comment on this calibration


 node name
Fraterculinae     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Smith, 2015
  node minimum age
6.7 Ma
The vertebrate assemblages of the San Mateo Formation were reviewed by Barnes et al. (1981), who designated the lower assemblage, from which the holotype specimen of Aethia barnesi was recovered, the San Luis Rey River Local Fauna (SLRRLF). Age estimates for the SLRRLF based upon terrestrial mammal and marine bird fossils range from approximately 6.7-10.0 Ma (Late Miocene or Tortonian-Messinian equivalent; Barnes et al. 1981; Domning and Deméré, 1984). Therefore, 6.7 Ma is suggested as a minimum age for the divergence of Aethiini from Fraterculini.
  node maximum age
0 Ma
none specified.
 primary fossil used to date this node 
LACM 107031
Aethia barnesi, Smith, 2013
Location relative to the calibrated node: Stem

[show fossil details]
     Locality: San Luis Rey River Local Fauna
     Stratum: San Mateo Formation
     Geological age: Messinian, Miocene, Neogene, Cenozoic

  phylogenetic justification
The systematic position of Aethia barnesi was established based on a combined analysis of morphological and molecular sequence data (Smith, 2011a; Smith, 2013). Aethia barnesi was placed at the base of an unresolved Aethiini clade. Aethia barnesi was alternatively placed in a polytomy with the extant species Aethia pygmaea and Aethia cristatella (Smith, 2013). Apomorphies supporting referral of A. barnesi to Aethiini are provided by Smith (2013). Because Aethia barnesi is older than known fossils of Fraterculini (Smith, 2011a; Smith, 2013), thus, it provides a hard minimum bound on the age of divergence between those clades.
  phylogenetic reference(s)
Smith, N. A. 2011a. Systematics and evolution of extinct and extant Pan-Alcidae (Aves, Charadriiformes): combined phylogenetic analyses, divergence estimation, and paleoclimatic interactions. PhD Dissertation. The University of Texas at Austin. 748pp
Smith, N.A.2013. The fossil record and phylogeny of the auklets (Pan-Alcidae, Aethiini). Journal of Systematic Palaeontology
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 tree image (click image for full size) 
tree image
Figure 2 from Smith (2015).