Journal Article

A lamprey from the Devonian period of South Africa

Gess, Robert W., Coates, Michael I., Rubidge, Bruce S.

2006

Overview

Out of the shadows Lampreys and hagfish are the only remaining jawless vertebrates and are commonly used as surrogate ancestors for comparative research on living jawed vertebrates. Until recently little was known of the evolutionary history of lampreys as the only known fossils were enigmatic examples from the Carboniferous period, around 300 million years ago. Then earlier this year Nature published a report of a fine specimen from the Cretaceous of China that looked very close to modern forms. This is now joined by a well preserved fossil from the Devonian of South Africa, which at about 360 million years old is the oldest known lamprey. It looks slightly different from modern lampreys, but is the same in essentials and differs from the various now-extinct armoured fishes with which it shared the Devonian world. Lampreys are the most scientifically accessible of the remaining jawless vertebrates, but their evolutionary history is obscure. In contrast to the rich fossil record of armoured jawless fishes, all of which date from the Devonian period and earlier 1 , 2 , 3 , only two Palaeozoic lampreys have been recorded, both from the Carboniferous period 1 . In addition to these, the recent report of an exquisitely preserved Lower Cretaceous example 4 demonstrates that anatomically modern lampreys were present by the late Mesozoic era. Here we report a marine/estuarine fossil lamprey from the Famennian (Late Devonian) of South Africa 5 , 6 , the identity of which is established easily because many of the key specializations of modern forms are already in place. These specializations include the first evidence of a large oral disc, the first direct evidence of circumoral teeth and a well preserved branchial basket. This small agnathan, Priscomyzon riniensis gen. et sp. nov., is not only more conventionally lamprey-like than other Palaeozoic examples 7 , 8 , but is also some 35 million years older. This finding is evidence that agnathans close to modern lampreys had evolved before the end of the Devonian period. In this light, lampreys as a whole appear all the more remarkable: ancient specialists that have persisted as such and survived a subsequent 360 million years.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Animals / Brackish / Carboniferous / Cretaceous / Devonian / Earth sciences / Earth, ocean, space / Evolutionary biology / Exact sciences and technology / Fossils / History, Ancient / Humanities and Social Sciences / Lampreys - anatomy & histology / Lampreys - growth & development / Larva - anatomy & histology / letter / Marine / Marine biology / Mesozoic / multidisciplinary / Paleontology / Paleozoic / Petromyzontidae / Phylogeny / Science / Science (multidisciplinary) / South Africa / Teeth / Vertebrate paleontology / Vertebrates