Context: The early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the sauropsid line that led to today's reptiles and birds. The line following the stem group Sphenacodontia split-off several diverse groups of non-mammalian synapsids—sometimes referred to as mammal-like reptiles—before giving rise to the proto-mammals (Therapsida) in the early Mesozoic era. The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of the non-avian dinosaurs 66 million years ago.

Question: From which time period did birds and reptiles began to appear from?
Answer: Carboniferous period

Question: When did non-avian dinosaurs become extinct?
Answer: 66 million years ago

Question: Which early mammalian ancestor produced non-mammalian Dimetroden?
Answer: sphenacodont pelycosaurs

Question: When did sphenacodont pelycosaurs become extinct?
Answer: Unanswerable

Question: What were the modern mammalian orders ancestors called?
Answer: Unanswerable

Question: At the end of the synapsid period what non-mammal was produced?
Answer: Unanswerable

Question: The Sphenacodontia arose in the Paleogene and Neogene periods of what era?
Answer: Unanswerable

Question: At the end of the Carboniferous period what did the Neogene diverge from that led to today's reptiles and birds?
Answer: Unanswerable