The study by Near et al. (2012) addresses the long-standing issues in the phylogenetic relationships and diversification timing of ray-finned fish (Actinopterygii), which make up half of all living vertebrate species. The authors used multiple nuclear gene sequences and 36 fossil age constraints to construct a well-supported phylogeny of major ray-finned fish lineages and provide molecular age estimates that align with the fossil record. Key findings include: 1. **Phylogenetic Resolution**: The phylogeny resolves 89% of the 232 nodes with strong support, confirming the sister relationship between elopomorphs and all other teleosts, and placing polypterids as the sister lineage to all other actinopterygians. 2. **Divergence Times**: Molecular age estimates for major lineages are consistent with the fossil record, suggesting that the first 100 million years of crown teleost history are absent from the fossil record. The study identifies a period from the late Mesozoic to the early Cenozoic as the "Second Age of Fishes," where major teleost lineages originated and diversified. 3. **Reconciliation with Fossil Record**: The molecular age estimates reconcile with paleontological data, providing a more consistent time scale for the evolutionary diversification of ray-finned fishes. This reconciliation suggests that the missing record of crown teleost fossils from the Permo-Carboniferous to Middle Jurassic may be due to a lack of suitable fossil deposits during this period. 4. **Implications for Research**: The comprehensive molecular perspective on the evolutionary history of ray-finned fishes provides valuable data and calibration information for integrating clade resolution at lower taxonomic levels and estimating ages of actinopterygian lineages lacking a fossil record. Overall, the study advances our understanding of the phylogenetic relationships and diversification timing of ray-finned fishes, highlighting the importance of molecular data and fossil calibrations in resolving long-standing phylogenetic and age estimation issues.The study by Near et al. (2012) addresses the long-standing issues in the phylogenetic relationships and diversification timing of ray-finned fish (Actinopterygii), which make up half of all living vertebrate species. The authors used multiple nuclear gene sequences and 36 fossil age constraints to construct a well-supported phylogeny of major ray-finned fish lineages and provide molecular age estimates that align with the fossil record. Key findings include: 1. **Phylogenetic Resolution**: The phylogeny resolves 89% of the 232 nodes with strong support, confirming the sister relationship between elopomorphs and all other teleosts, and placing polypterids as the sister lineage to all other actinopterygians. 2. **Divergence Times**: Molecular age estimates for major lineages are consistent with the fossil record, suggesting that the first 100 million years of crown teleost history are absent from the fossil record. The study identifies a period from the late Mesozoic to the early Cenozoic as the "Second Age of Fishes," where major teleost lineages originated and diversified. 3. **Reconciliation with Fossil Record**: The molecular age estimates reconcile with paleontological data, providing a more consistent time scale for the evolutionary diversification of ray-finned fishes. This reconciliation suggests that the missing record of crown teleost fossils from the Permo-Carboniferous to Middle Jurassic may be due to a lack of suitable fossil deposits during this period. 4. **Implications for Research**: The comprehensive molecular perspective on the evolutionary history of ray-finned fishes provides valuable data and calibration information for integrating clade resolution at lower taxonomic levels and estimating ages of actinopterygian lineages lacking a fossil record. Overall, the study advances our understanding of the phylogenetic relationships and diversification timing of ray-finned fishes, highlighting the importance of molecular data and fossil calibrations in resolving long-standing phylogenetic and age estimation issues.