea, Colubridae. Palaeontologia Electronica, 19.2.2FC
[View electronic resource]
 
 tree image (click image for full size) 
tree image
Figure 1 from Head et al. (2016).
login