1
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Poulhazan A, Baer A, Daliaho G, Mentink-Vigier F, Arnold AA, Browne DC, Hering L, Archer-Hartmann S, Pepi LE, Azadi P, Schmidt S, Mayer G, Marcotte I, Harrington MJ. Peculiar Phosphonate Modifications of Velvet Worm Slime Revealed by Advanced Nuclear Magnetic Resonance and Mass Spectrometry. J Am Chem Soc 2023; 145:20749-20754. [PMID: 37722679 PMCID: PMC10540779 DOI: 10.1021/jacs.3c06798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Indexed: 09/20/2023]
Abstract
Nature is rich with examples of highly specialized biological materials produced by organisms for functions, including defense, hunting, and protection. Along these lines, velvet worms (Onychophora) expel a protein-based slime used for hunting and defense that upon shearing and dehydration forms fibers as stiff as thermoplastics. These fibers can dissolve back into their precursor proteins in water, after which they can be drawn into new fibers, providing biological inspiration to design recyclable materials. Elevated phosphorus content in velvet worm slime was previously observed and putatively ascribed to protein phosphorylation. Here, we show instead that phosphorus is primarily present as phosphonate moieties in the slime of distantly related velvet worm species. Using high-resolution nuclear magnetic resonance (NMR), natural abundance dynamic nuclear polarization (DNP), and mass spectrometry (MS), we demonstrate that 2-aminoethyl phosphonate (2-AEP) is associated with glycans linked to large slime proteins, while transcriptomic analyses confirm the expression of 2-AEP synthesizing enzymes in slime glands. The evolutionary conservation of this rare protein modification suggests an essential functional role of phosphonates in velvet worm slime and should stimulate further study of the function of this unusual chemical modification in nature.
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Affiliation(s)
- Alexandre Poulhazan
- Department
of Chemistry, Université du Québec
à Montréal, Montreal, Quebec H2X 2J6, Canada
| | - Alexander Baer
- Department
of Zoology, Institute of Biology, University
of Kassel, Kassel D-34132, Germany
| | - Gagan Daliaho
- Department
of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | | | - Alexandre A. Arnold
- Department
of Chemistry, Université du Québec
à Montréal, Montreal, Quebec H2X 2J6, Canada
| | - Darren C. Browne
- Department
of Biological and Chemical Sciences, University
of the West Indies, Cave Hill Campus, Barbados BB11000, West Indies
| | - Lars Hering
- Department
of Zoology, Institute of Biology, University
of Kassel, Kassel D-34132, Germany
| | | | - Lauren E. Pepi
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Parastoo Azadi
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Stephan Schmidt
- Chemistry
Department, Heinrich-Heine-Universität
Düsseldorf, Düsseldorf D-40225, Germany
| | - Georg Mayer
- Department
of Zoology, Institute of Biology, University
of Kassel, Kassel D-34132, Germany
| | - Isabelle Marcotte
- Department
of Chemistry, Université du Québec
à Montréal, Montreal, Quebec H2X 2J6, Canada
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2
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Kihm JH, Smith FW, Kim S, Rho HS, Zhang X, Liu J, Park TYS. Cambrian lobopodians shed light on the origin of the tardigrade body plan. Proc Natl Acad Sci U S A 2023; 120:e2211251120. [PMID: 37399417 PMCID: PMC10334802 DOI: 10.1073/pnas.2211251120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 05/22/2023] [Indexed: 07/05/2023] Open
Abstract
Phylum Tardigrada (water bears), well known for their cryptobiosis, includes small invertebrates with four paired limbs and is divided into two classes: Eutardigrada and Heterotardigrada. The evolutionary origin of Tardigrada is known to lie within the lobopodians, which are extinct soft-bodied worms with lobopodous limbs mostly discovered at sites of exceptionally well-preserved fossils. Contrary to their closest relatives, onychophorans and euarthropods, the origin of morphological characters of tardigrades remains unclear, and detailed comparison with the lobopodians has not been well explored. Here, we present detailed morphological comparison between tardigrades and Cambrian lobopodians, with a phylogenetic analysis encompassing most of the lobopodians and three panarthropod phyla. The results indicate that the ancestral tardigrades likely had a Cambrian lobopodian-like morphology and shared most recent ancestry with the luolishaniids. Internal relationships within Tardigrada indicate that the ancestral tardigrade had a vermiform body shape without segmental plates, but possessed cuticular structures surrounding the mouth opening, and lobopodous legs terminating with claws, but without digits. This finding is in contrast to the long-standing stygarctid-like ancestor hypothesis. The highly compact and miniaturized body plan of tardigrades evolved after the tardigrade lineage diverged from an ancient shared ancestor with the luolishaniids.
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Affiliation(s)
- Ji-Hoon Kihm
- Division of Earth Sciences, Korea Polar Research Institute, Yeonsu-gu, Incheon21990, Korea
| | - Frank W. Smith
- Department of Biology, University of North Florida, Jacksonville, FL32224
| | - Sanghee Kim
- Division of Life Sciences, Korea Polar Research Institute, Yeonsu-gu, Incheon21990, Korea
| | - Hyun Soo Rho
- East Sea Environment Research Center, East Sea Research Institute, Korea Institute of Ocean Science and Technology, Uljin, Gyeongsangbuk-do36315, Korea
| | - Xingliang Zhang
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, Xi’an710069, China
| | - Jianni Liu
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, Xi’an710069, China
| | - Tae-Yoon S. Park
- Division of Earth Sciences, Korea Polar Research Institute, Yeonsu-gu, Incheon21990, Korea
- Polar Science, University of Science and Technology, Yuseong-gu, Daejeon34113, Korea
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3
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Jahn H, Hammel JU, Göpel T, Wirkner CS, Mayer G. A multiscale approach reveals elaborate circulatory system and intermittent heartbeat in velvet worms (Onychophora). Commun Biol 2023; 6:468. [PMID: 37117786 PMCID: PMC10147947 DOI: 10.1038/s42003-023-04797-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 04/03/2023] [Indexed: 04/30/2023] Open
Abstract
An antagonistic hemolymph-muscular system is essential for soft-bodied invertebrates. Many ecdysozoans (molting animals) possess neither a heart nor a vascular or circulatory system, whereas most arthropods exhibit a well-developed circulatory system. How did this system evolve and how was it subsequently modified in panarthropod lineages? As the closest relatives of arthropods and tardigrades, onychophorans (velvet worms) represent a key group for addressing this question. We therefore analyzed the entire circulatory system of the peripatopsid Euperipatoides rowelli and discovered a surprisingly elaborate organization. Our findings suggest that the last common ancestor of Onychophora and Arthropoda most likely possessed an open vascular system, a posteriorly closed heart with segmental ostia, a pericardial sinus filled with nephrocytes and an impermeable pericardial septum, whereas the evolutionary origin of plical and pericardial channels is unclear. Our study further revealed an intermittent heartbeat-regular breaks of rhythmic, peristaltic contractions of the heart-in velvet worms, which might stimulate similar investigations in arthropods.
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Affiliation(s)
- Henry Jahn
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany.
| | - Jörg U Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon at DESY, Notkestraße 85, D-22607, Hamburg, Germany
| | - Torben Göpel
- Multiscale Biology, Johann-Friedrich-Blumenbach Institut für Zoologie und Anthropologie, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077, Göttingen, Germany
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
| | - Christian S Wirkner
- Institut für Allgemeine und Spezielle Zoologie, Institut für Biowissenschaften, Universität Rostock, Universitätsplatz 2, D-18055, Rostock, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
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4
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Strausfeld NJ, Hou X, Sayre ME, Hirth F. The lower Cambrian lobopodian Cardiodictyon resolves the origin of euarthropod brains. Science 2022; 378:905-909. [PMID: 36423269 DOI: 10.1126/science.abn6264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
For more than a century, the origin and evolution of the arthropod head and brain have eluded a unifying rationale reconciling divergent morphologies and phylogenetic relationships. Here, clarification is provided by the fossilized nervous system of the lower Cambrian lobopodian Cardiodictyon catenulum, which reveals an unsegmented head and brain comprising three cephalic domains, distinct from the metameric ventral nervous system serving its appendicular trunk. Each domain aligns with one of three components of the foregut and with a pair of head appendages. Morphological correspondences with stem group arthropods and alignments of homologous gene expression patterns with those of extant panarthropods demonstrate that cephalic domains of C. catenulum predate the evolution of the euarthropod head yet correspond to neuromeres defining brains of living chelicerates and mandibulates.
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Affiliation(s)
| | - Xianguang Hou
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
| | - Marcel E Sayre
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Frank Hirth
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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5
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Wang X, Vannier J, Yang X, Leclère L, Ou Q, Song X, Komiya T, Han J. Muscle systems and motility of early animals highlighted by cnidarians from the basal Cambrian. eLife 2022; 11:74716. [PMID: 35098925 PMCID: PMC8837203 DOI: 10.7554/elife.74716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/11/2022] [Indexed: 12/02/2022] Open
Abstract
Although fossil evidence suggests that various animal groups were able to move actively through their environment in the early stages of their evolution, virtually no direct information is available on the nature of their muscle systems. The origin of jellyfish swimming, for example, is of great interest to biologists. Exceptionally preserved muscles are described here in benthic peridermal olivooid medusozoans from the basal Cambrian of China (Kuanchuanpu Formation, ca. 535 Ma) that have direct equivalent in modern medusozoans. They consist of circular fibers distributed over the bell surface (subumbrella) and most probably have a myoepithelial origin. This is the oldest record of a muscle system in cnidarians and more generally in animals. This basic system was probably co-opted by early Cambrian jellyfish to develop capacities for jet-propelled swimming within the water column. Additional lines of fossil evidence obtained from ecdysozoans (worms and panarthropods) show that the muscle systems of early animals underwent a rapid diversification through the early Cambrian and increased their capacity to colonize a wide range of habitats both within the water column and sediment at a critical time of their evolutionary radiation.
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Affiliation(s)
- Xing Wang
- China Geological Survey, Qingdao Institute of Marine Geology, Qingdao, China
| | - Jean Vannier
- CNRS UMR 5276, Laboratoire de géologie de Lyon, Claude Bernard University Lyon 1, Lyon, France
| | - Xiaoguang Yang
- Department of Geology, Northwest University, Xi'an, China
| | - Lucas Leclère
- CNRS, Laboratoire de Biologie du Développement, Sorbonne Université, Villefranche-sur-mer, France
| | - Qiang Ou
- Early Life Evolution Laboratory, School of Earth Sciences and Resources, China University of Geosciences, Beijing, China
| | - Xikun Song
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Tsuyoshi Komiya
- Department of Earth Science and Astronomy, University of Tokyo, Tokyo, Japan
| | - Jian Han
- Department of Geology, Northwest University, Xi'an, China
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6
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Edgecombe GD. Arthropod Origins: Integrating Paleontological and Molecular Evidence. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-011720-124437] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Phylogenomics underpins a stable and mostly well-resolved hypothesis for the interrelationships of extant arthropods. Exceptionally preserved fossils are integrated into this framework by coding their morphological characters, as exemplified by total-evidence dating approaches that treat fossils as dated tips in analyses numerically dominated by molecular data. Cambrian fossils inform on the sequence of character acquisition in the arthropod stem group and in the stems of its main extant clades. The arthropod head problem incorporates unique appendage combinations and remains of the nervous system in fossils into a scheme mostly based on neuroanatomy and Hox expression domains for extant forms. Molecular estimates of arthropod origins in the Cryogenian or Ediacaran predate a coherent picture from the arthropod fossil record, which commences as trace fossils in the earliest Cambrian. Probabilistic morphological clock analysis of trilobites, which exemplify the earliest arthropod body fossils, supports a Cambrian origin, without the need to posit an unfossilized Ediacaran history.
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Affiliation(s)
- Gregory D. Edgecombe
- Department of Earth Sciences, The Natural History Museum, London SW7 5BD, United Kingdom
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7
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Howard RJ, Hou X, Edgecombe GD, Salge T, Shi X, Ma X. A Tube-Dwelling Early Cambrian Lobopodian. Curr Biol 2020; 30:1529-1536.e2. [PMID: 32109391 DOI: 10.1016/j.cub.2020.01.075] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 12/09/2019] [Accepted: 01/24/2020] [Indexed: 01/27/2023]
Abstract
Facivermis yunnanicus [1, 2] is an enigmatic worm-like animal from the early Cambrian Chengjiang Biota of Yunnan Province, China. It is a small (<10 cm) bilaterian with five pairs of spiny anterior arms, an elongated body, and a swollen posterior end. The unusual morphology of Facivermis has prompted a history of diverse taxonomic interpretations, including among annelids [1, 3], lophophorates [4], and pentastomids [5]. However, in other studies, Facivermis is considered to be more similar to lobopodians [2, 6-8]-the fossil grade from which modern panarthropods (arthropods, onychophorans, and tardigrades) are derived. In these studies, Facivermis is thought to be intermediate between cycloneuralian worms and lobopodians. Facivermis has therefore been suggested to represent an early endobenthic-epibenthic panarthropod transition [6] and to provide crucial insights into the origin of paired appendages [2]. However, the systematic affinity of Facivermis was poorly supported in a previous phylogeny [6], partially due to incomplete understanding of its morphology. Therefore, the evolutionary significance of Facivermis remains unresolved. In this study, we re-examine Facivermis from new material and the holotype, leading to the discovery of several new morphological features, such as paired eyes on the head and a dwelling tube. Comprehensive phylogenetic analyses using parsimony, Bayesian inference, and maximum likelihood all support Facivermis as a luolishaniid in a derived position within the onychophoran stem group rather than as a basal panarthropod. In contrast to previous studies, we therefore conclude that Facivermis provides a rare early Cambrian example of secondary loss to accommodate a highly specialized tube-dwelling lifestyle.
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Affiliation(s)
- Richard J Howard
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Chenggong Campus, Kunming 650500, China; Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9TA, UK; Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Xianguang Hou
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Chenggong Campus, Kunming 650500, China; Yunnan Key Laboratory for Palaeobiology, Yunnan University, Chenggong Campus, Kunming 650500, China.
| | - Gregory D Edgecombe
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Chenggong Campus, Kunming 650500, China; Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Tobias Salge
- Imaging and Analysis Centre, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Xiaomei Shi
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Chenggong Campus, Kunming 650500, China; Yunnan Key Laboratory for Palaeobiology, Yunnan University, Chenggong Campus, Kunming 650500, China
| | - Xiaoya Ma
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Chenggong Campus, Kunming 650500, China; Yunnan Key Laboratory for Palaeobiology, Yunnan University, Chenggong Campus, Kunming 650500, China; Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9TA, UK.
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8
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Gross V, Mayer G. Cellular morphology of leg musculature in the water bear Hypsibius exemplaris (Tardigrada) unravels serial homologies. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191159. [PMID: 31824724 PMCID: PMC6837179 DOI: 10.1098/rsos.191159] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/23/2019] [Indexed: 05/03/2023]
Abstract
Tardigrades (water bears) are microscopic, segmented ecdysozoans with four pairs of legs. Lobopodous limbs that are similar to those seen in tardigrades are hypothesized to represent the ancestral state of Panarthropoda (Tardigrada + Onychophora + Arthropoda), and their evolutionary history is important to our understanding of ecdysozoan evolution. Equally important is our understanding of the functional morphology of these legs, which requires knowledge of their musculature. Tardigrade musculature is well documented but open questions remain. For example, while the muscular organization of each trunk segment and its legs is unique, three of the four trunk segments are nevertheless relatively homonomous. To what extent, then, do leg muscles show segmental patterns? Specifically, which leg muscles are serially repeated and which are unique? The present study addresses these questions using a combination of techniques intended to visualize both the overall layout and fine structure of leg muscles in the eutardigrade Hypsibius exemplaris. In doing so, we propose serial homologies for all leg muscles in each of the four legs and reveal new details of their cellular structure and attachment sites. We compare our results to those of previous studies and address the functional implications of specialized muscle cell morphologies.
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Affiliation(s)
- Vladimir Gross
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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9
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Oliveira IDS, Kumerics A, Jahn H, Müller M, Pfeiffer F, Mayer G. Functional morphology of a lobopod: case study of an onychophoran leg. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191200. [PMID: 31824728 PMCID: PMC6837196 DOI: 10.1098/rsos.191200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/09/2019] [Indexed: 05/08/2023]
Abstract
Segmental, paired locomotory appendages are a characteristic feature of Panarthropoda-a diversified clade of moulting animals that includes onychophorans (velvet worms), tardigrades (water bears) and arthropods. While arthropods acquired a sclerotized exoskeleton and articulated limbs, onychophorans and tardigrades possess a soft body and unjointed limbs called lobopods, which they inherited from Cambrian lobopodians. To date, the origin and ancestral structure of the lobopods and their transformation into the jointed appendages are all poorly understood. We therefore combined high-resolution computed tomography with high-speed camera recordings to characterize the functional anatomy of a trunk lobopod from the onychophoran Euperipatoides rowelli. Three-dimensional reconstruction of the complete set of muscles and muscle fibres as well as non-muscular structures revealed the spatial relationship and relative volumes of the muscular, excretory, circulatory and nervous systems within the leg. Locomotory movements of individual lobopods of E. rowelli proved far more diverse than previously thought and might be governed by a complex interplay of 15 muscles, including one promotor, one remotor, one levator, one retractor, two depressors, two rotators, one flexor and two constrictors as well as muscles for stabilization and haemolymph control. We discuss the implications of our findings for understanding the evolution of locomotion in panarthropods.
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Affiliation(s)
- Ivo de Sena Oliveira
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Andreas Kumerics
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
| | - Henry Jahn
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
| | - Mark Müller
- Chair of Biomedical Physics, Department of Physics and Munich School of Bioengineering, Technical University of Munich, Garching, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of Bioengineering, Technical University of Munich, Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
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10
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Wang D, Vannier J, Schumann I, Wang X, Yang XG, Komiya T, Uesugi K, Sun J, Han J. Origin of ecdysis: fossil evidence from 535-million-year-old scalidophoran worms. Proc Biol Sci 2019; 286:20190791. [PMID: 31288707 DOI: 10.1098/rspb.2019.0791] [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] [Indexed: 12/14/2022] Open
Abstract
With millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation ( ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.
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Affiliation(s)
- Deng Wang
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China.,2 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Université Claude Bernard Lyon 1 , Villeurbanne Cedex 69622 , France
| | - Jean Vannier
- 2 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Université Claude Bernard Lyon 1 , Villeurbanne Cedex 69622 , France
| | - Isabell Schumann
- 3 Department of Genetics, University of Leipzig , Talstraße 33, 04103 Leipzig , Germany.,4 Molecular Evolution & Animal Systematics, Institute of Biology, University of Leipzig , Talstraße 33, 04103 Leipzig , Germany
| | - Xing Wang
- 5 Qingdao Institute of Marine Geology, China Geological Survey , Qingdao 266071 , People's Republic of China
| | - Xiao-Guang Yang
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
| | - Tsuyoshi Komiya
- 6 Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, University of Tokyo , Tokyo 153-8902 , Japan
| | - Kentaro Uesugi
- 7 Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo , Japan
| | - Jie Sun
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
| | - Jian Han
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
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11
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12
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Yang J, Ortega-Hernández J, Drage HB, Du KS, Zhang XG. Ecdysis in a stem-group euarthropod from the early Cambrian of China. Sci Rep 2019; 9:5709. [PMID: 30952888 PMCID: PMC6450865 DOI: 10.1038/s41598-019-41911-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/20/2019] [Indexed: 11/26/2022] Open
Abstract
Moulting is a fundamental component of the ecdysozoan life cycle, but the fossil record of this strategy is susceptible to preservation biases, making evidence of ecdysis in soft-bodied organisms extremely rare. Here, we report an exceptional specimen of the fuxianhuiid Alacaris mirabilis preserved in the act of moulting from the Cambrian (Stage 3) Xiaoshiba Lagerstätte, South China. The specimen displays a flattened and wrinkled head shield, inverted overlap of the trunk tergites over the head shield, and duplication of exoskeletal elements including the posterior body margins and telson. We interpret this fossil as a discarded exoskeleton overlying the carcass of an emerging individual. The moulting behaviour of A. mirabilis evokes that of decapods, in which the carapace is separated posteriorly and rotated forward from the body, forming a wide gape for the emerging individual. A. mirabilis illuminates the moult strategy of stem-group Euarthropoda, offers the stratigraphically and phylogenetically earliest direct evidence of ecdysis within total-group Euarthropoda, and represents one of the oldest examples of this growth strategy in the evolution of Ecdysozoa.
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Affiliation(s)
- Jie Yang
- Key Laboratory for Palaeobiology, Yunnan University, Kunming, 650091, China
- MEC International Joint Laboratory for Palaeoenvironment, Yunnan University, Kunming, 650091, China
| | - Javier Ortega-Hernández
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Harriet B Drage
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
- Institute of Earth Sciences, University of Lausanne, Géopolis, CH-1015, Lausanne, Switzerland
| | - Kun-Sheng Du
- Key Laboratory for Palaeobiology, Yunnan University, Kunming, 650091, China
- MEC International Joint Laboratory for Palaeoenvironment, Yunnan University, Kunming, 650091, China
| | - Xi-Guang Zhang
- Key Laboratory for Palaeobiology, Yunnan University, Kunming, 650091, China.
- MEC International Joint Laboratory for Palaeoenvironment, Yunnan University, Kunming, 650091, China.
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Ou Q, Mayer G. A Cambrian unarmoured lobopodian, †Lenisambulatrix humboldti gen. et sp. nov., compared with new material of †Diania cactiformis. Sci Rep 2018; 8:13667. [PMID: 30237414 PMCID: PMC6147921 DOI: 10.1038/s41598-018-31499-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 08/14/2018] [Indexed: 11/09/2022] Open
Abstract
Cambrian marine lobopodians are generally considered as predecessors of modern panarthropods (onychophorans, tardigrades, and arthropods). Hence, further study of their morphological diversity and early radiation may enhance our understanding of the ground pattern and evolutionary history of panarthropods. Here, we report a rare lobopodian species, †Lenisambulatrix humboldti gen. et sp. nov. ("Humboldt lobopodian"), from the early Cambrian Chengjiang Lagerstätte and describe new morphological features of †Diania cactiformis, a coeval armoured lobopodian nicknamed "walking cactus". Both lobopodian species were similar in possessing rather thick, elongate lobopods without terminal claws. However, in contrast to †Diania cactiformis, the body of which was heavily armored with spines, the trunk and limbs of the Humboldt lobopodian were entirely unarmored. Our study augments the morphological diversity of Cambrian lobopodians and presents two evolutionary extremes of cuticular ornamentation: one represented by the Humboldt lobopodian, which was most likely entirely "naked", the other epitomized by †D. cactiformis, which was highly "armoured".
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Affiliation(s)
- Qiang Ou
- Early Life Evolution Laboratory, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China. .,Department of Zoology, University of Kassel, 34132, Kassel, Germany.
| | - Georg Mayer
- Department of Zoology, University of Kassel, 34132, Kassel, Germany
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Caron JB, Aria C. Cambrian suspension-feeding lobopodians and the early radiation of panarthropods. BMC Evol Biol 2017; 17:29. [PMID: 28137244 PMCID: PMC5282736 DOI: 10.1186/s12862-016-0858-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 12/17/2016] [Indexed: 11/19/2022] Open
Abstract
Background Arthropoda, Tardigrada and Onychophora evolved from lobopodians, a paraphyletic group of disparate Palaeozoic vermiform animals with soft legs. Although the morphological diversity that this group encompasses likely illustrates the importance of niche diversification in the early radiation of panarthropods, the ecology of lobopodians remains poorly characterized. Results Here we describe a new luolishaniid taxon from the middle Cambrian Burgess Shale (Walcott Quarry) in British Columbia, Canada, whose specialized morphology epitomizes the suspension-feeding ecology of this clade, and is convergent with some modern marine animals, such as caprellid crustaceans. This species possesses two long pairs and four shorter pairs of elongate spinose lobopods at the front, each bearing two slender claws, and three pairs of stout lobopods bearing single, strong, hook-like anterior-facing claws at the back. The trunk is remarkably bare, widening rearwards, and, at the front, extends beyond the first pair of lobopods into a small “head” bearing a pair of visual organs and a short proboscis with numerous teeth. Based on a critical reappraisal of character coding in lobopodians and using Bayesian and parsimony-based tree searches, two alternative scenarios for early panarthropod evolution are retrieved. In both cases, hallucigeniids and luolishaniids are found to be extinct radiative stem group panarthropods, in contrast to previous analyses supporting a position of hallucigeniids as part of total-group Onychophora. Our Bayesian topology finds luolishaniids and hallucigeniids to form two successive clades at the base of Panarthropoda. Disparity analyses suggest that luolishaniids, hallucigeniids and total-group Onychophora each occupy a distinct region of morphospace. Conclusions Hallucigeniids and luolishaniids were comparably diverse and successful, representing two major lobopodian clades in the early Palaeozoic, and both evolved body plans adapted to different forms of suspension feeding. A Bayesian approach to cladistics supports the view that a semi-sessile, suspension-feeding lifestyle characterized the origin and rise of Panarthropoda from cycloneuralian body plans. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0858-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Bernard Caron
- Department of Natural History (Palaeobiology Section), Royal Ontario Museum, Toronto, Ontario, Canada. .,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada. .,Department of Earth Sciences, University of Toronto, Toronto, Ontario, Canada.
| | - Cédric Aria
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Abstract
An analysis of Hox genes reveals that the body of the adorably weird tardigrades is essentially a truncated front end. This illustrates that loss and simplification are a hallmark of the evolution of animal body plans.
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