Gondwanan Affinities Research Articles

Femoral diversity in titanosaur sauropods from the Villalba de la Sierra Fm. (Central Spain): Implications for the characterization of faunal turnover in the Ibero-Armorican Late Cretaceous

The late Campanian-Maastrichtian in the Ibero-Armorican domain is rich in titanosaurian fossils. The sauropod remains exhibit a high degree of morphological variability, especially in the commonly-found appendicular elements. The phylogenetic relationships of the Ibero-Armorican titanosaurs are still uncertain but we do know that they experienced a Campanian-Maastrichtian herbivorous faunal turnover. It is probable that the small-to-medium-sized Lirainosaurinae-dominated faunas of the Campanian were replaced by late–early Maastrichtian large-bodied lithostrotian dominated faunas. In this context, the Villalba de La Sierra Formation has yielded an abundant sample of medium-to-large sized titanosaurs. In this study we analyze the morphological variability in the appendicular skeleton of the titanosaurs from the Campanian-Maastrichtian Ibero-Armorican domain. We follow previous attempts to classify the commonly-found isolated titanosaurian femora and expand the proposed methodology. The use of combined phenotypic characters and linear morphometrics can be helpful to analyze the morphological variability and diversity of the Ibero-Armorican titanosaurs. Our findings corroborate the presence of at least two exclusive morphotypes in the Lo Hueco fossil site and one exclusive morphotype in the Poyos site, as well as the presence of previously defined Lirainosaurinae across the Pyrenees during the Campanian-Maastrichtian. The Villalba de La Sierra Formation titanosaurs are also clustered with large-bodied late Maastrichtian titanosaurs. It is possible that either the large-bodied late–early Maastrichtian immigrants, with possible Gondwanan affinities, entered the Iberian Peninsula much earlier or that this group was already present at least during the Campanian-Maastrichtian transition, as the small-sized Lirainosaurinae declined.

Detrital zircon and rutile of southern Mexico Cambrian–Ordovician sandstone: Their significance for sediment provenance and Rheic Ocean evolution

The Cambrian–Ordovician Tiñú Formation of southern Mexico is key for identifying sediment sources along the northern margin of Gondwana, enhancing our understanding of early Paleozoic paleogeography and linking it with age-equivalent units in terranes with Gondwanan affinity. This study integrates detrital zircon U–Pb ages, Hf isotope signatures, and heavy mineral chemical data. U–Pb detrital zircon ages indicate sources from Stenian–Tonian (900–1200 Ma) to Calymmian (1400–1600 Ma) ages. The Stenian to Tonian zircon population, with peak ages around 1.0 Ga and model ages ranging from 1.68 to 1.90 Ga, suggests a provenance from the metaigneous rocks of the Oaxacan and Guichicovi complexes. The presence of the Calymmian zircon population, tourmaline crystals, and rutile grains displaying lower crystallization temperatures compared to the high-temperature rutile from the Oaxacan Complex suggests additional sources. Hf isotope signatures from Calymmian-aged zircon grains, with model ages between 1.95 and 2.30 Ga, match well with the Paleo-Mesoproterozoic Catarina Unit in the southern Chiapas Massif Complex. Further potential sources may include the basement of the Putumayo Province in Colombia and igneous rocks from the western Guiana Shield and the Rio Negro-Juruena Province. The Tiñú Formation provenance is comparable to coeval metasedimentary units across the northwestern margin of Gondwana found in Belize, the southern Chiapas Massif Complex, and Guatemala. The Tiñú Formation was likely deposited adjacent to the rifted margin of the Rheic Ocean. The results also emphasize combining U–Pb–Hf isotope analysis and trace elements in detrital zircon and rutile as effective provenance tracers.

Lower Cisuralian brachiopod faunas from the Lhasa and South Qiangtang blocks in Tibet and their biostratigraphical and palaeobiogeographical implications

The opening time of the Bangong-Nujiang Ocean (BNO, also known as the Meso-Tethys Ocean) remains controversial. It was documented to have opened during the Permian, Early Palaeozoic or Mesozoic times. The Permian faunas and their palaeobiogeographical affinities of the Lhasa and South Qiangtang blocks bordered by the Bangong-Nujiang Suture Zone are crucial for reconstructing the tectonic evolution of both blocks and determining the opening time of the BNO. This paper describes two new lower Cisuralian brachiopod faunas from the uppermost Yunzhug Formation of the Lhasa Block and the Zhanjin Formation of the South Qiangtang Block. These two faunas exhibit a high similarity in composition, both containing species of Bandoproductus, Spirelytha and Sulciplica thailandica. Comparable brachiopod faunas are found from the glaciomarine diamictites in the blocks of the eastern Cimmerian belt including the Baoshan, Irrawaddy and Sibuma, as well as the Tethys Himalaya and the Gondwanaland. They are herein named the Bandoproductus-Spirelytha association, which exhibits apparent Gondwanan affinities. Cluster analysis and principal components analysis are employed to conduct a palaeobiogeographical reconstruction of the Asselian–Sakmarian brachiopod faunas primarily from the aforementioned tectonic units. A single palaeobiogeographical unit, the Indoralian Province, is recognised and represented by the unified brachiopod association. This suggests that most of the Cimmerian blocks, including the Lhasa and South Qiangtang blocks, were attached to the northern Gondwanan margin during the early Cisuralian. This is in contrast to our previous results revealed by multiple quantitative analyses for the Kungurian–Roadian brachiopod faunas in the Tethys, which show distinct faunal differences between the Lhasa and South Qiangtang blocks. This palaeobiogeographical discrepancy suggests that the two blocks probably had varying northward drifting tempos after they detached from the Gondwanaland, that is, the South Qiangtang Block drifted faster and incorporated into the temperate-warm region of the Northern Cimmerian Subprovince; whereas the Lhasa Block drifted relatively slowly and retained to be close to the northern Gondwanan margin and belonged to the Southern Cimmerian Subprovince during the late Cisuralian. The faunal differences provided critical implications that the BNO probably had opened in the Artinskian and reached a certain width with distinct faunal differences during the Kungurian.

Cisuralian–Guadalupian brachiopod assemblages from the northern Tengchong Block in western Yunnan, China and their paleogeographical implications—a revisit

AbstractThe early to middle Permian brachiopods from the Tengchong Block in western Yunnan, southwestern China, play important roles in biostratigraphic correlation and paleogeographic inferences of tectonic units on eastern peri-Gondwana. However, detailed taxonomic studies of these brachiopods have been limited. In this paper, we provide the systematic description of three Permian brachiopod assemblages from the Shanmutang section in the northern Tengchong Block, which in ascending order include the Elivina-Etherilosia Assemblage from the top of the Kongshuhe Formation, and the Spiriferella-Spiriferellina Assemblage and the Waagenites-Costiferina Assemblage from the base and lower part, respectively, of the overlying Dadongchang Formation. Based on the biostratigraphic assessment of the brachiopod taxa as well as the age constraints from the associated fusulinid assemblages, the age of the Elivina-Etherilosia Assemblage is considered to be most likely late Sakmarian to early Artinskian, the Spiriferella-Spiriferellina Assemblage probably late Artinskian, and the Waagenites-Costiferina Assemblage late Roadian to early Wordian. A transition from cool-water faunas with Gondwanan affinities to mixed warm-temperate (transitional) faunas with Cathaysian elements is evident for the Artinskian and through the Guadalupian. The climatic transition inferred from the faunal evidence is interpreted to have resulted from the combined effect of Gondwana deglaciation and the northward drift of the peri-Gondwanan blocks (including the Tengchong Block) during the Cisuralian and Guadalupian.

The oribatid mite superfamily Eutegaeoidea (Acari, Oribatida), with descriptions of new taxa from Australia and New Caledonia and a re-assessment of genera and families.

Twenty-four new species of Eutegaeoidea from Australia and New Caledonia are described, and two new genera are proposed. These are Eutegaeus woiwurrung sp. nov., E. nothofagi sp. nov., E. bidhawal sp. nov., E. ptilosus sp. nov., Humerotegaeus carinatus gen. et sp. nov., H. concentricus gen. et sp. nov., Atalotegaeus crobylus sp. nov., Neoeutegaeus torsteini sp. nov., N. melipsilon sp. nov. N. malcolmi sp. nov., N. corniculatus sp. nov. (Eutegaeidae), Compactozetes goongerah sp. nov., C. crenellatus sp. nov. (Compactozetidae) and Pterozetes lawrencei sp. nov. (Pterozetidae) from temperate rainforests in Victoria and Tasmania; Compactozetes bundjalung sp. nov., C. calderi sp. nov., C. duonodulus sp. nov., Sadocepheus remus sp. nov. (Compactozetidae) and Porrhotegaeus githabul sp. nov. (Porrhotegaeidae fam. nov.) from temperate and sub-tropical rainforests of the Great Dividing Range in central and northern New South Wales and southern Queensland, Porrhotegaeus catherinae sp. nov. from scalybark closed forest on Lord Howe Island, Eutegaeus odontatus sp. nov. and Compactozetes pirumorpha sp. nov. from moist upland forest on Norfolk Island and Neseutegaeus wardi sp. nov. and Atalotegaeus deficiens sp. nov. from tropical rainforest and moss forest in New Caledonia. Based on the predominantly Southern Hemisphere distribution of Eutegaeoidea, indicating strong Gondwanan affinities, and the morphology of adults and immatures, this taxon is treated as distinct from the Cepheoidea which has a distribution almost entirely within the Northern Hemisphere. Eutegaeoid species previously described from Australia (Eutegaeus soror P. Balogh, 1985, Atalotegaeus mensarosi J. & P. Balogh, 1983, Neseutegaeus monteithi J. & P. Balogh, 1983, Neoeutegaeus phyllophorus J. & P. Balogh, 1983 and Porrhotegaeus ornatus J. Balogh & Mahunka, 1966) are redescribed based on type material and new distribution records provided. Species have distribution patterns predominantly indicative of short-range endemics associated with remnant Gondwanan rainforest. Neseutegaeus monteithi is recombined with Atalotegaeus Luxton, 1988a. The definitions of genera and families of Eutegaeoidea are revised, and their relationships are reconsidered. Birotegaeus Luxton, 1988a and Pareutegaeus Woolley, 1965 are designated junior synonyms of Eutegaeus Berlese, 1916. Immatures are described for the genera Atalotegaeus, Eutegaeus, Neoeutegaeus Aoki, 1964 and Porrhotegaeus J. Balogh & Mahunka, 1966. Neoeutegaeidae fam. nov. is established for Neoeutegaeus Aoki, 1964 and Humerotegaeus gen. nov., Porrhotegaeidae fam. nov. for Porrhotegaeus and Bornebuschiidae fam. nov. for Bornebuschia Hammer, 1966 and Dicrotegaeus Luxton, 1988 which had previously been placed in Cerocepheidae or Compactozetidae. Eutegaeus aysenensis Ermilov, 2021 and E. queulatensis Ermilov, 2021 from Chile, are recombined with Atalotegaeus. A key is provided to the genera of the eight families of Eutegaeoidea, as recognised herein: Eutegaeidae, Neoeutegaeidae fam. nov., Cerocepheidae, Compactozetidae, Bornebuschiidae fam. nov., Pterozetidae and Porrhotegaeidae fam. nov.

Water beetles (Coleoptera) associated with Afrotemperate Forest patches in the Garden Route National Park, South Africa.

Southern Afrotemperate Forest is concentrated in the southern Cape region of South Africa and whilst it is relatively well known botanically, the fauna, specifically the aquatic invertebrate fauna, is poorly documented. The majority of remaining intact forest habitat is contained within the Garden Route National Park (GRNP), which straddles the provincial boundary between the Western and Eastern Cape. This study undertakes a survey of the water beetle fauna inhabiting the GRNP. The aquatic ecosystems within temperate forests of the region are poorly researched from an ecological and biodiversity perspective, despite being known to harbour endemic invertebrate elements. We collected water beetles and in situ physico-chemical data from a total of 31 waterbodies across the park over two seasons (summer and late winter) in 2017. The waterbodies sampled were mostly small freshwater perennial streams and isolated forest ponds. A total of 61 beetle taxa was recorded (29 Adephaga, 32 Polyphaga) from these waterbodies. The water beetle fauna of these forests appears to be diverse and contains many species endemic to the fynbos-dominated Cape Floristic Region, but very few of the species appear to be forest specialists. This is in contrast to the fynbos heathland habitat of the region, which harbours a high number of water beetle species endemic to this habitat, often with Gondwanan affinity. Our study is the first to document the water beetles of Afrotemperate Forests in the southern Cape region and provides an important baseline for future work on such habitats in the region and in other parts of southern Africa.

The Manhattan project: Isotope geochemistry and detrital zircon geochronology of schists in New York City, USA

The geology of New York City (USA) consists primarily of metasedimentary rocks that were deformed during the series of orogenies between ca. 470 Ma and ca. 300 Ma that culminated in the amalgamation of Pangea. The rocks in New York City play a key role in understanding the tectonic history of these orogenies because they lie at a critical location at the boundary between the Northern and Southern Appalachian Mountains. The primary question addressed here is where these metasedimentary rocks originated prior to the assembly of Pangea. Through detrital zircon and whole-rock Nd isotope analyses, we show that all the metasedimentary rocks of New York City, mapped as the Manhattan Schist and the Hartland Group, are primarily derived from Laurentia as indicated by detrital zircon populations dominated by 1200−900 Ma grains and εNd values between −7 and −13. The results presented here do not necessitate an exclusively Laurentian source for the detrital material found in New York City, but the data strongly suggests protoliths represent sedimentary units that are primarily derived from the Laurentian margin. Another important result from this study is the limited contributions from any rift volcanics and/or Gondwanan material(s). There is some subtle variability across our zircon sample suite, but there is no convincing evidence for major changes in bulk provenance signal that would be consistent with derivation from vastly different continental sources for these rocks. The shared provenance signal observed here is counter to the previous suggestions that a major terrane boundary, often called Cameron’s Line, exists in New York City, separating Laurentian rocks from those of a Gondwanan affinity.

New sauropod dinosaur from the Lower Cretaceous of Morella (Spain) provides new insights on the evolutionary history of Iberian somphospondylan titanosauriforms

Abstract A new somphospondylan titanosauriform from the Lower Cretaceous of Spain is described from the remains found at the Sant Antoni de la Vespa site (upper Barremian Arcillas de Morella Formation) located in Morella. Garumbatitan morellensis gen. et sp. nov. is diagnosed by 11 autapomorphies and eight local autapomorphies; and our phylogenetic analyses suggest that Garumbatitan morellensis might correspond to an early-branching somphospondylan. The presence of several somphospondylan traits in Garumbatitan morellensis supports the somphospondylan hypothesis. The phylogenetic distribution of some titanosauriform and somphospondylan novelties in the femur (markedly developed lateral bulge, high shaft eccentricity, linea intermuscularis cranialis, and trochanteric shelf) is discussed. The tarsus and pes of Garumbatitan morellensis are distinctive, being characterized by the loss of the calcaneum, relative slenderness of the metatarsals II, III, and IV when compared to the retracted metatarsals I and V, three pedal phalanges in digit IV, and reduced ungual III. The sauropod fauna of the Iberian Peninsula during the Hauterivian–Aptian shows a complex phylogenetic mosaic, including forms with Laurasian affinities, mainly titanosauriforms (Soriatitan, Garumbatitan, and possibly Tastavinsaurus and Europatitan), and Gondwanan affinities, the rebbachisaurid Demandasaurus. Faunal exchange during the Early Cretaceous between the Europe, North America, East Asia, and Africa is plausible.

Long forgotten record of a freshwater leech on Madagascar indicates a host-associated dispersal event from continental Africa

Madagascar houses a peculiar and largely endemic biota, having ancient Gondwanan affinities. However, the faunal composite of many invertebrate groups on the island is poorly known. For a long time, it was believed that the freshwater leech fauna of Madagascar contains a salifid species (Salifidae) only. Here, we report on a historical record of Placobdelloides multistriatus (Johansson, 1909) (Glossiphoniidae), a widespread African species, from Andrahomana, Southern Madagascar. Franz Sikora (1863-1902), an Austrian traveler and collector, who visited Andrahomana in 1899 to excavate fossils from a cave, collected the leech sample. The two specimens were obtained from an unspecified turtle species. We assume that P. multistriatus may have arrived to Madagascar relatively recently (i.e., in the Late Pleistocene or Holocene) via a long-distance dispersal event from continental Africa with its reptilian hosts such as the Nile crocodile and marsh terrapin. Based on a review of the body of available literature, two more freshwater leech species are known to occur on Madagascar: Linta be Westergren & Siddall, 2004 (Salifidae) and Alboglossiphonia sp. (Glossiphoniidae). Our findings indicate that Madagascar houses at least three freshwater leech species and that some additional taxa may have been overlooked there due to the scarcity of sampling efforts in the island’s freshwater bodies.

Anatomy and phylogeny of an exceptionally large sebecid (Crocodylomorpha) from the middle Eocene of southern France

ABSTRACT Post Cretaceous–Paleogene (K–Pg) boundary continental ecosystems of Europe host a distinctive assemblage of derived neosuchians related to modern semi-aquatic lineages, including the alligatoroid Diplocynodon and the crocodyloid Asiatosuchus but also a less well-understood group known as the Planocraniidae. Yet, uniquely in its faunal composition, Europe also preserves some of the last representatives of Notosuchia, a group that previously underwent a successful radiation in terrestrial ecosystems of the Cretaceous, especially in Gondwana. Although Europe harbored a few members of Sebecosuchia during the Cretaceous, their affinities with post-K–Pg forms is not ascertained, in part due to their rare and fragmentary nature on both sides of the stratigraphic boundary. Paleogene European sebecosuchians have been reported from the Eocene of France, Germany, Portugal, and Spain. Resolving their phylogenetic position may shed light on their suspected Gondwanan affinities. Based on new cranial and postcranial remains, we provide a description of the most complete and largest European sebecosuchian to date from the middle Eocene (Bartonian) of Issel and Réalmont, southern France. Dentaneosuchus gen. nov. is proposed to designate the taxon originally described as Atacisaurus crassiproratus. A phylogenetic analysis recovers Dentaneosuchus crassiproratus as the basalmost branching member of Sebecidae, a clade otherwise known from abundant specimens from the Paleogene and Miocene of South America. Among post-K–Pg sebecids, Dentaneosuchus crassiproratus rivalled in size with Barinasuchus arveloi from the Miocene of Venezuela, demonstrating that sebecids achieved the status of apex predators in terrestrial ecosystems of both Europe and South America.

An enigmatic large mawsoniid coelacanth (Sarcopterygii, Actinistia) from the Upper Jurassic Kimmeridge Clay Formation of England

ABSTRACT A large mawsoniid coelacanth from the lower part of the marine Kimmeridge Clay Formation of England (Kimmeridgian, Upper Jurassic) is studied here. The material is constituted by a group of bones from the head and shoulder girdle of a considerably large individual (estimated length ca. 1.5 m), including the left angular, left dentary, left prearticular, left palatoquadrate complex, both ceratohyals and right cleithrum. Characters such as the coarse external ornamentation of the angular, and the robustness of the quadrate and the cleithrum allow classification of the individual as a member of the Mawsoniidae; whereas the configuration of external bones of the lower jaw (ornamentation of the angular constituted mainly by longitudinal ridges, the presence of a lateral swelling in the dentary) indicates stronger Gondwanan affinities than previously expected (i.e., with the genus Mawsonia, up to now only recorded in South America by the end of the Jurassic). Considering the above, two alternative evolutionary, paleobiogeographic, and taxonomic scenarios are discussed: (1) the new individual can be referred to the European mawsoniid genus Trachymetopon (Lower–Middle Jurassic), in which case it should be assumed this genus reached the Upper Jurassic, and with a morphological variability higher than previously suspected (including some characters previously assumed as diagnostic for Mawsonia). Or (2) an unknown Mawsonia-like form was present in the Upper Jurassic of Europe. The last scenario puts the identification of isolated elements of European Jurassic giant mawsoniids in a new complex taxonomic and paleobiogeographic context, which will deserve further research.

A titanosaurian sauropod with Gondwanan affinities in the latest Cretaceous of Europe.

The origin of the last sauropod dinosaur communities in Europe and their evolution during the final 15 million years of the Cretaceous have become a complex phylogenetic and palaeobiogeographic puzzle characterized by the controversy on the alleged coexistence of immigrant, Gondwana-related taxa alongside relictual and insular clades. In this context, we describe a new titanosaurian sauropod dinosaur, Abditosaurus kuehnei gen. et sp. nov., from the Late Cretaceous (Maastrichtian) Tremp Group of Catalonia (Spain). Phylogenetic analyses recover Abditosaurus separately from other European titanosaurs, within a clade of otherwise South American and African saltasaurines. The affinity of the new taxon with southern landmasses is reinforced by spatiotemporal co-occurrence with Gondwanan titanosaurian oospecies in southern Europe. The large size and the lack of osteohistological features potentially related to insular dwarfism or size reduction support the idea that Abditosaurus belongs to an immigrant lineage, unequivocally distinct from some of the island dwarfs of the European archipelago. The arrival of the Abditosaurus lineage to the Ibero-Armorican Island is hypothesized to have occurred during the earliest Maastrichtian (70.6 Ma), probably as a result of a global and regional sea-level drop that reactivated ancient dispersal routes between Africa and Europe. The arrival of large-bodied titanosaurs to the European archipelago produced dramatic changes in its insular ecosystems and important evolutionary changes in its dinosaur faunas, especially with respect to the 'island rule' effect.

Cambrian and earliest Ordovician fauna and geology of the Sông Đà and adjacent terranes in Việt Nam (Vietnam)

AbstractLater Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from five localities within the Sông Mã, Hàm Rồng and Đông Sơn formations of the Thanh Hóa province of Việt Nam, constrain the age and faunal affinities of rocks within the Sông Đà terrane, one of several suture/fault-bounded units situated between South China to the north and Indochina to the south. ‘Ghost-like’ preservation in dolomite coupled with tectonic deformation leaves many of the fossils poorly preserved, and poor exposure precludes collecting within continuously exposed stratigraphic successions. Cambrian carbonate facies pass conformably into Lower Ordovician carbonate-rich strata that also include minor siliciclastic facies, and the recovered fauna spans several uppermost Cambrian and Lower Ordovician biozones. The fauna is of equatorial Gondwanan affinity, and comparable to that from South China, North China, Sibumasu and Australia. A new species of Miaolingian ‘ptychopariid’ trilobite,Kaotaia xuanensis, is described. Detrital zircon samples from Cambrian–Ordovician rocks of the North Việt Nam and Sông Đà terranes, and from Palaeozoic samples from the Trường Sơn sector of Indochina immediately to the south, contain a predominance of ages spanning the Neoproterozoic period and have a typical equatorial Gondwanan signature. We associate the Cambrian and Tremadocian of the Sông Đà terrane with areas immediately to the north of it, including the North Việt Nam terrane and the southern parts of Yunnan and Guangxi provinces of China.

Geochemistry and U-Pb-Hf detrital zircon geochronology of metamorphic rocks in terranes of the West Kunlun Orogen: Protracted subduction in the northernmost Proto-Tethys Ocean

The West Kunlun Orogenic Belt (WKOB) is a key area for evaluating the evolution of the Proto-Tethys Ocean. To constrain this history, we present geochemical and zircon U-Pb geochronological data from a suite of metasedimentary rocks within this orogenic belt. Detrital zircons ages are clustered between 1000 and 400 Ma, with major peaks at ca. 510 Ma and 460 Ma, and minor peaks at ca. 840 Ma and 650 Ma. The age groups younger than 1000 Ma broadly overlap magmatic activity at ca. 540–420 Ma and minor magmatism at 920–540 Ma in the WKOB. The age data also reveal Early Paleozoic metamorphic basement rocks in the WKOB that were probably sourced from Kunlun terranes and blocks of Gondwanan affinity rather than the Tarim Craton. Compiled geochemical data suggest a protracted subduction setting in the WKOB in the Early Paleozoic. εHf(t) values show increasing trends at 900–740 Ma and 740–600 Ma and a distinct decreasing trend at 540–420 Ma, consistent with retreating subduction during the Neoproterozoic and advancing subduction in the Early Paleozoic. The retreating-advancing subduction cycle in the WKOB was possibly related to the opening and closure of the Proto-Tethys Ocean along the margin of Gondwana.

Early Permian macroinvertebrate assemblages from the Siang and Subansiri districts, Arunachal Pradesh: Implications on the regional stratigraphy, palaeoenvironment, palaeoecology, and palaeobiogeography

The Early Permian marine strata exposed at the Siang and Subansiri districts, Arunachal Pradesh are known for brachiopod and molluscan fossils. A stratigraphic review and palaeoenvironmental, palaeoecological, and palaeobiogeographic interpretation of these Early Permian fossils have been dealt here on the basis of additional fossil and rock materials. Our study confirms the following: (1) the brachiopod-dominated assemblage represents Early Permian, most likely the Sakmarian and younger, age; (2) all marine fossils were suspension feeding groups, representing normal marine condition. Based on the associated sediments and ecologies of taxa, the autecology of the assemblage represents an oxic, soft substrate condition, typical of shallow shelf environment; the plant remains of the upper Khelong/Bhareli Formation, however, indicate a coastal environment; (3) the depositional paleoenvironment indicates the waning phase of a marine glacial episode; and (4) this Early Permian bivalve-brachiopod assemblage show Gondwanan affinity, having strong faunal similarity with the East and West Australia, Nepal and North India (Kashmir) which were part of the Indoralian Province.

A new genus of the pseudoscorpion family Chernetidae (Pseudoscorpiones) from southern Australia with Gondwanan affinities

A new genus of pseudoscorpions of the family Chernetidae, Austinochernes, is described for two new Australian species, A. andrewaustini (type species) from South Australia and Victoria, and A. zigzag from Tasmania. They are most similar to species of the Neotropical genus PseudopilanusBeier, 1957 in the possession of a spine-like seta on the prolateral face of the chelal hand at the base of the fingers, but differ by the presence of acuminate setae on the male pedipalpal trochanter. The suspected relationship between Austinochernes and Pseudopilanus suggests that their distribution is the result of Gondwanan vicariance.

The second chthonioid pseudoscorpion (Pseudoscorpiones: Chthoniidae) from mid-Cretaceous Burmese amber: a new genus with unique morphological features and potential Gondwanan affinities

Pseudoscorpions are amongst the oldest terrestrial lineages but there is a major gap in the fossil record between the oldest fossils from the Devonian (ca. 385 million years ago) and rich fossil communities in amber that mostly originate from the Eocene of Europe. Burmese/Myanmar amber (or Burmite) from the middle Cretaceous preserves a diverse community of pseudoscorpions but these remain poorly documented, despite their exceptional preservation and potential to offer unique insights into evolutionary history. Here we describe a new genus and species of pseudoscorpion with a unique morphology of the chelicerae, Prionochthonius burmiticus gen. et sp. nov., from Burmese amber. Although some key characters remain obscure, the fossil can be confidently attributed to the basal pseudoscorpion family Chthoniidae, but it cannot be assigned to any extant or other fossil genus. Based on trichobothria patterns, it is most similar to extant genera that are found only in the Southern Hemisphere; findings that are in line with previous studies suggesting Gondwanan origins for at least some of the Burmese amber invertebrates. The fossil provides further evidence for a diverse community of litter- and soil-dwelling pseudoscorpions in the Late Cretaceous that comprises many extinct genera but represents many of the modern families. It also suggests that the diversification of chthoniid pseudoscorpions occurred well before the middle Cretaceous, and that the principle gestalt of its members has changed relatively little over time.

Oldest Jurassic wood with Gondwanan affinities from the Middle Jurassic of Tibetan Plateau and its paleoclimatological and paleoecological significance

Jurassic flora of the Tibetan Plateau is poorly known, with limited fossil records. The paleobiogeography of terrestrial biota is, however, one of the major evidences to reconstruct the intricate paleogeography of an area. Well-preserved fossil wood is described from the Middle Jurassic Xiali Formation (Callovian) in the South Qiangtang terrane of the Tibetan Plateau, SW China. The wood specimen is a well-preserved secondary xylem without growth rings. Bordered pits on the radial tracheid walls are mostly uniseriate distant, locally contiguous. Cross-fields have 1–2 large oopores. A systematic study indicates that the current fossil wood represents a new species, Circoporoxylon tibetense sp. nov. This is the earliest Laurasian data for the genus Circoporoxylon, which has a Gondwanan origin and subsequently became common in Laurasia during the Cretaceous. The present new finding indicates that Circoporoxylon might have reached the Laurasia via a Tibetan terrane. The presence of fungal remains and wood rotting structures resembling the extant white-rot testifies for the plant–fungal interaction in the Callovian. The absence of growth rings in Circoporoxylon wood and the absence of gypsum layers in the South Qiangtang terrane, together with the widely occurrence of gypsum layers in the North Qiangtang terrane, suggests the South Qiangtang terrane might be wetter than the latter during the Callovian age. The paleogeomorphological highlands of Central Uplift were most likely the boundary between the two. This paleoclimate zonation implies that the Permian to Mesozoic megamonsoon of the supercontinent Pangaea might have terminated in the northern of Paleo-Tethys before the Callovian.

Tectonic evolution of Anglesey and adjacent mainland North Wales

Abstract The Appalachian–Caledonian Orogen preserves a complex record of piecemeal trans-oceanic terrane transfer and accretion during the early Paleozoic collision between West Gondwana and Laurentia, whilst the intervening Iapetus oceanic tracts were largely destroyed. The now preserved terranes include arc fragments of Laurentian and Gondwanan affinity, oceanic fragments incorporated into the Gondwanan continental margin, and remnants of the Gondwanan continental slope apron and adjacent platform (both Ganderia and Megumia). A new tectonostratigraphic synthesis for the island of Anglesey (and adjacent NW Wales) reveals a comprehensive record of the Appalachian orogenic cycle in the UK segment of the orogen of the peri-Gondwanan margin prior to amalgamation into the Laurentian margin. We identify elements of Late Neoproterozoic accretion forming the pre-Appalachian basement; Cambrian extension, deposition and continental margin growth; Early Ordovician accretion and renewed extension; and, finally, terminal Caledonian collision and continental foreland-basin development.

Permian–Triassic magmatism in response to Palaeotethys subduction and pre-Late Triassic arrival of northeast Gondwana-derived continental fragments at the southern Eurasian margin: Detrital zircon evidence from Triassic sandstones of Central Iran

The closure of Palaeotethys that led to the collision of the Cimmerian blocks with the southern Eurasian margin causing the Eo-Cimmerian orogeny during the Early Mesozoic is still controversially discussed. The Triassic Nakhlak Group in Central Iran is a key sedimentary succession for better understanding the closure of Palaeotethys and the Eo-Cimmerian orogeny in the Middle East. The Nakhlak Group is composed of the Alam (Olenekian to Middle Anisian), Baqoroq (?Upper Anisian to Middle Ladinian) and Ashin (Upper Ladinian to ?Carnian) formations, which consist mainly of volcaniclastic sandstones, mixed siliciclastic conglomerates, and marine carbonates. Here we present for the first time detrital zircon UPb ages from the Nakhlak Group to unravel its provenance and constrain its palaeotectonic position within the Palaeotethyan realm. Most detrital zircons from the Nakhlak Group are euhedral and subhedral with Permian–Triassic ages (ca. 280–240 Ma) suggesting sediment supply from Permian–Triassic magmatic rocks of the Silk Road Arc. Minor zircon populations show pre-Permian Palaeozoic ages, with age peaks at ca. 320 Ma and 480 Ma, which are probably derived from the basement on which the magmatic arc developed. Neoproterozoic–latest Mesoproterozoic (ca. 550–1100 Ma) and Palaeoproterozoic (ca. 1800–2200 Ma) zircon grains are anhedral (rounded). The latter are prominent in the upper Baqoroq Formation (Middle Ladinian) suggesting recycling of older sedimentary rocks. Sandstone petrography points toward an additional metamorphic provenance for this formation. This short-lived provenance change can be explained by tectonic uplift in the source area that led to erosion of metamorphosed rocks with a northeast Gondwanan affinity. It clearly indicates that northeast Gondwana-derived continental fragments likely belonging to the Cimmerian blocks already arrived at the southern Eurasian margin in pre-Late Triassic time. Current palaeotectonic models of the closure of Palaeotethys and the Eo-Cimmerian orogeny in the Middle East during the Triassic may need to be revised.