Article

Alierasaurus ronchii, gen. et sp. nov., A Caseid from the Permian of Sardinia, Italy

Taylor & Francis
Journal of Verterbrate Paleontology
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Abstract

A giant caseid, Alierasaurus ronchii, gen. et sp. nov., is herein described, based on a partial postcranial skeleton collected from the Permian Cala del Vino Formation (Alghero, Nurra, northwest Sardinia). Despite the highly conservative morphology of ribs and vertebral material, typical of caseids, the very well-preserved foot elements show highly autapomorphic features, warranting assignment of the specimen to a new genus. In particular, the fourth metatarsal is not short and massive, as in other large caseids, and shows a distinct axial region. Finally, the claw-shaped ungual phalanges are autapomorphic in being proportionately very short, with a strong double ventral flexor tubercle positioned very close to the proximal phalangeal rim, and a distal end that is not spatulate, but rather subtriangular in transverse section. Principal component and reduced major axis slope analyses, performed on 10 caseid specimens, suggest that the observed changes in overall shape of metatarsal IV were mainly linked to the enormous body size reached by the Sardinian specimen.

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... The continuation to therapsid communities is not occupied by skeletal finds, and also sparsely bridged by the ichnological record (Gand & Durand, 2006;Buchwitz et al., 2020). Bone fossils of amniotes in the higher Rotliegend are restricted to the southern European giant caseids Lalieudorhynchus (Werneburg et al., 2022a) and Alierasaurus (Romano & Nicosia, 2014), as well as an undescribed sphenacodont (Romano et al., 2018). The early amniotes of the Thuringian Forest known to date originate from three formations (stratigraphy see Fig. 1, according to Schneider et al., 2020; for maps, sections and trophic pyramids see Schneider et al., 2024): • The Manebach Formation reflects humid conditions with rich vegetation (two isolated bones from sandstone units at the Kammerberg locality, Manebach). ...
... See text for records from the Thuringian Forest; other finds are from the Pennines (Paton, 1974;Spindler, 2019), Rodez (Reisz et al., 2011b), Autun (Falconnet, 2010(Falconnet, , 2012Spindler, 2015;Spindler et al., 2016Spindler et al., , 2020, Jura and Lodève (Falconnet, 2007(Falconnet, , 2015Werneburg et al., 2022a), Saar-Nahe Basin (Voigt et al., 2014;Fröbisch et al., 2011;Spindler et al., 2020;Fischer et al., 2024), Chemnitz Basin as part of the Erzgebirge/Ore Mountains Basin (Kissel, 2010;Spindler et al., 2018), Döhlen Basin (Kissel, 2010;Spindler, 2013Spindler, , 2016Spindler et al., 2020), Sudetes , as well as Kladno-Ravovník and Boskovice (Štamberg & Zajíc, 2008;Spindler et al., 2020). Left out here: Russian parareptiles, diapsids, varanopids, caseids and therapsids starting with the middle Permian (Modesto & Rybczynski, 2000;Ivakhnenko, 2008), lower Middle Permian remains of Sardinia with the caseid Alierasaurus and an undescribed sphenacodont (Romano & Nicosia, 2014;Romano et al., 2018), the indeterminate amniote Tridentinosaurus from the Lower Permian of Trento (Bernardi et al., 2014;Spindler et al., 2019;Rossi et al., 2024), indeterminate synapsid remains from the middle Gzhelian of Rozelay, as well as from the mentioned French areas (Falconnet, 2010(Falconnet, , 2014, and finally the indeterminate anapsid cotylosaur Sphenosaurus from the (?Lower) Permian of Bohemia (Kuhn, 1961;Štamberg & Zajíc, 2008). Abb. 1 (links): Amniote Körperfossilien (Gattungen der Kronengruppe und der Diadectomorpha) aus Gzhelian und Rotliegend-Faunen Europas; Stratigraphie nach Schneider et al. (2020). ...
... Siehe Text für Nachweise des Thüringer Waldes; andere Funde aus den Penninen (Paton, 1974;Spindler, 2019), Rodez (Reisz et al., 2011b), Autun (Falconnet, 2010(Falconnet, , 2012Spindler, 2015;Spindler et al., 2016Spindler et al., , 2020, Jura und Lodève (Falconnet, 2007(Falconnet, , 2015Werneburg et al., 2022a), Saar-Nahe-Becken (Voigt et al., 2014;Fröbisch et al., 2011;Spindler et al., 2020;Fischer et al., 2024), Chemnitz-Becken als Teil des Erzgebirge-Beckens (Kissel, 2010;Spindler et al., 2018), Döhlen-Becken (Kissel, 2010;Spindler, 2013Spindler, , 2016Spindler et al., 2020), Sudeten , sowie Kladno-Ravovník und Boskovice (Štamberg & Zajíc, 2008;Spindler et al., 2020). Ausgelassen sind: Russische Parareptilien, Diapsiden, Varanopiden, Caseiden und Therapsiden ab dem Mittelperm (Modesto & Rybczynski, 2000;Ivakhnenko, 2008), unter-mittelpermische Reste von Sardinien mit dem Caseiden Alierasaurus und einem unbeschriebenen Sphenacodonten (Romano & Nicosia, 2014;Romano et al., 2018), der unbestimmte Amniot Tridentinosaurus des Unterperms von Trient (Bernardi et al., 2014;Spindler et al., 2019;Rossi et al., 2024), unbestimmte Synapsidenreste aus dem mittleren Gzhelian von Rozelay sowie den erwähnten französischen Gebieten (Falconnet, 2010(Falconnet, , 2014, und schließlich der unbestimmte anapside Cotylosaurier Sphenosaurus des (unteren?) Perms aus Böhmen (Kuhn, 1961;Štamberg & Zajíc, 2008). ...
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In the Early Permian, amniotes – as those tetrapods with a completed transition to land – include stem reptiles and early mammalian precursors of the “pelycosaur” grade, presumably also diadectids. All three groups are known from the Thuringian Forest. In addition to the Bromacker site (Tambach Formation), amniote body fossils are also known from the Kammerberg (Manebach Formation) and the Cabarz quarry (Goldlauter Formation). After a general characterization of the amniote transition, the forms discovered in Thuringia are outlined: There are currently three diagnosed diadectids, a bolosaurid parareptile, a captorhinid eureptile, two varanopids, as well as a caseid and a sphenacodontid synapsid. There are also unidentifiable remains. A jaw fragment can be tentatively assigned to the varanopid Cabarzia. Overall, the Thuringian Forest represents the most diverse Permo- Carboniferous assemblage of early amniotes in Europe, with valuable ecological and palaeobiological insights. Amnioten – als die Tetrapoden mit vollständig abgeschlossenem Landgang – schließen im frühen Perm die Stammreptilien und frühe Säugertiervorläufer aus dem Stadium der „Pelycosaurier“ ein, wahrscheinlich auch die Diadectiden. Alle drei Gruppen sind aus dem Thüringer Wald bekannt. Neben der Fundstelle am Bromacker (Tambach Formation) sind auch vom Kammerberg (Manebach Formation) und aus dem Steinbruch Cabarz (Goldlauter Formation) Körperfossilien der Amnioten bekannt. Nach einer generellen Charakterisierung des amnioten Übergangs werden die in Thüringen nachgewiesenen Formen vorgestellt: Gegenwärtig sind drei Diadectiden diagnostiziert, ein bolosaurides Parareptil, ein captorhinides Eureptil, zwei Varanopiden, sowie ein caseider und ein sphenacodontider Synapside. Daneben existieren nicht näher bestimmbare Reste. Dem Varanopiden Cabarzia kann ein möglicher Kieferrest neu zugeschrieben werden. Insgesamt repräsentiert der Thüringer Wald die vielfältigste permo-karbonische Vergesellschaftung früher Amnioten in Europa, mit wertvollen ökologischen und paläobiologischen Einsichten.
... All material collected until 2014 was analysed in detail for the first time by Romano & Nicosia (2014) who, based on the autapomorphic characters recognised with respect to large North American caseids, formalised the new taxon of the Family Caseidae Alierasaurus ronchii (Romano & Nicosia, 2014). A. ronchi is characterised by vertebrae and ribs totally consistent to those of the large North American caseids, whereas the more autapomorphic elements are represented by the pedal phalanxes (Romano & Nicosia, 2014). ...
... All material collected until 2014 was analysed in detail for the first time by Romano & Nicosia (2014) who, based on the autapomorphic characters recognised with respect to large North American caseids, formalised the new taxon of the Family Caseidae Alierasaurus ronchii (Romano & Nicosia, 2014). A. ronchi is characterised by vertebrae and ribs totally consistent to those of the large North American caseids, whereas the more autapomorphic elements are represented by the pedal phalanxes (Romano & Nicosia, 2014). ...
... All material collected until 2014 was analysed in detail for the first time by Romano & Nicosia (2014) who, based on the autapomorphic characters recognised with respect to large North American caseids, formalised the new taxon of the Family Caseidae Alierasaurus ronchii (Romano & Nicosia, 2014). A. ronchi is characterised by vertebrae and ribs totally consistent to those of the large North American caseids, whereas the more autapomorphic elements are represented by the pedal phalanxes (Romano & Nicosia, 2014). The new caseid was characterised by a very wide 'barrel-shaped' rib cage, which is typical of high-fibres herbivorous diet, hosting long intestinal tracts for celluloses and hemicelluloses digestion (Hotton et al., 1997;Sues & Reisz, 1998;Reisz & Sues, 2000;Lombardo, 2008;Romano & Nicosia, 2014Romano, 2017a). ...
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Along the coast between Cala Viola and Cala del Turco in NW Sardinia, an upper Palaeozoic to lower Mesozoic continental sedimentary succession is wonderfully exposed. For the first time, detailed geological mapping, coupled with facies analysis and meso-structural studies, was carried out, allowing to better define the Permian- Triassic stratigraphy and structural setting of this sector of Nurra region. Field work was coupled with drone-based aerial photogrammetry, which led to the production of Digital Outcrop Models (DOMs). A lithofacies subdivision of the stratigraphic units is proposed with the aim of making a formalisation of the Triassic Porticciolo conglomerate and Cala Viola sandstones units possible. The combination of “classical” and “digital” field methodologies led to the mapping of 462 faults, the recognition and characterisation of six main fault sets, and differently oriented folds. The analysis of topology and cross cutting relationship of fault networks has allowed us to identify at least eight deformation phases, possibly spanning from Permian to Pleistocene-Holocene. These new data allow us to reconstruct the complex tectonic history affecting NW Sardinia since the deposition of the middle Permian deposits to the Holocene, with the Permian and Triassic deposits recording the whole deformation phases affecting them since the latest Palaeozoic.
... Overall, about eighty bones were recovered, both complete and fragmentary, all referable to the post-cranial skeleton of a very huge animal (Fig. 2). The preparation and study of the material allowed the description and formalization of a new taxon of the Family Caseidae, Alierasaurus ronchii (Romano and Nicosia, 2014) from 'Aliera' or 'Alighera', the old traditional name of the city of Alghero in Sardinia, and Ronchi in honor of Prof. Ausonio Ronchi from Pavia who reported us the new discovery. ...
... Ronchi et al. (2011 also discuss the stratigraphic occurrence of both North American and European caseids; using the North American Land Vertebrate faunochrons proposed by Lucas (2006), the authors suggest a late Kungurian-Roadian age for the upper part of the Cala del Vino Formation, and discuss the implication for the litostratigraphic correlation with the Permian-Triassic succession outcropping in Provence. Romano and Nicosia (2014) provide the first detailed description of the new material with the formalization of the new caseid Alierasaurus ronchii. The author stress how great part of the preserved post-cranial material, especially conformation in ribs and foot elements are fully compatible with the known anatomy of large north American caseids, in particular with that characterizing the genus Cotylorhynchus. ...
... However, Alierasaurus shows apomorphic character, especially in the autopodial elements, supporting the erection of a new genus and species of Caseidae. Romano and Nicosia (2014) discuss the huge size of the new taxon comparable only to the giant North American species Cotylorhynchus hancocki, more than six meters in total length. The author in addition stress how the conformation of preserved large ribs allow to infer a very large "barrel-shaped" rib cage, indicating an high-fibers herbivorous diet (see Hotton et al., 1997;Sues and Reisz, 1998). ...
... These fossils were collected in Permian fluvial deposits of the Cala del Vino Formation, exposed near Torre del Porticciolo, at the north-western corner of the island. In previous work, these fossils were ascribed to the new genus and species Alierasaurus ronchii, referable to the family Caseidae (Romano & Nicosia, 2014), a long-lived group of herbivorous "pelycosaurs" primarily known from North America, but with a few European records as well (Brocklehurst, Romano, & Fröbisch, 2016;Reisz et al., 2011;Romano, 2017;Romano, Brocklehurst, & Fröbisch, 2017;Romano & Nicosia, 2015;Sigogneau-Russell & Russell, 1974). ...
... The vertebrate remains that are the subject of this study were found in the Cala del Vino Fm. (Cassinis et al., 2003) in the Torre del Porticciolo locality. The chronostratigraphic position of this rock unit was not well established until the discovery of the caseid Alierasurus ronchii (Romano & Nicosia, 2014;Romano, Ronchi, et al., 2017;Ronchi et al., 2011), which established attribution of the unit to the latest Kungurian-Roadian. ...
... Thus, the new specimen from Torre del Porticciolo would represent the ninth report of a sphenacodontid from Europe, throwing new light on the diversity of this faunivorous clade of non-therapsid synapsids on the continent. In addition, with a late early Permian to early middle Permian age for the Cala del Vino Formation (see Romano & Nicosia, 2014; late Kungurian-Roadian in Ronchi et al., 2011), the specimen would represent, to date, the youngest occurrence of sphenacodontids in Europe. ...
Article
The Torre del Porticciolo fossil locality is notable for producing the first osteological material of a basal (i.e., non‐mammalian) synapsid in Italy, the giant herbivore Alierasaurus ronchii, which although known from fragmentary remains, likely represents the largest known late early to early middle Permian synapsid (6–7 m total length). Recently, a new productive site was discovered about 100 m from the Alierasaurus type locality, but roughly at the same stratigraphic level. The fragmentary nature of most of the recovered bones prompted a taphonomical analysis in order to define the type of find, the kind of burial, and the mode of preservation. The vertebrate remains allowed us to infer a complex taphonomical process involving a multiphase entombment. The recovered bones were subjected to both re‐exhumation and reworking. The last short and violent transportation phase before final entombment occurred as a high‐energy flow, probably caused by a river flood that carried sediment and bones together to be emplaced in a semi‐perennial pond in a crevasse splay deposit. Preliminary analysis of recovered material indicates the presence of a large carnivorous basal synapsid referable to the family Sphenacodontidae. This discovery represents the first carnivorous non‐therapsid synapsid from the Permian of Italy and one of only very few known from Europe.
... Furthermore, based on the topology provided by Maddin et al. (2008), Reisz et al. (2011) moved 'Casea' rutena to the new genus Euromycter, with the new combination E. rutenus. Ronchi et al. (2011) and Romano and Nicosia (2014) described the first skeletal material referable to non-therapsid synapsid from Italy, the caseid Alierasaurus ronchii from the Permian Cala del Vino Formation (Alghero, Nurra, northwest Sardinia). The taxon is known on the basis of partial but diagnostic postcranial material, including vertebrae, ribs, and peculiar autopod elements. ...
... Bones size and preservation, as well as the absence of double and repeated elements, allows us to refer with confidence all new material to the same individual of Alierasaurus ronchii. As already discussed in Ronchi et al. (2011) and Romano and Nicosia (2014) the preserved bone are frequently characterized by several tubercles, scattered on the surface. To understand whether these tubercles are made of bone or simply represent metallic incrustations, a phalanx and rib portion with tubercles were analyzed at CT-Scan, in the facilities of the Museum für Naturkunde in Berlin. ...
... Subclass SYNAPSIDA Osborn, 1903Suborder CASEASAURIA Williston, 1912 Family CASEIDAE Williston, 1911 Genus ALIERASAURUS Romano and Type species. Alierasaurus ronchii Romano and Nicosia, 2014 Alierasaurus ronchii Romano ...
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New characters of the giant caseid Alierasaurus ronchii are described here based on material recovered from the type locality in the Permian deposits of Cala del Vino Formation (Sardinia NW) and additional preparation of the previously collected material. All new described osteological elements are characterized by the same state of preservation and, given the absence of double elements and the total compatibility in absolute size, the new material can be attributed without doubt to the holotypic individual of A. ronchii. Highly diagnostic material includes a caudal neural spine with a broad bifid distal termination. This represents a synapomorphy characterizing the more derived caseids, thus fully confirming the attribution of the Sardinian specimen to Caseidae. Also the other vertebral material and newly collected ribs show a typical caseid structure, fully consistent with the previously published material. Despite the highly partial nature of Alierasaurus, the taxon was included in a recent phylogenetic analysis of caseids to investigate its phylogenetic position within the monophyletic Caseasauria. Alierasaurus falls as the sister taxon of Cotylorhynchus, and is autapomorphic in the general construction of MT-IV and proximal phalanx IV-I. The absolute size of the newly recovered material confirms a gigantic body size for Alierasaurus, comparable, if not greater, to that of the huge North American species Cotylorhynchus hancocki (up to 6 m in length). Such gigantic adult body size, closely correlated to its herbivorous lifestyle, must have been selected during evolution of caseids, leading to substantial advantages in terms of fitness.
... Guadalupian/Lopingian sites yielding tetrapod body fossils concentrate in areas representing the temperate palaeolatitudes of Pangaea (Bernardi et al., 2017 and references therein;Olroyd & Sidor, 2017 and references therein), whereas in the palaeoequator, body fossils are scarcer (Jalil & Dutuit, 1996;Jalil & Janvier, 2005;Werneburg et al., 2007bWerneburg et al., , 2022Steyer & Jalil, 2009;Germain, 2010;Romano & Nicosia, 2014;Mujal et al., 2016b;Romano et al., 2019;Laurin & Hook, 2022) and usually much of the information is inferred from the abundant track record (Gand & Durand, 2006;Voigt et al., 2010;Hminna et al., 2012;Mujal et al., 2017a;Contessi et al., 2018;Citton et al., 2019;Marchetti et al., 2020. The assemblage from the P3 unit of Menorca has not been studied in great detail yet, but the preliminary account provided in the present Ph.D. dissertation suggests that it was a moradisaurine captorhinid eureptile-dominated palaeoenvironment, with at least two different species: a large one, Balearosaurus bombardensis, and a smaller (unnamed) one. ...
... Guadalupian and Lopingian (middle and upper Permian) assemblages with abundant moradisaurines can be found in central Africa (de Ricqlès & Taquet, 1982;Smith et al., 2015;Modesto et al., 2019;Sidor et al., 2022), northern Africa (Jalil & Dutuit, 1996;Voigt et al., 2010;Hminna et al., 2012) and the Massif Central and Provençe (Gand & Durand, 2006;Logghe et al., 2021;, all of them in the lower palaeolatitudes of Pangaea, just like Menorca. Therefore, it appears that moradisaurines remained as key components of the intertropical palaeoecosystems of Pangaea even when other high-fibre herbivores were present, such as caseid "pelycosaur"-grade synapsids (Romano & Nicosia, 2014;Werneburg et al., 2022), tapinocephalian dinocephalian therapsids (Gand & Durand, 2006;Marchetti et al., 2019) and pareiasaur parareptiles (Jalil & Janvier, 2005;Valentini et al., 2009;Voigt et al., 2010;Marchetti et al., 2021). Conversely, moradisaurines may have not been well-suited for cooler climates, as the main herbivores in temperate palaeolatitudes were pareiasaurs, dicynodont therapsids and tapinocephalians . ...
... Caseidae is the second subclade of Caseasauria (Figs. 5.2 B and 5.6), and it is predominantly composed of distinctively specialized herbivores. The first caseid to appear in the fossil record is the recently described Eocasea martini from the Late Pennsylvanian of Kansas (Reisz and Fröbisch 2014;although see Spindler et al. 2018 for an alternative placement of Eocasea), but the clade is best known from the Cisuralian and Guadalupian (early to early middle Permian) of North America and Europe (e.g., Olson 1968, Reisz 1986, Sigogneau-Russell and Russell 1974, Reisz et al. 2010a, Romano and Nicosia 2014. Footprints and body fossils reported from the Lodève Basin in France and footprints from the Paraná Basin of Brazil have been taken as evidence that caseids survived into the late Permian (Schneider et al. 2006, da Silva et al. 2012. ...
... This clade includes five main subgroups: Varanopidae, Ophiacodontidae, Edaphosauridae, Sphenacodontidae, and Therapsida (including mammals as an extant subclade), as well as several taxa whose relationships are less certain (e.g., the "haptodonts"). Diagnostic characters for Eupelycosauria include an antorbital region of the skull that is deeper than fragmentary Alierasaurus appears to have reached comparable sizes (Ronchi et al. 2011, Romano andNicosia 2014). ...
... During the course of their evolution, they passed from very small faunivorous to herbivorous organisms of extremely large size, among the largest reached by terrestrial vertebrates throughout the Palaeozoic. In particular, in a series of recent papers new material and taxa have been described; cladistic analyses were conducted to understand the phylogenetic relationships within Caseasauria (the clade containing Caseidae and Eothyrididae), and also within the broader topic of basal synapsids; specific morphometric studies have been carried out to understand the evolution of specific traits of these basal synapsids (Reisz 2005;Maddin et al. 2008;Reisz et al. 2011;Ronchi et al. 2011;Benson 2012;LeBlanc & Reisz 2014;Reisz & Fr€ obisch 2014;Romano & Nicosia 2014Sumida et al. 2014;Brocklehurst et al. 2016a, b;Spindler et al. 2016;Romano 2017). ...
... The centra are amphicoelous, slightly taller than long in this area, and they do not have thick and rounded lips as observed in other caseids (e.g. Alierasaurus, Romano & Nicosia 2014), ending with a rather sharp and cutting edge. The diagenetic compression does not make it easy to reconstruct the exact outline of the centrum in anterior and posterior view; however, it seems to be roughly subcircular with the dorsal half slightly more expanded transversely than the ventral one. ...
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The postcranial material referable to the Russian caseid Ennatosaurus tecton from the middle Permian is described. Although the cranium has been recently restudied in detail, the descriptions currently available for the postcranial skeleton are essentially limited to the original short account on the holotype provided by Efremov in 1956. The postcranium of Ennatosaurus is informative with respect to both taxonomy and phylogeny, with autapomorphic characters present particularly in the vertebral column. In addition to the anatomical description of the elements presented here, eight principal component analyses were conducted to investigate the position of the various osteological elements of Ennatosaurus within caseid morphospace. The inclusion of members of all major groups of ‘pelycosaurs’ and selected outgroup taxa allowed us to make more extensive preliminary inferences regarding postcranial morphospace occupation of these basal synapsids for each individually considered bone. The analysis revealed a major decoupling among the morphospaces of stylopodial and zeugopodial elements, with femora and humeri showing a shared common pattern, and a wider overlap in their respective morphospace. Conversely, the ulnae, radii, tibiae and fibulae show well-separated regions of morphospace in the different clades, indicating their potential importance, not only for functional and biomechanical studies, but also for taxonomic differentiation. Finally, a 3D photogrammetric model of the mounted specimen at the Paleontological Institute in Moscow forms the basis for the first in vivo reconstruction of Ennatosaurus tecton, providing a potentially realistic picture of the Russian caseid in life. © The Trustees of the Natural History Museum, London 2017. All rights reserved.
... With a temporal distribution spanning from the Late Carboniferous (Eocasea martini Late Pennsylvanian of Kansas; Reisz & Fr€ obisch 2014) to the Middle Permian (Ennatosarus tecton from the Late Roadian-Wordian of Russia; Maddin et al. 2008), caseids are among the longest-surviving groups of non-therapsid ('pelycosaurian') synapsids. Of interest is the great diversity of body size reached by the members of this clade during their evolution, with the most basal species, such as the recently described E. martini (Reisz & Fr€ obisch 2014) and Callibrachion gaudryi (Spindler et al. 2016) being little more than 20 cm in length, whereas giant forms, such as Cotylorhynchus hancocki of North America and Alierasaurus ronchii from Italy (Romano & Nicosia 2014), could reach up to 6.5 m in length, and a substantial body weight (more than 500 kg in Co. hancocki; Reisz & Fr€ obisch 2014). ...
... The recently described basal caseid E. martini (Reisz & Fr€ obisch 2014) and recently re-identified caseids or basal caseasaurs C. gaudryi and Datheosaurus macrourus were not included in the analysis, because all known specimens of these taxa represent juvenile individuals in which the tips of long bones may be largely unfinished. Furthermore, the Sardinian caseid A. ronchii (Ronchi et al. 2011;Romano & Nicosia 2014) is not included because no long bones have been recovered from the holotype locality (apart from the distal end of the ulna). In addition to caseids, specimens of the non-caseid 'pelycosaur' genera Varanops, Ophiacodon, Dimetrodon, Sphenacodon and Edaphosaurus (taxa considered in the above-mentioned phylogenetic analysis) are also included in the analysis. ...
... The members of Caseidae are known in Europe since the uppermost Carboniferous; still, most of their specimens originate from the upper part of the lower Permian 95,102,103 . Caseids belong to the longest-survived non-therapsid synapsids, and were more resistant to the increasing aridification in the middle Permian [104][105][106] . The nearest occurrence of caseid synapsids is represented by Datheosaurus macrourus, which derives from the Gzhelian of the Intrasudetic Basin, Poland 94 . ...
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Lower Permian deposits of the Boskovice Basin in the Czech Republic have long been renowned for extraordinarily abundant specimens of discosauriscid seymouriamorphs, some of which showing exceptional preservation, including widespread soft tissues. The only other tetrapods from the strata are represented by rare temnospondyls. However, recent fieldwork in the Asselian (lowermost Permian) of the Boskovice Basin has yielded a diverse assemblage of tetrapod tracks, illuminating a hidden terrestrial tetrapod diversity. Here, we describe well-preserved isolated tracks, manus-pes couples, and a slab with trackways composed of approximately 20 tracks in at least four different directions belonging to early-diverging, or ‘pelycosaur-grade’, synapsids. The material originates from three localities situated within the Letovice and Padochov formations and is assignable to the ichnotaxon Dimetropus. The best-preserved specimen further shows rare skin impressions, which have not been observed from the hands or feet of early-diverging mammal-line amniotes before. The new material adds to the scarce record of synapsids from the Carboniferous/Permian transitional interval of equatorial Pangea. At the same time, it highlights the significance of the ichnological record of the Boskovice Basin which has long been neglected despite offering evidence for the presence of diverse faunal components that have not been reported from these basinal deposits before.
... For instance, the oldest tetrapod footprints from Italy were recorded in the upper Moscovian of the San Giorgio Basin, near Iglesias (Fondi, 1980;Marchetti et al., 2018Marchetti et al., , 2020. Furthermore, rich fresh-water vertebrate faunas were reported in the Permian of Guardia Pisano (Gonnesa) and Perdasdefogu Basin (Werneburg et al., 2007;Fischer et al., 2010), and the remains of two basal synapsids and tetrapod footprints were found in Permian continental deposits near Alghero (Romano & Nicosia, 2014;Romano et al., 2018;Citton et al., 2019b). ...
Article
As highlighted by literature data, the Mesozoic vertebrate fossil record of Sardinia is very poor. Two ichnotaxa (Rotodactylus isp. and Rhynchosauroides isp.) referred to the continental vertebrates have been reported in the Triassic (“Buntsandstein”) of the Nurra sub-region (north-western Sardinia). In the “Muschelkalk” of the same area, remains of an actinopterygian fish (Colobodus sp.) and seven conodont taxa (Budurovignathus japonicus, B. hungaricus, B. trümpyi, Neogondolella constricta, N. longa, “Algherella riegeli”, and “A. uniformis”) have also been recorded. Teeth of a hybodont shark and a marine reptile, probably an Ophthalmosauridae, are documented in the Middle Jurassic of the Ogliastra sub-region (central-eastern Sardinia). We present herein two chondrichthyans teeth belonging to an indeterminate Hybodontoidea and an indeterminate member of the Hexanchoidei. The specimens come from two different localities of northeastern Sardinia referable to the Bathonian and Oxfordian-Valanginian, respectively. The new data expand the Mesozoic fossil record of the Island and could be a starting point for future research.
... obs.), Ennatosaurus tecton Efremov, 1956from Russia (e.g., Efremov, 1956Ivakhnenko, 1990;Maddin et al., 2008;Romano et al., 2017a/b;RW pers. obs.), Alierasaurus ronchii Romano and Nicosia, 2014 from Italy (Ronchi et al., 2011, Romano andRomano et al., 2017a), and Caseopsis, Angelosaurus spp., and Cotylorhynchus spp. from the USA (e.g., Stovall et al., 1966;Olson and Beerbower, 1953;Olson, 1962Olson, , 1968Olson and Barghusen, 1962;RW + FS pers. ...
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Lalieudorhynchus gandi gen. nov. and sp. nov. is a new caseid synapsid from the Permian of the Lodève Basin, Occitanie, France. This new taxon is represented by a partial but well-preserved postcranial skeleton, and is characterized by the following apomorphies: a transverse section of the sacral and anterior caudal neural spines with a very thin keel-like process anteriorly, a slender dorsal tip of the dorsal and caudal spines, a narrow distal end of the first sacral rib, a fossa on triceps process of metacoracoid, and a very large distal tarsal 1 of same width than the astragalus, with nearly all sides being shallowly concave. The skeleton corresponds to a sub-adult individual that was excavated from the La Lieude Formation dated as Roadian-Capitanian (Guadalupian). A sedimentological and taphonomical analysis of the type locality, together with preliminary osteohistological observations, suggest that this new French caseid was rather aquatic, as already hypothesised for other large forms. A phylogenetic analysis of caseids is performed to test the position of this new taxon and to better understand the evolution of the clade: interestingly, Lalieudorhynchus gandi gen. nov. et sp. nov. is closer to the North American "Cotylorhynchus" hancocki than to the other French caseids Ruthenosaurus and Euromycter from the Artinskian of the geographically closer Rodez Basin. These two last caseids document the Artinskian radiation of the clade, which remained diverse until Olson's extinction. Caseids survived, as Lalieudorhynchus is one of the youngest representatives of the clade, and may have used novel ecological strategies to access their vegetarian food sources.
... This new evidence sheds more light on the faunal diversity within the late Kungurian?-Roadian "Cala del Vino formation", which is one of the few examples in the Permian of Europe of a combined ichno-and body-fossil record Romano and Nicosia, 2014;Romano et al., 2019. The tracks have been referred by to Merifontichnus, an ichnotaxon established from the uppermost portion of the Permian succession of the Lodève Basin, in southern France (Gand et al., 2000). ...
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The Cisuralian tetrapod ichnoassociation from Italy is long known, in fact it is the first described from the Southern Alps. After some pioneering works in the 19th Century, several new research and discoveries were undertaken starting from the second half of the 20 th Century until now. This ichnoassociation is characterised by abundant and diverse reptile tracks (Dromopus, Erpetopus, Hyloidichnus, Merifontichnus and Varanopus), uncommon anamniote tracks (Amphisauropus, Batrachichnus and Limnopus) and very rare synapsid tracks (cf. Dimetropus). The bulk of discoveries are located in the central Southern Alps, in the Orobic and Collio basins, and in minor part in the Athesian District. These basins include a well-preserved and diverse ichnoassociation that is central to tetrapod footprint biostratigraphy and in the definition of the late Cisuralian reptile radiation inferred from the footprint record, well-calibrated by several recent radiometric dates that constrain the ages of the footprint-bearing units. The new site from NW Sardinia includes few late Kungurian?-Roadian tetrapod footprints, that however deserve great attention because of the possible biostratigraphic implications and the unusual co-occurrence with tetrapod remains.
... A potentially important site for the faunal correlation of the latest Cisuralian and possibly the base of the Guadalupian is the Torre del Porticciolo locality in NW Sardinia, belonging to the Cala del Vino Formation (Fig. 2). Although this formation lacks independent age control from radioisotopic dates and marine fossils, the occurrence of large caseid Romano and Nicosia, 2014;Romano et al., 2017) and sphenacodont remains is remarkable for the Permian of Western Europe, as is the presence at the same site of tetrapod footprints . The co-existence of these tetrapod remains is consistent with a Redtankian-Littlecrotonian LVF age according to Lucas (2006Lucas ( , 2017Lucas ( , 2018, so a late Kungurian to early Roadian age can be hypothesized. ...
Article
Nonmarine biostratigraphic/biochronologic schemes have been created for all or parts of the late Carboniferous–Middle Triassic using palynomorphs, megafossil plants, conchostracans, blattoid insects, tetrapod footprints and tetrapod body fossils, and these provide varied temporal resolution. Cross correlation of the nonmarine biochronologies to the Standard Global Chronostratigraphic Scale has been achieved in some parts of the late Carboniferous–Middle Triassic in locations where nonmarine and marine strata are intercalated, the nonmarine strata produce biochronologically significant fossils and the marine strata yield fusulinids, conodonts and/or ammonoids. Other cross correlations have been aided by magnetostratigraphy, chemostratigraphy and a growing database of radioisotopic ages. A synthetic nonmarine biochronology for the late Carboniferous–Middle Triassic based on all available nonmarine index fossils, integrated with the Standard Global Chronostratigraphic Scale, is presented here. The focus is on the nonmarine biostratigraphy/biochronology of blattoid insects, conchostracans, branchiosaurid amphibians, tetrapod footprints and tetrapod body fossils within the biochronological framework of land-vertebrate faunachrons. Correlation to the Standard Global Chronostratigraphic Scale presented here is divided into seven time intervals: Pennsylvanian, Carboniferous–Permian boundary, Cisuralian, Guadalupian, Lopingian, Permian–Triassic boundary and Early to Middle Triassic. The insects, conchostracans and branchiosaurs provide robust nonmarine correlations in the Pennsylvanian–Cisuralian, and the footprints and tetrapod body fossils provide robust correlations of varied precision within the entire Pennsylvanian–Middle Triassic. Radioisotopic ages are currently the strongest basis for cross correlation of the nonmarine biostratigraphy/biochronology to the Standard Global Chronostratigraphic Scale, particularly for the Pennsylvanian–Cisuralian. Chemostratigraphy and magnetostratigraphy thus far provide only limited links of nomarine and marine chronologies. Improvements in the nonmarine-marine correlations of late Paleozoic–Triassic Pangea require better alpha taxonomy and stratigraphic precision for the nonmarine fossil record integrated with more reliable radioisotopic ages and more extensive chemostratigraphic and magnetostratigraphic datasets.
... Amongst basal synapsids, large body size had already evolved in the 'pelycosaurs' during the late Early Permian and the early Middle Permian, especially amongst the large herbivorous members of the Family Caseidae (Olson 1968;Reisz 1986). The largest were the North American genus Cotylorhynchus (especially C. hanckocky), and the huge Italian Permian caseid from Sardinia Alierasaurus ronchii (Ronchi et al. 2011;Romano and Nicosia 2014;Romano et al. 2017), with an estimated body length of 6.5-7 m. The independent evolution of large body size amongst basal synapsids at different geological periods is linked to a complex combination of physiological and ecological factors. ...
Article
Dinocephalians were the earliest large terrestrial tetrapods from Gondwana, making this group crucial in understanding body mass (BM) evolution in basal synapsids, but no detailed weight determinations are available for the clade. Here we present the first BM estimate for a dinocephalian on the basis of the remarkably well preserved and complete skeleton of the basal tapinocephalid Tapinocaninus pamelae from the lowermost Beaufort Group of South Africa. We reconstructed three 3D models of Tapinocaninus using mounted skeletons of the dinocephalians Moschops and Ulemosaurus to reconstruct the missing elements. Applying a density range between 0.9 and 1.15 Kg/1000 cm3 for living tissue to the model we reconstructed an average BM of 892.63 Kg for the taxon. Classic regression formulae, based on humerus and femur circumference, provide higher values of 1694.5 Kg and 2015.8 Kg, with an overestimation of 90% and 126% respectively. The study confirms that volumetric BM estimates are more precise, and are recommended if relatively complete skeletons are available. The ‘intermediate’ posture recognized for Tapinocaninus, more upright with respect to the sprawling condition characterizing sphenacodontid ‘pelycosaurs’, could represent a response to a large BM, which, for the first time in synapsids, reaches weights close to a tonne.
... nov. (Romano and Nicosia, 2014), based on a partial postcranial skeleton, seems to support a late Early Permian to early Mid-Permian transitional age. Moreover, this datum probably rests below a pronounced stratigraphic gap, which could be linked at a large scale to the 'Mid-Permian Episode' of Deroin andBonin, 2003 (Cassinis et al., 2012). ...
... As in captorhinids, caseids explore different diets and body sizes. These include forms such as the very small Eocasea martini (Reisz & Fr€ obisch 2014) to the huge North American taxa Cotylorhynchus hancocki and the giant caseid from Italy Alierasaurus ronchii, which was 6-7 m long (see Ronchi et al. 2011;Romano & Nicosia 2014;Romano et al. 2017b) and likely had a bulky torso for high-fibre fermentation. The study indicated that the portion of a long bone most affected by allometric growth is the mid-shaft width of the bone (Romano 2017a). ...
Article
Captorhinids are a speciose clade of sauropsids that are crucial to understand several aspects of basal amniote general biology. Members of the Captorhinidae explored different diets and, amongst basal amniotes, were one of the first groups to demonstrate high-fibre herbivory. Several papers have been published on the cranial anatomy of captorhinids, but there are relatively few studies which focus on the post-cranium, especially on the appendicular skeleton and long bones. This contribution presents the first quantitative long bone scaling in Captorhinidae performed through morphometric analyses. From classical biomechanical research, it is well-established that to accommodate an increase in size, gravity will result in elastic deformation of long bones. This outcome is especially significant in terrestrial tetrapods with a sprawling limb posture such as captorhinids, where great torsional stresses are applied to long bones, both during locomotion and in the resting phase. In this paper, we test whether the consistent evolutionary size increase in captorhinids led to major re-patterning in long bone structure as theoretically expected, based on the theory of elastic similarity. Morpho-metric analysis shows that, apart from a small positive allometry in the humerus, cap-torhinid long bones scale geometrically as body size increases. Thus, the predicted elastic similarity to maintain similar levels in peak stress with an increase in dimensions does not seem not to apply to long bone evolution in captorhinids. We propose that, as already observed experimentally in larger-bodied varanid lizards, large cap-torhinids could also mitigate size-related increases in stress by reducing femur rotation and increasing the percentage of the stride cycle during which the right hindfoot was on the ground (i.e. the duty factor). In this way, large captorhinids could avoid reaching peak stress thresholds by sacrificing speed during locomotion and without a substantial long bone re-patterning or postural change. □ Allometry, duty factor, locomotion, long bone scaling, Palaeozoic. Marco Romano ✉ [marco.romano@uniroma1.it], and Bruce Rubidge [bruce.rubidge@ wits.ac.za], Evolutionary Studies Institute (
... Together, the records provide different representations of the faunal composition and, once integrated, enhance the understanding of the faunal diversity of this area of Pangea during the latest early Permian to early middle Permian time interval. While the skeletal remains indicated medium to large carnivorous basal synapsids presently referred to the family Sphenacodontidae (Romano et al., 2018) and giant herbivorous caseid (i.e., Alierasaurus ronchii, Romano & Nicosia, 2014Romano et al., 2017), the recently discovered ichnosite adds a further constituent of the terrestrial palaeofauna, at least, also a small animal, represented by Merifontichnus footprints, ranging between 4 and 10 cm in length. ...
Article
The Torre del Porticciolo palaeontological locality (Alghero, northwest Sardinia, Italy) is important for having provided the skeletal remains of the first Permian basal synapsid from Italy, Alierasaurus ronchii, the largest late early Permian to early middle Permian non-therapsid synapsid known to date. Recently, other skeletal remains preliminarily attributed to a carnivorous non-therapsid synapsid were described from a second site, approximately from the same stratigraphic level within the Cala del Vino Fm. During the excavation of this second site, tetrapod tracks were found near Cala Viola, about 1 km from the first two sites. The new find represents the first ichnological record from the Permian of Sardinia. The ichnological analysis allowed the recognition of tetrapods presently not recognized, just on the base of skeletal remains. This new evidence sheds more light on the faunal diversity within the Cala del Vino Fm., which is one of the few examples in the Permian of Europe of a combined ichno-and body-fossil record. The tracks have been referred to as Merifontichnus, an ichnotaxon established from the uppermost portion of the Permian succession of the Lodève Basin in southern France. The new material is the first reliable occurrence of this ichnotaxon from Italy and would represent, to date, the oldest occurrence of the ichnogenus.
... Noteworthy, this vertebra is stratigraphically above the tetrapod footprints, thus the latter might be older than Wordian. Regarding similar caseid record in nearing basins, large specimens are known from the Permian localities of Sardinia Romano and Nicosia, 2014) and the French La Lieude (Reisz et al., 2011). Additionally, the large footprints of Planipes, ichnogenus from the middle Permian of France (Lodève Basin, Gand et al., 2000;Saint-Raphaël Estérel Basin, Gand et al., 1995) and South Africa (Tapinocephalus assemblage zone, Valentini et al., 2009), are assigned to caseids and/or therapsid trackmakers. ...
... The presence of a caseid vertebra in the Catalan Pyrenees (Fig. 2) indicates a minimum age of Middle Permian for the part of the succession where it was found (Fig. 5). This group of synapsids was relatively abundant during this time interval, although few specimens have been so far reported in Europe (e.g., Sigogneau-Russell and Russell, 1974;Wernerburg et al., 2007;Reisz et al., 2011;Romano and Nicosia, 2014). The Pyrenean vertebra is tentatively attributed to cf. ...
... Subsequent to , the list of European 'pelycosaurs' can be extended as follows: (1) Datheosaurus and Callibrachion, previously mistaken as basal sphenacodontians, have been recognized as basal Caseasauria or Caseidae ); (2) further renaming or first description of caseids applied to Euromycter and Ruthenosaurus (Reisz et al. 2011a), as well as Alierasaurus (Ronchi et al. 2011;Romano and Nicosia 2014). A large but undescribed caseid is known from the Lopingian of the Lodéve Basin (Schneider et al. 2006;Werneburg et al., in prep.). ...
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A new fossil amniote from the Fossil Forest of Chemnitz (Sakmarian-Artinskian transition, Germany) is described as Ascendonanus nestleri gen. et sp. nov., based on five articulated skeletons with integumentary preservation. The slender animals exhibit a generalistic, lizard-like morphology. However, their synapsid temporal fenestration, ventrally ridged centra and enlarged iliac blades indicate a pelycosaur-grade affiliation. Using a renewed data set for certain early amniotes with a similar typology found Ascendonanus to be a basal varanopid synapsid. This is the first evidence of a varanopid from Saxony and the third from Central Europe, as well as the smallest varanopid at all. Its greatly elongated trunk, enlarged autopodia and strongly curved unguals, along with taphonomical observations, imply an arboreal lifestyle in a dense forest habitat until the whole ecosystem was buried under volcanic deposits. Ascendonanus greatly increases the knowledge on rare basal varanopids; it also reveals a so far unexpected ecotype of early synapsids. Its integumentary structures present the first detailed and soft tissue skin preservation of any Paleozoic synapsid. Further systematic results suggest a varanodontine position for Mycterosaurus, the monophyly of South African varanopids including Anningia and the distinction of a skeletal aggregation previously assigned to Heleosaurus, now renamed as Microvaranops parentis gen. et sp. nov.
... Although there has been substantial debate surrounding the biostratigraphy of the terrestrial faunas across the lowermiddle Permian transition [1,12,14,[19][20][21][22][23], it is now widely accepted that the San Angelo Formation of Texas, the Chickasha Formation of Oklahoma and the faunas of the Kazanian series from Russia (the Golyusherma Subassemblage) are contemporaneous and of Roadian age (but see discussion in the electronic supplementary material text). The Cala del Vino Formation of Sardinia is also included as an equatorial Laurasian locality (see electronic supplementary material text), despite only having produced a single tetrapod species: the caseid Alierasaurus ronchii [24,25]. ...
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The terrestrial vertebrate fauna underwent a substantial change in composition between the lower and middle Permian. The lower Permian fauna was characterized by diverse and abundant amphibians and pelycosaurian-grade synapsids. During the middle Permian, a therapsid-dominated fauna, containing a diverse array of parareptiles and a considerably reduced richness of amphibians, replaced this. However, it is debated whether the transition is a genuine event, accompanied by a mass extinction, or whether it is merely an artefact of the shift in sampling from the palaeoequatorial latitudes to the palaeotemperate latitudes. Here we use an up-to-date biostratigraphy and incorporate recent discoveries to thoroughly review the Permian tetrapod fossil record. We suggest that the faunal transition represents a genuine event; the lower Permian temperate faunas are more similar to lower Permian equatorial faunas than middle Permian temperate faunas. The transition was not consistent across latitudes; the turnover occurred more rapidly in Russia, but was delayed in North America. The argument that the mass extinction is an artefact of a latitudinal biodiversity gradient and a shift in sampling localities is rejected: sampling correction demonstrates an inverse latitudinal biodiversity gradient was prevalent during the Permian, with peak diversity in the temperate latitudes.
... It is overlain by weathered volcaniclastic rocks of uncertain origin (Case Satta ignimbrites), and pumiceous tuffs or lava-rich layers. The age of the uppermost part of TSU 2 was long considered to be post-Autunian, but is now constrained to the early Guadalupian by the presence of fossil bones of a large vertebrate Romano and Nicosia, 2014). ...
... By the Kungurian, the lineage leading to Dimetrodon grandis had exceeded the largest known edaphosaurid. The increased diversity and abundance of some of the largest terrestrial animals of the early Permian, the caseids, in the latter stages of the Cisuralian (Olson 1954(Olson , 1968Reisz et al. 2011;Brocklehurst et al. 2013;Romano and Nicosia 2014) may provide a reason for the continued increase in body size: the need to expand the possible diet range to include these even larger prey items. The sphenacodontids also evolved a more sophisticated dental apparatus at this time: "true" ziphodonty, where the serrations of the teeth have denticles with a dentine core . ...
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Body size is one of the most important characteristics of an organism, impacting a great variety of ecological characteristics. The influence of diet on body size has received considerable attention, with previous studies suggesting a greater tendency towards increased body size in herbivores than macro-carnivores. The earliest known herbivorous and macro-carnivorous synapsids provide an ideal case study for examining body size evolution in different dietary regimes. Sphenacomorpha contains two lineages: Edaphosauridae (some of the most abundant terrestrial herbivores in the late Carboniferous and early Permian), and Sphenacodontia (the largest and most abundant carnivores of that time). Phylogenetic comparative analyses are used to compare trait evolution in sphenacomorphs, including a Bayesian method for identifying branches along which phenotypic selection occurred. Two branches show rapid increases in body size in the late Carboniferous. The first occurred in Edaphosauridae, along the branch leading to the herbivorous members. The later shift towards larger size occurred in Sphenacodontia, producing a clade of large carnivores. It is possible that the rapid appearance of large herbivorous synapsids in the Carboniferous provided the selective pressure for carnivores to increase their size. Following these two shifts, rates of evolution in edaphosaurids slowed significantly, but the carnivorous sphenacodontians showed further increases.
... It is overlain by weathered volcaniclastic rocks of uncertain origin (Case Satta ignimbrites), and pumiceous tuffs or lava-rich layers. The age of the uppermost part of TSU 2 was long considered to be post-Autunian, but is now constrained to the early Guadalupian by the presence of fossil bones of a large vertebrate Romano and Nicosia, 2014). ...
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The latest Carboniferous to lower Permian volcanism of the southern Variscides in Sardinia developed in a regional continental transpressive and subsequent transtensile tectonic regime. Volcanism produced a wide range of intermediate–silicic magmas including medium- to high-K calc-alkaline andesites, dacites, and rhyolites. A thick late Palaeozoic succession is well exposed in the four most representative Sardinian continental basins (Nurra, Perdasdefogu, Escalaplano, and Seui–Seulo), and contain substantial stratigraphic, geochemical, and geochronological evidence of the area’s complex geological evolution from the latest Carboniferous to the beginning of the Triassic. Based on major and trace element data and LA–ICP–MS U–Pb zircon dating, it is possible to reconstruct the timing of post-Variscan volcanism. This volcanism records active tectonism between the latest Carboniferous and Permian, and post-dates the unroofing and erosion of nappes in this segment of the southern Variscides. In particular, igneous zircon grains from calc-alkaline silicic volcanic rocks yielded ages between 299 ± 1 and 288 ± 3 Ma, thereby constraining the development of continental strike-slip faulting from south (Escalaplano Basin) to north (Nurra Basin). Notably, andesites emplaced in medium-grade metamorphic basement (Mt. Cobingius, Ogliastra) show a cluster of older ages at 332 ± 12 Ma. Despite the large uncertainty, this age constrains the onset of igneous activity in the mid-crust. These new radiometric ages constitute: (1) a consistent dataset for different volcanic events; (2) a precise chronostratigraphic constraint which fits well with the biostratigraphic data and (3) insights into the plate reorganization between Laurussia and Gondwana during the late Palaeozoic evolution of the Variscan chain.
... The presence of a caseid vertebra in the Catalan Pyrenees (Fig. 2) indicates a minimum age of Middle Permian for the part of the succession where it was found (Fig. 5). This group of synapsids was relatively abundant during this time interval, although few specimens have been so far reported in Europe (e.g., Sigogneau-Russell and Russell, 1974;Wernerburg et al., 2007;Reisz et al., 2011;Ronchi et al., 2011;Romano and Nicosia, 2014). The Pyrenean vertebra is tentatively attributed to cf. ...
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The Permian and Triassic successions of the Catalan Pyrenees provide key information on the stratigraphic and paleontological record of Southern Europe. These deposits are encompassed in a long terrestrial succession ranging from the Late Carboniferous to the Middle Triassic, having been historically studied by different disciplines (e.g., Mey et al., 1968; Nagtegaal, 1969; Hartevelt, 1970; Gisbert, 1981; Speksnijder, 1985; Saura, 2004; Saura and Teixell, 2006; Gretter et al., 2015). Nevertheless, there are few works focused on the paleontological record, especially on vertebrate remains. A detailed revision of the known Permian and Triassic vertebrate record of the Pyrenean Basin was provided by Fortuny et al. (2011). More recently, the Lower Permian has been biostratigraphically constrained by vertebrate footprints (e.g., Mujal et al., in press), and the Permian-Triassic transition was analyzed in detail in Mujal et al. (2016). Concerning this latter work, our international and interdisciplinary team carried out new stratigraphic, sedimentological and paleontological analyses from the Permian Upper Red Unit (URU) and the Triassic Buntsandstein facies of the Catalan Pyrenees. We aimed to constrain the Permian-Triassic succession in the Western Tethys sub-basins providing new (bio-) chronologic data together with a general sedimentological revision of the fossil bearing stratigraphic units.
... Middle Permian for the URU. This group of synapsids was relatively abundant duringRonchi et al., 2011;Romano and Nicosia, 2014). As a matter of fact, some of them have been poorly dated, especially Euromycter and Ruthenosaurus, from the Rodez Basin (France), whose ages range from the late Early to the early Late Permian(Reisz et al., 2011). ...
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The continental Permian-Triassic transition in southern Europe presents little paleontological evidence of the Permian mass extinction and the subsequent faunal recovery during the early stages of the Triassic. New stratigraphic, sedimentological and paleontological analyses from Middle-Upper Permian to Lower-Middle Triassic deposits of the Catalan Pyrenees (NE Iberian Peninsula) allow to better constrain the Permian-Triassic succession in the Western Tethys basins, and provide new (bio-) chronologic data. For the first time, a large vertebra attributed to a caseid synapsid from the ?Middle Permian is reported from the Iberian Peninsula - one of the few reported from western Europe. Osteological and ichnological records from the Triassic Buntsandstein facies reveal a great tetrapod ichnodiversity, dominated by small to medium archosauromorphs and lepidosauromorphs (Rhynchosauroides cf. schochardti, R. isp. 1 and 2, Prorotodactylus-Rotodactylus, an undetermined Morphotype A and to a lesser degree large archosaurians (chirotheriids), overall suggesting a late Early Triassic-early Middle Triassic age. This is in agreement with recent palynological analyses in the Buntsandstein basal beds that identify different lycopod spores and other bisaccate and taeniate pollen types of late Olenekian age (Early Triassic). The Permian caseid vertebra was found in a playa-lake setting with a low influence of fluvial water channels and related to the distal parts of alluvial fans. In contrast, the Triassic Buntsandstein facies correspond to complex alluvial fan systems, dominated by highenergy channels and crevasse splay deposits, hence a faunal and environmental turnover is observed. The Pyrenean biostratigraphical data show similarities with those of the nearby Western Tethys basins, and can be tentatively correlated with North African and European basins. The Triassic Pyrenean fossil remains might rank among the continental oldest records of the Western Tethys, providing new keys to decipher the Triassic faunal biogeography and recovery.
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Pareiasaurs were among the world’s first large terrestrial tetrapods, first appearing during the Guadalupian Epoch, and were later widespread across Pangea during the Lopingian where they formed a significant part of the large herbivore guild. The Bradysauria of the Lower Beaufort Group of the Karoo Basin of South Africa are among the oldest pareiasaurs, yet little is known of their palaeobiology. Here, we present the first volumetric body mass estimate and a new in vivo reconstruction of the earliest Karoo pareiasaur, and the phylogenetically basal-most pareiasaur, Bradysaurus baini, based on two almost complete adult mounted skeletons. Using 3D photogrammetric models of the two skeletons, we calculated a possible body mass range for B. baini by applying different densities for living tissue to reconstructions of differing soft tissue mass. Considering the larger adult Bradysaurus specimen, our volumetric body masses range from a minimum of 851.4 kg to a maximum of 1,276.5 kg, with an overall mean body mass of 1,022 kg, approximately the body weight of a large domestic cow. The study provides a more precise estimate of body mass in early members of Pareiasauridae, and we suggest that they were somewhat smaller than some late Permian taxa such as Scutosaurus karpinskii.
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Pareiasaurs (Amniota, Parareptilia) were characterized by a global distribution during the Permian period, forming an important component of middle (Capitanian) and late Permian (Lopingian) terrestrial tetrapod biodiversity. This clade represents an early evolution of sizes over a ton, playing a fundamental role in the structure of middle and late Permian biodiversity and ecosystems. Despite their important ecological role and relative abundance around the world, our general knowledge of the biology of these extinct tetrapods is still quite limited. In this contribution we provide a possible in vivo reconstruction of the largest individual of the species Scutosaurus karpinskii and a volumetric body mass estimate for the taxon, considering that body size is one of the most important biological aspects of organisms. The body mass of Scutosaurus was calculated using a 3D photogrammetric model of the complete mounted skeleton PIN 2005/1537 from the Sokolki locality, Arkhangelsk Region, Russia, on exhibit at the Borissiak Paleontological Institute, Russian Academy of Sciences (Moscow). By applying three different densities for living tissues of 0.99, 1, and 1.15 kg/1,000 cm³ to reconstructed “slim,” “average” and “fat” 3D models we obtain average body masses, respectively, of 1,060, 1,160, and 1,330 kg, with a total range varying from a minimum of one ton to a maximum of 1.46 tons. Choosing the average model as the most plausible reconstruction and close to the natural condition, we consider a body mass estimate of 1,160 kg as the most robust value for Scutosaurus, a value compatible with that of a large terrestrial adult black rhino and domestic cow. This contribution demonstrates that barrel-shaped herbivores, subsisting on a high-fiber diet and with a body mass exceeding a ton, had already evolved in the upper Palaeozoic among parareptiles, shedding new light on the structure of the first modern terrestrial ecosystems.
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A new genus and species of a basal synapsid Caseidae, Martensius bromackerensis, is described based on four partial to nearly complete mostly articulated skeletons that provide a comprehensive knowledge of the skeletal morphology. All four specimens were collected from a single site, the Bromacker quarry, in the Lower Permian Artinskian Tambach Formation, Germany. The Bromacker caseid is the first to be reported from Germany and can be easily distinguished from all other caseids based on substantial lists of autapomorphic and plesiomorphic characters. Of the four caseid specimens only the smallest, a juvenile, and the largest, an adult designated as the holotype, are nearly complete, articulated, and possess skull material: in the juvenile a small partially articulated portion of the skull, and in the adult a nearly complete but dorsoventrally crushed skull. The two specimens are distinguished from one another by features attributed to different ontogenetic stages of development, which include skeletal ossification, proportional dimensions of elements, and most interestingly marginal dentitions. The last category includes a feature unique among caseids of an ontogenetic change in the dentition from insectivorous in the juvenile specimen to what is believed to be an omnivorous dentition in the adult. A phylogenetic analysis posits the Late Pennsylvanian Eocasea martiniReisz and Fröbisch, 2014, as the basalmost member of the monophyletic Caseidae and the later occurring middle Early Permian Bromacker caseid as the sister taxon of the remaining late Early and Middle Permian members of the clade. This series of relationships parallels a proposed chronology of evolutionary changes in the dentitions and associated diets of caseids.
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According to a traditional view, the specific diet in vertebrates is one of the key factors structuring the composition of the gut microbiota. In this interpretation, the microbiota assumes a subordinate position, where the larger host shapes, through evolution and its fitness, the taxonomical composition of the hosted microbiota. The present contribution shows how the evolution of herbivory, framed within the new concept of holobiont, the possibility of inter-kingdom crosstalk and its epigenetic effects, could pave the way to a completely reversed interpretation: instead of being passively shaped, the microbiota can mold and shape the general host body structure to increase its fitness. Central elements to consider in this context are the inter-kingdom crosstalk, the possibility of transporting RNAs through nanovesicles in feces from parents to offspring, and the activation of epigenetic processes passed on vertically from generation to generation. The new hypothesis is that the gut microbiota could play a great role in the macroevolutionary dynamics of herbivorous vertebrates, causing directly through host-microbiota dialog of epigenetic nature (i.e., methylation, histone acetylation, etc.), major changes in the organisms phenotype. The vertical exchange of the same microbial communities from parents to offspring, the interaction of these microbes with fairly uniform genotypes, and the socially restricted groups where these processes take place, could all explain the reasons why herbivory has appeared several time (and independently) during the evolution of vertebrates. The new interpretation could also represent a key factor in understanding the convergent evolution of analogous body structures in very distant lineages.
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The origin of the diaphragm remains a poorly understood yet crucial step in the evolution of terrestrial vertebrates, as this unique structure serves as the main respiratory motor for mammals. Here, we analyze the paleobiology and the respiratory apparatus of one of the oldest lineages of mammal-like reptiles: the Caseidae. Combining quantitative bone histology and functional morphological and physiological modeling approaches, we deduce a scenario in which an auxiliary ventilatory structure was present in these early synapsids. Crucial to this hypothesis are indications that at least the phylogenetically advanced caseids might not have been primarily terrestrial but rather were bound to a predominantly aquatic life. Such a lifestyle would have resulted in severe constraints on their ventilatory system, which consequently would have had to cope with diving-related problems. Our modeling of breathing parameters revealed that these caseids were capable of only limited costal breathing and, if aquatic, must have employed some auxiliary ventilatory mechanism to quickly meet their oxygen demand upon surfacing. Given caseids' phylogenetic position at the base of Synapsida and under this aquatic scenario, it would be most parsimonious to assume that a homologue of the mammalian diaphragm had already evolved about 50 Ma earlier than previously assumed.
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In a recent study, the phylogeny of Caseidae (a herbivorous family of Palaeozoic synapsids belonging to the paraphyletic grade known as pelycosaurs) was analysed with a dataset employing more than three hundred continuous morphological characters in an effort to follow the principles of total evidence. Continuous characters are a source of great debate, with disagreements surrounding their suitability for and treatment in phylogenetic analysis. A number of shortcomings were identified in the handling of continuous characters in this study of caseids, including the use of gap weighting to discretize the characters and potential issues with redundancy and character non-independence. Therefore , an alternative treatment for these characters is suggested here. First, rather than using gap weighting, the continuous characters were analysed in the program TNT, in which the raw values can be treated as continuous rather than discrete. Second, prior to the phylogenetic analysis, the continuous characters were subjected to a log-ratio principal component analysis, and then the principal components were included in the character matrix rather than the raw ratios. Analysing the original data in TNT produced little difference in the results, but using the principal components as continuous characters resulted in alternative positions for Caseopsis agilis, Ennatosaurus tecton and Caseoides sanangeloensis. The differences are judged to be due to the reduced redundancy of the characters, the smaller number of principal components not overwhelming the discrete characters and the use of a scaling method which allows principal components with a higher variance to have a greater influence on the analysis. The positions of highly fragmentary fossils depended heavily on the method used to treat the missing characters in the principal component analysis, and so the method proposed here is not recommended for analysing very incomplete taxa.
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This study represents a reinvestigation of two historical fossil discoveries, Callibrachion gaudryi (Artinskian of France) and Datheosaurus macrourus (Gzhelian of Poland), that were originally classified as haptodontine-grade sphenacodontians and have been lately treated as nomina dubia. Both taxa are here identified as basal caseasaurs based on their overall proportions as well as dental and osteological characteristics that differentiate them from any other major synapsid subclade. As a result of poor preservation, no distinct autapomorphies can be recognized. However, our detailed investigations of the virtually complete skeletons in the light of recent progress in basal synapsid research allow a novel interpretation of their phylogenetic positions. Datheosaurus might represent an eothyridid or basal caseid. Callibrachion shares some similarities with the more derived North American genus Casea. These new observations on Datheosaurus and Callibrachion provide new insights into the early diversification of caseasaurs, reflecting an evolutionary stage that lacks spatulate teeth and broadened phalanges that are typical for other caseid species. Along with Eocasea, the former ghost lineage to the late Pennsylvanian origin of Caseasauria is further closed. For the first time, the presence of basal caseasaurs in Europe is documented.
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Occupying the role of primary consumer and having an early–middle Permian age range, caseids (Caseasauria, Synapsida) are fundamental to the interpretation of the early history of terrestrial vertebrate ecosystems. Despite this importance, no comprehensive, species-level phylogenetic study of Caseidae has yet been performed. Herein, we present a phylogenetic analysis of the group, using gap weighting to include poorly known taxa. Besides the description and comments on the resultant topologies, some more general issues concerning cladistic methodologies are briefly addressed. This study highlights the importance of a total-evidence approach, including as many within-group taxa and characters as possible. Continuously varying characters, in the form of indices derived from measurement of individual skeletal elements, proved to be highly important, adding significantly to the resolution of, and support for, recovered trees. The utility of the postcranial skeleton in understanding relationships among basal synapsids is highlighted.
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Detailed stratigraphical-sedimentological investigations have recently focused on the Permian to Triassic continental sequences of Nurra (NW Sardinia) and Provence (SE France) with the shedding of new light on the chrono- and lithostratigraphical correlations between these two distant areas today. The target of this research is to reconstruct the paleogeography of this western Mediterranean sector during the Late Palaeozoic-Early Mesozoic transition, and to make inferences on the most reliable palaeoposition of the Corsica- Sardinia block before its drift toward the Tyrrhenian area. The investigated successions are presently and mainly exposed in Sardinia, along the coastal area of Cala Viola-Porto Ferro, up to Punta Lu Caparoni (N of Alghero) and in France, between Sanary and Carqueiranne (W and E of Toulon). Facies and palaeoenvironmental analysis, enhanced by the outstanding quality of outcrops, allowed us to correlate both the successions and, consequently, to highlight three main stratigraphic sequences which are recognisable at a regional scale. The stacking pattern of these sequences is as follow: The first sequence shows reduced thicknesses and lies unconformably on the Variscan metamorphic basement. It is initially represented by a Basal Conglomerate entirely composed of basement lithoclasts and later by alluvial-to-lacustrine deposits, named the Punta Lu Caparoni Fm. in Sardinia and the Les Pellegrins Fm. in Provence. The first «Formation» is rich in Autunian mega- and microfloras, while for the second, new palynological research is in progress. In both areas, volcanic rocks of presumed calc-alkaline affinity are discontinuously associated within and above these sediments. The second sequence is the most represented both in Sardinia and France. It consists of an alluvial megacycle which begins with tens of metres of channelised quartz-conglomerates and arenites, deposited in a braided alluvial setting. These deposits, represented in Nurra by the Pedru Siligu Fm. and in Provence by the Transy Fm., unconformably overlie the first sedimentary and volcanic sequence. Further volcanic activity, ascribed to the Bron Fm. in Provence and identified possibly with that of the Casa Satta volcaniclastics in Nurra, followed the above-mentioned quartz-rich formations. The sequence passes upwards into reddish alluvial sediments with very similar facies (Porto Ferro and Les Salettes Fms). A terminal lacustrine event in the latter unit yielded rich macro- and microflora, which allowed us to relate these deposits to post-Kungurian/pre- Tatarian times. The first episodes of undoubtedly alkaline volcanism (basalts) also occur in the Salettes Fm. The overlying St.-Mandrier and Fabregas Fms in Provence, and the Cala del Vino Fm. in Nurra, are represented again by very thick alluvial, mainly meandering deposits, locally grading, as in the second unit, into playa sediments. Volcanic rocks crop out moderately in both regions. The top of this second, mainly siliciclastic succession probably pertains to undefined Late Permian (Tatarian?) times. The third sequence begins with a thin quartz-conglomerate band, which includes wind-worn clasts testifying to an arid climate, named Poudingues de Port-Issol in Provence and Conglomerato del Porticciolo in Nurra. These basal layers rest unconformably on the previous formations and are followed by over 50 m of medium to fine reddish sandstones and siltstones, laid down in a floodplain by terminal fans, which are known as the Grès de Gonfaron in the former area and the Arenarie di Cala Viola in the latter. The age of this sequence, which reaches up to the Middle Triassic marine Muschelkalk, is generally delimited between the Olenekian and the Anisian. Later, the authors of this paper highlight some preliminary results about the stratigraphic position and petrographic affinity of the Permian volcanics in Nurra, which have been long debated. In particular, a conspicuous mainly ignimbritic body was in places identified between the Punta Lu Caparoni and the Pedru Siligu Fms.; the volcaniclastic products of Casa Satta, more than 20 m thick, appear intercalated between the Pedru Siligu and the Porto Ferro Fms, and thus they pertain to the second sequence; a third and younger volcanic episode, which is represented by some metre-thick tuffs and cinerites cropping out within the Cala del Vino Fm. at the Ponte Crabolu locality, occurs below the Triassic Buntsandstein, though is as yet lacking in a clear stratigraphic position. The serial affinity of the aforementioned volcanics, which appear generally affected by heavy hydrothermal alteration or induced by significant secondary depletion of mobile elements, needs further research. Only the alkaline affinity of the welded tuffs at M. Santa Giusta has been recently confirmed. As a consequence, in order to define appropriately their petrographic and geochemical composition, a comparative study of these Permian volcanics of Nurra with the relatively well known igneous sequences of South- Provence is in progress.
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Abstract - After theoretical analyses on the application of the main straligraphic methods to continental deposits, we carried out a feasibility analysis to assess the ages of Permian and Tri¬assic continental sediments by means of tetrapod footprints. The data mainly originate from the Central and Southern Alps. The paleogeography of the Alpine region during Permian and Triassic times gave rise to a unique geological situation and well-exposed sections in which marine sediments, continental deposits rich in footprints and volcanic rocks are interfingered. The resulting mixed sections enable us to build a framework of biostratigraphical and chronological data in which tetrapod footprint-based evolutionary groups can be considered as biochronological units. Such units (Land Ichnofaunal Units) and the corresponding biochronological units (Land Ichnofaunal Ages), still to be formalized, seems to reveal some advantages, with respect to other dating systems.
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The cranial anatomy of the Early Permian synapsid Varanosaurus is restudied on the basis of previously described specimens from Texas and a recently discovered specimen from Oklahoma. Cladistic analysis of the Eupelycosauria, using a data matrix of 95 characters, provides the following hypothesis of relationships of Varanosaurus: 1) Varanosaurus is a member of the family Ophiacodontidae; 2) of the ophiacodontid genera included in the analysis, Varanosaurus and Ophiacodon share a more recent common ancestor than either does with the more primitive Archaeothyris; and 3) a clade containing the progressively more derived taxa Edaphosauridae, Haptodus, and Sphenacodontoidea (Sphenacodontidae plus Therapsida), together with Varanopseidae and Caseasauria, are progressively more distant outgroups or sister taxa to Ophiacodontidae. A revised diagnosis is given for Varanosaurus. -Authors
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Stream channel infills near Garnett, Kansas preserve the most abundant and diverse assemblage of amniotes known from the Carboniferous. In addition to the diapsid Petrolacosaurus kansensis and the synapsids Haptodus garnettensis, Xyrospondylus ecordi, and Ianthasaurus hardestiorum, at least three additional synapsid taxa can be recognized, including a new eupelycosaur genus that is represented by a partial skull and an isolated maxilla. Ianthodon schultzei n. gen. et sp. possesses three premaxillary and seventeen or eighteen maxillary teeth, and the individual teeth are generally conical in outline with only a slight recurvature near the tip. On the lingual surface, the teeth possess densely packed longitudinal fluting that extends to the tip of each tooth. No distinct caniniform tooth is present on the maxilla, but there is a modest caniniform region along the anterior one-third of the bone. I. schultzei is also characterized by a tall lacrimal, and the pineal foramen is found at the midpoint of the median parietal suture. Available evidence suggests that Ianthodon is a member of Sphenacodontia and is positioned within the "haptodont" grade of synapsids. Phylogenetic evidence and a review of occurrence data from Garnett and the 21 other reported Pennsylvanian amniote-bearing localities indicate that the early history of Amniota is characterized by: 1) a basal dichotomy into synapsids and sauropsids; and 2) an uneven rate of diversification, with synapsids rapidly diversifying and quickly developing a dominant role in the terrestrial ecosystems of the late Paleozoic.
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The origin and early evolution of amniotes (fully terrestrial vertebrates) led to major changes in the structure and hierarchy of terrestrial ecosystems. The first appearance of herbivores played a pivotal role in this transformation. After an early bifurcation into Reptilia and Synapsida (including mammals) 315 Ma, synapsids dominated Paleozoic terrestrial vertebrate communities, with the herbivorous caseids representing the largest vertebrates on land. Eocasea martini gen. et sp. nov., a small carnivorous caseid from the Late Carboniferous, extends significantly the fossil record of Caseidae, and permits the first clade-based study of the origin and initial evolution of herbivory in terrestrial tetrapods. Our results demonstrate for the first time that large caseid herbivores evolved from small, non-herbivorous caseids. This pattern is mirrored by three other clades, documenting multiple, independent, but temporally staggered origins of herbivory and increase in body size among early terrestrial tetrapods, leading to patterns consistent with modern terrestrial ecosystem.
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["Short communication", no abstract. The conclusions follow:] The result of our study that Apsisaurus witteri is a varanopid synapsid, not an eosuchian diapsid, has significant implications to our understanding of both synapsid and diapsid evolution. First, this finding increases the known diversity of varanopid synapsids even further. Even though varanopids are relatively rare members of Lower and Middle Permian assemblages, their fossil record has been expanding steadily in the last three decades both taxonomically and temporally. Varanopids are now known from Carboniferous and Lower Permian rocks in North America and Europe, and from Middle Permian strata of Russia and South Africa. Varanopids range in size from 30 cm to over 200 cm in total body length (Reisz and Laurin, 2004), and they are distinct from other members of their terrestrial vertebrate assemblages in being relatively gracile predators. Conversely, and more significantly, the taxonomic diversity of diapsid reptiles in the Paleozoic has suffered another loss, resulting in an extremely scant fossil record for these reptiles. This is a startling development when considering that diapsids came to dominate theMesozoic era so completely and continue to be taxonomically more diverse than synapsids even today. Although diapsid reptiles first appear in the fossil record in the Pennsylvanian, less than 10 million years after the first appearance of the oldest known reptiles and synapsids, their fossil record is very poor throughout the remainder of the Paleozoic, when amniote evolution experienced its first massive diversification. With the recognition that Apsisaurus is not a diapsid reptile, the Middle Permian Lanthanolania (Modesto and Reisz 2002) from north-central Russia becomes the oldest known neodiapsid (oldest known eosuchian, sensu Laurin, 1991). All other, older diapsid reptiles are members of Araeoscelidia, a clade of small, gracile forms that represent the initial Carboniferous and Early Permian diversification of diapsids (deBraga and Reisz 1995). These diapsids are only known from a handful of localities in North America and Europe. Only in the Late Permian do we see the appearance of other diapsids, the younginiform eosuchians. Future discoveries may alter this perceived pattern of early diapsid evolution, but for now, the picture that emerges is that diapsids were rare during the initial stages of amniote diversification, or that they diversified in habitats that where the fossilization potential was low.
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Key ri.oi.ds -Stratigrriphy; rctl beds; arcnite composition; Sar-clinia: Pcrinian-Triassic. Al?sfrcict-This work rcprcsents a preliminary revision of the ter-rigenous Permian and Triassic siratigraphic successions of ihe Nurra region (northwcsicrn Sartlinia). On thc basis of litho-stratigraphical, sedimentological iintl pctrographic cvidcnce, sup-ported by scaitered and rare biosiratigraphical data, thc wholc post-Variscan succession has bccn suhdiviclcd into the Iòllowing units: I) thc "Punta Lu Caparoni Formation" (PLC), made by the traditional alluvial-to-lacusirine deposits and upwards by a whitish succcssion which corrcsponds to the unit 1 of Gasperi & Gelmini, 1980; 11) a volcanic-hearing unii of prohlcrnatic gco-chemistry, scarcely cropping out in ihc Lu Caparoiii-Cala Viola area and well-documented in the Monte Sania Giusta scction, where shows an alkaline coinposiiion; 111) a clastic uni[ of rcd-dish conglomerates, sandstones and minor pelites. rich in vol-canic-dcrived clasts; as in the Montc Santa Giusia. this unit rep-resenis a fining-upwards sequence, evolving rrom alluvial fantbraided river settiiigs io ineandcring river and coasial plain deposits. and coiresponds t« units 2 and 3 of Gasperi 8: Gelrnini (1980); IV) an upper clastic unit, separated lioin ihc tinderlying deposiis hy a marked disconformity. li compriscs a hasal quartz conglomerate grading upwards into reddish sandstones and mi-nor pelites, showing alternating fluvial and tidal intlux. Scarce hiosiratigraphical data allow iis to relate the base of ihc investigated siliciclastic succession to the Early Permian ("Au-iunian" Auci.) and the top to an Olenekian (?)-early Anisian to late Anisian time, but do not allow a chronostratigraphical clas-silication, unii by unit. of the whole sequence and thc cvaluntion of the duration of hiatuses at the inain unconlòrinities. Plirole rliicii~e -Stratigrafia; rrd l~erlc; compoiizionc delle arc-niti; Sardegna; Permiano-Triassico. Rinssiri~to -Questo lavoro fornisce una revisione preliminare del-la successione permiana e triassica della Nurra dal punto di vista stratigrafico, sedimentologico e composizionale. Sulla base di nuovi dati di campagna, gli autori propongono di sucldividcre la successione in quattro unità principali: I) la "Formazione di Pun-ia Lu Caparoni" (PLC), che oltre ai tradizionali dcpositi alliivio-lacustri comprende, per la prima volta, la sovrastaiitc unità clasii-ca, di colore biancastro, già denominata come ~iniià I da Gasperi & Gelmini (1980); 11) uno o piìi corpi vulcanici. rappresentati da igniinhriti e tufi a composizione riolitica. spesso molto alterati. Questi prodotti affiorano sia ad un livcllo stratigrafico imprecisa-to ira la PLC e la successione rossastra permiana C triassica di Lu Caparoni-Cala Viola e sia, benchè la correlazionc tra i rispcttivi episodi vulcanici iisulti tuttora incerta. alla base della sezionc di Monte Santa Giusta; 111) la successione soprasiante. che corri-sponde alle unità 2 e 3 di Gasperi & Gelmini (1980), C costiiuiia da conglomerati e arenarie fluviali. con abbondanti clasti di origi-nc vulcanica. In base ai dati forniti dalla sezione di Montc Santa Giusta. per quanto condensata e lacunosa. si può ritcncrc chc le iiniià 2 e 3 di Gaspcri & Gclmini (1980) costituiscano ~in'linica se-quenza tining-tipward, con transizione da facies hraided a facies mcandrilòrmi e quindi di piana costierri; [V) l'unità siliciclastica superiore (uniti 4 di Gasperi & Gelmini, 1980) è discordante sul-la successione prcccdcnte; la discordanza è marcata da un banco conglomeratico ricco in ciottoli di quarLo provenienti dal basa-mento metarnorfico. Verso l'alto passa ad arenarie a stratificazio-nc incrociata bipolare e successivamente a siltiti ed arenaric fini con inlliissi iilternativamerite fluviali c ticlali. Il liinitc con i soprastanti dcpositi dcl Muschelkalk è graduale e parzialmente visibile nella sezione di Monte Santa Giusta, mcn-irc a Cala Viola la successione si trova in contatto tettonico con i sedimenti del Kcuper. I dati coniposizionali indicano contributi prevalenti dal hasa-mento metaniorfico C dalle vulcaniti pcriniane. Con la deposi-zionc dcll'uiiità soinmitale (IV), areiiarie e conglomerati mo-strano un'clevaia maturità tessiturale e composizionalc, con un consistente incremento nella quantità di quarzo. Sulla succcssione in csamc noiio disponibili solo rari dati crono-straiigralici. La parte inferiore della "Formazione di Punta Lu Caparoni" è datata al Permiano inferiore ("Autuniano" Auct.) in base al contenuto macroflorisiico e palinologico; la parte supc-riore dell'unità IV a Cala Viola ha fornito flore mal conservate (Eq~risetiriir cfr. illoirgeotii). Le associazioni palinologiche rinve-nute nel pozzo Cugiarcddu, entro depositi elastici probabilmen-tc corrclabili con l'unità IV, indicherebbero la presenza dell'Olc-nekiano(?)-Anisico inferiore e dell'Anisico superiore.
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The aigialosaur Carsosaurus marchesetti is represented by a nearly complete skeleton from the Upper Cretaceous (Cenomanian-Turonian) of Slovenia. Dermal girdle elements include por-tions of the clavicles and a small interclavicle with a short anterior process. Endochondral girdle elements include a small scapula and large unfenestrated coracoid. A mineralized sternum is also present. The carpus is anguid-like and consists of ten ossified elements. Reduction of the procoelous nature of centrum articular surfaces is restricted to the caudal series. The type of C. marchesetti is the largest aigialosaur specimen known (> 1.5 m) and has proportionally larger propodials than any other aigialosaur. Phylogenetic reconstruction places Carsosaurus within a polytomous clade composed of all known aigialosaurs. Aigialosaurs are the sister-group to Mosasauridae, forming the Mosasauroidea, and are within Anguimorpha but distinct from Varanoidea. Supposed synapomorphies of varanids and mosasauroids are identified as either plesiomorphies ofAnguimorpha, or as misidentified homologs. Results of a principal component analysis of limb measurements suggest that aigialosaurs occupy a position on a functional continuum reflective of terrestrial not aquatic animals. Morphometric criteria cannot validate the exclusion of Carsosaurus from the Aigialosauridae.
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Elliotsmithia longiceps Broom, 1937 is a varanopseid synapsid from the middle part of the Tapinocephalus Assemblage Zone (Late Permian) of the Abrahamskraal Formation (Beaufort Group), South Africa. Its placement within this basal eupelycosaur clade is supported by the presence of the following features: strongly recurved, mediolaterally flattened marginal dentition, a tall and posteroventrally enlarged temporal fenestra, a narrow lower temporal bar formed by the jugal and quadratojugal with only a small contribution from the maxilla, a long medial process of the parietal that extends far anteriorly over the orbital region, and distinctive ornamentation on three circumorbital bones. Analysis of varanopseid phylogenetic relationships indicates that Elliotsmithia is a sister taxon to the clade formed by the medium-sized North American varanopseids Varanops, Aerosaurus, and Varanodon. Elliotsmithia is unique among Paleozoic synapsids in showing evidence of supravertebral armor. Elliotsmithia is important biogeo-graphically because it is the only known Permo-Carboniferous synapsid from the Southern Hemisphere in an assemblage dominated both numerically and taxonomically by therapsids. It demonstrates that Permo-Carboniferous synapsids were not excluded ecologically by therapsids and restricted to equatorial regions during the Late Permian.
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A new species of the sphenacodontid synapsid Dimetrodon, D. teutonis, is described on the basis of a single, adult specimen consisting of a large portion of the presacral vertebral column. The holotype was collected from the Lower Permian Tambach Formation, lowermost formational unit of the Upper Rotliegend, of the Bromacker quarry locality in the midregion of the Thuringian Forest near Gotha, central Germany. This is the first record of the genus outside of North America and, therefore, provides not only additional biological evidence of a continuous Euramerican landmass during the Early Permian, but also the absence of any major physical or biological barrier to faunal interchange of terrestrial vertebrates. An estimated weight of 14 kg for D. teutonis is half that of the smallest, previously recognized species, D. natalis. Sphenacodontid phylogeny indicates that the diminutive size of D. teutonis represents an autapomorphy and is in general accord with the absence of large-sized, basal synapsid predators at this truly terrestrial upland locality. It is speculated that the diminutive size of D. teutonis was probably an adaptation to a truly terrestrial, relatively uplands existence like that represented by the Bromacker locality. Here it subsisted on small vertebrates (and possibly large invertebrates) of the Bromacker assemblage, in which the dominant members in both size and abundance were herbivorous diadectids, and it was unlikely to encounter large predators.
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The skeletal anatomy of the Early Permian eureptile Thuringothyris mahlendorffae from the Bromacker Quarry, Germany, is redescribed on the basis of several new specimens. The taxon retains some plesiomorphic characters, such as an ectopterygoid and a tabular, but it also possesses low neural spines and nonswollen neural arches, a combination that is unique for early eureptiles. A phylogenetic analysis places Thuringothyris as the sister taxon of Captorhinidae, excluding any potential "protorothyridid" affinities. Implications of this study are that the swollen neural arches of captorhinids and araeosceloids might have evolved independently, that a downturned rostrum occurred only later in captorhinid evolution, and that the European Permian is important to the understanding of the origin of eureptiles.
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The monospecific genera Eothyris (Petrolia Formation, Leonardian, Archer County, Texas) and Oedaleops (Abo/Cutler Formation, Wolfcampian, Rio Arriba County, New Mexico), known solely from cranial remains, are confidently assigned to the monophyletic Caseasauria based on cranial and dental characters. In addition, Eothyris and Oedaleops comprise the monophyletic Eothyrididae based on nine cranial and dental characters. In contrast to the medium to large sized herbivorous caseids, the small eothyridids exhibit dental features that indicate that they were faunivores. The presence of well-developed caniniform teeth suggests that they were predators. Both Eothyris parkeyi Romer and Oedaleops campi Langston exhibit a suite of plesiomorphic cranial characters that identify them as basal synapsids. Thus, the eothyridids are better representatives of the primitive synapsid cranial morphotype than the often-used ophiacodontids. Although they appear relatively late in synapsid evolution, both eothyridids are significantly older than all other caseasaurs, forcing the establishment of a long unrecorded lineage for caseids.
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Although herbivory probably first appeared over 300 million years ago, it only became established as a common feeding strategy during Late Permian times. Subsequently, herbivory evolved in numerous lineages of terrestrial vertebrates, and the acquisition of this mode of feeding was frequently associated with considerable evolutionary diversification in those lineages. This book, originally published in 2000, represented the first comprehensive overview of the evolution of herbivory in land-dwelling amniote tetrapods in recent years. In Evolution of Herbivory in Terrestrial Vertebrates leading experts review the structural adaptations for, and the evolutionary history of, feeding on plants in the major groups of land-dwelling vertebrates, especially dinosaurs and ungulate mammals. As such it will be the definitive reference source on this topic for evolutionary biologists and vertebrate paleontologists alike.
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A new species of the sphenacodontid synapsid Dimetrodon, D. teutonis, is described on the basis of a single, adult specimen consisting of a large portion of the presacral vertebral column. The holotype was collected from the Lower Permian Tambach Formation, lowermost formational unit of the Upper Rotliegend, of the Bromacker quarry locality in the midregion of the Thuringian Forest near Gotha, central Germany. This is the first record of the genus outside of North America and, therefore, provides not only additional biological evidence of a continuous Euramerican landmass during the Early Permian, but also the absence of any major physical or biological barrier to faunal interchange of terrestrial vertebrates. An estimated weight of 14 kg for D. teutonis is half that of the smallest, previously recognized species, D. natalis. Sphenacodontid phylogeny indicates that the diminutive size of D. teutonis represents an autapomorphy and is in general accord with the absence of large-sized, basal synapsid predators at this truly terrestrial upland locality. It is speculated that the diminutive size of D. teutonis was probably an adaptation to a truly terrestrial, relatively uplands existence like that represented by the Bromacker locality. Here it subsisted on small vertebrates (and possibly large invertebrates) of the Bromacker assemblage, in which the dominant members in both size and abundance were herbivorous diadectids, and it was unlikely to encounter large predators.
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Past approaches to understanding the evolution of locomotory strategies among Paleozoic amniotes ("primitive reptiles" of previous parlance) have been influenced by preservational bias: early occurrences of some amniote taxa were used to polarize the acquisition or development of locomotory structures among the earliest amniotes. Using a phylogeny representing the current consensus in the literature, we investigate the major locomotory strategies that have been posited for Paleozoic amniotes (basal synapsids on one hand and early reptiles on the other) by optimizing the major locomotory styles identified for these taxa onto the consensus tree, in order to present an overview of the pattern of evolution of locomotory strategies inherited and adopted by various amniote lineages.
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The cranial anatomy of ceratopsian (“horned”) dinosaurs is well understood, but the postcranial skeleton has been largely ignored in previous studies of phylogeny, evolution, and function. In order to study morphological differences among ceratopsian postcranial elements and to compare evolutionary patterns, multivariate (Principal Components Analysis) and bivariate methods were used to analyze linear measurement data, and the shape methods Resistant-Fit Theta-Rho Analysis (RFTRA), Least-Squares Theta-Rho Analysis (LSTRA), and Euclidean Distance Matrix Analysis (EDMA) were applied to biological landmark data. Results of the analyses show that size is the primary change through ceratopsian skeleton evolution. Elements display positive allometry, and increasing structural support is evident, especially in the radius and fibula. Phylogenetic distribution of ceratopsian postcrania agrees with the skull material included in recent cladistic analyses. Psittacosaurus elements are in many ways derived relative to those of non-ceratopsid neoceratopsians, and evidence suggests that Psittacosaurus was bipedal, while non-ceratopsid neoceratopsians were not, except maybe for Udanoceratops. With increasing body size, neoceratopsian limbs bowed laterally. The variety of methods allows for unbiased interpretation of results, provides more information than any one method, and provides controls for each other. However, sample sizes are not ideal, and all results should be treated with caution at this time.
Article
Description of the first varanodontine varanopid material from the highly fossiliferous limestone fissure fill deposits at Richards Spur (Dolese Brothers Limestone Quarry), Oklahoma, is based on elements of at least three individuals recovered from two separate blocks of sedimentary rock. One block, which yielded associated cranial and postcranial bones from both adult and juvenile individuals, includes two well-preserved parabasisphenoid complexes, vertebrae, forelimb, pelvic girdle, and hind limb bones. An isolated maxilla fragment from another block preserves the diagnostic dorsal process characteristic of varanodontines. Preserved cranial and postcranial material is virtually identical to the varanodontine Varanops brevirostris. Taxonomic assessment of this new material in the context of the most comprehensive phylogenetic analysis of Varanopidae to date indicates the Richards Spur varanodontine is referable to Varanops brevirostris based on distinctive characters of the maxilla and the parabasisphenoid. The large size of Varanops suggests it was one of the top predators of the Richards Spur ecosystem. The Richards Spur locality records the only known co-occurrence of a mycterosaurine and a varanodontine varanopid at a single locality, and varanopids are the most common synapsids in the assemblage. As generally rare components of the more typically preserved lowland environments, the relative abundance and diversity of varanopids at Richards Spur suggests that they may have been more common components of the upland ecosystems in the Early Permian.
Article
The spectacular evolutionary history of terrestrial vertebrates is uncharacteristically poorly documented between the Paleozoic sub-equatorial exposures of the Permo-Carboniferous of North America and Europe, and the much higher latitude, Upper Permian deposits of central Russia and southern Africa. We report here that the discovery of the reptile Macroleter in Oklahoma provides the first direct vertebrate evidence of biochronological correlation between continental sediments from the Upper Permian of North America and Russia. The presence of the reptile Macroleter, a member of a major group of Upper Permian amniotes known previously only from central Russia, in North America improves dramatically our understanding of this early phase of amniote evolution, and also provides evidence of terrestrial tetrapod faunal interchange between North America and Russia in Late Permian time.
Article
A new genus and species of trematopid amphibian, Tambachia trogallas, is described on the basis of the greater portion of a skeleton, including the skull. The holotype was collected from the Early Permian Tambach Formation, the lowermost unit of the Upper Rotliegend, of the Bromacker locality in the midregion of the Thuringian Forest near Gotha, central Germany. Not only is this the first trematopid to be reported outside the United States, but it is the first specimen to include the greater portion of the postcranial skeleton. Analysis of the interrelationships of the trematopids agrees with the results of other recent studies: (1) Tambachia and the Late Pennsylvanian Anconastes, on the one hand, and the Early Permian Acheloma and Phonerpeton on the other, form sister clades of the monophyletic Trematopidae; and (2) Actiobates, although almost certainly a trematopid, is too poorly known to determine its intrafamilial relationships. The Bromacker locality is the only Early Permian site in Europe to produce a diverse assemblage of terrestrial or semi-terrestrial tetrapods, several of which are known otherwise only from the Upper Pennsylvanian and Lower Permian of the United States. The Bromacker assemblage is, therefore, of great interest in indicating: (1) an earliest Permian Wolfcampian age for the Tambach Formation, the basal unit of the Upper Rotliegend of the Thuringian Forest. This in turn suggests a Late Pennsylvanian age for all or most of the underlying Lower Rotliegend, rather than the widely accepted Early Permian; (2) a cosmopolitan, Euramerican distribution of Early Permian terrestrial or semi-terrestrial tetrapods previously reported only from the United States. This suggests an absence of any strong physical barriers to tetrapod dispersal across Euramerica during the Early Permian.
Article
Previously, known specimens of the Lochkovian (Lower Devonian) diplacanthid acanthodian genus Tetanopsyrus (all from the MOTH locality in the Northwest Territories, Canada) were thought to belong to a single species, T. lindoei. New specimens from the same locality have shown that two species are present. Tetanopsyrus lindoei is revised and T. breviacanthias, sp. nov. is described, leading to a revised diagnosis of the genus. Both species lack rostral tesserae; instead they have irregularly-shaped, monodontode, rostral scales without basal tissue and with an open pulp cavity. Both species also have enlarged, tuberculated, anterior circumorbital plates. Dorsal spines are shallowly inserted and each is supported by a basal plate that ossified early in ontogeny. The two species are distinguished from each other by the structure of the dorsal spines, the length of the pectoral spines, and the shape of the procoracoids.The revision of Tetanopsyrus has implications also for relationships among acanthodian families. Both Tetanopsyrus (Tetanopsyridae) and Gladiobranchus (Gladiobranchidae) are seen as diplacanthiforms rather than as ischnacanthiforms. Similarities are found in the jaws, circumorbital plates, anterior dorsal spine, dorsal spine basal plates, prepelvic spines, and scapulocoracoids. Other potential relatives of diplacanthids include Uraniacanthus, which has similarities in pre-pelvic and dorsal spines, and Culmacanthus, whose relationships cannot be settled without further study.
Article
Long bone allometry has been analyzed in a large sample of non-avian theropod dinosaurs spanning almost the entire size range of known adult species. Theropod long bone allometry closely parallels the trends observed in extant mammals. Like mammals, large theropods scale with significantly lower regression slopes than do smaller species. As in extant mammals non-avian theropods are neither geometrically nor elastically similar. Large non-avian theropods tend to be elastically similar, whereas small species approach geometric similarity. As in extant mammals non-avian theropods appear to show a size dependent change in limb posture, aligning the individual long bones more steeply to vertical with increasing size, thus probably reducing the mass specific amount of force necessary to counteract moments about the joints. The main difference between non-avian theropods and mammals appears to be the retention of very long limbs among large non-avian theropod species, which, however, is not unparalleled among extant large mammals.
Article
Three of the six earliest ichthyosaurs, namely, Chaohusaurus geishanensis, Chensaurus chaoxianensis, and Chensaurus faciles, occur in the Lower Triassic (Spathian) of the Chaohu area, Anhui Province, China. A reexamination of the three holotypes and two referred specimens indicates that the three species share derived features; however, the characters originally used to distinguish among the three are either growth-related or absent. Measurements of the specimens suggest that they represent a growth series of a single species, Chaohusaurus geishanensis Young and Dong 1972. The forefin of this species shows a strongly positive allometry, leading to the unusually large forefin in the largest specimen (the holotype). The use of the standard allometric equation may be problematic when two structures compared start their developments asynchronically. However, the alternative equation of Schmalhausen is also problematic, and therefore more scrutiny is required. The lunate fin elements, which commonly occur in the first and fifth digits of Early Triassic ichthyosaurs, first become ossified as biconcave elements, as in other metacarpals and phalanges.
Article
Well preserved skulls of Triceratops are extremely abundant in Maastrictian rocks from western North America. Although ossification obscures sutural and structural details in many skulls, others reveal much previously undescribed morphology. The circumnarial area includes enlarged nares and a complex narial fossa. A nasal horn of varying size, augmented by an epinasal ossification, caps the snout. The anterodorsal orbital margin is formed by the lacrimal and the supraorbital, which has fused to the lateral side of the prefrontal. This thick and laterally extensive orbital rim restricted forward vision in Triceratops. The ossified braincase completely surrounds the brain cavity, and is overlain by a deep frontal and cornual sinus complex. These sinuses probably acted as shock absorbers to counteract stresses placed on the postorbital horns during intraspecific interactions. The frill is heavily vascularized, lacks fenestrae, and is well buttressed by expansive paroccipital processes. Endocasts reflect all twelve cranial nerves, major structures of the brain, and some arterial and venous drainage systems.
Article
A vertebrate fauna has been obtained from the San Angelo formation, Permian, of Hardeman and Foard counties, Texas. This formation, which is composed of sandstones, red shales, and conglomerates, is considered to be of earliest middle Permian age. It appears to have been deposited by a series of major streams with three different source areas. The environment of deposition was deltaic, and beds seem to have been laid down under alternating wet and dry conditions. Eight genera of vertebrates, a xenacanth shark, a captorhinomorph reptile, and six synapsid reptiles have been determined. Six of the genera and seven species are new. The vertebrate fauna occurs in large part in floodplain deposits of the delta. It is believed to have been derived from an upland chronofauna that developed concurrently with the deltaic chronofauna of the Wichita and Clear Fork rather than from this deltaic assemblage. In evolutionary position the San Angelo fauna is notably advanced over that known from the Clear Fork. It includes adaptive equivalents of various middle Permian vertebrates of Russia and South Africa, but none of the San Angelo forms is ancestral to any of the Old World types. There is no indication that there were any connections between the Old and New World faunas at this time.
Article
The Bromacker section of the Lower Permian, Tambach Formation, in central Germany, yields an important fossil-vertebrate assemblage that was deposited in an upland setting near the center of a small, internally-drained paleograben. The fossil-vertebrate assemblage shares many taxa in common with others that are well-documented from North America, but is atypical in the: (1) unusually large abundance of the terrestrial herbivore Diadectes; (2) complete absence of aquatic and semi-aquatic vertebrates; and (3) rarity of medium-to-large carnivorous synapsids. The graben setting and the low-diversity, terrestrial, fossil-vertebrate assemblage together comprise a unique upland paleoecosystem, heretofore undocumented in the Early Permian. The composition of and relative abundances within the assemblage at Bromacker suggest that experiments with 'high-fiber' vertebrate herbivores as the dominant or significant basal component of vertebrate food webs had begun by the Early Permian, but only in settings with few or no aquatic and semi-aquatic vertebrates. The combined stratigraphic section at Bromacker consists of portions of two conformable stratigraphic intervals-the Lower and the Upper beds. Depositional events in both were dominated by seasonal-to-subseasonal cycles of flooding in an ephemeral, alluvial-to-lacustrine setting that was hot year-round with annual precipitation similar to that of a wet-and-dry tropical or wetter climate. Excellently preserved, articulated and disarticulated fossil vertebrates indicate subaerial exposure times of short duration and limited reworking. In the case of articulated specimens, death and burial were probably coeval events, most likely caused by floods.
Article
Description of the first varanodontine varanopid material from the highly fossiliferous limestone fissure fill deposits at Richards Spur (Dolese Brothers Limestone Quarry), Oklahoma, is based on elements of at least three individuals recovered from two separate blocks of sedimentary rock. One block, which yielded associated cranial and postcranial bones from both adult and juvenile individuals, includes two well-preserved parabasisphenoid complexes, vertebrae, forelimb, pelvic girdle, and hind limb bones. An isolated maxilla fragment from another block preserves the diagnostic dorsal process characteristic of varanodontines. Preserved cranial and postcranial material is virtually identical to the varanodontine Varanops brevirostris. Taxonomic assessment of this new material in the context of the most comprehensive phylogenetic analysis of Varanopidae to date indicates the Richards Spur varanodontine is referable to Varanops brevirostris based on distinctive characters of the maxilla and the parabasisphenoid. The large size of Varanops suggests it was one of the top predators of the Richards Spur ecosystem. The Richards Spur locality records the only known co-occurrence of a mycterosaurine and a varanodontine varanopid at a single locality, and varanopids are the most common synapsids in the assemblage. As generally rare components of the more typically preserved lowland environments, the relative abundance and diversity of varanopids at Richards Spur suggests that they may have been more common components of the upland ecosystems in the Early Permian.