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Chen A, Vannier J, Guo J, Wang D, Gąsiorek P, Han J, Ma W. Molting in early Cambrian armored lobopodians. Commun Biol 2024; 7:820. [PMID: 38969778 PMCID: PMC11226638 DOI: 10.1038/s42003-024-06440-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 06/11/2024] [Indexed: 07/07/2024] Open
Abstract
Lobopodians represent a key step in the early history of ecdysozoans since they were the first animals to evolve legs within this clade. Their Cambrian representatives share a similar body plan with a typically cylindrical annulated trunk and a series of non-jointed legs. However, they do not form a monophyletic group and likely include ancestors of the three extant panarthropod lineages (Tardigrada, Onychophora, Euarthropoda). Some species display astonishing protective devices such as cuticular plates and spines. We describe here the armor and molting process of Microdictyon from the early Cambrian of China. Microdictyon secreted ovoid paired cuticular sclerites that were duplicated in a non-synchronous way along the animal's body. The reticulated pattern and cuticular architecture of these sclerites have similarities to extant armored tardigrades that recently served in hypothesizing that tardigrades are possibly miniaturized lobopodians. Ecdysis and hard cuticular protection are now well documented in the whole spectrum of early Cambrian ecdysozoans such as soft-bodied scalidophorans, lobopodians and fully articulated euarthropods. We hypothesize that the secretion of sclerotized cuticular elements periodically renewed via ecdysis was a key innovation that opened large-scale evolutionary opportunities to invertebrate animal life, specifically ecdysozoans, both in terms of anatomical functionalities and ecological success.
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Affiliation(s)
- Ailin Chen
- Research Centre of Palaeobiology, Yuxi Normal University, 653100, Yuxi, China.
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 210008, Nanjing, China.
| | - Jean Vannier
- Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Université de Lyon, Université Claude Bernard Lyon 1, ENS de Lyon, CNRS, Villeurbanne, 69622, France.
| | - Jin Guo
- Chengjiang Science Museum, Management Committee of the Chengjiang Fossil Site World Heritage, 652500, Chengjiang, China
| | - Deng Wang
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, 710069, Xi'an, China
| | - Piotr Gąsiorek
- Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Universitetsparken 15, DK-2100, Copenhagen, Denmark
- Department of Invertebrate Evolution, Faculty of Biology, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland
| | - Jian Han
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, 710069, Xi'an, China
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Park TYS, Nielsen ML, Parry LA, Sørensen MV, Lee M, Kihm JH, Ahn I, Park C, de Vivo G, Smith MP, Harper DAT, Nielsen AT, Vinther J. A giant stem-group chaetognath. SCIENCE ADVANCES 2024; 10:eadi6678. [PMID: 38170772 PMCID: PMC10796117 DOI: 10.1126/sciadv.adi6678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today.
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Affiliation(s)
- Tae-Yoon S. Park
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Morten Lunde Nielsen
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- School of Earth Sciences, Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- British Geological Survey, Nicker Hill, Keyworth NG12 5GG, UK
| | - Luke A. Parry
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | | | - Mirinae Lee
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Ji-Hoon Kihm
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Inhye Ahn
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Changkun Park
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Giacinto de Vivo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - M. Paul Smith
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
| | - David A. T. Harper
- Palaeoecosystems Group, Department of Earth Sciences, Durham University, Durham DH1 3LE, UK
| | - Arne T. Nielsen
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, Copenhagen DK-1350, Denmark
| | - Jakob Vinther
- School of Earth Sciences, Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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Martynov AV, Korshunova TA. Renewed perspectives on the sedentary-pelagic last common bilaterian ancestor. CONTRIBUTIONS TO ZOOLOGY 2022. [DOI: 10.1163/18759866-bja10034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Various evaluations of the last common bilaterian ancestor (lcba) currently suggest that it resembled either a microscopic, non-segmented motile adult; or, on the contrary, a complex segmented adult motile urbilaterian. These fundamental inconsistencies remain largely unexplained. A majority of multidisciplinary data regarding sedentary adult ancestral bilaterian organization is overlooked. The sedentary-pelagic model is supported now by a number of novel developmental, paleontological and molecular phylogenetic data: (1) data in support of sedentary sponges, in the adult stage, as sister to all other Metazoa; (2) a similarity of molecular developmental pathways in both adults and larvae across sedentary sponges, cnidarians, and bilaterians; (3) a cnidarian-bilaterian relationship, including a unique sharing of a bona fide Hox-gene cluster, of which the evolutionary appearance does not connect directly to a bilaterian motile organization; (4) the presence of sedentary and tube-dwelling representatives of the main bilaterian clades in the early Cambrian; (5) an absence of definite taxonomic attribution of Ediacaran taxa reconstructed as motile to any true bilaterian phyla; (6) a similarity of tube morphology (and the clear presence of a protoconch-like apical structure of the Ediacaran sedentary Cloudinidae) among shells of the early Cambrian, and later true bilaterians, such as semi-sedentary hyoliths and motile molluscs; (7) recent data that provide growing evidence for a complex urbilaterian, despite a continuous molecular phylogenetic controversy. The present review compares the main existing models and reconciles the sedentary model of an urbilaterian and the model of a larva-like lcba with a unified sedentary(adult)-pelagic(larva) model of the lcba.
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Affiliation(s)
- Alexander V. Martynov
- Zoological Museum, Moscow State University, Bolshaya Nikitskaya Str. 6, 125009 Moscow, Russia,
| | - Tatiana A. Korshunova
- Koltzov Institute of Developmental Biology RAS, 26 Vavilova Str., 119334 Moscow, Russia
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Caron JB, Cheung B. Amiskwia is a large Cambrian gnathiferan with complex gnathostomulid-like jaws. Commun Biol 2019; 2:164. [PMID: 31069273 PMCID: PMC6499802 DOI: 10.1038/s42003-019-0388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/15/2019] [Indexed: 11/12/2022] Open
Abstract
Phylogenomic studies have greatly improved our understanding of the animal tree of life but the relationships of many clades remain ambiguous. Here we show that the rare soft-bodied animal Amiskwia from the Cambrian of Canada and China, which has variously been considered a chaetognath, a nemertine, allied to molluscs, or a problematica, is related to gnathiferans. New specimens from the Burgess Shale (British Columbia, Canada) preserve a complex pharyngeal jaw apparatus composed of a pair of elements with teeth most similar to gnathostomulids. Amiskwia demonstrates that primitive spiralians were large and unsegmented, had a coelom, and were probably active nekto-benthic scavengers or predators. Secondary simplification and miniaturisation events likely occurred in response to shifting ecologies and adaptations to specialised planktonic habitats.
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Affiliation(s)
- Jean-Bernard Caron
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2 Canada
- Department of Natural History—Palaeobiology, Royal Ontario Museum, 100 Queen’s Park, Toronto, ON M5S 2C6 Canada
- Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1 Canada
| | - Brittany Cheung
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2 Canada
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Vinther J, Parry LA. Bilateral Jaw Elements in Amiskwia sagittiformis Bridge the Morphological Gap between Gnathiferans and Chaetognaths. Curr Biol 2019; 29:881-888.e1. [PMID: 30799238 DOI: 10.1016/j.cub.2019.01.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/28/2018] [Accepted: 01/21/2019] [Indexed: 01/10/2023]
Abstract
Amiskwia sagittiformis Walcott 1911 is an iconic soft-bodied taxon from the Burgess Shale [1-3]. It was originally interpreted as a chaetognath [1], but it was later interpreted as a pelagic nemertean [2] or considered of uncertain affinity [3]. Part of this ambiguity is due to direct comparisons with members of the crown groups of extant phyla [4] and a lack of clarity regarding the systematic position of chaetognaths, which would allow for assessing character polarity in the phylum with respect to outgroups. Here, we show that Amiskwia preserves a bilaterally arranged set of head structures visible in relief and high reflectivity. These structures are best interpreted as jaws situated within an expanded pharyngeal complex. Morphological studies have highlighted a likely homology between bilateral and chitinous jaw elements in gnathiferans and chaetognaths [5], which is congruent with a shared unique Hox gene that suggests a close relationship between Gnathifera and Chaetognatha [6]. Molecular phylogenetic studies have recently found gnathiferans to be a deep branch of Spiralia and Chaetognaths either a sister group to Spiralia [7] or forming a clade with gnathiferans [6, 8]. Our phylogenetic analyses render Gnathifera paraphyletic with respect to Chaetognatha, and we therefore suggest that Amiskwia is best interpreted as a stem chaetognath, but crown gnathiferan.
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Affiliation(s)
- Jakob Vinther
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK; School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
| | - Luke A Parry
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK; Department of Geology and Geophysics, Yale University, 210 Whitney Ave., New Haven, Connecticut 06511, USA
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A New Spiralian Phylogeny Places the Enigmatic Arrow Worms among Gnathiferans. Curr Biol 2019; 29:312-318.e3. [PMID: 30639106 DOI: 10.1016/j.cub.2018.11.042] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/12/2018] [Accepted: 11/14/2018] [Indexed: 11/23/2022]
Abstract
Chaetognaths (arrow worms) are an enigmatic group of marine animals whose phylogenetic position remains elusive, in part because they display a mix of developmental and morphological characters associated with other groups [1, 2]. In particular, it remains unclear whether they are a sister group to protostomes [1, 2], one of the principal animal superclades, or whether they bear a closer relationship with some spiralian phyla [3, 4]. Addressing the phylogenetic position of chaetognaths and refining our understanding of relationships among spiralians are essential to fully comprehend character changes during bilaterian evolution [5]. To tackle these questions, we generated new transcriptomes for ten chaetognath species, compiling an extensive phylogenomic dataset that maximizes data occupancy and taxonomic representation. We employed inference methods that consider rate and compositional heterogeneity across taxa to avoid limitations of earlier analyses [6]. In this way, we greatly improved the resolution of the protostome tree of life. We find that chaetognaths cluster together with rotifers, gnathostomulids, and micrognathozoans within an expanded Gnathifera clade and that this clade is the sister group to other spiralians [7, 8]. Our analysis shows that several previously proposed groupings are likely due to systematic error, and we propose a revised organization of Lophotrochozoa with three main clades: Tetraneuralia (mollusks and entoprocts), Lophophorata (brachiopods, phoronids, and ectoprocts), and a third unnamed clade gathering annelids, nemerteans, and platyhelminthes. Consideration of classical morphological, developmental, and genomic characters in light of this topology indicates secondary loss as a fundamental trend in spiralian evolution.
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Parry LA, Smithwick F, Nordén KK, Saitta ET, Lozano-Fernandez J, Tanner AR, Caron JB, Edgecombe GD, Briggs DEG, Vinther J. Soft-Bodied Fossils Are Not Simply Rotten Carcasses - Toward a Holistic Understanding of Exceptional Fossil Preservation. Bioessays 2017; 40. [DOI: 10.1002/bies.201700167] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/21/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Luke A. Parry
- School of Earth Sciences, University of Bristol, Wills Memorial Building; Queen's Road Bristol BS8 1RJ UK
- Royal Ontario Museum; 100 Queen's Park Toronto ON M5S 2C6 Canada
- Department of Earth Sciences, The Natural History Museum; Cromwell Road London SW7 5BD UK
| | - Fiann Smithwick
- Royal Ontario Museum; 100 Queen's Park Toronto ON M5S 2C6 Canada
| | - Klara K. Nordén
- Royal Ontario Museum; 100 Queen's Park Toronto ON M5S 2C6 Canada
| | - Evan T. Saitta
- Royal Ontario Museum; 100 Queen's Park Toronto ON M5S 2C6 Canada
| | - Jesus Lozano-Fernandez
- School of Biological Sciences, University of Bristol; Life Sciences Building, 24 Tyndall Avenue Bristol BS8 1TQ UK
| | - Alastair R. Tanner
- School of Biological Sciences, University of Bristol; Life Sciences Building, 24 Tyndall Avenue Bristol BS8 1TQ UK
| | - Jean-Bernard Caron
- School of Earth Sciences, University of Bristol, Wills Memorial Building; Queen's Road Bristol BS8 1RJ UK
| | - Gregory D. Edgecombe
- Department of Earth Sciences, The Natural History Museum; Cromwell Road London SW7 5BD UK
| | - Derek E. G. Briggs
- Department of Geology and Geophysics, Yale University; 210 Whitney Avenue New Haven CT 06511 USA
- Yale Peabody Museum of Natural History; 170 Whitney Avenue New Haven CT 06520 USA
- Departments of Ecology and Evolutionary Biology and Earth Sciences, University of Toronto; Toronto ON M5S 3B2 Canada
| | - Jakob Vinther
- School of Earth Sciences, University of Bristol, Wills Memorial Building; Queen's Road Bristol BS8 1RJ UK
- Royal Ontario Museum; 100 Queen's Park Toronto ON M5S 2C6 Canada
- School of Biological Sciences, University of Bristol; Life Sciences Building, 24 Tyndall Avenue Bristol BS8 1TQ UK
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