Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates

Anatomy of the extinct

30 January 2020

Cells famed for imparting colour to fur and feathers are helping us map the anatomy of ancient animals.

A light-sensitive pigment, melanin is produced by cells called melanosomes, which are responsible for the colour of the hair, skin and scales of animals. Melanosomes were recently found in internal tissues of amphibians, raising questions about their role.

A team led by researchers from University College Cork analysed the chemical composition of melanosomes extracted from internal tissues, including the heart, liver and lung, of a range of existing and fossilized animals. They found that each organ had a distinct signature in its metal content, suggesting that melanosomes also manage metal metabolism around the body.

These chemical signatures are preserved in fossils, which will enable researchers to reconstruct the internal anatomy of extinct species. In a Libros tadpole fossil, for example, a region rich in titanium and copper reveals the liver’s location.

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References

1. PNAS 116, 17880–17889 (2019). doi: 10.1073/pnas.1820285116