Data from: The smallest known Devonian tetrapod shows unexpectedly derived features, Part 2 of 2

<p>A new genus and species of Devonian tetrapod, <i>Brittagnathus minutus</i> gen. et sp. nov., is described from a single complete right lower jaw ramus recovered from the <i>Acanthostega</i> mass-death deposit in the upper part of the Britta Dal Formation (upper Famennian) of Stensiö Bjerg, Gauss Peninsula, East Greenland. Visualisation by propagation phase contrast synchrotron microtomography (PPC-SRμCT) allows a complete digital dissection of the specimen. With a total jaw ramus length of 44.8 mm, <i>Brittagnathus</i> is by far the smallest Devonian tetrapod described to date. It differs from all previously knownDevonian tetrapods in having only a fang pair without a tooth row on the anterior coronoid, and a large posterior process on the posterior coronoid. The presence of an incipient surangular crest and a concave prearticular margin to the adductor fossa together cause the fossa to face somewhat mesially, reminiscent of the condition in Carboniferous tetrapods. A phylogenetic analysis places <i>Brittagnathus</i> crownward to other Devonian tetrapods, adjacent to the Tournaisian genus <i>Pederpes</i>. Together with other recent discoveries, it suggests that diversification of 'Carboniferous-grade' tetrapods had already begun before the end of the Devonian and that the group was not greatly affected by the end-Devonian mass extinction.</p>