A recent 160-million-year-old fossil found by a farmer in China represents what is — now — the oldest-record of post-natal parental care in the world, according to new research from
The fossil — which shows an adult Philydrosauras (a type of choristodere) accompanied by six juveniles — dates to the Middle Jurassic, and notably extends back-in-time the date of the earliest known post-natal parental care amongst animals.
While the finding isn’t particularly surprising — especially considering that many relatively ancient animals, such as crocodilians, show similar behavior — it is strong (perhaps un-contestable) evidence that the practice was around back then as well. On the note of crocodilians — it may surprise some people, but crocodilians actually provide a great deal of food and protection for their young.
The behavior is its-self not rare at all really — and appears to have emerged numerous times in vertebrates, across many very different branches of that tree — but fossil evidence has been scant. Before this discovery the only two occurrences of “unequivocal evidence” with regard to post-natal parental care are with regard to 2 types of dinosaurs, and a group of reptiles resembling monitor lizards, known as pelycosaurs.
For a bit more background, the animal whose fossil was recently found was (as noted before) a type of choristodere — which were a group of aquatic + semi-aquatic diapsid reptiles that emerged sometime in the Middle Jurassic Period, over 160 million years ago.
A bit more, via a recent press release:
The specimen was donated to the Jinzhou Paleontological Museum in Jinzhou City four years ago by a local farmer who discovered the skeleton. The skeletons are of an apparent family group with an adult, surrounded by six juveniles of the same species. Given that the smaller individuals are of similar sizes, the group interpreted this as indicating an adult with its offspring, apparently from the same clutch.
Dr Charles Deeming, from the School of Life Sciences, University of Lincoln, UK, stated: “That Philydrosauras shows parental care of the young after hatching suggests protection by the adult, presumably against predators. Their relatively small size would have meant that choristoderes were probably exposed to high predation pressure and strategies, such as live birth, and post-natal parental care may have improved survival of the offspring. This specimen represents the oldest record of post-natal parental care in diapsids to our knowledge and is the latest in an increasingly detailed collection of choristoderes exhibiting different levels of reproduction and parental care.”
Interesting, while the common perception has for sometime now been that earlier reptiles — and various other genera for that matter — wouldn’t have exhibited the “full-range” of complex behavior seen in the various specie of today, that doesn’t appear to be the case does it? Recent finds seem to regularly suggest that the behavior of the animals living back then was quite complex, and not in any way “simpler”.
The study is published in the Geosciences Journal.