Elpistostege and the origin of the vertebrate hand

Richard Cloutier, Alice Clement, Michael Lee, Roxanne Noel, Isabelle Bechard, Vincent Roy, John Long

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)
16 Downloads (Pure)

Abstract

The evolution of fishes to tetrapods (four-limbed vertebrates) was one of the most important transformations in vertebrate evolution. Hypotheses of tetrapod origins rely heavily on the anatomy of a few tetrapod-like fish fossils from the Middle and Late Devonian period (393–359 million years ago) 1. These taxa—known as elpistostegalians—include Panderichthys 2, Elpistostege 3,4 and Tiktaalik 1,5, none of which has yet revealed the complete skeletal anatomy of the pectoral fin. Here we report a 1.57-metre-long articulated specimen of Elpistostege watsoni from the Upper Devonian period of Canada, which represents—to our knowledge—the most complete elpistostegalian yet found. High-energy computed tomography reveals that the skeleton of the pectoral fin has four proximodistal rows of radials (two of which include branched carpals) as well as two distal rows that are organized as digits and putative digits. Despite this skeletal pattern (which represents the most tetrapod-like arrangement of bones found in a pectoral fin to date), the fin retains lepidotrichia (fin rays) distal to the radials. We suggest that the vertebrate hand arose primarily from a skeletal pattern buried within the fairly typical aquatic pectoral fin of elpistostegalians. Elpistostege is potentially the sister taxon of all other tetrapods, and its appendages further blur the line between fish and land vertebrates.

Original languageEnglish
Pages (from-to)549-554
Number of pages6
JournalNature
Volume579
Issue number7800
DOIs
Publication statusPublished - 26 Mar 2020

Keywords

  • Elpistostege
  • vertebrate hand
  • evolution
  • tetrapod

Fingerprint

Dive into the research topics of 'Elpistostege and the origin of the vertebrate hand'. Together they form a unique fingerprint.

Cite this