Affiliation:
1. Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
2. University Museum of Zoology Cambridge, Downing Street, Cambridge CB2 3EJ, UK
Abstract
A new genus and species of Devonian tetrapod,
Brittagnathus minutus
gen. et sp. nov., is described from a single complete right lower jaw ramus recovered from the
Acanthostega
mass-death deposit in the upper part of the Britta Dal Formation (upper Famennian) of Stensiö Bjerg, Gauss Peninsula, East Greenland. Visualization by propagation phase contrast synchrotron microtomography allows a complete digital dissection of the specimen. With a total jaw ramus length of 44.8 mm,
Brittagnathus
is by far the smallest Devonian tetrapod described to date. It differs from all previously known Devonian 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
Brittagnathus
crownward to other Devonian tetrapods, adjacent to the Tournaisian genus
Pederpes
. 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.
Funder
Knut och Alice Wallenbergs Stiftelse
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