A new dipnoan species Janvierpaucidentes tuulingi gen. et sp. nov. from the Pragian (Early Devonian) of Mimerdalen, Svalbard (Norway), with an unusual dentition

Abstract

A new dipnoan lower jaw from the Wood Bay Formation (Pragian) of Svalbard (Norway), preserves a partial dentary and partial toothplates referred to the new species Janvierpaucidentes tuulingi gen. et sp. nov. The more complete toothplate is elongate with three short rows of teeth but is damaged medially. A large number of dipnoans are known from the early Devonian, showing a range of dentitions. Other tooth-plated dipnoans from this time period include Diabolepis speratus, Speonesydrion iani, Tarachomylax oepiki, Tarachomylax multicostatus, Ichnomylax kurnae and Ichnomylax karatajae, and two unnamed toothplates from Vietnam. In Melanognathus canadensis, rows of teeth are located along the prearticular, which is otherwise covered in a shagreen of denticles; this denticle-dominated dentition also characterized Uranolophus wyomingensis. The dentition of Janvierpaucidentes tuulingi differs from these toothplate morphologies and is highly unusual in having the more rostral and caudal tooth rows nearly paralleling the jaw margin, with a maximum angle between the tooth rows approaching 180 degrees. In this character, Janvierpaucidentes tuulingi is more comparable to taxa such as Xylognathus macrustenus from the Carboniferous, increasing the already high disparity of lungfish dental morphology in the Devonian.