Fluxes and isotopic composition of planktonic foraminifera off Hainan Island, northern South China Sea: implications for paleoceanographic studies Publication date: Available online 21 July 2019 Source: Palaeoworld Author(s): Ismail Adejare Ladigbolu, Bao-Hua Li, Hong-Liang Li, Martin G. Wiesner, Zhou-Fei Yu, Jing-Jing Zhang, Lin Sun, Li-Hua Ran, Ying Ye, Jian-Fang Chen Abstract Planktonic foraminifera collected from a sediment trap deployed off Hainan in the northwestern South China Sea (SCS-NW) between July 2012 and April 2013 were studied to evaluate their seasonal variability and ecology as well as to infer the factors controlling their shell fluxes. The total planktonic foraminifera flux, as well as the fluxes of the dominant species (Globigerinoides ruber, Globigerinoides sacculifer and Neogloboquadrina dutertrei), showed three distinct maxima during SW-monsoon in August 2012, the SW-NE intermonsoon in October 2012 and the NE-monsoon in December 2012–February 2013. These periods were characterized by upwelling, aerosol fallout, and intense wind mixing, respectively, from which the foraminiferal assemblages benefitted, as indicated by the close correlation between wind speed, sea surface temperature (SST), chlorophyll ɑ concentration (Chl-ɑ), δ18O of G. ruber and the shell fluxes. The correlation also suggests that temperature and food availability might have been the primary drivers of the observed changes in foraminiferal abundance. The offset between the SST deduced from flux-weighted of G. ruber δ18O and annual mean SST is only ˜0.3 °C, much lower than ˜5.2 °C between the summer and winter temperature, indicating a balanced seasonality bias in the shell flux. The linear regression between the satellite-derived sea surface temperature and G. ruber δ18O reveals the strong potential of this species, at least in the studied region, as an ecological indicator for past oceanic environments.

Tsuga seed cones from the late Paleogene of southwestern China and their biogeographical and paleoenvironmental implications Publication date: Available online 21 July 2019 Source: Palaeoworld Author(s): Meng-Xiao Wu, Jian Huang, Tao Su, Qin Leng, Zhe-Kun Zhou Abstract Six Tsuga ovuliferous/seed cone impression fossils were discovered from the late Eocene (34.6 ± 0.8 Ma) Lawula Formation in Mangkang County, eastern Tibet and the early Oligocene (32 ± 1 Ma) lacustrine deposits in Lühe Basin, Nanhua County, Yunnan Province. These two fossil sites are both located in southwestern China, ˜800 km apart from each other. These fossils represent the oldest records of this genus in southwestern China, even earliest reliable macrofossil records of this genus in the world. These well-preserved seed cones provide sufficient materials for the establishment of Tsuga asiatica Wu et Zhou n. sp. to accommodate five specimens, leaving one to be assigned to T. cf. dumosa Eichler (cf. Wu et Zhou). Both qualitative and quantitative comparisons with other cone fossils and cones of all living species of the genus suggested that T. asiatica shares more similarities with one of the basal species of the genus T. heterophylla. The discovery of late Paleogene macrofossil records of Tsuga in southwestern China supports the previous hypothesis of the early disposal routes of this coniferous genus predicted by phylogenetic analysis. The elevation ranges and the climate requirements of living species that are closely related to our fossils suggest that the southeastern edge of the Qinghai-Tibetan Plateau should be much warmer, and wetter in late Paleogene than nowadays.

Cyclocrinitids from the Lower Palaeozoic Tethyan sequence of Spiti, India Publication date: Available online 21 July 2019 Source: Palaeoworld Author(s): Husain Shabbar, Anju Saxena, Kamal Jeet Singh, Shreerup Goswami Abstract Well preserved cyclocrinitids (calcareous green algae) are reported from early Palaeozoic deposits of Spiti, Himachal Pradesh, India. Casts of the algal fossils are preserved in calcareous grey siltstone unit of the Takche Formation (Late Ordovician–Early Silurian) which appears rusty/earthy brown due to weathering. The assemblage includes Cyclocrinites favus, Cyclocrinites pyriformis, Cyclocrinites cf. welleri, Cyclocrinites sp. and Cyclocrinites globosus. Both Cyclocrinites cf. welleri and Cyclocrinites globosusare reported for the first time from the entire Tethyan Himalaya, India. The described algal flora basically denotes relatively shallow marine depositional setting and low to moderate hydrodynamic conditions.

The Upper Devonian tetrapodomorph Gogonasus andrewsae from Western Australia: Reconstruction of the shoulder girdle and opercular series using X-ray Micro-Computed Tomography Publication date: Available online 21 July 2019 Source: Palaeoworld Author(s): Yuzhi Hu, Gavin C. Young, Jing Lu Abstract The tetrapodomorph fish, Gogonasus andrewsae is a three dimensionally well-preserved sarcopterygian from the Gogo Formation (Frasnian, early Upper Devonian, ∼380 million years ago) in Western Australia. High-resolution X-ray Micro-Computed Tomography and 3D printouts were used to obtain a digital reconstruction of its shoulder girdle and opercular series. Our new findings show the opercular series in a close fit against the upper bones of the shoulder girdle only if the anocleithrum, supracleithrum and post-temporal are aligned more horizontally than in previous reconstructions. The lowermost subopercular bone also differs, in partly covering the clavicle of the shoulder girdle. The ascending process of the clavicle, and the ventral process of the anocleithrum, do not fit closely inside the cleithrum, and perhaps functioned for ligamentous attachment. A rugose area on the anocleithral process is in a similar relative position to the attachment of a muscle ligament on the shoulder girdle of various living actinopterygians. Our manipulation of 3D printouts permits testing of the morphological fit of extremely fragile acid-etched bones, and indicates a new way to investigate the constructional morphology of one or more mechanical units of the vertebrate skeleton. It is suggested that Micro-CT imaging, reconstruction, visualisation and 3D printing techniques will provide a rigorous new test leading to modification of previous reconstructions of extinct vertebrates that were based on graphical methods and 2D imaging.

The latest Ordovician Hirnantia brachiopod fauna of Myanmar: Significance of new data from the Mandalay Region Publication date: Available online 12 July 2019 Source: Palaeoworld Author(s): Jia-Yu Rong, Kyi Pyar Aung, Ren-Bin Zhan, Bing Huang, David A.T. Harper, Di Chen, Hang-Hang Zhou, Xiao-Le Zhang Abstract A new, latest Ordovician brachiopod fauna is systematically described from the Hwe Mawng Purple Shale Member (Hirnantian) of the Naungkangyi Group of the Pa-thin area, Mandalay Region, Myanmar, revealing one of the most diverse representatives of the typical Hirnantia Fauna. Rhynchonelliformean, craniiformean and linguliformean brachiopods studied belong to 23 genera and a few indeterminate taxa, among which the most abundant genus Kinnella, along with the four common genera (Paromalomena, Pseudopholidops, Fardenia, and Dalmanella), and other genera (such as Cliftonia, Draborthis, Hindella, Hirnantia, Leptaena, Mirorthis, Plectothyrella, Skenidioides, and Xenocrania) are recorded for the first time. This high diversity Hirnantia Fauna represents an ecological differentiation within the benthos of the Sibumasu Terrane during the end Ordovician global crisis. The palaeoeco-unit named herein as the Kinnella-Paromalomena Association is assigned to lower BA3. This paper includes a taxonomic revision with the following conclusions: 1) Sinomena Zeng et al. and Yichangomena Zeng et al. are treated as junior synonyms of Eostropheodonta Bancroft; 2) Hubeinomena Zeng et al. is regarded as a juvenile form of Coolinia Bancroft; 3) Paramirorthis Zeng et al. is considered an immature growth stage of Mirorthis Zeng; 4) Shanomena Cocks and Fortey is treated as a junior synonym of Paromalomena Rong; 5) Scenidium? medlicotti Reed is redesignated as the type species of Kinnella Bergström to replace Hirnantia? kielanae Temple. The distribution of the Hirnantia Fauna in Myanmar, Thailand and western Yunnan of the Sibumasu Terrane highlights the distinctive nature of the Mandalay fauna, and the analyses of the Hirnantia Fauna and others of Sibumasu shows that Sibumasu was not located far from the South China and Lhasa palaeoplates during late Middle and Late Ordovician.

Early Cambrian organophosphatic brachiopods from the Xinji Formation, at Shuiyu section, Shanxi Province, North China Publication date: Available online 12 July 2019 Source: Palaeoworld Author(s): Bing Pan, Christian B. Skovsted, Glenn A. Brock, Timothy P. Topper, Lars E. Holmer, Luo-Yang Li, Guo-Xiang Li Abstract Abundant and diverse small shelly fossils have been reported from rocks of Cambrian Series 2 in North China, but the co-occurring brachiopods are still poorly known. Herein, we describe seven genera, five species and two undetermined species of organophosphatic brachiopods including one new genus and new species from the lower Cambrian Xinji Formation at Shuiyu section, located on the southern margin of North China Platform. The brachiopod assemblage comprises one mickwitziid (stem group brachiopoda), Paramickwitzia boreussinaensis n. gen. n. sp., a paterinide, Askepasma toddense Laurie, 1986, an acrotretoid, Eohadrotreta cf. zhenbaensis Li and Holmer, 2004, a botsfordiid, Schizopholis yorkensis (Holmer and Ushatinskaya in Gravestock et al., 2001) and three linguloids, Spinobolus sp., Eodicellomus cf. elkaniiformis Holmer and Ushatinskaya in Gravestock et al., 2001 and Eoobolus sp. This brachiopod assemblage suggests a late Age 3 to early Age 4 for the Xinji Formation and reveals a remarkably strong connection with coeval faunas from East Gondwana, particularly the Hawker Group in South Australia. The high degree of similarity (even at species level) further supports a close palaeogeographic position between the North China Platform and Australian East Gondwana during the early Cambrian as indicated by small shelly fossil data.

A new species of Lygodium (Schizaeaceae) from the Buxin Formation (middle Paleocene), Sanshui Basin, South China Publication date: Available online 10 July 2019 Source: Palaeoworld Author(s): Sergey V. Naugolnykh, Ming Tu, Xiao-Yan Liu, Jian-Hua Jin Abstract The morphology, epidermal features and details of the conducting tissues are described for Lygodium sterile pinnules from the oil-bearing middle Paleocene strata of the Sanshui Basin, Guangdong Province, South China. A new species, Lygodium sanshuiensen. sp., is erected on the basis of being petiolulate, with palmately-lobed sterile pinnules that are often strongly dissected and have acute to acuminate apices. Lygodium is typically associated with mesic floras and its presence in the Buxin palaeoflora suggests the overall regional palaeoclimate was subtropical and humid during the middle Paleocene.

The postparietal shield of the Pragian dipnomorph Arquatichthys and its implications for the rhipidistian cranial anatomy Publication date: Available online 10 July 2019 Source: Palaeoworld Author(s): Jing Lu, Min Zhu Abstract Rhipidistians comprise dipnomorphs (the lungfish lineage) and tetrapodomorphs (the tetrapod lineage). Arquatichthys porosus Lu and Zhu, 2008 is a Pragian dipnomorph from the Posongchong Formation of Zhaotong, Yunnan, South China (∼409 million years ago, Early Devonian), previously represented by a lower jaw and few scattered scales. Here we describe a newly-discovered postparietal shield of Arquatichthys by means of high-resolution computed tomography. The cranial morphology of Arquatichthysresembles that of the basal dipnomorph Powichthys in having more than two supratemporal bones each side, more than one row of openings for sensory canals on the marginal bones, and a straight posterior margin of the shield. An intricate occipital artery system is present between the skull roof and neurocranium, as in Youngolepis and the tetrapodomorph Eusthenopteron. The discovery of the postparietal shield of Arquatichthys adds new evidence in the cranial evolution of rhipidistians, and helps to improve our understanding of the character transformations during the early diversification of rhipidistians.

Early Permian radiolarians from Southern Thailand, the deglaciation of Gondwana and the age of the basal Ratburi Group Publication date: Available online 2 July 2019 Source: Palaeoworld Author(s): Hathaithip Thassanapak, Mongkol Udchachon, Jirasak Chareonmit, Clive Burrett Abstract The first radiolarian fauna obtained from Permian carbonates in Thailand is of late Kungurian age and is present in the basal beds of the carbonate–mudstone–chert Phap Pha Formation, Ratburi Group. This succession contains several species of the radiolarian Pseudoalbaillella, and some sponge spicules. The radiolarian fauna consists of abundant Pseudoalbaillella aidensis and P. elegans together with P. fusiformis, P. longtanensis, P. m. rhombothoracata and P. sp. A. Other species include P. cf. aidensis, P. cf. elongata, P. cf. fusiformis, P. cf. ishigai, P. cf. lomentaria, P. cf. longicornis, P. cf. longtanensis, P. cf. ornata, P. cf. simplex, P. cf. m. scalprata, P. cf. m. postscalprata, P. cf. u–forma m. I, P. cf. u–forma m. II, and P. spp. The radiolarian assemblage suggests its correlation to the P. longtanensis Zone which, in turn, is correlated to the P. ishigai Zone of late Kungurian age. The occurrence of an abundant but generically low–diversity radiolarian fauna suggests restricted physical conditions and, with other evidence, suggests deposition along a cool deglaciating or deglaciated continental margin with an abundance of silica possibly provided by glacial meltwaters. The abundant chert in the Phap Pha Formation is part of the widespread Permian Chert Event.

Palaeocupressinoxylon uniseriale n. gen. n. sp., a gymnospermous wood from the upper Permian of Central Taodonggou, southern Bogda Mountains, northwestern China Publication date: Available online 21 June 2019 Source: Palaeoworld Author(s): Ming-Li Wan, Wan Yang, Jun Wang Abstract A silicified wood, Palaeocupressinoxylon uniseriale n. gen. n. sp., is described from the upper Permian of the Central Taodonggou section, Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. Multidisciplinary data including U–Pb ID–TIMS zircon dating, vertebrate and invertebrate biostratigraphic, and cyclostratigraphic correlation from current and previous studies indicate that the fossil bearing interval is Wuchiapingian (late Permian) in age. The pycnoxylic wood consists of thick-walled tracheids and parenchymatous rays. It is characterized by separated uniseriate radial tracheidal pits, uniseriate ray cells, and cupressoid cross-field pitting. The absence of growth rings in the wood, together with the occurrence of Argillisols, Gleysols, and Histosols above and below the fossil interval, suggests that a stable landscape and a perennially humid climate prevailed in the Taodonggou area during the Wuchiapingian.