Friday, December 09, 2016

Feathering the nest

A wonderful discovery from Myanmar (Burma); what looks like a feather duster is in fact the tail of a dinosaur trapped in amber, and yes those are in fact feathers. The 100 million year old specimen is in fantastic condition and confirms a number of working hypothesis about how dinosaurs eventually evolved into birds. The tail would have been made up of around 25 vertebrae, which are articulated (i.e. they move independently) like a lizard or snake. In birds the tail bones are fused so that the much larger tail feathers can move as a single unit. So, it's clear that this tail is not a structure that any bird would have and the feathers are primitive, probably for keeping the little creature warm rather than flying or gliding. 

It's an interesting feature of evolution by natural selection that quite often a characteristic appears and evolves (like feathers) and it's use changes over time, i.e. what started in dinosaurs as modified skin cells, then became a warming coat that eventually ended up as flight feathers, all done by tiny, imperceptible increments over many millions of years and generations.

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