Letters to Nature

Nature 425, 501-504 (2 October 2003) | doi:10.1038/nature02001; Received 12 February 2003; Accepted 11 August 2003

The oldest articulated chondrichthyan from the Early Devonian period

Randall F. Miller1, Richard Cloutier2 & Susan Turner1,3

  1. Steinhammer Palaeontology Laboratory, New Brunswick Museum, Saint John, New Brunswick E2K 1E5, Canada
  2. Laboratoire de Biologie évolutive, Université du Québec à Rimouski, Rimouski, Quebec G5L 3A1, Canada
  3. School of Geosciences, Monash University, Clayton, Victoria 3088, and Queensland Museum, South Brisbane, Queenland 4101, Australia

Correspondence to: Randall F. Miller1 Email: millerrf@nb.aibn.com

Chondrichthyans (including living sharks, skates, rays and chimaeras) have a fossil record of scales and dermal denticles perhaps dating back to the Late Ordovician period, about 455 million years ago1, 2. Their fossil tooth record extends to the earliest Devonian period, almost 418 million years ago3, whereas the oldest known articulated shark remains date from the Early Devonian period4, about 394 million years ago5. Here we report the discovery of an articulated shark that is almost 409 million years old5 from the Early Devonian (early Emsian) period of New Brunswick, Canada. The specimen, identified as Doliodus problematicus (Woodward)6, sheds light on the earliest chondrichthyans and their interrelationships with basal jawed vertebrates. This species has been truly problematic7. Previously known only from isolated teeth2, 6, 8, it has been identified as an acanthodian and a chondrichthyan. This specimen is the oldest shark showing the tooth families in situ, and preserves one of the oldest chondrichthyan braincases. More notably, it shows the presence of paired pectoral fin-spines, previously unknown in cartilaginous fishes.