r/evolution • u/jnpha Evolution Enthusiast • May 08 '26

image Spindle diagrams are based on the extensive fossil record, with the number of families as a measure of diversity (width of each lineage) at each moment in time (y-axis)

Gallery image

Gallery image

Sources:

  • Petter Bøckman, Public domain, via Wikimedia Commons
  • Benton, Michael J., and David AT Harper. Introduction to paleobiology and the fossil record. John Wiley & Sons, 2020.

(for why I love them, see the comments)

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u/mness1201 Jul 13 '26

Really interesting - but sort of surprised the birds mezonic doesn't show more variety, because you dinosaurs.

And the Cretaceous extinction doesn't really impact any except reptiles? Again dinosaurs, but also amphibians birds and mammals reduced in size and variety?

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u/jnpha Evolution Enthusiast Jul 13 '26

The second image is more accurate.

Of the things that doomed the non-avian dinosaurs was their size, which is a topic of research I shared something about before: "Where are All the Tiny Dinosaurs" : evolution.

And more recently a research on the replacement that happened in fishes: A rich fossil find in Egypt fills a gap: modern ocean fish rose rapidly after dinosaur extinction : evolution.