“…Since there are no known fossil records for Heptapteridae, two calibration points were used, one for the Pseudopimelodidae node and one for the Pimelodidae node, which are part of the outgroup. Cephalosilurus from the Miocene of South America (Lundberg et al, 2010) was used to calibrate the Pseudopimelodidae node (lognormal distribution, mean 0.1, SD 0.8, offset 11.5, range 15.9-11.5 million years ago [mya]), and the Pimelodus group (Lundberg et al, 2010) from the Paleogene of South America was used to calibrate the Pimelodidae node (lognormal distribution, mean 0.6, SD 1.0, offset 30.0, range 40-30 mya; Campbell, 2004). Although additional fossils in other outgroups are known, the number of outgroups was minimized so as to avoid problems of analysis due to saturation of the DNA data.…”