comment on this calibration


 node name
Caudata     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Benton et al. 2015
  node minimum age
146.8 Ma
The Brushy Basin Member of the Morrison Formation is dated as Kimmeridgian or early Tithonian. The upper boundary of the Early Tithonian is 147.7 Ma ± 0.9 Myr (Gradstein et al., 2012, pp. 764, 777), so 146.8 Ma.
  node maximum age
175.1 Ma
The soft maximum constraint is based on the possibility that the Kirtlington ‘Salamander B’ might be a crown caudate, lowering the age estimate to Late Bathonian, and indeed, the range is extended to the base of the Middle Jurassic, dated as 174.1 Ma ± 1.0 Myr, so 175.1 Ma.
 primary fossil used to date this node 
DINO 16453a
Iridotriton hechti, Evans et al., 2005
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Brushy Basin Member
     Stratum: Morrison Formation
     Geological age: Kimmeridgian, Late Jurassic, Jurassic, Mesozoic

More information in Fossilworks   PaleoBioDB

  phylogenetic justification
Iridotriton is identified as a member of Salamandroidea, and hence crown Caudata, by the possession of several apomorphies, including the presence of spinal nerve foramina in the tail.
  phylogenetic reference(s)
Evans, S.E., Lally, C., Chure, D.C., Elder, A., and Maisano, J.A. 2005. A late Jurassic salamander (Amphibia: Caudata) from the Morrison formation of North America. Zoological Journal of the Linnean Society, 143:599–616.
 tree image (click image for full size) 
tree image
Figure 7 from Benton et al. (2015).