comment on this calibration


 node name
Gymnophiona     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Benton et al. 2015
  node minimum age
56 Ma
The fissure fillings of São José de Itaboraí, near Rio de Janeiro, are dated as early Late Paleocene (Mayr et al., 2011), and the minimum age bound is then 56.0 Ma ± 0.0 Myr = 56.0 Ma (Gradstein et al., 2012, pp. 883, 904).
  node maximum age
145.8 Ma
Two unnamed possible crown caecilians are an unnamed form from the Wadi Milk Formation of Sudan (Cenomanian) and a terminal Cretaceous fossil from the Pajcha Pata in Bolivia. These provide hints that older caecilians, whose fossils appear to be so im
 primary fossil used to date this node 
DGM 551
Apodops pricei, Estes and Wake, 1972.
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: São José de Itaboraí
     Geological age: Paleocene, Paleogene, Cenozoic

More information in Fossilworks   PaleoBioDB

  phylogenetic justification
Apodops pricei was identified as a caecilian related to the Holocene genus Dermophis and the extant Geotryptes. It is assigned to crown Gymnophiona based on the apomorphies of having compact vertebrae, and enlarged, projecting parapophyses (Estes and Wake, 1972).
  phylogenetic reference(s)
Estes, R., and Wake, M.H. 1972. The first fossil record of caecilian amphibians. Nature, 239:228-231.
 tree image (click image for full size) 
tree image
Figure 7 from Benton et al. (2015).