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  • 1. Fu, Rao
    et al.
    Hu, Yazhou
    Topper, Timothy P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Liu, Fan
    Liang, Yue
    Zhang, Zhifei
    First report of Sphenothallus Hall, 1847 from the lower Cambrian of North China2023Ingår i: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sphenothallus is a tubular organism that is one of the most widely distributed and longest-ranging genera through the Palaeozoic. Despite its apparent cosmopolitan distribution, the genus has never been reported from North China. New specimens of Sphenothallus sp. have been discovered in the upper part of the Houjiashan and base of the Mantou formations (early to middle Age 4, Epoch 2, Cambrian) in Jiangsu Province, North China. The specimens are small tubes (up to 5 mm long) and have typical Sphenothallus characteristics, such as a multilayered lamellar structure, and subcircular to elliptical transverse cross-section with a pair of longitudinal thickenings situated at the widest diameter. Our material shows that both the rate of apertural expansion and the curvature of the tubes are significantly larger in early growth stages than in the later growth stages. As the diameter of the aperture increases, the transverse cross-section of the Sphenothallus sp. tube changes from subcircular at the proximal end to elliptical or lenticular at the distal end, and its wall thickness changes from uniform to thickening longitudinally. The discovery of Sphenothallus sp. from the North China Platform represents an extension of its palaeogeographic range during the Cambrian.

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  • 2.
    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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  • 3. Liang, Yue
    et al.
    Strotz, Luke C.
    Topper, Timothy P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Holmer, Lars E.
    Budd, Graham E.
    Chen, Yanlong
    Fang, Ruisen
    Hu, Yazhou
    Zhang, Zhifei
    Evolutionary contingency in lingulid brachiopods across mass extinctions2023Ingår i: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 33, nr 8, s. 1565-1572.e3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Morphology usually serves as an effective proxy for functional ecology,1,2,3,4,5 and evaluating morphological, anatomical, and ecological changes permits a deeper understanding of the nature of diversification and macroevolution.5,6,7,8,9,10,11,12 Lingulid (order Lingulida) brachiopods are both diverse and abundant during the early Palaeozoic but decrease in diversity over time, with only a few genera of linguloids and discinoids present in modern marine ecosystems, resulting in them frequently being referred to as “living fossils.”13,14,15 The dynamics that drove this decline remain uncertain, and it has not been determined if there is an associated decline in morphological and ecological diversity. Here, we apply geometric morphometrics to reconstruct global morphospace occupation for lingulid brachiopods through the Phanerozoic, with results showing that maximum morphospace occupation was reached by the Early Ordovician. At this time of peak diversity, linguloids with a sub-rectangular shell shape already possessed several evolutionary features, such as the rearrangement of mantle canals and reduction of the pseudointerarea, common to all modern infaunal forms. The end Ordovician mass extinction has a differential effect on linguloids, disproportionally wiping out those forms with a rounded shell shape, while forms with sub-rectangular shells survived both the end Ordovician and the Permian-Triassic mass extinctions, leaving a fauna predominantly composed of infaunal forms. For discinoids, both morphospace occupation and epibenthic life strategies remain consistent through the Phanerozoic. Morphospace occupation over time, when considered using anatomical and ecological analyses, suggests that the limited morphological and ecological diversity of modern lingulid brachiopods reflects evolutionary contingency rather than deterministic processes.

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  • 4. Liu, Fan
    et al.
    Skovsted, Christian B.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Topper, Timothy P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Zhang, Zhifei
    A fresh look at the Hyolithid Doliutheca from the Early Cambrian (Stage 4) Shipai Formation of the Three Gorges Area, Hubei, South China2022Ingår i: Biology, E-ISSN 2079-7737, Vol. 11, nr 6, s. 875-875Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New hyolith specimens from the early Cambrian (Stage 4) of the Three Gorges area, western Hubei Province are described and assigned to the species Doliutheca orientalis. Doliutheca are preserved in two taphonomic modes: casts in silty mudstone revealing gross morphology and some soft parts, and internal molds in calcareous pelites, which exhibit new morphological details of the conch and operculum. SEM and Micro-CT analyses show that Doliutheca preserve well-developed platy clavicles and cardinal processes on the interior of the operculum composed of rod-shaped tubular elements. This observation and the distinct cardinal and conical shields of the operculum indicate that Doliutheca could be placed within the Family Paramicrocornidae, most recently established as a group of hyoliths closely related to hyolithids.

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  • 5.
    Liu, Fan
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Topper, Timothy, P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Zhang, Zhifei
    Department of Geology, Northwest University, Xi’an.
    Shu, Degan
    Are hyoliths Palaeozoic lophophorates?2020Ingår i: National Science Reviews, ISSN 2095-5138, Vol. 7, nr 2, s. 453-469Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The phylogenetic position of hyoliths has long been unsettled, with recent discoveries of a tentaculate feeding apparatus (‘lophophore’) and fleshy apical extensions from the shell (‘pedicle’) suggesting a lophophorate affinity. Here, we describe the first soft parts associated with the feeding apparatus of an orthothecid hyolith, Triplicatella opimus from the Chengjiang biota of South China. The tuft-like arrangement of the tentacles of T. opimus differs from that of hyolithids, suggesting they collected food directly from the substrate. A reassessment of the feeding organ in hyolithids indicates that it does not represent a lophophore and our analysis of the apical structures associated with some orthothecids show that these represent crushed portions of the shell and are not comparable to the brachiopod pedicle. The new information suggests that hyoliths are more likely to be basal members of the lophotrochozoans rather than lophophorates closely linked with the Phylum Brachiopoda.

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  • 6.
    Liu, Fan
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. mState Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments and Department of Geology, Northwest University, Xi’an, 710069, China.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Topper, Timothy
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Zhang, Zhifei
    State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments and Department of Geology, Northwest University, Xi’an, 710069, China.
    Hyolithid-like hyoliths without helens from the early Cambrian of South China, and their implications for the evolution of hyoliths2022Ingår i: BMC Ecology and Evolution, E-ISSN 2730-7182, Vol. 22, nr 1, artikel-id 64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: A small hyolith, with a triangular operculum and a conical-pyramidal conch with a sharp apex, originally documented as Ambrolinevitus ventricosus, is revised based on new material from the Chengjiang biota. The operculum of ‘Ambrolinevitus’ ventricosus displays strong morphological similarities with the operculum of Paramicrocornus from the Shuijingtuo Formation (Cambrian Series 2), indicating that the species should be reassigned to Paramicrocornus.

    Results: Based on the unusual morphology of Paramicrocornus, we herein propose a new family Paramicrocornidae fam. nov. A cladistic analysis of Cambrian and Ordovician hyoliths clearly delineates hyolithids as a monophyletic group which evolved from the paraphyletic orthothecids in the early Cambrian and with Paramicrocornidae as its closest relative.

    Conclusions: The phylogenetic analysis, together with the distribution of hyoliths from the Cambrian to the Ordovician, reveals the presumptive evolution model of both the skeleton and soft-part anatomy of hyoliths. The Family Paramicrocornidae plays an intermediate role in hyolith evolution, representing the transitional stage in the evolution from orthothecids to hyolithids.

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  • 7.
    Skovsted, Christian
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Marti Mus, Monica
    Universidad de Extremadura.
    Zhang, Zhiliang
    Macquarie university.
    Bing, Pan
    Nanjing Institute of Geology & Palaeontology.
    Li, Luoyang
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Liu, Fan
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Li, Guoxiang
    Zhang, Zhifei
    Department of Geology, Northwest University, Xi’an.
    On the origin of hyolith helens2020Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 555, artikel-id 109848Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Helens, the curved lateral spines inserted between the conch and operculum of some hyoliths, are a unique morphological adaptation characterizing the order Hyolithida. These structures are paired, movable and had a mechanical function, probably related to orienting the hyolith conch and lifting its aperture above the sea floor. We show that helens are intimately associated with the hyolith opercula and are structurally comparable to the rod like units that constitute the clavicles, internal wall-like structures of the hyolithid operculum that probably evolved to secure the operculum from lateral displacement in the conch aperture. In some early Cambrian hyolith taxa that lack helens, such as Paramicrocornus, new clavicle rods are added in the gap separating the clavicles from the cardinal processes, the same position where helens are inserted in later hyolithids. We also show that the size of incipient helens at the earliest ontogenetic stage matches the size of the clavicles in associated opercula. We propose that helens are modified clavicle rods that were detached from the operculum and developed into lateral spines through allometric growth during early ontogeny. Further, we suggest a four-step model for the evolution of hyolithid hyoliths from orthothecid ancestors: 1, Externally fitting operculum; 2, Stabilizing, radially arranged structures on the inside of the operculum; 3, Ligula and folded operculum; 4, Detachment of clavicle rods and origin of helens.

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  • 8.
    Topper, Timothy, P.
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Guo, Junfeng
    Clausen, Sébastien
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Zhang, Zhifei
    Department of Geology, Northwest University, Xi’an.
    Reply to ‘Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella’2020Ingår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, artikel-id 1287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently we documented a bilaterally symmetrical, solitary organism, Yanjiahella biscarpa from the early Cambrian (Fortunian) of China1. We interpreted that Y. biscarpa possessed an echinoderm-like plated theca, a muscular stalk similar to hemichordates and a pair of long, feeding appendages. Our interpretation and our phylogenetic analysis suggest that Y. biscarpa is a stem-echinoderm, which would confirm that echinoderms acquired plates before pentaradial symmetry and that their history is firmly rooted in bilateral forms. Zamora et al.2 however, have criticized our interpretation, arguing against an echinoderm affinity, instead suggesting that the phylogenetic placement of Y. biscarpa is dubious and its significance for understanding deuterostome evolution is uncertain.

    This criticism2 seems to stem from our interpretation of particular morphological features in Y. biscarpa1 and the perceived lack of echinoderm synapomorphies. Echinoderms possess a calcitic skeleton with a distinctive three-dimensional mesh-like microstructure called stereom, that is considered a major synapomorphy of the Echinodermata3. Zamora et al.2 highlighted the absence of stereom in Y. biscarpa, additionally stating that we had omitted appropriate methods, specifically latex casting, that may confirm the presence of stereom in our specimens. We concede that initially we did not latex cast any specimens of Y. biscarpa, predominantly due to the fragile nature and the associated risk of damaging the specimens in question. In lieu of latex casting we employed Scanning Electron Microscopy (SEM) to investigate the surface and the details of Y. biscarpa specimens. SEM has been extensively used in the past to study stereom microstructure4,5,6 and if such a microstructure was preserved in Y. biscarpa it would have been detected using this technique.

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  • 9.
    Zhang, Zhifei
    et al.
    Department of Geology, Northwest University, Xi’an.
    Strotz, Luke C.
    Department of Geology, Northwest University, Xi’an.
    Topper, Timothy, P.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Chen, Feiyang
    Department of Geology, Northwest University, Xi’an.
    Chen, Yanlong
    Department of Geology, Northwest University, Xi’an.
    Liang, Yue
    Department of Geology, Northwest University, Xi’an.
    Zhang, Zhiliang
    Macquarie university.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Brock, Glenn, A.
    Macquarie University.
    An encrusting kleptoparasite-host interaction from the early Cambrian2020Ingår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, artikel-id 2625Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Parasite–host systems are pervasive in nature but are extremely difficult to convincingly identify in the fossil record. Here we report quantitative evidence of parasitism in the form of a unique, enduring life association between tube-dwelling organisms encrusted to densely clustered shells of a monospecific organophosphatic brachiopod assemblage from the lower Cambrian (Stage 4) of South China. Brachiopods with encrusting tubes have decreased biomass (indicating reduced fitness) compared to individuals without tubes. The encrusting tubes orient tightly in vectors matching the laminar feeding currents of the host, suggesting kleptoparasitism. With no convincing parasite–host interactions known from the Ediacaran, this widespread sessile association reveals intimate parasite–host animal systems arose in early Cambrian benthic communities and their emergence may have played a key role in driving the evolutionary and ecological innovations associated with the Cambrian radiation.

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  • 10.
    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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  • 11.
    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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  • 12. Zhang, Zhiliang
    et al.
    Zhang, Zhifei
    Ma, Junye
    Taylor, Paul D.
    Strotz, Luke C.
    Jacquet, Sarah M.
    Skovsted, Christian
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Chen, Feiyang
    Han, Jian
    Brock, Glenn, A.
    Macquarie University.
    Fossil evidence unveils an early Cambrian origin for Bryozoa2021Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 599, nr 7884, s. 251-255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bryozoans (also known as ectoprocts or moss animals) are aquatic, dominantly sessile, filter-feeding lophophorates that construct an organic or calcareous modular colonial (clonal) exoskeleton. The presence of six major orders of bryozoans with advanced polymorphisms in lower Ordovician rocks strongly suggests a Cambrian origin for the largest and most diverse lophophorate phylum. However, a lack of convincing bryozoan fossils from the Cambrian period has hampered resolution of the true origins and character assembly of the earliest members of the group. Here we interpret the millimetric, erect, bilaminate, secondarily phosphatized fossil Protomelission gatehousei from the early Cambrian of Australia and South China as a potential stem-group bryozoan. The monomorphic zooid capsules, modular construction, organic composition and simple linear budding growth geometry represent a mixture of organic Gymnolaemata and biomineralized Stenolaemata character traits, with phylogenetic analyses identifying P. gatehousei as a stem-group bryozoan. This aligns the origin of phylum Bryozoa with all other skeletonized phyla in Cambrian Age 3, pushing back its first occurrence by approximately 35 million years. It also reconciles the fossil record with molecular clock estimations of an early Cambrian origination and subsequent Ordovician radiation of Bryozoa following the acquisition of a carbonate skeleton.

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