Rapid braincase evolution between Panderichthys and the earliest tetrapods

  title={Rapid braincase evolution between Panderichthys and the earliest tetrapods},
  author={Per Erik Ahlberg and Jennifer Alice Clack and Ervīns Lukevi{\vc}s},
THE panderichthyids (or elpistostegids) are the most tetrapod-like fishes that still retain paired fins rather than limbs. During the transition from fish to tetrapod, the braincase, previously subdivided by a joint, was remodelled into a solid structure4. Here we present the complete braincase of the fish Panderichthys rhombolepis, a Middle Devonian1 member of the tetrapod stemgroup2,3. Panderichthys has an externally tetrapod-like skull2, but we show that the braincase retained 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.

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.

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

Sarcopterygian Fishes, the “Lobe-Fins”

This chapter will introduce you to groups now known exclusively from fossils such as “dagger-toothed” onychodonts and porolepiforms named so for the special pores in their scales.

Osteolepiforms and the ancestry of tetrapods

The supposedly discredited idea of osteolepiforms as tetrapod ancestors is supported by the first detailed analysis of the lower part of the Tetrapodomorpha, based on 99 characters scored for 29 taxa.

A Devonian tetrapod-like fish reveals substantial parallelism in stem tetrapod evolution

A large, lobe-finned fish from the Late Devonian of China disrupts previously accepted stem-tetrapod phylogeny and reveals parallel evolution within the lineage, suggesting that ecological diversity and biogeographical provinciality in the tetrapod stem group have been underestimated.

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.


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.

Morphology of Palaeospondylus shows affinity to tetrapod ancestors.

Palaeospondylus gunni, from the Middle Devonian period, is one of the most enigmatic fossil vertebrates, and its phylogenetic position has remained unclear since its discovery in Scotland in 1890

Ventastega curonica and the origin of tetrapod morphology

The skull, exceptionally preserved braincase, shoulder girdle and partial pelvis of Ventastega curonica are presented, a transitional intermediate form between the ‘elpistostegids’ Panderichthys and Tiktaalik and the Devonian tetrapods (limbed vertebrates) Acanthostega and Ichthyostega.



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

The postcranial skeleton of the Devonian tetrapod Tulerpeton curtum Lebedev

A cladistic analysis indicates that Tulerpeton is a reptiliomorph stem-group amniote and the earliest known crown-group tetrapod: Acanthostega and Ichthyostega are successively more derived plesion stem- group tetrapods and do not consititute a monophyletic ichthyostegalian radiation.

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.

The First Tetrapod Finds from the Devonian (Upper Famennian) of Latvia

The lower jaw of Ventastega is strikingly primitive in retaining fangs on the coronoid series, but shares many characters with those of other known Devonian tetrapods, and some of these features are interpreted as basal tetrapod synapomorphies.

Elginerpeton pancheni and the earliest tetrapod clade

Elginerpeton, described here on the basis of cranial remains from Scat Craig, is, together with the fragmentary genus Obruchevichthys from the Upper Frasnian of Latvia and Russia, the oldest known stem tetrapod.

Mechanisms of intracranial kinetics in fossil rhipidistian fishes (Crossopterygii) and their relatives

While in the Amphibia the kinetic ability of the skull is almost wholly restricted, the dynamic features of the ancestral condition are modified and developed as the basal articulation between the palate and endocranium is retained.

Tetrapod or near-tetrapod fossils from the Upper Devonian of Scotland

  • P. Ahlberg
  • Geography, Environmental Science
  • 1991
SINCE 1932, the earliest known undisputed tetrapods have been of uppermost Famennian (late Upper Devonian) age1–3. Although a probable tetrapod jaw has been described from the Lower Famennian4, and


A recent review by Rosen et al. (1981) claims that Dipnoi (lungfish) are the sister‐group of the Tetrapoda, that Osteolepiformes is a non‐taxon and that Eusthenopteron is more distant from tetrapods than are Dip noi, coelacanths and probably the fossil Porole piformes, are refuted by use of the same cladistic technique.

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.

The origin and early diversification of tetrapods

Devonian tetrapods were more fish-like than believed previously, whereas Lower Carboniferous tetrapod faunas contain early representatives of the amphibian and amniote lineages.