Those Tracks Really Were Made by Feet – #365papers – 2018 – 26

Qvarnstrom, Szrek, Ahlberg, and Niedzwiedzki, 2018, Non-marine palaeoenvironment associated to the earliest tetrapod tracks: Scientific Reports, v. 8, 1074.

What’s it about?

Ichnofossils – the tracks and traces left by the activities of organisms – are some of the oldest evidence of life and certain activities in the rock record. Foot prints, specifically those made on land by animals with toes, are the first evidence of tetrapods, the land-dwelling vertebrates.

It had been argued that footprints from Zachelmie (middle Devonian) weren’t good evidence for land-dwelling vertebrates because they were made in ocean sediments. The authors here show that the rocks are actually deposits of ephemeral lakes, showing that the ichnofossils do represent real land-dwelling vertebrates.

Why does it matter?

Knowing that the footprints were made by land-dwelling vertebrates allows scientists to pin an ‘oldest’ age to vertebrates on land. This age is significantly older than what would be hypothesized based only on body fossils.

Why did I read this?

A topic that I have an interest in, but do not personally research, is the origin of terrestrial (land-dwelling) vertebrates. This paper is particularly interesting and may wind up being discussed in my vertebrate paleontology course this semester.

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