A new sawshark, Pristiophorus laevis, from the Eocene of Antarctica with comments on Pristiophorus lanceolatus

Abstract

The highly fossiliferous Eocene deposits of the Antarctic Peninsula are among the most productive sites for fossil remains in the Southern Hemisphere and offer rare insights into high-latitude faunas during the Palaeogene. Chondrichthyans, which are represented by abundant isolated remains, seemingly dominate the marine assemblages. Eocene Antarctic sawsharks have only been known from few isolated rostral spines up to now, that were assigned to Pristiophorus lanceolatus. Here, we present the first oral teeth of a sawshark from the Eocene of Seymour Island and a re-evaluation of previously described Pristiophorus remains from Gondwana consisting exclusively of rostral spines. The holotype of Pristiophorus lanceolatus represents a single, abraded and insufficiently illustrated spine from the Oligocene of New Zealand. All other Cenozoic rostral spines assigned to this species are morphologically very indistinct and closely resemble those of living taxa. Consequently, we regard this species as dubious and introduce a new species, Pristiophorus laevis, based on oral teeth. The combination of dental characteristics of the new species makes it unique compared to all other described species based on oral teeth. Rostral spines from the Eocene of Seymour Island are assigned to this new species whereas those from other Cenozoic Gondwana localities remain ambiguous.

LSID urn:lsid:zoobank.org:pub:7177A373-527B-4315-85F6-25180DB5E087

Keywords:

• Seymour Island
• Palaeogene
• Southern Ocean
• Pristiophoridae
• new taxon

Acknowledgement

The Argentinian Antarctic Institute (IAA-DNA), Argentinian Air Force and Swedish Polar Research Secretariat (SPFS) are acknowledged for logistic support for field-work on Seymour Island. The authors are grateful to Martin de los Reyes, Museo de La Plata, for picking the small fractions in the laboratory.