comment on this calibration


 node name
Cichlidae     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations Benton et al. 2015
  node minimum age
45.46 Ma
The fossil deposits at Mahenge represent lacustrine sediments that accumulated within a crater formed by intrusion of kimberlite. U-Pb dating of a zircon crystal provides a well-constrained age estimate of 45.83 Ma ± 0.17 Myr for the kimberlite at Mahenge (Harrison et al., 2001), but the lacustrine sediments yielding Mahengechromis must postdate this intrusive event. Harrison et al. (2001) provide a convincing argument, based on other crater lakes, that kimberlite emplacement likely predates lacustrine deposition and complete basin infill by only 0.2 to 0.1 Ma. We therefore define a minimum age of 45.46 Ma for Mahengechromis and crown-group Cichlidae.
  node maximum age
100.5 Ma
A soft maximum age for crown Cichlidae can be derived from the earliest fossil occurrences of more inclusive acanthomorph clades containing the family. The oldest well-substantiated remains of Ovalentaria only predate the earliest fossil chichlids by a few million years (see node 36). We prefer to adopt a more generous soft maximum based on the rich fish faunas of Cenomanian age that yield a diversity of acanthomorphs belonging to deeply diverging groups like polymixiids, lampridiforms, paracanthopterygians, and beryciforms, but only questionable percomorphs (faunas reviewed in Forey et al., 2003; see calibration for node 35 for a discussion of uncertainties surrounding early Late Cretaceous tetraodontiforms). The base of the Cenomanian is dated as 100.5 Ma (Ogg et al., 2012b), which we propose as a soft maximum age for crown Cichlidae.
 primary fossil used to date this node 
NMT WM 339/96a,b
Mahengechromis pletho, Murray 2001
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Mahenge, Singida Plateu
     Stratum: Mahenge crater
     Geological age: Eocene, Paleogene, Cenozoic

  phylogenetic justification
The most compelling evidence for cichlid monophyly derives from aspects of soft-tissue anatomy and other details unlikely to be preserved in fossils (Stiassny, 1981), but placement of Mahengechromis within Cichlidae is supported by the structure of the lower pharyngeal jaw, details of squamation, and meristic counts of the vertebral column and median fins (Murray, 2000, 2001a, b). The derived presence of a single supraneural and ctenoid scales indicate that Mahengechromis belongs to crown-group Cichlidae generally and Pseudocrenilabrinae specifically (Murray, 2000: fig. 11; Murray, 2001b: fig. 4).
  phylogenetic reference(s)
Murray, A.M. 2001. The oldest fossil cichlids (Teleostei: Perciformes): indication of a 45 million-year-old species flock. Proceedings of the Royal Society, Series B, 268:679-684.
Murray, A.M. 2000. Eocene cichlid fishes from Tanzania, East Africa. Journal of Vertebrate Paleontology, 20:651-664.
 tree image (click image for full size) 
tree image
Figure 6 from Benton et al. (2014).