Discovery of the earliest-known tetrapod stapes

  title={Discovery of the earliest-known tetrapod stapes},
  author={Jennifer Alice Clack},
  • J. Clack
  • Published 1 November 1989
  • Medicine
  • Nature
THE evolution of the middle ear is central to the discussion of how the first tetrapods adapted to life on land as well as their phylogeny1–3. Here I report the discovery of the stapes of Acanthostega gunnari, from the Upper Devonian of east Greenland. This is the earliest tetrapod stapes so far described, and it throws new light on both these aspects of early tetrapod biology. It has been assumed that the common inheritance of all early tetrapods was a light, rod-like stapes associated with a… 

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

Patterns and processes in the early evolution of the tetrapod ear.

  • J. Clack
  • Geography
    Journal of neurobiology
  • 2002
The changes that can be documented across the fish-tetrapod transition, the patterns that they show and what can be inferred of the processes that brought some of them about are looked at.

Tetrapod-like middle ear architecture in a Devonian fish

It is shown that the spiracular region is radically transformed from osteolepiforms and represents the earliest stages in the origin of the tetrapod middle ear architecture, suggesting that the middle ear of early tetrapods evolved initially as part of a spiracular breathing apparatus.

Fish-like gills and breathing in the earliest known tetrapod

The discovery of a fish-like branchial skeleton in Acanthostega gunnari, from the Upper Devonian of East Greenland, one of the earliest tetrapods known, provides information on the sequence of acquisition of tetrapod characters, and supports previous suggestions that such characters as legs with digits evolved first for use in water.

Homologies in the fossil record: The middle ear as a test case

Examining the middle ear of fossil living animals in terms of the homologies which have been drawn between its parts in different vertebrate groups finds that most of the conceptions have been overturned in recent years by new fossil discoveries and new ways of looking at old data.

The Evolution of Single- and Multiple-Ossicle Ears in Fishes and Tetrapods

The Ostariophysi are the hearing specialists of the ray-finned world and include the gonorynchiforms and a much larger group called the Otophysi, distinguished by having some of the anterior neural arches and supraneurals modified into the Weberian apparatus.

The Water-to-Land Transition: Evolution of the Tetrapod Basilar Papilla, Middle Ear, and Auditory Nuclei

The water-to-land transition apparently coincided with the coevolution of a tympanic middle ear, a basilar papilla, and a periotic labyrinth in the inner ear, as well as neural pathways devoted to the processing of airborn sound in tetrapods.

The ear region of Latimeria chalumnae: functional and evolutionary implications.

The possibility is considered that the canalis communicans does not possess any auditory function but rather is involved in sensing pressure changes during movements involving the intracranial joint, and earlier hypotheses of a putative tympanic ear are refuted.

The neurocranium of Acanthostega gunnari Jarvik and the evolution of the otic region in tetrapods

Abstract The neurocranium of Acanthostega gunnari is described from several specimens, and is the first full description of a Devonian tetrapod braincase. It is shown to resemble the osteolepiform

fossil The neurocranium of Acanthostega gunnari Jarvik and the evolution of the otic region in tetrapods

The neurocranium of Acanthoskga gunnari is described from several specimens, and is the first full description of a Devonian tetrapod braincase. It is shown to resemble the osteolepiform



The stapes of the Coal Measures embolomere Pholiderpeton scutigerum Huxley (Amphibia: Anthracosauria) and otic evolution in early tetrapods

The embolomere middle ear structure is reinterpreted as a receiver for low-frequency sound and the ‘otic notch’ is not considered to have housed a tympanum, a conclusion which forces the abandonment of the concept of a ‘labyrinthodont middle ear’.

The skull and skeleton of Eogyrinus attheyi Watson (Amphibia: Labyrinthodontia)

The material described in this paper is combined with that used in an earlier account of the axial skeleton to give a reconstruction of the whole skeleton of Eogyrinus in articulation, together with a restoration of the appearance of the living animal.

The cranial morphology of Greererpeton burkemorani Romer (Amphibia: Temnospondyli)

These systematic conclusions endorse the recent suggestions that neither the Lepospondyli nor the Labyrinthodontia are natural groups, and both terms should be abandoned.

The Nothosaur Pachypleurosaurus and the Origin of Plesiosaurs

It is concluded that the transition between primitive terrestrial diapsids and plesiosaurs occurred via a succession of changes in patterns of aquatic locomotion and Pachypleurosaurus has the greatest degree of development of the anterior portion of the shoulder girdle, suggesting that the recovery stroke was of considerable importance.

Evolution of the amphibian tympanic ear and the origin of frogs

The otic features described here reinforce the concept of the amphibian tympanic ear as a prior “invention” with no genealogical relationship to amniote tympic ears.

On the Amphibian Crassigyrinus scoticus Watson from the Carboniferous of Scotland

A case is made for the 'sister-group' relation of Crassigyrinus to the anthracosauroids and a cladogram presented of the subgroups involved; it is, however, difficult to make a case for the close relationship of CrASSIGyrinus and the Seymouriamorpha and the closeness of relationship of the latter to anthracosaurs is questioned.

Pholiderpeton scutigerum Huxley, an Amphibian from the Yorkshire Coal Measures

The evidence suggests that the eogyrinids, like the archeriids, were long-bodied with a presacral count of 40 and forelimb function in Pholiderpeton was more flexible than that proposed for the related Proterogyrinus.

The Evolution of the amphibian auditory system

This book summarizes all aspects of the amphibian auditory system, reviewing current knowledge of the structure, function and evolution of this sensory system, and offers new contributions to the authors' understanding of this subject.

The Evolution of Air Breathing in Vertebrates

Preface 1. Introduction: air breathing in vertebrates 2. Gas transfer: the transition from water to air breathing 3. Ventilation and perfusion relationships 4. Mechanisms of ventilation 5.