a very early tetrapod indeed

I’ve been fascinated by the story of early tetrapod evolution (where ‘tetrapod’ = an animal with 4 legs) for years, since reading Carl Zimmer’s wonderful book At the water’s edge (1998). Our understanding of when & where tetrapods evolved has been steadily extended by a series of fossil finds, most recently the ‘fishapod’ Tiktaalik. This was definitely […]

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a pregnant placoderm

 And what’s a placoderm, you ask? It’s an ancient armoured fish. The placoderms were a group of fish that were common during the Devonian (410 – 360 million years ago), but then became extinct. The reason for the title of this post? A group of Australian researchers (Long et al., 2008) have just reported on a placoderm fossil that contained embryos […]

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more forensic genetics – and the origins of multicellular animals

When I'm lecturing about animal diversity and the origins of the multicellular animals (aka metazoans), I point out the similarity between the single-celled protozoans called choanoflagellates and the choanocytes (or 'feeding cells') of sponges. The textbook interpretation is that choanoflagellates may have shared a common ancestor with metazoans, and there's an increasing amount of genetic […]

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