Late Triassic Research Articles

Judahella kangpla: a new marine ostracod from the Upper Triassic of Thailand

The record of Mesozoic marine ostracods from South-East Asia is poorly known. This lack of data has led to uncertainty regarding their diversity and geographical distribution during this key interval of the Phanerozoic. Here, we report ostracod fossils from the Rong Kwang-Ngao highway section in northern Thailand, type locality for Upper Triassic (Carnian) Kang Pla Formation of the Lampang Group. The studied material comprises almost 100 specimens, most representing a new species, Judahella kangpla sp. nov., which is the first to be formally described from the Upper Triassic of Thailand. The morphology of Judahella kangpla, together with its diagnostic normal pore pattern and sexual dimorphism are discussed. The stratigraphical and geographical distribution of Judahella from the Upper Permian to Upper Triassic is summarized. Although preliminary, our work adds significant information to the biodiversity of marine ostracods during the Triassic along the eastern Tethyan coast. Marie-Béatrice Forel [marie-beatrice.forel@mnhn.fr], Muséum national d’Histoire naturelle, CR2P, MNHN-CNRS-Sorbonne Université, 8 rue Buffon (CP38), 75005 Paris, France; Anisong Chitnarin [anisong@sut.ac.th], School of Geotechnology, Institute of Engineering, Suranaree University of Technology, 111 University Avenue, Mueang District, Nakhon Ratchasima Province 30000, Thailand.

A saurischian (Archosauria, Dinosauria) ilium from the Upper Triassic of southern Brazil and the rise of Herrerasauria.

The Carnian (Upper Triassic) rocks of the Candelária Sequence present a rich record of dinosaurs, including some of the oldest known dinosaurs worldwide. In this contribution we describe the first unequivocal dinosaur from the Pivetta site, located in the Restinga Sêca municipality, Southern Brazil. The specimen CAPPA/UFSM 0373 is an isolated but well-preserved left ilium. A thorough examination of the specimen's anatomy and a phylogenetic analysis provides evidence that CAPPA/UFSM 0373 belongs to the Herrerasauria. We were able to identify several similarities with potential non-herrerasaurid herrerasaurians (e.g., Tawa hallae, "Caseosaurus crosbyensis"), which were previously only known from North American deposits. In contrast, herrerasaurids (e.g., Herrerasaurus ischigualastensis) are almost exclusively known from South America. Our results support the nesting of CAPPA/UFSM 0373 as an early-diverging herrerasaurian. Furthermore, this is potentially the first record of a non-herrerasaurid herrerasaurian in unambiguous Carnian beds, suggesting a hidden diversity of dinosaurs in the Carnian rocks of the Candelária Sequence, which can be revealed even by fragmentary specimens.

A new lungfish from the Upper Triassic of the Mid-Zambezi Basin, Zimbabwe

ABSTRACT The lungfish, the extant sister group of the tetrapods, have an evolutionary history illustrated by a fossil record extending for ∼420 million years. The post-Paleozoic fossil record of the clade is almost exclusively restricted to sediments deposited in freshwater paleoenvironments and is characterized by an abundance of highly mineralized tooth plates, whereas cranial and postcranial remains are scarce. Here, we report a sample of isolated tooth plates found in the Upper Triassic Pebbly Arkose Formation of the Mid-Zambezi Basin, Zimbabwe. It consists of pterygoid and prearticular tooth plates from adult individuals, plus some dental plates referred to juvenile individuals, which we refer to a new species of Ferganoceratodus. This discovery provides an opportunity to review briefly the tooth plates of the ‘ptychoceratodontid morphotype’ reported from around the world. We discuss how various occurrences previously referred to Ptychoceratodus may be more appropriately referred, with caution, to Ferganoceratodus. We also describe the histology of the tooth plates of the new species and note similarities with other Mesozoic taxa. The scarcity of histological data for Mesozoic lungfish tooth plates compounds the problem of assigning isolated tooth plates to genus and species level. Ferganoceratodus and closely related taxa arose in the Early Triassic in southern Gondwana and diversified worldwide in the Late Triassic. The genus then became more common in Laurasia during the Jurassic and Early Cretaceous and declined thereafter with relict Late Cretaceous occurrences in Madagascar and South America.

A new lizard-like reptile with unusual mandibular neurovasculature from the Upper Triassic of Virginia

ABSTRACT Here, we report a new small-bodied reptile taxon, Idiosaura virginiensis gen. et sp. nov., from the Upper Triassic (Carnian) Vinita Formation of the Richmond basin (Newark Supergroup) in east-central Virginia, U.S.A. The material consists of a fragmentary dentary bearing numerous tall cylindrical teeth implanted in a pleurodont fashion into spongy alveolar tissue. Micro-CT scan data reveal an unusual and complex network of interconnected neurovascular canals within the dentary with connections to the alveolar tissue and pulp cavities of the teeth. The external anatomy of the dentary is consistent with that of Triassic kuehneosaurid reptiles, suggesting affinities to that group; the results of a phylogenetic analysis were inconclusive but do not exclude kuehneosaurid relationships. Alongside the recently described Micromenodon pitti (Rhynchocephalia) and Vinitasaura lizae (Lepidosauromorpha), the new taxon adds to the relatively diverse assemblage of small-bodied reptiles known from the Tomahawk microvertebrate bonebed (USNM locality 39981). Relative tooth complexities of I. virginiensis and V. lizae were analyzed using the Orientation Patch Count Rotated method, and results suggest that the rise of lepidosauromorph ecomorphologies specializing for feeding on invertebrates occurred in Triassic communities alongside non-lepidosauromorph taxa with similar mandibulo-dental features, as in kuehneosaurs.

Basal sauropodomorph locomotion: ichnological lessons from the Late Triassic trackways of bipeds and quadrupeds (Elliot Formation, main Karoo Basin).

Using modern ichnological and stratigraphic tools, we reinvestigate two iconic sauropodomorph-attributed tetradactyl ichnogenera, Pseudotetrasauropus and Tetrasauropus, and their stratigraphic occurrences in the middle Upper Triassic of Lesotho. These tracks have been reaffirmed and are stratigraphically well-constrained to the lower Elliot Formation (Stormberg Group, Karoo Basin) with a maximum depositional age range of <219-209 Ma (Norian). This represents the earliest record of basal sauropodomorph trackways in Gondwana, if not globally. Track and trackway morphology, the sedimentary context of the tracks, and unique features (e.g., drag traces) have enabled us to discuss the likely limb postures and gaits of the trackmakers. Pseudotetrasauropus has bipedal (P. bipedoida) and quadrupedal (P. jaquesi) trackway states, with the oldest quadrupedal Pseudotetrasauropus track and trackway parameters suggestive of a columnar, graviportal limb posture in the trackmaker. Moreover, an irregularity in the intermanus distance and manus orientation and morphology, in combination with drag traces, is indicative of a non-uniform locomotory suite or facultative quadrupedality. Contrastingly, Tetrasauropus, the youngest trackway, has distinctive medially deflected, robust pedal and manual claw traces and a wide and uniform intermanus distance relative to the interpedal. These traits suggest a quadrupedal trackmaker with clawed and fleshy feet and forelimbs held in a wide, flexed posture. Altogether, these trackways pinpoint the start of the southern African ichnological record of basal sauropodomorphs with bipedal and quadrupedal locomotory habits to, at least, c. 215 Ma in the middle Late Triassic.

Microfloristic regions of the Middle–Upper Triassic: New insights into the phytogeographical affinities of southwestern Gondwana

Two phytogeographic units were defined for the Middle–Upper Triassic of Gondwana, the warm humid Onslow and the cool-temperate Ipswich microfloras; nevertheless, many uncertainties remain regarding the geographical scope of such assemblages, as well as to the degree of similarity between phytogeographical regions and the existence of different microfloristic domains within the Laurasian territory. To tackle these questions, a hierarchical cluster analysis complemented with ordination methods and bipartite network analysis was performed over a list of 70 palynomorph species and selected localities of the Anisian–Ladinian, Carnian and Norian time-intervals, with special emphasis on southwestern Gondwana units. Obtained results showed a clear dichotomy between tropical and extratropical associations, within which different microfloristic regions also developed from gradual changes in the frequency distribution of palynotaxa. These findings are significant because they confirm for first time through quantitative methods a phytogeographic separation between ‘Onslow’ and ‘Euro-Mediterranean’ assemblages, considered for a long time to be part of the same microflora. Furthermore, and contrary to expectations, two distinct phytogeographic units were recognized for the Laurasian territory, where the first is related to the hot and dry margins of western Tethys, and the other to the temperate and humid zones of Boreal Pangea. Likewise, a separate and well defined assemblage was recognized for southwestern Gondwanan, during the late Anisian–Carnian of central-western Argentina, named here as the Cuyo microfloristic region. This unit showed a close resemblance to microfloras of northern Laurasia due to the shared presence of several species of miospores that are largely absent from the eastern part of Pangea. We hypothesize that the migration of such species occurred through a trans-equatorial temperate and humid landway, following the rift basins and topographic highs developed along the suture lines of the Variscan orogenic belt and western South America at the beginning of Pangea separation.

Metallogenic Model and Prospecting Progress of the Qiandongshan–Dongtangzi Large Pb-Zn Deposit, Fengtai Orefield, West Qinling Orogeny

The Qiandongshan–Dongtangzi large Pb-Zn deposit is located in the Fengxian–Taibai (abbr. Fengtai) polymetallic orefield. The ore bodies primarily occur within and around the contact surface between the limestone of the Gudaoling Formation and the phyllite of the Xinghongpu Formation, which are clearly controlled by anticline and specific lithohorizon. Magmatic rocks are well developed in the mining area, consisting mainly of granitoid plutons and mafic–felsic dikes. Previous metallogenic geochronology studies have yielded a narrow range of ages between 226 and 211 Ma, overlapped by the extensive magmatism during the Late Triassic period in this region. The ω(Co)/ω(Ni) ratio of pyrite in lead–zinc ore ranges from 4.44 to 15.57 (avg. 8.56), implying that its genesis is probably related to volcanic and magmatic-hydrothermal fluids. The δD and δ18O values (ranging from −94.2‰ to −82‰, and 18.89‰ to 20.72‰, respectively,) of the ore-bearing quartz indicate that the fluids were perhaps derived from a magmatic source. The δ34S values of ore-related sulfides display a relatively narrow range of 4.29‰ to 9.63‰ and less than 10‰, resembling those of magmatic-hydrothermal origin Pb-Zn deposits. The Pb isotopic composition of the sulfides from the Qiandongshan–Dongtangzi Pb-Zn deposit (with 206Pb/204Pb ratios of 18.06 to 18.14, the 207Pb/204Pb ratios of 15.61 to 15.71, and 208Pb/204Pb ratios of 38.15 to 38.50) is similar to that of the Late Triassic Xiba granite pluton, suggesting that they share the same Pb source. The contents of W, Mo, As, Sb, Hg, Bi, Cd, and other elements associated with magmatic-hydrothermal fluids are high in lead–zinc ores, and the contents of Sn, W, Co, and Ni are also enriched in sphalerite. The contents of trace elements and rare earth elements in the ore are similar to those in the Xiba granite pluton, and they maybe propose a magmatic-hydrothermal origin as well. As a result of this information, the Qiandongshan–Dongtangzi large Pb-Zn deposit may be classified as a magmatic hydrothermal stratabound type, with the Si/Ca contact area being the ore-forming structural plane. Thus, a mineralization model has been proposed based on a comparative analysis of the geological and geochemical properties of the lead–zinc deposit in the Fengtai orefield. It is considered that the secondary anticlines developed on both wings of the Qiandongshan–Dongtangzi composite anticline are the favorable sites for Pb-Zn deposition. Accordingly, the Si/Ca plane and secondary anticline are the major ore-controlling factors and prospecting targets. The verification project was first set up on the north wing of the composite anticline, and thick lead–zinc ore bodies were found in all verification boreholes, accumulating successful experience for deep exploration of lead–zinc deposits in this region.

A new fossil insect locality from the Upper Triassic of Jiyuan, Henan Province, Central China

The Triassic insects are relatively abundant from the Anisian to Rhaetian stages. Several well-known Triassic insect localities are distributed worldwide. Examples include the Anisian Grès à Voltzia in France, the Ladinian–Carnian Madygen Formation in Kyrgyzstan, Uzbekistan, and Tajikistan, the Cow Branch Formation of the latest Triassic in the USA, and the Carnian Molteno Formation in South Africa (Grimaldi &amp; Engel, 2005).

First Fossil Record of Trichomanes sensu lato (Hymenophyllaceae) from the Mid-Cretaceous Kachin Amber, Myanmar.

Hymenophyllaceae (filmy ferns), with ca. 430 species, are the most species-rich family of early diverging leptosporangiate ferns but have a poor fossil record dating back to the Late Triassic period. Traditionally, Hymenophyllaceae comprise two species-rich genera or clades: Hymenophyllum (hymenophylloids) and Trichomanes sensu lato (s.l.) (trichomanoids). Unequivocal fossils of Hymenophyllum have been reported from the Early Cretaceous of central Mongolia and the early Eocene of Okanogan Highlands, Washington, USA. However, despite being a highly diversified lineage with an estimated 184 extant species, Trichomanes s.l. lack a definitive fossil record, which severely affects the reliability of the molecular dating of this group. Here, we report the first unequivocal fossil record of Trichomanes s.l. as T. angustum comb. nov. on the basis of fertile material with tubular involucres and long exserted receptacles from the mid-Cretaceous Kachin amber, Myanmar. This species was previously tentatively assigned to Hymenophyllites due to a lack of fertile evidence. Inferred to be an epiphytic fern, T. angustum further enriches the species diversity of the epiphytic palaeocommunities in the mid-Cretaceous Kachin amber, which are mainly composed of Porellalean leafy liverworts and Dicranalean and Hypnodendralean mosses. Fossil records indicate that Hymenophyllaceae probably originated in the tropical Pangea at the latest in the Triassic when all continents were coalesced into a single landmass and had already accumulated some notable diversity in low-middle latitude areas of Laurasia by the mid-Cretaceous period.

Palynological investigation of an Upper Triassic sequence in Nanjing area, eastern China, with paleoecological implications

The end-Triassic is characterized by a significant biotic crisis in both marine and terrestrial realms. However, terrestrial records in eastern Tethys are relatively limited, especially in eastern China. The Fanjiatang Formation represents the Upper Triassic sequence in southern Jiangsu and Anhui provinces of eastern China, yielding a rich plant and bivalve fossil record. The present study provides the first detailed palynological investigation for the Upper Triassic of Nanjing area, eastern China. Six of twenty processed palynological samples are productive, and more than 70 terrestrial spore and pollen fossil taxa were identified. A palynological assemblage, namely, the Concavisporites–Dictyophyllidites–Kyrtomisporis–Classopollis Assemblage was established, characterized by abundant fern spores, mainly including Concavisporites, Dictyophyllidites and Kyrtomisporis, and much less abundant gymnosperm pollen grains (important taxa include Alisporites, Chasmatosporites, and Classopollis), indicating a Late Triassic Norian–Rhaetian age. In conjunction with previously reported macro-plant data, the palynofloral analysis reveals a vegetation dominated by ferns, with diverse cycadophytes, less abundant lycophytes, bryophytes, equisetales, ginkgophytes and seed ferns, and a few conifers. Paleovegetation and semiquantitative palynological analysis permit a paleoecological interpretation, suggesting a lowland groundcover-dominated vegetation under (sub)tropical warm and humid climate in Nanjing area during this time interval. More detailed palynological and macro-plant data through the whole Upper Triassic in this region are necessary in the future to better reveal the Late Triassic paleoecological settings and variations on land prior to the end-Triassic mass extinction in eastern Tethys.

Late Triassic Tectonic Setting in Northeastern Margin of North China Craton: Insight into Sedimentary and Apatite Fission Tracks

The closure timing of the Paleo-Asian Ocean and the terminal stage of the Central Asian Orogenic Belt have been widely debated in the geological community. It’s known that the gradual scissor-like closure of the Paleo-Asian Ocean occurred from west to east during the Paleozoic period. However, it was not until the Triassic period that the complete closure of the ocean occurred at the northeastern margin of the North China Craton. Nevertheless, there is still much uncertainty regarding the Late Triassic tectonic setting in Northeast China. In this study, we focused on the Upper Triassic Dajianggang Formation, located in the Shuangyang area of central Jilin Province, which is situated on the northeastern margin of the North China Plate. Our aim was to determine the formation age of the Dajianggang Formation by analyzing the detrital particle composition, petrogeochemistry, detrital zircon U-Pb isotope dating, and apatite fission track thermochronology. Our results indicated that the primary sandstone provenance area of the Dajianggang Formation in the Shuangyang area is the island arc orogenic belt. The tectonic background of the sandstone provenance area is mainly a continental island arc environment. The provenance area is mostly composed of felsic rocks with sedimentary tendencies, and some of its material may have originated from the northern margin of the North China Craton or the eroded recycle orogenic belt. LA-ICP-MS U-Pb dating of detrital zircons shows that the Dajianggang Formation formed after 226.8 ± 5 Ma. Moreover, analysis of the thermal evolution history modelling shows that the Dajianggang Formation in the Shuangyang area continued to be deposited and heated in the early stage, and then experienced rapid exhumation around 30 Ma. This suggests that the study area underwent an orogenic process during the early stage of formation, but then transitioned into a post-orogenic extension period, which constrained the final closure of the Paleo-Asian Ocean prior to the Late Triassic period. In addition, our study indicates that the remote effect of the Pacific subduction did not reach the study area until 30 Ma. The central age of the detrital apatite fission track of sample 19DJ-1 is 94.2 ± 8.3 Ma, which is younger than its corresponding stratigraphic age. The two peak ages of the fission track analysis are 62.9 ± 5.4 Ma and 126 ± 11 Ma. These findings provide new evidence for the tectonic evolution of Northeast China and shed light on the Late Triassic tectonic setting, as well as the influence time of subsequent tectonic domains in the southern part of Northeast China.

Alluvial development during climate fluctuations depicted with spectral decomposition of the Middle Triassic to Lower Jurassic post‐rift succession in the Horda Platform (Norway) and the impact on reservoir properties

AbstractFor the first time, this study presents interpretations of alluvial fans in spectral decomposition RGB Blends, analysed in seismic time slices from the Middle Triassic to Lower Jurassic stratigraphical interval of the Horda Platform (northern North Sea). The time slices record a shifting alluvial fan front, fluvial variability, uplift and erosion and reveals depositional elements that may set the common conception of the geological development of this area during the Early–Middle Mesozoic up for discussion. Results show that the Upper Triassic Lunde Formation in the eastern margin of the Horda Platform was characterized by the deposition of coalesced alluvial fans. A variable extent of the fan front through the Upper Triassic is linked to interplaying allogenic factors: uplifted source areas in the aftermath of Early–Middle Triassic rifting determined sediment availability; climate transitioning from arid to semi‐humid, with increasingly fluctuating precipitation, controlled sedimentation, and run‐off; provenance dictated bulk sedimentology and affected prevailing alluvial processes. An overall retreat of the fan system through the Late Triassic coincided with a significant change in landscape characteristics at the transition into the overlying Statfjord Group. Uplift and initial tilting of the Horda Platform caused landscape degradation and the formation of plateaus and incised valleys, contemporaneous with increased humidity and marine transgression, forming estuaries. The shift in depositional style has implications for reservoir properties, creating complexity and heterogeneity in terms of facies distribution and connectivity, which may benefit potential CO2 storage. Upper Triassic alluvial fan development in the Horda Platform (northern North Sea) depicted through spectral decomposition of seismic time slices Enhanced level of seismic stratigraphic interpretation with RGB blending Impact of allogenic factors on alluvial depositional development Implications of alluvial variability on reservoir properties

DE GALHO EM GALHO — LAGERPETIDAE &amp; A ORIGEM DOS PTEROSSAUROS

Leaping from branch to branch - Lagerpetidae and the origin of pterosaurs. Pterosaurs are a group of extinct flying reptiles with emergence in the Triassic and great radiation in the Jurassic and Cretaceous, being the first vertebrates to develop active flight. Since the first pterosaurs already show morphologic patterns that are typical for the clade, there is a substantial gap between the first preserved pterosaurs in the fossil record and their closest relatives. Here, we discuss different phylogenetics proposals presented through decades, being the Dinosauromorpha–Pterosauromorpha Hypothesis the most usually recovered. Even considering this hypothesis, however, the morphological gap persists. Thus, we discuss how the knowledge about Lagerpetidae has helped to elucidate the origin of pterosaurs, since recent works indicates that the group would be nested inside the Pterosauromorpha. Lagerpetidae is a group of small reptiles found in the Upper Triassic of North America, Brazil, Argentina and Madagascar, with the Carnian record thus far restricted to the South hemisphere, and with the first records for North America being Norian in age. Recent discoveries point to the presence of insectivorous dentition among Lagerpetidae, as it happens in Triassic pterosaurs. Thus, insectivory can be assigned as an ancestral diet in Pterosauromorpha. This diet is assigned as a possible driving force to the evolution of flight in Pterosauria. Keywords: Pterosauria, Lagerpetidae, Ornithodira, Triassic.

Carbonate Concretions in Triassic Yanchang Formation (Ordos Basin, China) as Evidence of Hydrothermal Activity

The discovery of concretions of Chang 7 shale formations in the Ordos basin has increased interest in the exploration of lacustrine carbonate genesis in these basins. In this paper, these concretions were sampled and used in major, trace, and isotopic geochemistry tests. We used a microscope to investigate these concretions, and the results showed that the concretions consisted of carbonate rocks, the calcite was hydrothermal calcite, and obvious hydrothermal activity was present in the Yanchang period. We used seismic data to interpret the faults, and we determined that tectonic activity was relatively frequent in the middle–late Triassic period and that the faults were channels for hydrothermal upwelling. During the middle–late Triassic period, tectonic movement of the basin occurred, and synsedimentary faults developed in the Yanchang Formation. As deep hydrothermal gushers rose through faults and fractures, they carried particles upward through the deep limestone strata. When the hydrothermal gushers reached the lake bottom, the particles precipitated and eventually formed concretions via diagenesis.

Understanding the provenance and depositional conditions of Triassic sedimentary rocks from the Spiti region, Tethys Himalaya, India

The Spiti region, renowned as the Museum of Indian Geology, is a world-famous sedimentary succession containing well-exposed sequences from Neoproterozoic to Cretaceous age. In this study, Triassic siliciclastic sedimentary rocks of the Lilang Supergroup were chosen to understand weathering history, provenance, paleoclimate, and depositional conditions using a geochemical and isotopic approach. Triassic shales show more or less similar compositions with substantial enrichment in CaO compared to PAAS (Post Archean shales from Australia), which may be attributed to the association with limestones in the region. However, the sandstones display significant depletion in the trace element concentrations signifying the effect of quartz dilution. The relative depletion of mobile elements (Rb, Ba) as against immobile elements (Zr, Nb, Hf) can be noticed in the trace element spider diagram of the shales. The Triassic sedimentary rocks are characterized by enriched LREE and depleted HREE patterns with pronounced negative Eu anomalies. The Chemical Index of Alteration (CIA; 56–86) indicates low to intense chemical weathering in the source area. The unusual decrease in CIA and other weathering indices in the stratigraphically up section is attributed to changes in climate and environmental conditions during the deposition of sediments in the Triassic period. Detangling the signatures is crucial to understanding the mass extinction crisis, particularly the role of anoxia in these events. Triassic black shales represent suboxic to anoxic depositional conditions in the redox-sensitive elemental binary diagrams. The carbon isotope data of the present study is very well supported by the Total Organic Carbon (TOC), which infers that the oceanic biological system tried to recover from the depletion of biological life. The εNd and 87Sr/86Sr systematics record a shift in source terrains from the Early to Late Triassic period. The Early Triassic samples show much older depleted mantle model ages (TDM = 1.94–1.98 Ga) compared to Late Triassic sediments (TDM = 1.76–1.91 Ga). Similar interpretations can be drawn from Th/Sc ratios (from ∼ 6 to ∼ 0.05) and (La/Yb) N ratios (from ∼ 32 to ∼ 5), which record an increase in these ratios from Early Triassic to Late Triassic formations of the Spiti sedimentary rocks. Overall, trace elemental ratios and radiogenic isotopic signatures of the Triassic rocks of the Spiti region point towards Pan African granitic origin with minor impressions from the juvenile mafic-rich sources, such as Panjal Traps, the African craton, and Arabian-Nubian shield.

El Barrancazo: a new locality of possible semi-aquatic turtle tracks from the Upper Triassic of Cortes de Pallás (Eastern Iberia)

This work describes the new vertebrate tracksite named El Barrancazo, located in Cortes de Pallás (Eastern Iberia). This new site turns this area into the one that concentrates the largest number of vertebrate footprints from the Upper Triassic of Iberia. The footprints are presented as natural casts distributed in isolated blocks belonging to the Manuel Formation (K2, Keuper facies), deposited during the Carnian Pluvial Episode (Late Triassic). The blocks come from two beds of the same outcrop. The tracks are made up of sub-parallel digital impressions, displaying occasional curved traces, often without forming a complete outline, and showing a set of features such as lateral and posterior overhangs, longitudinal striations or digital reflectures, among others. These features, taken together with the sedimentological analysis carried out, suggest that animals moving in totally or partially buoyant conditions in a fluvial environment produced most of these tracks. The size and morphology of these paleoichnological impressions suggest that they were probably produced, in some cases, by turtles, adding to the understanding of the paleoenvironmental and paleofaunistic conditions of the Late Triassic of Iberia during the Carnian, a key period in the evolution of different groups of continental vertebrates. In this paper we show the comparative study of the three sites described to date in Cortes de Pallás and an analysis of the interplay of trackmaker organism, animal behavior and substrate in the resulting morphology of tracks made under subaqueous conditions.

Biological decay by microorganisms in stems from the Upper Triassic Ischigualasto Formation (San Juan Province, Argentina): A striking microbial diversity in Carnian-Norian terrestrial ecosystems

We studied degradation patterns and microorganisms preserved in permineralized stems of Rhexoxylon piatnitzky, Protojuniperoxylon ischigualastense, and Agathoxylon argentinum from the Valle de la Luna Member of the Ischigualasto Formation (Upper Triassic, San Juan, Argentina). All three species show loss of middle lamella, thinning, and whitening of tracheid cell walls, and detachment of the S3 layer, consistent with selective delignification by white rot. This type of rot is the product of lignin and cellulosic degradation by Basidiomycetes and Ascomycetes. Rhexoxylon piatnitzkyi also shows small cavities, more or less circular in outline, on the wall of tracheids. This is known as soft rot and can be produced by some Ascomycetes, the anamorphic phases of diverse fungi, and tunneling bacteria. Additionally, abundant and diverse microorganisms were found. Rhexoxylon piatnitzkyi shows fragments of septate hyphae, evidence of bacterial activity, and structures of unknown affinity. Protojuniperoxylon ischigualastense presents structures common to anamorphic phases of diverse fungi, such as chlamydospores and conidiophores. Lastly, Agathoxylon argentinum bears coiled and septate hyphae, and a fan-shaped mycelium, whose significance is discussed. The microbiological study was complemented by the assessment of sedimentary and taphonomic data of the fossil-bearing beds. A gradual increment in humidity for the Valle de la Luna Member is interpreted, which concludes with a humidity peak in its upper section. This contribution represents the first detailed study of xylophagous and saprophyte micro-communities for the Ischigualasto Formation. The abundance and diversity of microorganisms described illustrate the complexity of wood-inhabiting micro-communities from the Carnian-Norian interval of Argentina.

Latest Triassic and Early Jurassic Spiriferinida (Brachiopoda) of Zealandia(New Zealand and New Caledonia).

The Late Triassic spiriferinides of Zealandia include the endemic or Austral genera Rastelligera, Psioidea and Psioidiella, and the cosmopolitan Zugmayerella. Mentzelia kawhiana is revised and placed in Callospiriferina. It appears in the late Rhaetian and is found in the Téremba Terrane in New Caledonia and throughout the Murihiku Terrane in New Zealand. The spiriferinides were severely affected at the Triassic-Jurassic boundary in Zealandia as elsewhere, but a moderately diverse fauna developed in the Early Jurassic. This has strong links to South America, and affinities with southern Europe and North Africa. In this study, a total of six species of Jurassic spiriferinides are recognised. Callospiriferina ongley is present in middle and late Hettangian and Sinemurian faunas. It is succeeded in the Pliensbachian and early Toarcian by Callospiriferina radiata. Two species of Spiriferina are recognised. S. sophiaealbae n. sp. first appears in the Middle Hettangian and is present in the Southland and Kawhia Synclines until the early Toarcian. S. arakiwa n. sp. is found mainly on the southwest limb of the Southland Syncline in the Pliensbachian and early Toarcian. The non-costate European genus Cisnerospira is represented in Zealandia by the small C. antipoda n. sp. This species ranges from Hettangian to early Toarcian. Two specimens of a spiriferinide with a costate sulcus are tentatively identified as Dispiriferina sp. cf. D. chilensis. The highest stratigraphic level at which Zealandian spiriferinides have been found is that of the Dactylioceras band at Kawhia, which is correlated with the Crassum Subzone of the Bifrons Zone (highest Early Toarcian) and includes three species of spiriferinide. This suggests that the Zealandian spiriferinides survived the Toarcian Event, only to meet their demise slightly later.

Lepidosauromorphs and associated vertebrate fauna from the Late Triassic Tiki Formation, South Rewa, Gondwana basin, India: implication for paleoenvironment and paleobiogeography

Tiki Formation is well known for the presence of rich vertebrate fossil assemblages including archosaurians, cynodonts, xenacanthids, hybodonts and actinopterygians in the Gondwana succession of India. Here, we report indeterminate Sphenodontia and indeterminate Lepidosauromorpha from the Late Triassic Tiki Formation. The presently reported early diverging lepidosauromorphs might have fed on small invertebrates and small vertebrates/insects. The presence of early diverging lepidosauromorphs from the Tiki Formation extends their geographic range from Europe, N. America and S. America to the Indian sub-continent during the Late Triassic Period. Further, the reports of archosauromorph assemblages and the aquatic vertebrates from the Tiki Formation have strengthened the idea of affinities of vertebrate assemblages between Laurasia and Gondwana sub-continents of the Pangea.

First discovery of the leafhopper family Archijassidae in the Jurassic of China (Hemiptera, Cicadomorpha)

ABSTRACT As basal group of mega-diverse Cicadelloidea (leafhoppers), the Mesozoic family Archijassidae has been widely recorded from the Upper Triassic of Australia and the Lower Jurassic to mid-Cretaceous of Eurasia; its precise document in China, however, is scarce. We herein describe and illustrate Karamayojassus xinjiangensis gen. et sp. n. based upon an isolated tegmen from the Lower Jurassic Badaowan Formation at the Tuziakeneigou outcrop of Junggar Basin, Xinjiang, NW China, representing the first discovery of Archijassidae in the Jurassic of China. The new genus and species can be attributed to the subfamily Archijassinae on the basis of a series of venational characteristics, and is distinctly discriminated from known archijassines by some critical tegminal traits. Karamayojassus gen. n. is likely related to the two genera (Cixiella and Mesocicada) from the Lower Jurassic of Kyrgyzstan by sharing a synapomorphic venational feature (long stem R + M present). We propose to resurrect Cixiella and Mesojassus from synonymy, since the two genera possess tegminal venation distinctly different from that of Archijassus. Our find not only adds novel morphological information on extinct archijassids, but also provides new data about the entomological assemblage of the Tuziakeneigou outcrop.