comment on this calibration


 node name
Carnivora     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Benton et al. 2015
  node minimum age
37.3 Ma
The oldest caniforms are amphicyonids such as Daphoenus and canids such as Hesperocyon, known from the earliest Duchesnean NALMA, which corresponds to magnetochron 18N and is dated as 39.74 Ma ± 0.07 Myr, based on radiometric dating of the LaPoint Tuff (Robinson et al., 2004). This correlates to the Bartonian stage with a minimum limit of 37.8 ± 0.5 Ma (Gradstein et al., 2012), thus providing a minimum constraint of 37.3 Ma.
  node maximum age
66 Ma
The soft maximum constraint is based on the occurrence of the oldest stem-carnivorans (miacids, viverravids) in the early Paleocene (Fox et al., 2010), so 66.04 Ma ± 0.4 Myr = 66 Ma.
 primary fossil used to date this node 
SMNH(c) P1899.6
Hesperocyon , Scott, 1890
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Lac Pelletier local fauna
     Geological age: Eocene, Paleogene, Cenozoic

More information in Fossilworks   PaleoBioDB

  phylogenetic justification
Phylogenetic analysis shows that Hesperocyon is closely related to Canidae, based on its possession of a fully ossified auditory bulla composed mainly of the caudal entotympanic, with contributions from the ecotympanic and rostral entotympanic, and the caudla entotympanic forms a partial septum within the middle-ear cavity (Wesley-Hunt and Flynn, 2005).
  phylogenetic reference(s)
Wesley-Hunt, G. and Flynn, J.J. 2005. Phylogeny of the Carnivora:basal relationships among the carnivoramorphans, and assessment of the position of ‘Miacoidea’ relative to Carnivora. Journal of Systematic Palaeontology, 3:1-28.
 tree image (click image for full size) 
tree image