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On a new stereospondylomorph temnospondyl from the Middle-Late Permian of Southern Brazil

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Strapasson A., Pinheiro F. L., Soares M. B.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 4

A new temnospondyl is described from the Middle-Upper Permian sequence of the Paraná Basin (Rio do Rasto Formation) in southern Brazil. The material consists of disarticulated cranial and postcranial elements, preserved in association. The cranial elements include part of the orbital region of the skull roof, the basicranium, a number of en-docranial elements, stapes and a right hemimandible. The postcranial elements include vertebrae, ribs, pectoral girdle elements, a right femur and a cluster of scales. The new species displays a rhinesuchid pattern, which is similar to the South African rhinesuchids from the Upper Permian Beaufort Group of the Karoo Basin, but differs from them by the presence of a robust and elongated epipterygoid with a blade-like anterior process in addition to elongated and deeper muscular pockets on the parasphenoid, which allow the assignment of this specimen to a new species. However, the phylogenetic analysis grouped the material described herein andAustralerpeton cosgriffi inside Stereospondylomorpha, in a transitional position between the Laurasian assemblages and South African temnospondyls. This result supports a connection between the Brazilian and Eastern European Permian fauna and provides important data for future biostratigraphic studies.

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On the presence of a pustulated temnospondyl in the Lower Triassic of southern Brazil

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Dias-da-Silva S., Ramos Ilha A. L.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 4

The fossil record of temnospondyls in South America has been greatly expanded in the last 10 years, increasing their overall significance. They occur in Argentina, Brazil, and Uruguay, and range from the Guadalupian to the Late Triassic. The Early Triassic temnospondyl record in southern Brazil is mainly composed of fragmentary specimens, usually represented by dermal skull bones from the Sanga do Cabral Formation. Some of these fragments were tentatively referred to Lydekkerinidae and Rhytidosteidae based on their characteristic ridge−grooved “spider−web” pattern of ornamentation. In this contribution we report, for the first time, a temnospondyl skull fragment with pustulated sculpturing pattern, which is tentatively ascribed to Plagiosauridae. This new record could indicate the presence of a new temnospondyl taxon for the Lower Triassic of South America.

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Revision of the amphibian genus Limnerpeton [Temnospondyli] from the Upper Carboniferous of the Czech Republic

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Milner A. R., Sequeira S. E. K.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 1

The Late Carboniferous amphibian genus Limnerpeton Fritsch, 1881 is revised on the basis of the type specimens of the eight original species described by Fritsch using material from Nýřany, Třemošná and Kounov, now in the Czech Republic. The type species Limnerpeton modestum is a nomen dubium restricted to a mandible that almost certainly belongs to an amphibamid temnospondyl but is not critically diagnostic. “Limnerpeton” laticeps and “Limnerpeton” macrolepis lectotypes are both small individuals of the same taxon as the later described Mordex calliprepes Steen, 1938 and thus form part of the hypodigm of Mordex laticeps comb. nov. “Limnerpeton” elegans is now Limnogyrinus elegans and is a member of the temnospondyl family Micromelerpetontidae. “Limnerpeton” obtusatum is a specimen of the microsaur Microbrachis pelikani. “Limnerpeton” dubium is an indeterminate tetrapod, probably either a temnospondyl or a pelycosaur. “Limnerpeton” difficile is a nomen dubium but the type is probably a small specimen of the tuditanomorph microsaur Crinodon limnophyes. “Limnerpeton” caducum is almost certainly a specimen of the ophiderpetontid aïstopod Oestocephalus granulosus. Several other described small temnospondyls from Nýřany are discussed and shown to be specimens of either Limnogyrinus elegans, Mordex laticeps or Amphibamidae incertae sedis. The tetrapod fauna at Nýřany includes four dissorophoid temnospondyls as proposed by Milner (1986) but with two changes in nomenclature. They comprise the branchiosaurid Branchiosaurus salamandroides, the micromelerpetontid Limnogyrinus elegans, the amphibamid Platyrhinops cf. lyelli and the primitive trematopid Mordex laticeps. These represent four of the five major dissorophoid families and demonstrate that the group had already diversified by the late Westphalian.

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Anatomy and relationships of the Triassic temnospondyl Sclerothorax

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Schoch R. R., Fastnacht M., Fichter J., Keller T.

Acta Palaeontologica Polonica

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2007

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tom 52

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nr 1

Recently, new material of the peculiar tetrapod Sclerothorax hypselonotusfrom the Middle Buntsandstein (Olenekian) of north−central Germany has emerged that reveals the anatomy of the skull and anterior postcranial skeleton in detail. Despite differences in preservation, all previous plus the new finds of Sclerothorax are identified as belonging to the same taxon. Sclerothorax is characterized by various autapomorphies (subquadrangular skull being widest in snout region, extreme height of thoracal neural spines in mid−trunk region, rhomboidal interclavicle longer than skull). Despite its peculiar skull roof, the palate and mandible are consistent with those of capitosauroid stereospondyls in the presence of large muscular pockets on the basal plate, a flattened edentulous parasphenoid, a long basicranial suture, a large hamate process in the mandible, and a falciform crest in the occipital part of the cheek. In order to elucidate the phylogenetic position of Sclerothorax, we performed a cladistic analysis of 18 taxa and 70 characters from all parts of the skeleton. According to our results, Sclerothorax is nested well within the higher stereospondyls, forming the sister taxon of capitosauroids. Palaeobiologically, Sclerothorax is interesting for its several characters believed to correlate with a terrestrial life, although this is contrasted by the possession of well−established lateral line sulci.

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On a small Cochleosaurus described as a large Limnogyrinus [Amphibia, Temnospondyli] from the Upper Carboniferous of the Czech Republic

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Milner A. R., Sequeira S. E. K.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 1

Limnogyrinus elegans (Fritsch) is the most primitive micromelerpetontid temnospondyl from the Upper Carboniferous of Nýřany, Czech Republic. Arecent revision of the taxon by Werneburg (1994) attributed to this species a skull in dorsal aspect which was significantly larger than any previously reported and showed evidence of snout elongation. Restudy of this specimen demonstrates it to be a skull, visible in ventral aspect, of a juvenile of Cochleosaurus bohemicus, a more primitive edopoid temnospondyl, which is frequent in the Nýřany assemblage. Werneburg’s diagnosis of Limnogyrinusis revised and the problems of constructing ontogenetic series are discussed.

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A new capitosaur from the Middle Triassic of Spain and the relationships within the Capitosauria

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Fortuny J., Galobart A., de Santisteban C.

Acta Palaeontologica Polonica

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2011

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tom 56

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nr 3

Capitosaurs were the largest and homogeneous group of Triassic temnospondyl amphibians with cosmopolitan distribution. However, their interrelationships are debated. The first capitosaur cranial remains found in the Iberian Peninsula were assigned to Parotosuchus; herein, a re−description of this material, together with information on other remains recovered from the same site, enables us to classify them as a new genus: Calmasuchus acri gen. et sp. nov. (Amphibia: Temnospondyli) from the early−to−middle Anisian (early Middle Triassic). This capitosaur had a combination of plesiomorphic and non−plesiomorphic characters, such as posterolaterally directed tabular horns, paired anterior palatal vacuities, and unique morphology of the lower jaw. By cladistic analysis, we propose a new phylogeny for the monophyletic capitosaurs. In the analysis, Capitosauria is supported by seven synapomorphies. Wetlugasaurus is the most basal member of the clade. The score of the Russian taxon Vladlenosaurus alexeyevi resulted in a clade including Odenwaldia and the latter taxa. The Madagascarian Edingerella is the sister taxon of Watsonisuchus. Finally, Calmasuchus acri, the new taxon described here, appears as a more derived form than Parotosuchus. The new genus is the sister taxon of the Cyclotosaurus–Tatrasuchus and Eryosuchus–Mastodonsaurus clades.

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A new large capitosaurid temnospondyl amphibian from the Early Triassic of Poland

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Sulej T., Niedzwiedzki G.

Acta Palaeontologica Polonica

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2013

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tom 58

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nr 1

The Early Triassic record of the large capitosaurid amphibian genus Parotosuchus is supplemented by new material from fluvial deposits of Wióry, southern Poland, corresponding in age to the Detfurth Formation (Spathian, Late Olenekian) of the Germanic Basin. The skull of the new capitosaurid shows an “intermediate” morphology between that of Paroto− suchus helgolandicus from the Volpriehausen−Detfurth Formation (Smithian, Early Olenekian) of Germany and the slightly younger Parotosuchus orenburgensis from European Russia. These three species may represent an evolutionary lineage that underwent a progressive shifting of the jaw articulation anteriorly. The morphology of the Polish form is dis− tinct enough from other species of Parotosuchus to warrant erection of a new species. The very large mandible of Parot− osuchus ptaszynskii sp. nov. indicates that this was one of the largest tetrapod of the Early Triassic. Its prominent anatomi− cal features include a triangular retroarticular process and an elongated base of the hamate process.

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The brachyopoid Hadrokkosaurus bradyi from the early Middle Triassic of Arizona, and a phylogenetic analysis of lower jaw characters in temnospondyl amphibians

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Ruta M., Bolt J. R.

Acta Palaeontologica Polonica

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2008

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tom 53

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nr 4

The holotype of the brachyopoid temnospondyl Hadrokkosaurus bradyi, represented by a right lower jaw ramus, is re−examined based upon new data and revision of various morphological features. Additional fragmentary jaw material referred to this species is briefly described. Prominent features are a large postsymphyseal foramen that is anteriorly open, and prearticular and surangular buttresses for support of the articular. Brachyopoid characters include a long and robust postglenoid area formed by surangular and prearticular, anterior and posterior keels on at least some marginal dentary teeth, and subtriangular outline of the adductor fossa in dorsal view. Five features of the holotype ramus, long thought to be at odds with its brachyopoid or temnospondyl nature, are critically re−evaluated. A phylogenetic analysis of lower jaw characters in temnospondyls retrieves most of the clades found in more comprehensive data sets, but the statistical node support is low. Brachyopoids are monophyletic, with Hadrokkosaurus emerging as their most basal taxon.

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Mandibles of mastodonsaurid temnospondyls from the Upper Permian–Lower Triassic of Uruguay

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Pineiro G., Marsicano C. A., Damiani R.

Acta Palaeontologica Polonica

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2007

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tom 52

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nr 4

Partially preserved temnospondyl mandibles from the Late Permian–Early Triassic Buena Vista Formation of Uruguay are referred to the basal stereospondyl taxon Mastodonsauridae. These represent the earliest known members of this group for South America. In most cases, this assignment was based on the characteristic morphology of the postglenoid (= postarticular) area of the lower jaw together with the presence of a hamate process. Comparisons with basal mastodonsaurids indicate that the Uruguayan specimens are phenetically similar to Gondwanan and Laurasian Early Triassic taxa, such as Watsonisuchus, Wetlugasarus, and Parotosuchus. Nevertherless, they display some characters which have not previously been described in Mesozoic temnospondyls. The Permo−Triassic Uruguayan mastodonsaurids support a Gondwanan origin for the group, an event which probably occurred sometime during the latest Permian.

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A giant skull of the temnospondyl Xenotosuchus africanus from the Middle Triassic of South Africa and its ontogenetic implications

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Damiani R.

Acta Palaeontologica Polonica

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2008

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tom 53

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nr 1

A previously unreported large skull of the mastodonsaurid temnospondyl Xenotosuchus africanus, from the Cynognathus Assemblage Zone (Early to Middle Triassic) of the Beaufort Group, Karoo Basin of South Africa, is described. The species is plesiomorphic in most aspects of its cranial anatomy, and only one autapomorphy is tentatively identified herein, namely contact between the left and right exoccipitals posterior to the parasphenoid. The new specimen permits recognition of a growth series for X. africanus from sub−adult (all previously known specimens) to fully adult (new specimen) stages. Ontogenetic changes associated with this include changes in skull proportions, and changes in the morphology of the lacrimal flexure, frontal, postfrontal, cultriform process and body of the parasphenoid, and the transvomerine tooth row.

Ograniczanie wyników

On a new stereospondylomorph temnospondyl from the Middle-Late Permian of Southern Brazil

On the presence of a pustulated temnospondyl in the Lower Triassic of southern Brazil

Revision of the amphibian genus Limnerpeton [Temnospondyli] from the Upper Carboniferous of the Czech Republic

Anatomy and relationships of the Triassic temnospondyl Sclerothorax

On a small Cochleosaurus described as a large Limnogyrinus [Amphibia, Temnospondyli] from the Upper Carboniferous of the Czech Republic

A new capitosaur from the Middle Triassic of Spain and the relationships within the Capitosauria

A new large capitosaurid temnospondyl amphibian from the Early Triassic of Poland

The brachyopoid Hadrokkosaurus bradyi from the early Middle Triassic of Arizona, and a phylogenetic analysis of lower jaw characters in temnospondyl amphibians

Mandibles of mastodonsaurid temnospondyls from the Upper Permian–Lower Triassic of Uruguay

A giant skull of the temnospondyl Xenotosuchus africanus from the Middle Triassic of South Africa and its ontogenetic implications