The Origin of the Amphibia

Szarski, Henryk

doi:10.1086/403656

Cited by 73 publications

(35 citation statements)

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“…2). This fully resolved tree supports the monophyly of living amphibians with respect to other living tetrapods (1,(8)(9)(10)(11)(12)(13)(14)(15)(16) and favors a sister group relationship for salamanders and frogs (the Batrachia hypothesis; refs. 1, 10, 11, 13, and 22).…”

Section: Resultssupporting

confidence: 63%

“…However, these studies failed to distinguish between ancestral and derived characters and did not employ any explicit phylogenetic methodology. Szarski (8) and Parsons and Williams (9) integrated previous morphological and paleontological evidence, and concluded that the Lissamphibia were a natural group. The monophyly of Lissamphibia has since gained wide acceptance among researchers (refs.…”

mentioning

confidence: 94%

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On the origin of and phylogenetic relationships among living amphibians

Zardoya

Meyer

2001

Proc. Natl. Acad. Sci. U.S.A.

103

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The phylogenetic relationships among the three orders of modern amphibians (Caudata, Gymnophiona, and Anura) have been estimated based on both morphological and molecular evidence. Most morphological and paleontological studies of living and fossil amphibians support the hypothesis that salamanders and frogs are sister lineages (the Batrachia hypothesis) and that caecilians are more distantly related. Previous interpretations of molecular data based on nuclear and mitochondrial rRNA sequences suggested that salamanders and caecilians are sister groups to the exclusion of frogs. In an attempt to resolve this apparent conflict, the complete mitochondrial genomes of a salamander (Mertensiella luschani) and a caecilian (Typhlonectes natans) were determined (16,656 and 17,005 bp, respectively) and compared with previously published sequences from a frog (Xenopus laevis) and several other groups of vertebrates. Phylogenetic analyses of the mitochondrial data supported with high bootstrap values the monophyly of living amphibians with respect to other living groups of tetrapods, and a sister group relationship of salamanders and frogs. The lack of phylogenetically informative sites in the previous rRNA data sets (because of its shorter size and higher among-site rate variation) likely explains the discrepancy between our results and those based on previous molecular data. Strong support of the Batrachia hypothesis from both molecule-and morphology-based studies provides a robust phylogenetic framework that will be helpful to comparative studies among the three living orders of amphibians and will permit better understanding of the considerably divergent vertebral, brain, and digit developmental patterns found in frogs and salamanders.iving amphibians (Lissamphibia) are highly successful tetrapods that evolved diverse body plans that differ in modes of locomotion, reproductive specializations, and life histories (1, 2). For instance, the slender body of living salamanders (Caudata) has a well developed tail and proportionally paired limbs, whereas modern caecilians (Gymnophiona) are completely limbless, and are adapted to a fossorial lifestyle, with elongated bodies, protrusible tentacles, and reduced eyes. Extant frogs (Anura) lack tails, and evolved powerful hind limbs and a shortened, stiffened vertebral column (the urostyle)-a unique adaptation for jumping. The earliest fossils currently known of salamanders (Marmorerpeton; ref. , and demonstrate that all three lineages of extant amphibians acquired their peculiar body plan early on in their evolutionary history. The diversity among amphibians coupled with the lack of shared derived characters plus a poor fossil record complicate assessment of the phylogenetic relationships among the three living orders.Early workers on amphibian systematics repeatedly rejected the monophyly of Lissamphibia by proposing independent origins of the living orders of modern amphibians (see ref. 7 for a review). However, these studies failed to distinguish between ancestral and derived c...

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Section: Resultssupporting

confidence: 63%

mentioning

confidence: 94%

On the origin of and phylogenetic relationships among living amphibians

Zardoya

Meyer

2001

Proc. Natl. Acad. Sci. U.S.A.

103

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“…Most researchers agree that modern amphibians (Lissamphibia) form a monophyletic group that appeared in the Permian (280-248 mya) (Duellman & Trueb 1994, Parsons & Williams 1963, Szarski 1962. Among paleontologists it is still debated whether the extinct temnospondyls (e.g., Panchen & Smithson 1987, Trueb & Cloutier 1991 or the extinct lepospondyls (Carroll 1995, Laurin 1998, Laurin & Reisz 1997) are their sistergroup.…”

Section: Phylogenetic Relationships Among Modern Amphibiansmentioning

confidence: 99%

Recent Advances in the (Molecular) Phylogeny of Vertebrates

Meyer

Zardoya

2003

Annu. Rev. Ecol. Evol. Syst.

181

142

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Tetrapodas Abstract The analysis of molecular phylogenetic data has advanced the knowledge of the relationships among the major groups of living vertebrates. Whereas the molecular hypotheses generally agree with traditional morphology-based systematics, they sometimes contradict them. We review the major controversies in vertebrate phylogenetics and the contribution of molecular phylogenetic data to their resolution: (a) the mono-paraphyly of cyclostomes, (b) the relationships among the major groups of rayfinned fish, (c) the identity of the living sistergroup of tetrapods, (d ) the relationships among the living orders of amphibians, (e) the phylogeny of amniotes with particular emphasis on the position of turtles as diapsids, (f ) ordinal relationships among birds, and (g) the radiation of mammals with specific attention to the phylogenetic relationships among the monotremes, marsupial, and placental mammals. We present a discussion of limitations of currently used molecular markers and phylogenetic methods as well as make recommendations for future approaches and sets of marker genes.

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“…Basic features of the amphibian life cycle are first seen in ancient Labyrinthodontia (Szarski, 1962;Baird, 1965), with later forms, especially dissorophids, showing ecological and morphological differences between life cycle phases (DeMar, 1968;Bolt, 1979). Some taxa in all extant salamander families have a larval stage.…”

Section: Tigrinummentioning

confidence: 99%

Shaping intraspecific variation: Development, ecology and the evolution of morphology and life history variation in tiger salamanders

1993

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The tiger salamander, Ambystoma tigrinum, is a geographically widespread, morphologically variable, polytipic species. It is among the most variable species of salamanders in morphology and life history with two larval morphs (typical and cannibal) and three adult morphs (metamorphosed, typical branchiate, cannibal branchiate) that vary in frequency between subspecies and between populations within subspecies. We report morphometric evidence suggesting that branchiate cannibals arose through intraspecific change in the onset or timing of development resulting in the wider head and hypertrophied tooth-bearing skull bones characteristic of this phenotype. We also quantified bilateral symmetry of gill raker counts and abnormalities, then evaluated fluctuating asymmetry as a measure of the developmental stability of each morph. There was a significant interaction between fluctuating asymmetry of developmental abnormalities in cannibals and typicals and the locality where they were collected, suggesting that relative stability of each phenotype could vary among populations. While altered timing of developmental events appears to have a role in the evolution and maintenance of morphs, novel phenotypes persist only under favorable ecological conditions. Predictability of the aquatic habitat, genetic variation, kinship, body size, intraspecific competition and predation all affect expression and survival of the morphs in A. tigrinum. This taxon provides an excellent model for understanding the diversity and complexity of developmental and ecological variables controlling the evolution and maintenance of novel phenotypes.

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The Origin of the Amphibia

Cited by 73 publications

References 0 publications

On the origin of and phylogenetic relationships among living amphibians

On the origin of and phylogenetic relationships among living amphibians

Recent Advances in the (Molecular) Phylogeny of Vertebrates

Shaping intraspecific variation: Development, ecology and the evolution of morphology and life history variation in tiger salamanders

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