Fish-like gills and breathing in the earliest known tetrapod

  title={Fish-like gills and breathing in the earliest known tetrapod},
  author={Michael I. Coates and Jennifer Alice Clack},
THE origin of tetrapods is generally associated with the emergence of terrestrial vertebrate life. Anatomical features unique to tetrapods are usually considered to be adaptations to the terrestrial environment. Here we report the discovery of a fish-like branchial skeleton in Acanthostega gunnari, from the Upper Devonian of East Greenland, one of the earliest tetrapods known. It shows a proximally expanded ceratohyal and large, ventrally grooved ceratobranchials. Such grooves are found in the… 

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.

Proposed habitats of early tetrapods: gills, kidneys, and the water–land transition

It is suggested that the apparent loss of the gills in tetrapods more derived than Acanthostega signals their descent from a more terrestrial phase in Tetrapod evolution, following the primary assumption by the kidney of the excretion of nitrogenous wastes.

Proposed habitats of early tetrapods: gills, kidneys, and the waterland transition

Recent finds of early tetrapods have established that the most primitive form, Acanthostega, retained internal gills and other fish-like features; this has led to the conclusion that it was a

Bystrow’s Paradox – gills, fossils, and the fish-to-tetrapod transition

It is found that internal gills were present in a range of early crown tetrapods (temnospondyls) based on the anatomy of gill lamellae and location of branchial arteries on the ventral side of gills arch elements (ceratobranchials).

Terrestrial-style feeding in a very early aquatic tetrapod is supported by evidence from experimental analysis of suture morphology

The suture morphologies of Acanthostega are inconsistent with the hypothesis that it captured prey primarily by means of suction, which suggests that it may have bitten directly on prey at or near the water's edge, and the data strongly support the hypotheses that the terrestrial mode of feeding first emerged in aquatic taxa.

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

Plastic loss of motile cilia in the internal gills of Polypterus in response to high CO2 or terrestrial environments

The evolutionary transition of vertebrates from water to land during the Devonian period was accompanied by major changes in animal respiratory systems in terms of physiology and morphology. Indeed,

Phylogenetic patterns of character evolution in the hyobranchial apparatus of early tetrapods

  • F. Witzmann
  • Environmental Science, Biology
    Earth and Environmental Science Transactions of the Royal Society of Edinburgh
  • 2013
A fish-like hyobranchium in basal tetrapod lineages does not necessarily represent a larval or paedomorphic character, respectively, as was often suggested in analogy to extant salamanders, rather, it represents the plesiomorphic state of the adult hyob Franchium in tetrapods.

The cranial endoskeleton of Tiktaalik roseae

The braincase, palatoquadrate and branchial skeleton of Tiktaalik roseae, the Late Devonian sarcopterygian fish most closely related to tetrapods, is described and suggests changes in head mobility and intracranial kinesis that have ramifications for the origin of vertebrate terrestriality.

Earliest known tetrapod braincase and the evolution of the stapes and fenestra ovalis

ACANTHOSTEGA gunnari, from the Upper Devonian (Famennian) of East Greenland, is the most primitive known tetrapod, and retains many fish-like characters1–4. I report here the discovery of further



Dipnoan (lungfish) skulls and the relationships of the group: a study based on new species from the Devonian of Australia

Four new species of dipnoan fishes (lungfishes) are described from the Frasnian of Western Australia: Griphognathus whitei, Chirodipterus australis, C. paddyensis and Holodipterus gogoensis. These

Discovery of the earliest-known tetrapod stapes

It is suggested that the temporal notch of Acanthostega and other early tetrapods supported a spiracular opening rather than a tympanum, and that the stapes controlled palatal and spiracular movements in ventilation.

Polydactyly in the earliest known tetrapod limbs

The morphology of the specimens suggests that limbs with digits may have been adaptations to an aquatic rather than a terrestrial environment, and challenges pentadactyly as primitive for tetrapods.

Two Perspectives on the Evolution of the Tetrapod Limb

A re-analysis of the limb characters advocated by Rosen et al. (1981) does not support their contention that lungfishes are the sister group of tetrapods, but instead suggests that rhipidistian fishes of the family Osteolepidae are the closest relatives of the tetrapoda.

Geological and palaeontological information and phylogenetic hypotheses

Abstract A number of workers have accepted the proposition that phylogenetic relations between extant organisms can be determined only by reference to the characters of those organisms.

Biology of Amphibians

This chapter discusses the origins and status of the lissamphibia cytogenetic, molecular and genomic evolution - cytogenetics, molecular evolution, genomic evolution phylogeny, and the evolutionary significance of metamorphosis.

Invertebrate Palaeontology and Evolution

The fossil record of Macrofossils on CD--Rom is presented in detail, with examples from the Cretaceous, Tournaisian, and Jurassic periods, as well as new discoveries from the Carboniferous period.