The first real fossil evidence for terrestrial vertebrates
comes from Greenland with Icthyostegalia fossils. 
The Icthyostegalia were streamlined for swimming but could hold themselves on land without difficulty. This species was already considerably adapted to a terrestrial environment and could be considered too advanced for their to be no additional link between lobe fins and the Icthyostegalia's.
One of the striking features of the Icthyostegalia's were
their teeth. A cross section of their teeth showed deep infolding
of the enamel which is characteristic of the amphibian group Labyrinthodonts.
Cross-section of teeth showing
infolding observed in Icthyostegalia and Labyrinthodont's.
Next