Hidden morphological diversity among early tetrapods

@article{Pardo2017HiddenMD,
  title={Hidden morphological diversity among early tetrapods},
  author={Jason D. Pardo and Matt Szostakiwskyj and Per Erik Ahlberg and Jason S. Anderson},
  journal={Nature},
  year={2017},
  volume={546},
  pages={642-645}
}
Phylogenetic analysis of early tetrapod evolution has resulted in a consensus across diverse data sets in which the tetrapod stem group is a relatively homogenous collection of medium- to large-sized animals showing a progressive loss of ‘fish’ characters as they become increasingly terrestrial, whereas the crown group demonstrates marked morphological diversity and disparity. [...] Key Result Digital dissection reveals extremely primitive cranial morphology, including a spiracular notch, a large remnant of the…Expand
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References

SHOWING 1-10 OF 28 REFERENCES
A uniquely specialized ear in a very early tetrapod
TLDR
Ichthyostega's braincase and ear region defied interpretation, such that conventional anatomical terms seemed inapplicable, and can now be seen to form part of a highly specialized ear, probably a hearing device for use in water. Expand
Cranial Morphology of the Carboniferous-Permian Tetrapod Brachydectes newberryi (Lepospondyli, Lysorophia): New Data from µCT
TLDR
The morphology of the skull of a partial growth series of the lysorophian Brachydectes newberryi is studied using x-ray micro-computed tomography and reveals similarities between the braincase of BrachydECTes and brachystelechid recumbirostrans, corroborating prior work suggesting a close relationship between these taxa. Expand
New information on Lethiscus stocki (Tetrapoda: Lepospondyli: Aistopoda) from high-resolution computed tomography and a phylogenetic analysis of Aistopoda
High-resolution computed tomography provides an alternative to serial sectioning and other destructive tech - niques of studying fossils (data available at http://www.DigiMorph.org). This technologyExpand
Cranial anatomy of ophiderpetontid aı̈stopods: Palaeozoic limbless amphibians
Oestocephalus, an ophiderpetontid from the Middle Pennsylvanian of both Europe and North America provides the best known basis for evaluating the relationships of the aistopods. All aistopods areExpand
An early tetrapod from ‘Romer's Gap’
TLDR
Pederpes is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and was at least functionally pentadactyl, bridging the temporal, morphological and phylogenetic gaps that have hitherto separated Late Devonian and mid-Carboniferous tetrapOD faunas. Expand
CRANIAL MORPHOLOGY AND AFFINITIES OF MICROBRACHIS, AND A REAPPRAISAL OF THE PHYLOGENY AND LIFESTYLE OF THE FIRST AMPHIBIANS
TLDR
An anatomical study of Microbrachis reveals inaccuracies in previous studies, especially in the palate and cranial proportions, which corroborates previous suggestions that lissamphibians are part of a clade that includes the taxa classically referred to as “lepospondyls,” and that seymouriamorphs and temnospONDyls are not part of Tetrapoda. Expand
The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution
TLDR
Comparison between axial skeletons of primitive tetrapods suggests that plesiomorphic fish-like morphologies were re-patterned in a cranio-caudal direction with the emergence of tetrapod vertebral regionalisation. Expand
Dates, nodes and character conflict: Addressing the Lissamphibian origin problem
TLDR
Tests of different crown topologies show that placement of amphibians within lepospondyls is not a significantly worse fit for the whole character set than a close temnospondyl‐lissamphibian relationship, and the latter phylogenetic hypothesis best captures the most coherent assembly of derived lissampshibian apomorphies. Expand
Late to the table: diversification of tetrapod mandibular biomechanics lagged behind the evolution of terrestriality.
TLDR
The substantial temporal gap between the origin of postcranial features associated with terrestriality, such as limbs with functional elbow/knee and wrist/ankle joints capable of weight-bearing, and the onset of divergence in jaw biomechanics provides a compelling example of "functional modularity" during a major adaptive radiation. Expand
REVISION OF THE AÏSTOPOD GENUS PHLEGETHONTIA (TETRAPODA: LEPOSPONDYLI)
TLDR
Details of Cranial anatomy contradict a previous model of cranial kinesis by severely limiting the skull's potential mobility and three species are recognised within the family Phlegethontiidae. Expand
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