Proto-Synapsida and Proto-Diapsida

Basal synapsids, sometimes called pelycosaurs, were large carnivores of the Late Carboniferous, EarlyPermian and some stragglers (relic taxa) made it into the Middle and Late Permian were they hobnobbed with the next clade of basal synapsids, the Therapsida.

These were not the first reptiles to break away from all the others, contra tradition.

Figure 1. Basal synapsids. Those leading toward diapsids, the pro to-diapsids, are shown in green. We'll look at those in greater detail tomorrow. Here Protothyris and Echinerpeton are the outgroup. Aerosaurus and Elliotsmithia nest together. Archaeothyris nests at the base of the more familiar pelycosaurs.

Figure 1. Basal synapsids. Those leading toward diapsids, the pro to-diapsids, are shown in green. We’ll look at those in greater detail tomorrow. Here Protothyris and Echinerpeton are the outgroup. Aerosaurus and Elliotsmithia nest together. Archaeothyris nests at the base of the more familiar pelycosaurs.

Proto-Synapsids, Synapsids and Proto-Diapsids

  1. Protorothyris – Early Permian
  2. Echinerpeton – Late Carboniferous
  3. Archaeovenator – Late Carboniferous
  4. Mycterosaurus – Middle Permian
  5. Aerosaurus – Early Permian
  6. Elliotsmithia – Late Permian
  7. Archaeothyris – Late Carboniferous

Perhaps because of their lack of odd traits, these taxa were survivors, either becoming relic taxa long after their phylogenetic origins or producing large clades of descendants, many of which indeed did develop odd traits.

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