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Did prehistoric reptiles care for their offspring?

Reconstruction/Chuang Zhao

Well, if tortoises right other upended tortoises, we might reasonably hope so. From a recent find in China we learn:

A fossil specimen discovered by a farmer in China represents the oldest record of post-natal parental care, dating back to the Middle Jurassic.

The tendency for adults to care for their offspring beyond birth is a key feature of the reproductive biology of living archosaurs — birds and crocodilians — with the latter protecting their young from potential predators and birds, not only providing protection but also provision of food.

However, unequivocal evidence of post-natal parental care is extremely rare in the fossil record and is only reported for two types of dinosaurs and varanopid ‘pelycosaurs’ — a reptile which resembled a monitor lizard.

Of course it would be rare in the fossil record because animals do not know when they are going to be fossilized. They will only sometimes be doing things we can identify as caring for offspring.

Note: An animal could be killing another animal with the intention of dragging it back to a den and feeding it to offspring. But if both were fossilized in the act, we might never know that fact.

Abstract Post-natal parental care seems to have evolved numerous times in vertebrates. Among extant amniotes, it is present in crocodilians, birds, and mammals. However, evidence of this behavior is extremely rare in the fossil record and is only reported for two types of dinosaurs, and a varanopid ‘pelycosaur’. Here we report new evidence for post-natal parental care in Philydrosaurus, a choristodere, from the Yixian Formation of western Liaoning Province, China. We review the fossil record of reproduction in choristoderes, and this represents the oldest record of post-natal parental care in diapsids to our knowledge.

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