Skull ontogeny: developmental patterns of fishes conserved across major tetrapod clades

摘要: In vertebrates, the ontogeny of bony skull forms a particularly complex part embryonic development. Although this area used to be restricted neontology, recent discoveries fossil ontogenies provide an additional source data. One most detailed ossification sequences is known from Permo-Carboniferous amphibians, branchiosaurids. These temnospondyls form near-perfect link between piscine osteichthyans and various clades extant tetrapods, retaining full complement dermal bones in skull. For first time, broader evolutionary significance these event analyzed, focusing on identification sequence heterochronies. A set 120 pairs was analyzed by pair cracking, which helped identify active movers. cladistic analysis data also carried out, highlighting some shared patterns widely divergent tetrapods. The analyses revealed unexpected degree similarity taxa. Most interesting apparently modular composition cranial sequence: five clusters were discovered each elements same time window: (1) jaw bones, (2) marginal palatal elements, (3) circumorbital (4) roof (5) neurocranial ossifications. studied taxa, "modules" have cases been shifted fore back trajectory relative Amia sequence, but did not disintegrate. Such might indicate high limitation (constraint).