Table - link million years ago (Ma)
||Gregory D. Edgecombe et al., Higher-level metazoan relationships: recent progress and remaining questions. Organisms Diversity & Evolution. June 2011, Volume 11, Issue 2, pp 151–172 p.157 table 1 and p.164 figure 4
||Dunn CW et al., Broad phylogenomic sampling improves resolution of the animal tree of life. Nature. 2008 Apr 10 452(7188):745-9. doi: 10.1038/nature06614PubMed ID18322464
||Primary source abstract: "Here [investigators] report a total of 39.9 Mb of expressed sequence tags from 29 animals belonging to 21 phyla, including 11 phyla previously lacking genomic or expressed-sequence-tag data."
||P.163 right column bottom paragraph: "Figure 4 is a chronogram based on the most likely topology in the 64-taxon Bayesian analysis of Dunn et al. (primary source) using relaxed-clock methods for a 150-gene sample. Because of the substantial incongruence among the relationships between the main non-bilaterian lineages in phylogenomic studies to date (Fig. 1), the topology used for dating is for Bilateria alone." P.164 right column: "Calibration to constraints was performed by penalized likelihood (Sanderson 2002), as implemented in r8s v1.71 (Sanderson 2003), with a truncated Newton (TN) algorithm. The optimization of the smoothing parameter was obtained using the cross-validation feature in r8s following the instructions of the program manual (available at link note-link is broken). All analyses passed the gradient check implemented in r8s. Calibration points were assigned from minimum dates for branch points in the tree based on the oldest well-corroborated fossil(s) for clades with reliable palaeontological data (Table 1: Electronic supplementary material)." P.165 left column 2nd paragraph: "The resulting chronogram is consistent with Ediacaran origins for many animal phyla, and with dates of 598, 603 and 618 Mya for Ecdysozoa, Spiralia and Protostomia, respectively (Fig. 4)."