Non-integumentary melanosomes can bias reconstructions of the colours of fossil vertebrates

The soft tissues of many fossil vertebrates preserve evidence of melanosomes-micron-scale organelles that inform on integumentary coloration and communication strategies. In extant vertebrates, however, melanosomes also occur in internal tissues. Hence, fossil melanosomes may not derive solely from the integument and its appendages. Here, by analyzing extant and fossil frogs, we show that non-integumentary melanosomes have high fossilization...