comment on this calibration


 node name
Aniliidae     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Head, 2015
  node minimum age
72.1 Ma
The Allen Formation is dated as late Campanian-Early Maastrichtian based on its stratigraphic position overlying the Anacleto Formation and underlying the Jagüel Formation (Gómez et al., 2008). The Anacleto Formation is dated to late Campanian based on magnetostratigraphic correlation to Chron C33R (83.5-79.5 Ma) (Dingus et al., 2000), whereas the Jagüel Formation is dated as mid-Maastrichtian to early Danian based on foraminiferal biostratigraphy (Leanza et al., 2004; Goméz et al., 2008). The horizon within the Allen Formation that produced Australophis specimens is measured at 48 meters below the K-Pg boundary and is considered no younger than early Maastrichtian (Goméz et al., 2008). The exact minimum age provided is for the Campanian- Maastrichtian boundary, which is likely to be slightly older than the actual age of the type specimen of Australophis.
  node maximum age
0 Ma
None specified.
 primary fossil used to date this node 
Australophis anilioides, Gómez et al. 2008
Location relative to the calibrated node: Stem

[show fossil details]
     Locality: Bajo Trapalcó
     Stratum: Allen Formation
     Geological age: Cretaceous, Mesozoic

More information in Fossilworks   PaleoBioDB

  phylogenetic justification
Assignment to Aniliidae Stejneger, 1907 sensu MacDiarmid et al. (1999) is based on the following apomorphic character combination: low neural arch does not rise much above zygapophyseal plane, neural spine reduced, elongate prezygapophyses that are elongate and high-angled, concave posterior margin of neural arch (Goméz et al., 2008).
  phylogenetic reference(s)
Gómez, R.O., Báez, A.M., and Rougier, G.W. 2008. An anilioid snake from the Upper Cretaceous of northern Patagonia. Cretaceous Research, 29:481-488.
 tree image (click image for full size) 
tree image
Figure 1 from Head (2015).