Tuesday, 6 December 2016

Romer’s Gap - What Gap?



Yesterday the TW:eed Team had an important paper about our new tetrapod finds published online in Nature Ecology & Evolution. We are really excited that this is out, after four years of hard work by the team and decades of fossil hunting prior to that by Tim Smithson and the late Stan Wood. Well done Team TW:eed and everyone who has been involved!

One of the new tetrapod species – Koilops herma, discovered at the site near Chirnside

The paper describes five new tetrapod species, along with isolated bones from at least seven other taxa. The tetrapods exhibit both primitive and derived characters, indicating that some tetrapod groups survived the end Devonian mass extinction, and that primitive amphibians evolved earlier than previously known, in the early Carboniferous. Several of the tetrapods show evidence of being able to walk on land, making these finds vitally important to the story of evolution and our ancient vertebrate ancestors.

Conclusively, this paper shows that Romer’s Gap was a result of people not knowing where to look, rather than a true absence of tetrapods at this time. New data from fossil charcoal shows that there was not a global drop in oxygen levels, previously proposed to account for Romer’s Gap. The presence of tetrapods in the Scottish Borders relates to their preservation in sandy siltstones, where bones were quickly buried in flooding events related to heavy tropical rainfall.

Environmental information, with the location of two new tetrapod species, within a sandy siltstone

The abstract is available to view on the Nature website and we’ll do a lay-person post on the website about it soon. The paper will be in the first edition (January 2017) of this new Nature journal that focuses on evolution.

We’ve hit the headlines worldwide in the following press:

Next week the team are at the AGM of the Palaeontological Association in Lyon, where we will be presenting on our latest research. Stay tuned!

Until next time
Carys