The Lower Permian amphibamidDoleserpeton(Temnospondyli: Dissorophoidea), the interrelationships of amphibamids, and the origin of modern amphibians

Sigurdsen, Trond; Bolt, John R.

doi:10.1080/02724634.2010.501445

Cited by 77 publications

(104 citation statements)

References 42 publications

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“…They range in size from the miniaturized amphibamid Doleserpeton, with delicate bicuspid pedicelate teeth and an average skull length of about 1 cm, to the large trematopid Acheloma, with dagger-like large teeth and an estimated skull length of about 20 cm. Some taxa are known from fragmentary remains, or one or two specimens (Anderson and Bolt, 2013;Fröbisch and Reisz, 2008;Fröbisch and Reisz, 2012), while the amphibamid Doleserpeton occurs in copious amounts (Bolt, 1969;Sigurdsen and Bolt, 2010). Nevertheless, we see a greater taxic diversity of dissorophoids than in any other Paleozoic locality.…”

Section: Introductionmentioning

confidence: 62%

New specimen of Cacops woehri indicates differences in the ontogenetic trajectories among cacopine dissorophids

2015

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Abstract. The Lower Permian Dolese locality has produced numerous exquisitely preserved tetrapod fossils representing members of a lower Permian upland fauna. Therein, at least nine taxa of the clade Dissorophoidea, ranging in size from the large predaceous trematopid Acheloma to the miniaturized amphibamid Doleserpeton, highlight the great taxic and ecological diversity of this anamniote clade. Here we describe a large specimen of the dissorophid Cacops woehri, which was previously only known from the juvenile or subadult holotype skull. Another member of the genus Cacops present at the Dolese locality, Cacops morrisi, is also represented by specimens spanning juvenile, subadult, and adult stages, allowing for a comparison of morphological changes taking place in the late phases of the ontogenetic trajectory of cacopine dissorophids. The new find shows that, in contrast to C. morrisi and C. aspidephorus, C. woehri only undergoes relatively subtle changes in skull morphology in late ontogeny and retains the overall more gracile morphology into adult stages. This includes retention of the rather shallow skull shape as well as a pattern of sculpturing consisting of elongate ridges and grooves and a large occipital flange. This suggests somewhat different functional demands in C. woehri than in other known species of Cacops, possibly associated with a different ecology paralleling the great taxic diversity of dissorophoids at the Dolese locality.

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Section: Introductionmentioning

confidence: 62%

New specimen of Cacops woehri indicates differences in the ontogenetic trajectories among cacopine dissorophids

2015

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“…In contrast to these features, the enlarged interpterygoid vacuities and the reduction of lateral palate elements appear to have evolved in parallel in amphibamids and dissorophoids: this is not only indicated by the possession of the plesiomorphic state in trematopids (which retain the pterygoid-vomer contact for instance), but more importantly by the slightly different architecture of amphibamid and dissorophid palates. Whereas amphibamids reduced the width of the posterior palatine and ectopterygoid (reaching a minimum in Doleserpeton, which might even have lost the ecotpterygoid -see Sigurdsen & Bolt 2010), dissorophids retained relatively broad palatine and ectopterygoid bones accommodating a foreshortened pterygoid. In adult Cacops morrisi and Kamacops, the palatine encloses the tip of the pterygoid medially, a condition that differs remarkably from all other temnospondyls.…”

Section: Character Evolutionmentioning

confidence: 99%

Character distribution and phylogeny of the dissorophid temnospondyls

Schoch

2012

Fossil Record

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“…Although the majority of contributions in this area have targeted primarily the Mesozoic radiation-namely the stereospondyls (Yates & Warren, 2000;Maganuco et al, 2009;see Schoch & Milner, 2000 for a compendium of this group)-the relationships of Paleozoic temnospondyls have recently gained attention (for a succinct bibliography, see Ruta & Bolt, 2006;Anderson, 2008;). In particular, among Permian and Carboniferous groups, dissorophoids have been the focus of cladistic works spurred by recent discoveries (e.g., Huttenlocker et al, 2007;Anderson et al, 2008a,b;Frö bisch & Reisz, 2008;Reisz et al, 2009;Bourget & Anderson, 2011), assembly of new character matrices (e.g., Schoch & Milner, 2008), and new data on previously described taxa (e.g., Schoch & Rubidge, 2005;Clack & Milner, 2010;Sigurdsen & Bolt, 2009. In addition, recent studies have re-emphasized the role of dissorophoids in the debate on the origin and status of the extant lissamphibians (e.g., Ruta et al, 2003;Ruta & Coates, 2007;Anderson, 2008;Anderson et al, 2008b;Frö bisch & Schoch, 2009a).…”

Section: A ''Backbone Supertree'' For Paleozoic Temnospondylsmentioning

confidence: 98%

The Roots of Amphibian Morphospace: A Geometric Morphometric Analysis of Paleozoic Temnospondyls

Angielczyk

Ruta

2012

Fieldiana Life and Earth Sciences

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Temnospondyls-a major component of Permian and Carboniferous terrestrial ecosystems-display great diversity in skull shapes and proportions. To quantify and interpret this diversity, we conducted a geometric morphometric analysis using 45 landmarks on the dorsal skull surface of 90 species with well-represented cranial material. Results show a correlation between morphospace occupation and phylogenetic proximity of taxa for trees in which dvinosaurs and dissorophoids are sister groups and join an edopoid--eryopoid-basal archegosauriform clade. Most large groups of Carboniferous and Permian temnospondyls occupy specific areas of morphospace. Nearest-neighbor analyses reveal significantly greater taxon clustering than expected under either uniform or Gaussian null models. Size correlates strongly with shape across the whole data set, highlighting the association of some features (short, broad snout; large orbits) with small size. A significant relationship between size and shape is not observed in clades such as branchiosaurids, dvinosaurs, and olsoniforms (the clade encompassing trematopids plus dissorophids). This suggests that evolutionary allometry patterns vary across temnospondyls. In the case of branchiosaurids, this pattern may be explained by the similar sizes and relatively conservative morphologies of the constituent species. Distance-based disparity measures indicate that edopoids, eryopoids, and basal archegosauriforms make the largest contributions to total disparity (reflecting the peripheral locations of some of the constituent taxa in morphospace), whereas amphibamids, dissorophids, and trematopids make the smallest contributions. Disparity correlates strongly with diversity within groups, suggesting that skull shape was not subject to character state exhaustion (decrease or cessation in the acquisition of novel morphological conditions during clade evolution). The Kasimovian, Roadian, Wordian, and Changhsingian are time intervals of high disparity despite their low diversity. We hypothesize that this pattern stems from the fact that times of high diversity are characterized by larger areas of morphospace, which results in mean shapes being located relatively close to the grand mean; in contrast, mean shapes for low-diversity stages are based on incomplete morphospace samples. Many of these patterns are similar to those observed in previous analyses of stereospondyls, suggesting that similar controls on skull shape may have operated throughout the history of temnospondyls.

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The Lower Permian amphibamidDoleserpeton(Temnospondyli: Dissorophoidea), the interrelationships of amphibamids, and the origin of modern amphibians

Cited by 77 publications

References 42 publications

New specimen of <i>Cacops woehri</i> indicates differences in the ontogenetic trajectories among cacopine dissorophids

New specimen of <i>Cacops woehri</i> indicates differences in the ontogenetic trajectories among cacopine dissorophids

Character distribution and phylogeny of the dissorophid temnospondyls

The Roots of Amphibian Morphospace: A Geometric Morphometric Analysis of Paleozoic Temnospondyls

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The Lower Permian amphibamidDoleserpeton(Temnospondyli: Dissorophoidea), the interrelationships of amphibamids, and the origin of modern amphibians

Cited by 77 publications

References 42 publications

New specimen of &lt;i&gt;Cacops woehri&lt;/i&gt; indicates differences in the ontogenetic trajectories among cacopine dissorophids

New specimen of &lt;i&gt;Cacops woehri&lt;/i&gt; indicates differences in the ontogenetic trajectories among cacopine dissorophids

Character distribution and phylogeny of the dissorophid temnospondyls

The Roots of Amphibian Morphospace: A Geometric Morphometric Analysis of Paleozoic Temnospondyls

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New specimen of <i>Cacops woehri</i> indicates differences in the ontogenetic trajectories among cacopine dissorophids

New specimen of <i>Cacops woehri</i> indicates differences in the ontogenetic trajectories among cacopine dissorophids