comment on this calibration

Brachyramphus marmoratus - B. brevirostris

 node name
Brachyramphus marmoratus - B. brevirostris     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Smith, 2015
  node minimum age
1.5 Ma
Deposition of the San Diego Formation was established to span the period between 3.6-1.5 Ma (Wagner et al., 2001).
  node maximum age
0 Ma
none specified.
 primary fossil used to date this node 
SDSNH 24573
Brachyramphus dunkeli, Chandler, 1990
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: San Diego Formation
     Stratum: San Diego Formation
     Geological age: Calabrian, Pleistocene, Quaternary, Cenozoic

  phylogenetic justification
Brachyramphus dunkeli was placed as the sister taxon to Brachyramphus marmoratus with Brachyramphus brevirostris placed at the base of that clade in the results of a combined analysis of morphological and molecular sequence data (Smith, 2011a). No alternative systematic position for Brachyramphus dunkeli has been proposed.
  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
 tree image (click image for full size) 
tree image