Ancestry of the Tetrapods

  title={Ancestry of the Tetrapods},
  author={Thomas Stanley Westoll},
DURING the last few decades it has become increasingly clear that theTetrapods were derived from a group of fishes having their closest affinities with the Devonian Crossopterygii and Dipnoi. In 1932, Save-Soderbergh published a valuable description1 of some fossils, from the “Upper Devonian” of East Greenland, which afford a valuable bridge between the Crossopterygii and the Carboniferous Stegocephalians. These forms, the Ichthyostegalia, are much closer to the Stegocephalians than to the… 
Baraminological analysis of Devonian and Carboniferous tetrapodomorphs
According to evolutionary theory, the origin of tetrapods (or limbed vertebrates) from a fish-like ancestor during the Devonian Period was one of the major events in the history of life. Devonian
Elpistostege and the origin of the vertebrate hand
It is suggested that the vertebrate hand arose primarily from a skeletal pattern buried within the fairly typical aquatic pectoral fin of elpistostegalians, and is potentially the sister taxon of all other tetrapods, and its appendages further blur the line between fish and land vertebrates.
A near‐tetrapod from the Baltic Middle Devonian
Livoniana has a strikingly autapomorphic dentary dentition comprising multiple tooth rows, providing evidence both for the unexpectedly early evolution of tetrapod characteristics and for morphological radiation around the fish‐tetrapod transition.
Early Tetrapods: Experimenting with Form and Function
This chapter describes the ear regions of tetrapods from the Paleozoic. In the past couple of decades, understanding of their morphology has been increased by discoveries of fossils from the Late
Litoniana has a strikingly autapomorphic dentary dentition comprising multiple tooth rows and provides evidence both for the unexpectedly early evolution of tetrapod characteristics and for morphological radiation around the fish-tetrapod transition.
The Devonian actinopterygian Cheirolepis Agassiz
The structure of the fishes constituting the Devonian genus Cheirolepis is investigated. Articulated remains from the Scottish Old Red Sandstone and the Canadian Upper Devonian were studied and two
The Fish–Tetrapod Transition: New Fossils and Interpretations
  • J. Clack
  • Geology
    Evolution: Education and Outreach
  • 2009
Study of modern vertebrates, especially the evolutionary developmental genetics of Hox genes, are beginning to provide clues to the origin of digits, and these include new tetrapod-like fish and very primitive tetrapods that help to resolve questions of the sequence of acquisition of Tetrapod characters.
IV.—The Origin of Continental Vertebrate Faunas
  • T. S. Westoll
  • Geology, Geography
    Transactions of the Glasgow Geological Society
  • 1958
It is now well-established that the land surfaces of the world have not always carried an extensive vegetation or a substantial animal population, and there are innumerable papers in the scientific
A Devonian tetrapod-like fish and the evolution of the tetrapod body plan
The discovery of a well-preserved species of fossil sarcopterygian fish from the Late Devonian of Arctic Canada that represents an intermediate between fish with fins and tetrapods with limbs, and provides unique insights into how and in what order important tetrapod characters arose is reported.


On a Specimen of Eusthenopteron from the Old Red Sandstone of Scotland
While examining the collection of Old Red Sandstone fishes in the Royal Scottish Museum, the writer found the frontoethmoid shield of a Crossopterygian fish, from Eoghole, on the Muckle Burn, near
On the Structures of the Dermal Ethmoid Shield of Osteolepis
The structure of the fronto-ethmoid shield of Osteolepis macrolepidotus Ag is described fully for the first time, and the homology of the dermal bones is discussed, with the recognition of a sensory-canal bone bearing teeth in the position of the premaxillary of Tetrapods.