The origin(s) of extant amphibians: a review with emphasis on the “lepospondyl hypothesis”

  title={The origin(s) of extant amphibians: a review with emphasis on the “lepospondyl hypothesis”},
  author={David Marjanovi{\'c} and Michel Laurin},
ABSTRACT The origins of the extant amphibians (frogs, salamanders, caecilians) remain controversial after over a century of debate. Three groups of hypotheses persist in the current literature: the “temnospondyl hypothesis” (TH) which roots Lissamphibia Haeckel, 1866 (the smallest clade composed of the extant amphibians) within the Paleozoic temnospondyls, the “lepospondyl hypothesis” (LH) which postulates a monophyletic Lissamphibia nested within the Paleozoic lepospondyls, and the “polyphyly… 

A review of the fossil record of caecilians (Lissamphibia: Gymnophionomorpha) with comments on its use to calibrate molecular timetrees

The caecilian fossil record is revisited, providing a brief description of all known extinct taxa described so far, along with general remarks about their impact on systematics, time range, and geographical distribution of the clade, as well as prospects for future research.

A Review of the Fossil record of Gymnophiona (Tetrapoda; Lissamphibia) with Comments on Its Use to Calibrate Molecular Timetrees

Gymnophiona, the most poorly known group of extant amphibians, includes elongated limbless tetrapods, with compact ossified skulls and reduced eyes, mainly adapted to fossorial life (only the

What do ossification sequences tell us about the origin of extant amphibians?

Analysis of the cranial data support a monophyletic origin among lepospondyls; a monophical origin among temnosponyls, the current near-consensus, is a distant second; all other hypotheses are exceedingly unlikely according to the data.

The putative lissamphibian stem-group: phylogeny and evolution of the dissorophoid temnospondyls

  • R. Schoch
  • Biology, Environmental Science
    Journal of Paleontology
  • 2018
An inclusive phylogenetic analysis of dissorophoids gives new insights into the large-scale topology of relationships, including a basal dichotomy between the large, heavily ossified Olsoniformes and the small salamander-like Amphibamiformes.

The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia

High Resolution X-ray Computed Microtomography has revealed previously unrecorded features of albanerpetontid skull morphology in three dimensions, including the presence of a supraoccipital and epipterygoids, neither of which occurs in any known lissamphibian.

Cranial Morphology of the Carboniferous-Permian Tetrapod Brachydectes newberryi (Lepospondyli, Lysorophia): New Data from µCT

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.

A Triassic stem-salamander from Kyrgyzstan and the origin of salamanders

A new specimen of Triassurus sixtelae is reported, a hitherto enigmatic tetrapod from the Middle/Late Triassic of Kyrgyzstan, which is identified as the geologically oldest stem-group salamander, shedding light not only on the early evolution of the salamanders body plan, but also on the origin of the group as a whole.

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.

Amphibia: A Case of Diversity and Convergence in the Auditory Region

It is argued that the loss of the tympanic system was an evolutionary option only available after the batrachian operculum had evolved, and is exemplified by the temnospondyl ear.

Cranial Morphology of the Brachystelechid ‘Microsaur’ Quasicaecilia texana Carroll Provides New Insights into the Diversity and Evolution of Braincase Morphology in Recumbirostran ‘Microsaurs’

The organization of the skull roof and braincase of Quasicaecilia is found to be more in line with that of other recumbirostrans than previously described, despite differences in overall shape, and the importance of future attention to the role of the cervical musculature is underscored.



The Origin(s) of Modern Amphibians: A Commentary

Anderson (2008) argues that the LH is mainly supported by loss char-acters, and that this is problematic ‘’given the relative easethat these losses can arise via paedomorphosis, which appears to evolve repeatedly’’, and emphasizes develop-ment characters such as digit development and skull ossi-fication order, which are known to be homoplastic.

A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders

The discovery of an amphibamid temnospondyl from the Early Permian of Texas that bridges the gap between other Palaeozoic amphibians and the earliest known salientians and caudatans from the Mesozoic is reported.

Focal Review: The Origin(s) of Modern Amphibians

The present paper reviews the impact of this fossil on morphological and molecular phylogenies, and divergence timing estimates based on molecular models and the fossil record, and raises questions over either the validity of morphological analyses that support lissamphibian polyphyly or about the possibility of long branch attraction given the short internal divergences and long subsequent branches.


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.

A New Amphibamid (Temnospondyli: Dissorophoidea) from the Early Permian of Texas

A new genus and species of amphibamid, Rubeostratilia texensis, represented by a skull from the Early Permian of Texas, shows many similarities with a recent described species from Richards Spur, Oklahoma, Pasawioops mayi.

A reevaluation of the evidence supporting an unorthodox hypothesis on the origin of extant amphibians

The most parsimonious trees - now longer by almost 64% - support one of the three commonly advocated hypotheses, namely a monophyletic Lissamphibia nested, together with its sister-group Albanerpetontidae, within the temnospondyls (next to Doleserpeton) - even though the authors did not add any characters or taxa to the very small data matrix.

The origin of modern amphibians: a re-evaluation

A matrix based on data from all three hypotheses and analysed key taxa phylogenetically using both Bayesian inference and parsimony supported the temnospondyl hypothesis of lissamphibian origins.

Dates, nodes and character conflict: Addressing the Lissamphibian origin problem

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.


The Palaeozoic Ancestry of Salamanders, Frogs and Caecilians

Recognition of a sister-group relationship between Permo-Carboniferous branchiosaurids and crown-group salamanders makes it possible to determine the sequence of changes in the anatomy and ways of life that occurred during the origin of urodeles, and to determine their time of divergence relative to that of frogs and caecilians.