Helms Deep for Metazoan Reef Builders Found From Permian Extinction era Slovenia?

Equatorial Palaeotethys as the last sanctuary for late Permian metazoan reef-builders: New evidence from the Bellerophon Formation of Slovenia

Authors:

Sremac et al

Abstract:

The rise and demise of warm-temperate Permian reefs and biostromes reflect the complex geologic history of this dynamic period. Environments suitable for reef-builders were devastated by the Guadalupian/Lopingian crisis, and Lopingian reefs have only been recorded at a small number of localities. The uppermost Permian limestones of the Bellerophon Formation, on the Vojsko Plateau (Slovenia), contain small, lenticular biostromes within a bioclastic wackestone/packstone lithofacies. The major biostrome builders are medium-sized coralline sponges (Demospongea and Calcarea), encrusted by smaller sponges, tube worms, sessile foraminifera, calcareous algae (Archaeolithoporella) and Shamovella (i.e., Tubiphytes), all of which are typically covered by microbial crusts. The biostromes are characteristically composed of bafflestone and bindstone, incorporating sporadic framestone. Narrow belts of floatstone surround the buildups, and sponge debris is also present in lenses within the mud matrix between metazoan bafflestones. The fossils are generally well-preserved, although the fine skeletal microstructure has been partially recrystallized. Sponges are heavily calcified, and ontogenic thickening of the skeleton can be observed in some encrusters. Framboidal pyrite, forming thin films on the inner walls of sponge chambers, suggests the presence of sulphate-reducing bacteria. These microbial symbionts may have enabled the sponges to survive in the anoxic marine environments of the uppermost Permian. The Changshingian sponge biostromes of the Vojsko Plateau represent the westernmost known occurrence of contemporary metazoan boundstones in the Palaeotethys.

The First Report of a Forest From Mid to Late Permian China

First report of a phytogeographically mixed (transitional) Middle–Late Permian fossil wood assemblage from the Hami area, northwest China, and implications for Permian phytogeographical, paleogeographical and paleoclimatic evolution in central Asia

Authors:

Wei et al

Abstract:

A diverse and well-preserved fossil wood assemblage is described, for the first time, from the Middle Permian Taerlang Formation and the Upper Permian Quanzijie Formation in the vicinity of the Tianshan Town, Hami City of northwestern China. On the basis of wood microstructure, the fossil woods are classified into three genera and five species, including one new genus: Prototianshanoxylon gen. nov. and two new species: Prototianshanoxylon erdaogouense sp. nov., Prototianshanoxylon hamiense sp. nov. The new genus is characterized by window-like cross-field pitting and mixed tracheid radial wall pitting that suggest a transitional type between araucarioid-type and protopinoid-type pittings.

Phytogeographically, the fossil wood assemblage is characterized by an admixture of elements of both temperate Angaran (represented by wood specimens with moderately to well defined growth rings in their secondary xylem) and tropical–subtropical north subregion of the Cathaysian floras (with wood specimens lacking well-defined growth rings). Such a phytogeographically mixed fossil wood assemblage is interpreted to represent a transitional and complex climate condition between a cool temperate and tropical to subtropical zones, showing both seasonal variation and unstable climate conditions. Previously, similarly mixed floras have already been found to exist widely in northern China ranging in age from Early to Late Permian, but the mechanisms thought to be responsible for their formation were varied and remain controversial. In this study, the formation of these mixed Permian floras of North China is linked to the closure of the Tianshan–Hingan seaway coupled with the collision and amalgamation of Siberia with North China and the Tarim block, in a manner much like closing a pair of scissors with the closure of the seaway proceeding gradually and progressively from west to the east.

Revising China's Pareiasaurs

The Chinese pareiasaurs

Author:

Benton

Abstract:

Pareiasaurs were important medium- to large-sized herbivores in the Middle and Late Permian, some 268–252 Ma. They are best known from abundant remains of several taxa found in South Africa and Russia, with isolated finds from other parts of the world. Six genera and species of pareiasaurs have been described from China, and yet they have not been reviewed. Of these six, Tsiyuania may be a synonym of Honania, but this taxon is not further considered here. The other four, which were named for separate finds from the Sunjiagou Formation (Changhsingian, 254–252 Ma), show considerable similarities. Despite earlier suggestions, there are no convincing anatomical characters to distinguish Shihtienfenia, Shansisaurus, and Huanghesaurus, and these three genera are synonymized as Shihtienfenia permica Young & Yeh, 1963. The fourth taxon, Sanchuansaurus pygmaeus Gao, 1989, shows distinctly different teeth from those of Huanghesaurus (= Shihtienfenia), and was about one-third of the size, so it is retained as a second valid pareiasaur from the Chinese latest Permian. Phylogenetic analysis confirms the validity of these two taxa, with Sanchuansaurus belonging among the derived forms, close to Elginiidae, and with Shihtienfenia associated with Pumiliopareiasauria and Pareiasuchus.

pop sci write up.

A Revision of Whaitsiid Therocephalian Theriognathus From Late Permian South Africa

Revision of the first therocephalian, Theriognathus Owen (Therapsida: Whaitsiidae), and implications for cranial ontogeny and allometry in nonmammaliaform eutheriodonts

Authors:

Huttenlocker et al

Abstract:

Historically, the whaitsiid therocephalian Theriognathus Owen was one of the earliest described nonmammalian therapsids, its morphology helping to link phylogenetically the Paleozoic synapsids of North America and southern Africa to their mammalian successors. However, decades of taxonomic over-splitting and superficial descriptions obscured the morphologic diversity of the genus, hindering its utility as a study system for the evolution of synapsid cranial function as well as its biostratigraphic significance in the Late Permian of southern Africa. Here, we revise the status and provenance of all the known specimens of Theriognathus from South Africa, Tanzania, and Zambia. We present both qualitative and quantitative support for the presence of a single morphospecies as proposed by some authors. Proportional differences in skulls that were previously ascribed to different morphotypes (‘Aneugomphius,’ ‘Notosollasia,’ ‘Moschorhynchus,’ and ‘Whaitsia’) are largely size-related and allometric trends are considered here in the context of jaw function and prey prehension. Our results suggest that the single species, Theriognathus microps, represented one of the most abundant Late Permian therocephalians in southern Africa and is consequently a potentially useful biostratigraphic marker for the upper Cistecephalus-lower Dicynodon Assemblage Zone transition (i.e., late Wuchiapingian). The wide range of preserved sizes in conjunction with recent paleohistological evidence supports that individuals spent much of their lives in an actively-growing, subadult phase. Later Dicynodon Assemblage Zone records (e.g., upper Balfour Formation) are unconfirmed as the genus was likely replaced by other theriodont predators (e.g., Moschorhinus) leading up to the Permo-Triassic boundary in the Karoo Basin of South Africa.

Evidence of Anoxic Oceans at in the Lopingian Permian South China

Lopingian (Upper Permian) trace fossils from the northern Penglaitan Section, Laibin, Guangxi, South China and their environmental implications

Authors:

Ding et al

Abstract:

The end-Permian mass extinction has been widely documented to be accompanied with oceanic anoxia, which was considered as one of the most plausible killing mechanisms. However, it is still unclear when anoxia began to occur and how widely affected during the pre-extinction interval. In this study, Lopingian bottom-water oxygen level changes around the Wuchiapingian–Changhsingian boundary (WCB) at the northern Penglaitan section in Guangxi are analysed based on trace fossil assemblages and ichnofabric indices. Detailed bed-by-bed ichnological analyses confirm the presence of trace fossils Chondrites intricatus, C. isp., Palaeophycus isp., Planolites isp. A, P. isp. B, Thalassinoides isp. A, T. isp. B, Trichichnus linearis, Zoophycos isp., and other bioturbational structures. The ichnofabric indices around the WCB are mostly 1-2, but rapidly increase to 4-5 in some short intervals. The distinct fluctuations of ichnofabric indices suggest that the oxygen level of sediments was generally deficient, but the dysoxic or anoxic periods were punctuated by several short oxic intervals. Thus, it can be inferred that the benthic organisms were under secularly environmental stresses around the WCB at the northern Penglaitan section. The anoxic conditions unfavourable for aerobiosis in the deep basin may start in the late Wuchiapingian. However, more sections need to be studied to determine whether this is a local or regional phenomenon.

Weigeltisaurus is a Valid, Distinct Gliding Diapsid Reptile From Late Permian Russia

Substantiation of Validity of the Late Permian Genus Weigeltisaurus Kuhn, 1939 (Reptilia, Weigeltisauridae)

Authors:

Bulanov et al

Abstract:

The previously rejected genus of Permian gliding diapsids Weigeltisaurus Kuhn, 1939 is actually valid. The skull morphology of Weigeltisaurus is reassessed based on the holotype of the type species W. jaekeli (specimen SSWG, no. 113/7). The genus Weigeltisaurus differs from the Gondwanian genus Coelurosauravus in the reduced infraorbital part of the jugal, the round contour of the posterior part of the orbit, the wider postorbital regions of the postorbital and jugal, the concave external surface of these elements, the shape and arrangement of ornamental structures on the elements forming the orbit, the flattened crowns of jaw teeth in the middle part of the maxilla, the rhomboid shape of the neural spines of the posterior cervical vertebrae, and other characters. The majority of the above features also distinguish Weigeltisaurus from the East European genus Rautiania.

Late Permian Tuskless Geikiid Cryptodont Dicynodont Pelanomodon Redescribed, Shows Sexual Dimorphism

Redescription of the geikiid Pelanomodon (Therapsida, Dicynodontia), with a reconsideration of ‘Propelanomodon’

Authors:

Kammerer et al

Abstract:

Cryptodont dicynodonts are some of the most abundant therapsid taxa in the upper Permian fossil record. Despite extensive taxonomic study of these families, the species diversity of geikiid cryptodonts remains problematic, particularly for the set of edentulous taxa in the genera Pelanomodon, Propelanomodon, and Geikia. Here, all known specimens of tuskless geikiid dicynodonts from the upper Permian Karoo Basin of South Africa are reevaluated. The genus Pelanomodon is redescribed based on a series of skulls representing a range of sizes. All tuskless geikiids from the Karoo Basin are considered to represent a single species (Pelanomodon moschops) that exhibited cranial dimorphism as adults. The nominal species Pe. moschops and Pe. rubidgei differ only in degree of facial boss development and are most parsimoniously interpreted as sexual dimorphs. Propelanomodon is considered to represent the juvenile morphotype of Pelanomodon moschops, as indicated by the geographic and stratigraphic overlap of the two taxa, the lack of any small skulls of the Pelanomodon morphotype in well-sampled localities, and the presence of specimens of intermediate size and morphology. ‘Propelanomodon’ specimens are distinctive among juvenile dicynodonts in having a significantly narrower intertemporal region than adults. Analysis of intertemporal width relative to total skull size in Pelanomodon and the abundant cryptodont taxa Aulacephalodon, Oudenodon, and Tropidostoma suggests that Pelanomodon had a unique growth trajectory. Based on available stratigraphic data, Pelanomodon was restricted to the uppermost Permian Daptocephalus Assemblage Zone of the South African Beaufort Group and was a victim of the end-Permian mass extinction.

Late Permian Cynodont Cynosaurus Lacked a Pineal eye, may Have Been Endothermic

Physiological implications of the abnormal absence of the parietal foramen in a late Permian cynodont (Therapsida)

Authors:

Benoit et al

Abstract:

The third eye (pineal eye), an organ responsible for regulating exposure to sunlight in extant ectotherms, is located in an opening on the dorsal surface of the skull, the parietal foramen. The parietal foramen is absent in extant mammals but often observed in basal therapsids, the stem-group to true mammals. Here, we report the absence of the parietal foramen in a specimen of Cynosaurus suppostus, a Late Permian cynodont from South Africa (SA). Comparison with Procynosuchus delaharpeae, a contemporaneous non-mammalian cynodont from SA, demonstrates that the absence of this foramen is an abnormal condition for such a basal species. Because seasonality was marked during the Late Permian in SA, it is proposed that the third eye was functionally redundant in Cynosaurus, possibly due to the acquisition of better thermoregulation or the evolution of specialized cells in the lateral eyes to compensate for the role of the third eye.

Lende chiweta: a new Burnetiamorph Biarmosuchian Therapsid From Upper Permian Malawi

Lende chiweta, a new therapsid from Malawi, and its influence on burnetiamorph phylogeny and biogeography

Authors:

Kruger et al

Abstract:

The Chiweta Beds of Malawi have yielded a diverse late Permian fossil tetrapod fauna that correlates with that of the Cistecephalus Assemblage Zone of the South African Karoo Supergroup. Amongst the fossil therapsids from the Chiweta Beds is the well-preserved skull and lower jaw of a burnetiamorph, a group of biarmosuchians with numerous bosses and swellings on the skull. This specimen was reported in a preliminary paper in 2005 as the first burnetiamorph described outside of South Africa and Russia. Reanalysis of the morphology and phylogeny of this specimen places Lende chiweta, gen. et sp. nov., as the sister taxon to the clade formed by Proburnetia (Paraburnetia (Pachydectes, Bullacephalus, Burnetia, Niuksenitia)). The greatest diversity of this basal therapsid group is from South Africa, with six of nine described genera and a stratigraphic range that extends from the middle Permian Tapinocephalus Assemblage Zone to the upper Permian Dicynodon Assemblage Zone. Bearing in mind the constraints that govern fossil preservation, current data suggest that what is now southern Africa may have been the area of origin for burnetiamorphs. Under this premise, what is now central Africa represented a corridor that allowed migration of representatives of the group between the southern and northern portions of Pangea during the late Permian.

A new Emydopoid Dicynodont From Upper Permian Tanzania

Distinctive emydopoid dicynodont (Therapsida, Anomodontia) mandibles from the Permian Ruhuhu and Usili formations (Songea Group), Ruhuhu Basin, Tanzania

Authors:

Angielczyk et al

Abstract:

Dicynodont therapsids were discovered in the Permian Usili Formation (Ruhuhu Basin, Tanzania) in the 1930s and in the Permian Ruhuhu Formation in the 1960s, with further collections being made in 2007, 2008, and 2012. Here we describe two fragmentary mandibles that represent a new morphotype of emydopoid dicynodont. One specimen was collected in the middle fossiliferous horizon of the Ruhuhu Formation, and the other originated in the overlying Usili Formation. Three synapomorphies support the placement of these specimens in the emydopoid subclade Kingoriidae: mandibular fenestra occluded by the dentary; curved ridge that follows the profile of the symphysis present on the edge between the anterior and lateral surfaces of the dentary; and posterior dentary sulcus absent. The specimens may represent a new dicynodont species, a previously known species for which mandibular material was unknown, or an intraspecific variant of Dicynodontoides nowacki. Regardless of which of these options is correct, the specimens constitute the first taxon with a stratigraphic range extending from the likely middle Permian middle fossiliferous horizon of the Ruhuhu Formation into the late Permian Usili Formation. They also improve our understanding of the middle Ruhuhu tetrapod fauna, which previously consisted only of Endothiodon tolani.

Bunostegos akokanensis: a Unique Nearly Parasagittal Pareiasaur From Upper Permian Niger

The vertebrate fauna of the upper Permian of Niger—IX. The appendicular skeleton of Bunostegos akokanensis (Parareptilia: Pareiasauria)

Authors:

Turner et al

Abstract:

Pareiasaurs were a group of herbivorous reptiles that lived during the middle to late Permian (˜265–252 Ma) in what is modern-day Europe, Asia, South America, and Africa. Field work in the Moradi Formation of northern Niger has produced multiple elements of the appendicular skeleton of the pareiasaur Bunostegos akokanensis. The considerable size disparity and morphological variation among the elements suggest that they represent ontogenetic stages ranging from relatively juvenile to adult. Here we present the first description of the scapulocoracoid, humerus, radius, ulna, pelvis, and femur of Bunostegos as well as some of the first ontogenetic data for postcranial osteology in pareiasaurs. As with the skull, numerous postcranial autapomorphies characterize Bunostegos, including laterally originating acromion process of the scapula; radius and ulna with continuous articular surface on humerus; paired crests on the olecranon process; ulna longer than humerus; pinched posterior margin of the acetabular rim; robust pelvic symphysis extending the length of the puboischiatic plate; lack of a distinct postaxial flange of the femur; and an elaborated femoral lateral condyle wrapping over the medial condyle. We incorporated data from the appendicular skeleton of Bunostegos into a revised phylogenetic analysis of pareiasaur relationships. The results of this analysis corroborate previous cranial analyses that place Bunostegos between Guadalupian taxa and the Lopingian velosaur subclade. Interestingly, several aspects of its postcranial anatomy suggest that Bunostegos possessed relatively upright forelimb posture, which would be unique among pareiasaurs and possibly Permian amniotes as a whole.

Evidence of a Tropical wet Desert From Late Permian Niger

Sedimentology and vertebrate taphonomy of the Moradi Formation of northern Niger: A Permian wet desert in the tropics of Pangaea

Authors:

Smith et al

Abstract:

Pangaean palaeogeographic models place the Tim Mersoi basin of northern Niger in a 5000 km wide corridor between Gondwana and Laurasia approximately 15 degrees south of the palaeoequator. Late Permian palaeoclimate models position this basin between tropical summerwet to the north and desert to the south. Recent investigations of the fossil vertebrates and palaeosols in the late Permian (Lopingian) Moradi Formation confirm that the climate was warm and hyperarid with highly seasonal monsoonal rainfall. Possibly as a result of these unusual “wet desert” conditions the tetrapod fauna shows a high degree of endemism. This study tests existing palaeoclimate models by providing additional data on sedimentary environments and vertebrate taphonomic processes. The Moradi red bed sequences accumulated in a gently subsiding sag basin to the west of the tectonically active Massif de l'Aïr. Low angle gravelly alluvial fans prograded westward from the massif and at times impinged on a large stable northward flowing meandering channel system. The interchannel mudrock sequences are over-thickened by the accumulation of loessic silts and preserve isolated skull and post crania of amphibians (Nigerpeton and Saharastega) as well as semi-articulated captorhinids (Moradisaurus). Detailed surface mapping of a fossil-rich exposure revealed an anastomosed network of loess-filled distributary channels incised into the floodplain mudrocks. This provided a locus for the accumulation and rapid burial of at least 15 associated skeletons of the pareiasaurian Bunostegos. Semi-permanent ponds are evidenced by patches of fissile red mudstone containing rare bivalves and spiral coprolites. In the distal floodplains away from the main river channels, the combination of a generally high groundwater table, warm mean annual temperatures and deflation of fines from the floodplain surface promoted the formation of gypsiferous palaeosols and endpoint playa lakes. Carbonate-rich mud accumulated around the lake margins and provided ideal conditions for the imprinting and preservation of tetrapod trackways.

Thar be Char! Evidence of Wild Fire During the Wuchiapingian Permian

Charred wood of Prototaxoxylon from the Wuchiapingian Wutonggou Formation (Permian) of Dalongkou, northern Bogda Mountains, northwestern China

Authors:

Wan et al

Abstract:

Charred wood occurs sporadically in sedimentary rocks in China. A marcroscopic charcoal with well-preserved anatomical structure is described from the Wuchiapiangian Wutonggou Formation in the southern part of Dalongkou section, northern Bogda Mountains in the Junggar Basin, northwestern China. It is characterized by uniseriate radial tracheidal pitting, taxaceous tertiary spiral thickenings in the tracheidal walls, uniseriate tangential tracheidal pitting, homogeneous, uniseriate, 2-10 cells high xylem rays, and 1-2 pits in each cross-field. It is assigned to Prototaxoxylon uniseriale Prasad. The uniseriate, bordered, contiguous, rarely separate tangential pitting of P. uniseriale is evidenced clearly for the first time. The features of this species shows a close affinity with conifers. The coniferous charred wood may have been derived from an extrabasinal forest, perhaps from upland environment deep within the hinterland, according to results of modern taphonomic research.

Highly Productive Polar Forests in Permian Antarctica Before Siberian Traps Eruptions

Highly Productive Polar Forests from the Permian of Antarctica

Authors:

Miller et al

Abstract:

Two stratigraphically closely spaced bedding planes exposed at Lamping Peak in the Upper Buckley Formation, Beardmore Glacier area, Antarctica contain abundant in situ stumps (n=53, n=21) and other plant fossils that allow reconstruction of forest structure and biomass of Glossopteris forests that thrived at ~ 75o S paleolatitude in the Permian. Mean trunk diameter is 14 and 25 cm, corresponding to estimated mean maximum heights of 12 and 19 m. Basal areas are 65 and 80 m2ha- 1. The above ground biomass was calculated using allometric equations for Ginkgo biloba, yielding biomasses of 147 and 178 Mg ha- 1. Biomass estimates based on comparison with biomass of modern forests with equivalent basal areas are higher (225 – 400 Mg ha- 1). The amount of above ground biomass added each year (Annual Net Primary Productivity), based on biomass estimates and growth rings in silicified plant material from the Buckley Formation nearby, is poorly constrained, ranging from ~ 100 – 2000 g m- 2 yr- 1.

Compared to modern forests at all latitudes, the Permian forests have high basal areas and high biomass, exceeded in both only by forests of the U.S. Pacific northwest and Sequoia forests. The estimated range of productivity (ANPP) is within that of many very productive modern forests. The Lamping Peak forests’ basal areas and calculated biomass are also larger than younger high paleolatitude fossil forests except for Arctic Cenozoic forests.

Presence of these highly productive fossil forests at high paleolatitude is consistent with hothouse conditions during the Late Permian, prior to the eruption of the Siberian flood basalts.

Late Permian Glossopteris Flora From Deglaciating Antarctica

Glossopteris flora in the Permian Weller Formation of Allan Hills, South Victoria Land, Antarctica: Implications for paleogeography, paleoclimatology, and biostratigraphic correlation

Authors:

Tewari et al

Abstract:

The Permo-Triassic Victoria Group in South Victoria Land, Antarctica, is a heterogeneous sequence of glacial tillite beds, carbonaceous and non-carbonaceous fluvial deposits, and volcaniclastic strata. The carbonaceous beds are rich in plant fossils associated with coal seams. In Antarctica, the geological record of the Late Paleozoic Ice Age is restricted to the Early Permian. After deglaciation, the Glossopteris flora thrived in polar forests in Antarctica throughout the Permian but disappeared at the end-Permian extinction. Here we describe the first comprehensive record of the Glossopteris flora from the Permian Weller Formation of Allan Hills, South Victoria Land, Antarctica. The flora is well preserved and comprises pteridophytes and gymnosperms. The pteridophytes include the sphenopsid order Equisetales and the gymnosperms comprise Glossopteridales. Equisetales are represented by branched and unbranched axes, whereas, Glossopteridales are highly diverse encompassing Gangamopteris, Glossopteris, Surangephyllum, sterile scale leaves namely Scirroma sp., Nautiyalolepis sp., Utkaliolepis indica, Scale leaf A and scale leaf of male fructification Eretmonia. The flora of the Weller Formation shows close similarity with the Late Permian assemblages of India, South Africa and Australia. Gangamopteris, an index fossil of the Early Permian formations of different Gondwana continents, had extended stratigraphic range in the Late Permian Weller Formation of Allan Hills. Antarctica played a crucial role in the dispersal of Glossopteris flora because of its central position in Gondwana.

Emydopoid Dicynodont Digalodon rubidgei Redescribed

Redescription of Digalodon rubidgei, an emydopoid dicynodont (Therapsida, Anomodontia) from the Late Permian of South Africa. (pdf)

Authors:

Fröbisch et al

Abstract:

The Late Permian dicynodont Digalodon rubidgei Broom and Robinson, 1948, is redescribed based on reanalysis of the holotype and newly recognized referable specimens. Digalodon can be diagnosed by the presence of a long “beak” sharply demarcated from the caniniform process; an extremely tall zygomatic ramus of the squamosal, with a thickened, “folded-over” dorsal margin; raised parietal “lips” along the lateral edges of the pineal foramen; and a broad posterolateral expansion of the parietal, excluding the postorbital from the back of the skull roof. Inclusion of Digalodon in a recent analysis of anomodont phylogeny recovers it as a kistecephalian emydopoid, specifically as the sister taxon to the clade containing the remaining kistecephalians. Four definite specimens of Digalodon are known, but several additional specimens lacking tusks, the swollen pineal “lips”, and a thickened zygoma may represent sexually dimorphic females or juveniles. Specimens of Digalodon are restricted to the central portion of the Karoo Basin, in the area around Graaff-Reinet, and are part of a characteristic fauna probably representing a limited time span.

How Well Late Permian, Burrowing Anomodont Kawingasaurus Felt Vibrations and Sounds

Bone-conduction hearing and seismic sensitivity of the late permian anomodont Kawingasaurus fossilis

Author:

Laaß

Abstract:

An investigation of the internal cranial anatomy of the anomodont Kawingasaurus from the Upper Permian Usili Formation in Tanzania by means of neutron tomography revealed an unusual inner and middle ear anatomy such as extraordinarily inflated vestibules, lateroventrally orientated stapes with large footplates, and a small angle between the planes of the anterior and lateral semicircular canals. The vestibule has a volume, which is about 25 times larger than the human vestibule, although Kawingasaurus has only a skull length of approximately 40 mm. Vestibule inflation and enlarged stapes footplates are thought to be functionally correlated with bone-conduction hearing; both morphologies have been observed in fossorial vertebrates using seismic signals for communication. The firmly fused triangular head with spatulate snout was probably used for digging and preadapted to seismic signal detection. The quadrate-quadratojugal complex was able to transmit sound from the articular to the stapes by small vibrations of the quadrate process, which formed a ball and socket joint with the squamosal. Mechanical considerations suggest that the ventrolaterally orientated stapes of Kawingasaurus was mechanically better suited to transmit seismic sound from the ground to the fenestra vestibuli than a horizontal orientated stapes. The low sound pressure level transformer ratio of 2–3 in Kawingasaurus points to a seismic sensitivity of the middle ear and a vestigial or reduced sensitivity to airborne sound. Three hypothetical pathways of bone conduction in Kawingasaurus are discussed: 1) sound transmission via the spatulate snout and skull roof to the otic capsules, 2) relative movements resulting from the inertia of the mandible if sound is percepted with the skull, and 3) bone conduction from the substrate via mandible, jaw articulation, and stapes to the inner ear.

The Jiyuan Tetrapod Fauna of the Upper Permian China

The Jiyuan tetrapod fauna of the Upper Permian of China—2. stratigraphy, taxonomical review, and correlation.

Authors:

Liu et al

Abstract:

Reexamination of the specimens from the Jiyuan tetrapod fauna, shows that this assemblage is dominated by the pareiasaur Honania complicidentata and comprises three chroniosuchian species including Bystrowiana sinica, Jiyuanitectum flatum gen. et sp. nov., and Dromotectum largum sp. nov., one cynodont species and possibly one gorgonopsian. It is roughly correlated to the Ilinskoe Subassemblage of the Sokolki Assemblage of Russia and the Cistecephalus Assemblage Zone of South Africa.

Evidence From Wuchiapingian Permian China Suggests Weakly Seasonal Humid Environment

Septomedullopitys szei sp. nov., a new gymnospermous wood from Lower Wuchiapingian (Upper Permian) continental deposits of NW China, and its implication for a weakly seasonal humid climate in mid-latitude NE Pangaea

Authors:

Wan et al

Abstract:

Septomedullopitys szei sp. nov. is described from the Wuchiapingian Wutonggou Formation of Tarlong Valley, southern Bogda Mountains, Xinjiang, in northwestern China. The stem has a heterogeneous pith ca. 15–20 mm in diameter, and containing numerous linear secretory ducts and parenchymatous bands. Primary xylem is endarch and the tracheids contain scalariform thickenings. Secondary xylem is of the Protophyllocladoxylon type. Comparisons with contemporaneous gymnospermous woods containing either heterogeneous pith with ducts or Protophyllocladoxylon-type secondary xylem from the Angara palaeocontinent indicate that the Tarlong stem represents a new Permian morphotaxon for the region. The presence of coprolites, borings, and spindle-shaped cavities within the stem suggests well-developed animal–plant–fungi interactions. The occurrence of numerous growth interruptions and absence of true growth rings within the stem suggest weak seasonality of annual precipitation. The interruptions suggest a humid climate with short-term, nonperiodic droughts.

Australerpeton cosgriffi: A new Specimen of a Stereospondyl Temnospondyl From Wuchiapingian Permian Brazil

A new specimen of the temnospondyl Australerpeton cosgriffi from the late Permian of Brazil (Rio do Rasto Formation, Paraná Basin): comparative anatomy and phylogenetic relationships

Authors:

Eltink et al

Abstract:

A new temnospondyl specimen from the Rio do Rasto Formation (late Permian, Paraná Basin) of south Brazil is composed of a left mandible, right pelvis, femur, tibia, and fibula. Preserved lower jaws are rare for Australerpeton cosgriffi, and the weak ossification of the temnospondyl postcranium renders their preservation generally uncommon. A detailed comparative description of the material allowed its assignment to Australerpeton cosgriffi, and yielded new information about the morphology of mandible, pelvis, and hind limb of that taxon. This long-snouted temnospondyl has uncertain affinities and has been assigned either to stereospondyl Rhinesuchidae or to archegosaurid Platyoposaurinae. Reassessment of the phylogenetic placement of Australerpeton cosgriffi, with information drawn from the new specimen, confirms a basal stereospondyl position, between Peltobatrachus pustulatus and Rhinesuchidae. The synapomorphies shared with other stereospondyls include tabular and exoccipital contacting in the paroccipital process; parasphenoid articulates with corpus of the pterygoid forming a broad contact along the lateral margins of the parasphenoid plate; internal carotid passes through the dorsal surface of the parasphenoid plate; and parasphenoid denticles field enlarged to a transverse ‘belt’ extending between the pterygoid-parasphenoid articulations. Accordingly, Australerpeton cosgriffi represents one of the first stereospondyls, and the oldest long-snouted member of the group. The Paraná Basin can be included within the stereospondyl ancestral range, and dispersion and diversification of this clade appears to have happened before the Permo-Triassic boundary.