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Scottish tetrapods fill Romer's Gap in fossil record



From: Ben Creisler
bcreisler@gmail.com

Not strictly dino-related, but Romer's Gap has been a long-standing
mystery in early tetrapod evolution:


Timothy R. Smithson, Stanley P. Wood, John E. A. Marshall, and
Jennifer A. Clack (2012)
Earliest Carboniferous tetrapod and arthropod faunas from Scotland
populate Romer's Gap.
Proceedings of the National Academy of Sciences (advance online publication)
doi: 10.1073/pnas.1117332109
http://www.pnas.org/content/early/2012/02/27/1117332109.abstract?sid=77288ea0-6da6-4f1e-b892-abece2f20bab


Abstract
Devonian tetrapods (limbed vertebrates), known from an increasingly
large number of localities, have been shown to be mainly aquatic with
many primitive features. In contrast, the post-Devonian record is
marked by an Early Mississippian temporal gap ranging from the
earliest Carboniferous (Tournaisian and early Viséan) to the
mid-Viséan. By the mid-Viséan, tetrapods had become effectively
terrestrial as attested by the presence of stem amniotes, developed an
essentially modern aspect, and given rise to the crown group. Up to
now, only two localities have yielded tetrapod specimens from the
Tournaisian stage: one in Scotland with a single articulated skeleton
and one in Nova Scotia with isolated bones, many of uncertain
identity. We announce a series of discoveries of Tournaisian-age
localities in Scotland that have yielded a wealth of new tetrapod and
arthropod fossils. These include both terrestrial and aquatic forms
and new taxa. We conclude that the gap in the fossil record has been
an artifact of collection failure.

News Story:

http://www.bbc.co.uk/news/uk-scotland-south-scotland-17258372