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  • 1.
    Bing, Pan
    et al.
    Nanjing Institute of Geology & Palaeontology.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Brock, Glenn, A.
    Macquarie University.
    Topper, Timothy, P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Holmer, Lars, E.
    Uppsala Universitet.
    Li, Luoyang
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Li, Guoxiang
    Nanjing Institute of Geology and Palaeontology.
    Early Cambrian organophosphatic brachiopods from the Xinji Formation, at Shuiyu section, Shanxi Province, North China2020Ingår i: Palaeoworld, ISSN 1871-174X, E-ISSN 1875-5887, Vol. 29, s. 512-533Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abundant and diverse small shelly fossils have been reported from 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.

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  • 2.
    Claybourn, Thomas M.
    et al.
    Uppsala Universitet.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Holmer, Lars, E.
    Uppsala Universitet.
    Bing, Pan
    Nanjing Institute of Geology & Palaeontology.
    Myrow, Paul M.
    Department of Geology, Colorado College.
    Topper, Timothy, P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Brock, Glenn, A.
    Macquarie University.
    BRACHIOPODS FROM THE BYRD GROUP (CAMBRIAN SERIES 2, STAGE 4) CENTRAL TRANSANTARCTIC MOUNTAINS, EAST ANTARCTICA: BIOSTRATIGRAPHY, PHYLOGENY AND SYSTEMATICS2020Ingår i: Papers in Palaeontology, ISSN 2056-2799, E-ISSN 2056-2802, Vol. 6, nr 3, s. 349-383Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Brachiopods from Cambrian Series 2, Stage 4 carbonate strata of the Byrd Group in the Central Transantarctic Mountains, East Antarctica, are described for the first time. These include six lingulate, one paterinate, and one rhynchonelliform taxa, including the new lingulate brachiopod Plicarmus wildi gen. et sp. nov. The biostratigraphy correlates closely to the brachiopods recently reported from the Xinji Formation (Shuiyu section) in North China, as well as brachiopods recovered from the Dailyatia odyssei Zone across the Arrowie Basin of South Australia. These findings also support the previously identified close palaeobiogeography of these regions. The first unambiguous example of the acrotretid brachiopod Eohadrotreta zhenbaensis Li and Holmer outside South China is also identified in the context of its ontogenetic stages. Well preserved specimens of the acrotheloid Schizopholis yorkensis (Holmer and Ushatinskaya in Gravestock et al.) facilitates a new reconstruction of its musculature and visceral region. This data is synthesised into a new cladistic analysis that resolves Acrotheloidea as a well-supported monophyletic clade and supports previous hypotheses of a morphocline in acrotheloid evolution.

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  • 3.
    Liang, Yue
    et al.
    Department of Geology, Northwest University, Xi’an.
    Holmer, Lars, E.
    Uppsala Universitet.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Duan, Xiao-Lin
    Department of Geology, Northwest University, Xi’an.
    Zhang, Zhifei
    Department of Geology, Northwest University, Xi’an.
    Shell structure, ornamentation and affinity of the problematic early Cambrian brachiopod Heliomedusa orienta2020Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 53, nr 4, s. 574-587Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The origin of the Brachiopoda has long been a hotly debated topic, and various models have been proposed following the latest finds of exceptionally preserved material. The lower Cambrian (Stage 3) Heliomedusa orienta from the Chengjiang Konservat‐Lagerstätte, eastern Yunnan of South China, is an important example of exceptional preservation. A wide variety of affinities have been proposed for Heliomedusa, but recently it has been suggested to reside within the mickwitziids, which may form a stem group to the Brachiopoda. Detailed studies of exceptionally preserved Heliomedusa have increased our knowledge of the soft‐part anatomy of this important early brachiopod, but unfortunately, almost nothing is known about its shell structure. Here, we describe new exceptionally preserved specimens from the Chengjiang biota to better reveal both shell structure and ornamentation. Its reticulate–pustulose ornament and tubular structure are reminiscent of traits seen in other mickwitziid brachiopods. In addition, two types of setae can be observed. Apart from the pyritized marginal mantle setae, some tubules are filled with iron oxides, potentially representing thinner and shorter penetrative setae. Both valves of H. orienta appear to have been less mineralized as compared to Mickwitzia monilifera, and the two species differ in diameter and density of tubules and pustules, and in terms of slightly less projected profile of ventral valve with lower umbo posteromedially placed. Although Heliomedusa clearly is closely related to Mickwitzia, their different preservational modes (compacted poorly mineralized/noncompacted mineralized) make detailed comparison difficult; they are provisionally kept as separate genera pending further studies of better‐preserved Chinese material.

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  • 4. Teece, Bronwyn L.
    et al.
    Brock, Glenn, A.
    Macquarie University.
    Paterson, John, R.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Holmer, Lars, E.
    Uppsala Universitet.
    George, Simon C.
    Using laser micropyrolysis to assess potential relationships between Cambrian tommotiids and organophosphatic brachiopods2021Ingår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 158, s. 105277-105277, artikel-id 105277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Laser micropyrolysis gas chromatography-mass spectrometry enables researchers to selectively obtain chemical information about the organic matter in specific parts of a variety of specimens, such as coals and fossils, in order to elucidate chemical composition. This paper briefly reviews the history of this type of pyrolysis and examines whether the technique can be used to isolate and recover biogeochemical signatures directly from the mineralised organophosphatic sclerites of Cambrian tommotiids—a group of enigmatic lophotrochozoans—and potentially related organophosphatic brachiopods. We analysed specimens of two tommotiids (Micrina etheridgei and Dailyatia sp.) and the paterinate brachiopod Askepasma toddense from the lower Cambrian of South Australia. Pyrolysate hydrocarbons from the sclerites of these species were detected and compared. Results indicate that A. toddense is more chemically complex than either of the two tommotiid taxa, but that M. etheridgei is compositionally more similar to A. toddense. Importantly, this study has demonstrated that laser micropyrolysis gas chromatography-mass spectrometry of Cambrian organophosphatic small shelly fossils yields detectable pyrolysates that have geochemical significance. It will be analytically possible and useful in the future to apply this technique to a larger sample set to elucidate deep time biogeochemical homologies, and to test intra-shell heterogeneity.

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  • 5.
    Zhang, Zhiliang
    et al.
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China;Department of Biological Sciences Macquarie University Sydney NSW 2109 Australia;Institute of Earth Sciences, Palaeobiology Uppsala University SE‐752 36 Uppsala Sweden.
    Topper, Timothy P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China;Department of Palaeobiology Swedish Museum of Natural History Box 50007 SE‐104 05 Stockholm Sweden.
    Chen, Yanlong
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China.
    Strotz, Luke C.
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China.
    Chen, Feiyang
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China;Department of Biological Sciences Macquarie University Sydney NSW 2109 Australia.
    Holmer, Lars E.
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China;Institute of Earth Sciences, Palaeobiology Uppsala University SE‐752 36 Uppsala Sweden.
    Brock, Glenn A.
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China;Department of Biological Sciences Macquarie University Sydney NSW 2109 Australia.
    Zhang, Zhifei
    State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China.
    Go large or go conical: allometric trajectory of an early Cambrian acrotretide brachiopod2021Ingår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 64, nr 5, s. 727-741Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Acrotretides are extinct micromorphic brachiopods that exhibited considerable morphological variation during their rapid evolution in the early Palaeozoic. The plano-conical shells of acrotretides are distinct in comparison to other brachiopod groups and despite their diversity and abundance in early Palaeozoic communities, their origins, early evolution, life history and phylogeny are poorly understood. Here, we employ advanced geometric morphometrics to quantitatively investigate ontogenetic variation and allometry in the ventral valve of the oldest known acrotretide species from the early Cambrian of South China. Our results identify substantial shape variation for Eohadrotreta zhenbaensis, along with a parabolic morphological trajectory through ontogeny, demonstrating a remarkable reversal to PC1 values equivalent to those obtained for juveniles, during later ontogenetic stages. The evolutionary novel body plan (diminutive and plano-conical) of Acrotretida was established gradually during two phases of allometry, formed initially during the final stage of the Cambrian evolutionary radiation from an ancestral low, equivalved lingulide body plan. The development of a conical shaped valve seems to have resulted in an overall smaller body size, when compared with non-conical forms. The heterochronic processes responsible for generating these ontogenetic modifications at different allometric phases may have facilitated the evolutionary diversification of acrotretide brachiopods during the early Palaeozoic.

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  • 6.
    Zhang, Zhiliang
    et al.
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China;School of Natural Sciences, Macquarie University, NSW 2109, Australia.
    Zhang, Zhifei
    State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments, Department of Geology, Northwest University, Xi’an, 710069, China.
    Holmer, Lars E.
    Institute of Earth Sciences, Palaeobiology, Uppsala University, SE-752 36 Uppsala, Sweden.
    Topper, Timothy P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Pan, Bing
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Li, Guoxiang
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods2023Ingår i: eLIFE, E-ISSN 2050-084XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biologically-controlled mineralization producing organic-inorganic composites (hard skeletons) by metazoan biomineralizers has been an evolutionary innovation since the earliest Cambrian. Among them, linguliform brachiopods are one of the key invertebrates that secrete calcium phosphate minerals to build their skeletons. One of the most distinct shell structures is the organo-phosphatic cylindrical column exclusive to phosphatic-shelled brachiopods, including both crown and stem groups. However, the complexity, diversity and biomineralization processes of these microscopic columns are far from clear in brachiopod ancestors. Here, exquisitely well-preserved columnar shell ultrastructures are reported for the first time in the earliest eoobolids. The hierarchical shell architectures, epithelial cell moulds, and the shape and size of cylindrical columns are scrutinised in Latusobolus xiaoyangbaensis gen. et sp. nov. and Eoobolus acutulus sp. nov from the Cambrian Series 2 Shuijingtuo Formation of South China. The secretion and construction of the stacked sandwich model of columnar architecture, which played a significant role in the evolution of linguliforms, is highly biologically controlled and organic-matrix mediated. Furthermore, a continuous transformation of anatomic features resulting from the growth of columnar shells is revealed between Eoobolidae, Lingulellotretidae and Acrotretida, shedding new light on the evolutionary growth and adaptive innovation of biomineralized columnar architecture among early phosphatic-shelled brachiopods during the Cambrian explosion.

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