1
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Figueroa RT, Weinschütz LC, Giles S, Friedman M. Soft-tissue fossilization illuminates the stepwise evolution of the ray-finned fish brain. Curr Biol 2024; 34:2831-2840.e2. [PMID: 38866006 DOI: 10.1016/j.cub.2024.05.027] [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: 02/06/2024] [Revised: 04/12/2024] [Accepted: 05/14/2024] [Indexed: 06/14/2024]
Abstract
A complex brain is central to the success of backboned animals. However, direct evidence bearing on vertebrate brain evolution comes almost exclusively from extant species, leaving substantial knowledge gaps. Although rare, soft-tissue preservation in fossils can yield unique insights on patterns of neuroanatomical evolution. Paleontological evidence from an exceptionally preserved Pennsylvanian (∼318 Ma) actinopterygian, Coccocephalus, calls into question prior interpretations of ancestral actinopterygian brain conditions. However, the ordering and timing of major evolutionary innovations, such as an everted telencephalon, modified meningeal tissues, and hypothalamic inferior lobes, remain unclear. Here, we report two distinct actinopterygian morphotypes from the latest Carboniferous-earliest Permian (∼299 Ma) of Brazil that show extensive soft-tissue preservation of brains, cranial nerves, eyes, and potential cardiovascular tissues. These fossils corroborate inferences drawn from ✝Coccocephalus, while adding new information about neuroanatomical evolution. Skeletal features indicate that one of these Brazilian morphotypes is more closely related to living actinopterygians than the other, which is also reflected in soft-tissue features. Significantly, the more crownward morphotype shows a key neuroanatomical feature of extant actinopterygians-an everted telencephalon-that is absent in the other morphotype and ✝Coccocephalus. All preserved Paleozoic actinopterygian brains show broad similarities, including an invaginated cerebellum, hypothalamus inferior lobes, and a small forebrain. In each case, preserved brains are substantially smaller than the enclosing cranial chamber. The neuroanatomical similarities shared by this grade of Permo-Carboniferous actinopterygians reflect probable primitive conditions for actinopterygians, providing a revised model for interpreting brain evolution in a major branch of the vertebrate tree of life.
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Affiliation(s)
- Rodrigo T Figueroa
- Department of Earth and Environmental Sciences, University of Michigan, North University Building, 1100 North University Avenue, Ann Arbor, MI 48109, USA; Museum of Paleontology, University of Michigan, Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI 48109, USA.
| | - Luiz Carlos Weinschütz
- Centro Paleontologico da Universidade do Contestado, CENPALEO, Av. Presidente Nereu Ramos 1071, Jardim Moinho, Mafra 89806-076, Santa Catarina, Brazil
| | - Sam Giles
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Matt Friedman
- Department of Earth and Environmental Sciences, University of Michigan, North University Building, 1100 North University Avenue, Ann Arbor, MI 48109, USA; Museum of Paleontology, University of Michigan, Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI 48109, USA
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2
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Brazeau MD, Castiello M, El Fassi El Fehri A, Hamilton L, Ivanov AO, Johanson Z, Friedman M. Fossil evidence for a pharyngeal origin of the vertebrate pectoral girdle. Nature 2023; 623:550-554. [PMID: 37914937 PMCID: PMC10651482 DOI: 10.1038/s41586-023-06702-4] [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: 04/14/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023]
Abstract
The origin of vertebrate paired appendages is one of the most investigated and debated examples of evolutionary novelty1-7. Paired appendages are widely considered as key innovations that enabled new opportunities for controlled swimming and gill ventilation and were prerequisites for the eventual transition from water to land. The past 150 years of debate8-10 has been shaped by two contentious theories4,5: the ventrolateral fin-fold hypothesis9,10 and the archipterygium hypothesis8. The latter proposes that fins and girdles evolved from an ancestral gill arch. Although studies in animal development have revived interest in this idea11-13, it is apparently unsupported by fossil evidence. Here we present palaeontological support for a pharyngeal basis for the vertebrate shoulder girdle. We use computed tomography scanning to reveal details of the braincase of Kolymaspis sibirica14, an Early Devonian placoderm fish from Siberia, that suggests a pharyngeal component of the shoulder. We combine these findings with refreshed comparative anatomy of placoderms and jawless outgroups to place the origin of the shoulder girdle on the sixth branchial arch. These findings provide a novel framework for understanding the origin of the pectoral girdle. Our evidence clarifies the location of the presumptive head-trunk interface in jawless fishes and explains the constraint on branchial arch number in gnathostomes15. The results revive a key aspect of the archipterygium hypothesis and help reconcile it with the ventrolateral fin-fold model.
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Affiliation(s)
- Martin D Brazeau
- Department of Life Sciences, Imperial College London, Ascot, UK.
- The Natural History Museum, London, UK.
| | - Marco Castiello
- Department of Life Sciences, Imperial College London, Ascot, UK
- London Academy of Excellence, London, United Kingdom
| | - Amin El Fassi El Fehri
- Department of Life Sciences, Imperial College London, Ascot, UK
- Paläontologisches Institut und Museum, Universität Zürich, Zurich, Switzerland
| | - Louis Hamilton
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - Alexander O Ivanov
- Department of Sedimentary Geology, Institute of Earth Sciences, St Petersburg State University, St Petersburg, Russia
- Institute of Geology and Petroleum Technologies, Kazan Federal University, Kazan, Russia
| | | | - Matt Friedman
- The Natural History Museum, London, UK
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
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3
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Allemand R, Abdul-Sater J, Macrì S, Di-Poï N, Daghfous G, Silcox MT. Endocast, brain, and bones: Correspondences and spatial relationships in squamates. Anat Rec (Hoboken) 2023; 306:2443-2465. [PMID: 36602153 DOI: 10.1002/ar.25142] [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: 10/13/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023]
Abstract
Vertebrate endocasts are widely used in the fields of paleoneurology and comparative neuroanatomy. The validity of endocranial studies is dependent upon the extent to which an endocast reflects brain morphology. Due to the variable neuroanatomical resolution of vertebrate endocasts, direct information about the brain morphology can be sometimes difficult to assess and needs to be investigated across lineages. Here, we employ X-ray computed tomography (CT), including diffusible iodine-based contrast-enhanced CT, to qualitatively compare brains and endocasts in different species of squamates. The relative position of the squamate brain within the skull, as well as the variability that may exist in such spatial relationships, was examined to help clarify the neurological regions evidence on their endocasts. Our results indicate that squamate endocasts provide variable representation of the brain, depending on species and neuroanatomical regions. The olfactory bulbs and peduncles, cerebral hemispheres, as well as the medulla oblongata represent the most easily discernable brain regions from squamate endocasts. In contrast, the position of the optic lobes, the ventral diencephalon and the pituitary may be difficult to determine depending on species. Finally, squamate endocasts provide very limited or no information about the cerebellum. The spatial relationships revealed here between the brain and the surrounding bones may help to identify each of the endocranial region. However, as one-to-one correspondences between a bone and a specific region appear limited, the exact delimitation of these regions may remain challenging according to species. This study provides a basis for further examination and interpretation of squamate endocast disparity.
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Affiliation(s)
- Rémi Allemand
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Jade Abdul-Sater
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Simone Macrì
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | | | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
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4
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Brazeau MD, Yuan H, Giles S, Jerve AL, Zorig E, Ariunchimeg Y, Sansom RS, Atwood RC. A well-preserved 'placoderm' (stem-group Gnathostomata) upper jaw from the Early Devonian of Mongolia clarifies jaw evolution. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221452. [PMID: 36844806 PMCID: PMC9943883 DOI: 10.1098/rsos.221452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
The origin of jaws and teeth remains contentious in vertebrate evolution. 'Placoderms' (Silurian-Devonian armoured jawed fishes) are central to debates on the origins of these anatomical structures. 'Acanthothoracids' are generally considered the most primitive 'placoderms'. However, they are so far known mainly from disarticulated skeletal elements that are typically incomplete. The structure of the jaws-particularly the jaw hinge-is poorly known, leaving open questions about their jaw function and comparison with other placoderms and modern gnathostomes. Here we describe a near-complete 'acanthothoracid' upper jaw, allowing us to reconstruct the likely orientation and angle of the bite and compare its morphology with that of other known 'placoderm' groups. We clarify that the bite position is located on the upper jaw cartilage rather than on the dermal cheek and thus show that there is a highly conserved bite morphology among most groups of 'placoderms', regardless of their overall cranial geometry. Incorporation of the dermal skeleton appears to provide a sound biomechanical basis for jaw origins. It appears that 'acanthothoracid' dentitions were fundamentally similar in location to that of arthrodire 'placoderms', rather than resembling bony fishes. Irrespective of current phylogenetic uncertainty, the new data here resolve the likely general condition for 'placoderms' as a whole, and as such, ancestral morphology of known jawed vertebrates.
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Affiliation(s)
- Martin D. Brazeau
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
- The Natural History Museum, London SW7 5BD, UK
| | - Haobo Yuan
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
| | - Sam Giles
- The Natural History Museum, London SW7 5BD, UK
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Anna L. Jerve
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
| | - E. Zorig
- Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar 15160, Mongolia
| | | | - Robert S. Sansom
- Department of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
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5
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Johanson Z. Vertebrate cranial evolution: Contributions and conflict from the fossil record. Evol Dev 2023; 25:119-133. [PMID: 36308394 DOI: 10.1111/ede.12422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 08/12/2022] [Accepted: 10/05/2022] [Indexed: 01/14/2023]
Abstract
In modern vertebrates, the craniofacial skeleton is complex, comprising cartilage and bone of the neurocranium, dermatocranium and splanchnocranium (and their derivatives), housing a range of sensory structures such as eyes, nasal and vestibulo-acoustic capsules, with the splanchnocranium including branchial arches, used in respiration and feeding. It is well understood that the skeleton derives from neural crest and mesoderm, while the sensory elements derive from ectodermal thickenings known as placodes. Recent research demonstrates that neural crest and placodes have an evolutionary history outside of vertebrates, while the vertebrate fossil record allows the sequence of the evolution of these various features to be understood. Stem-group vertebrates such as Metaspriggina walcotti (Burgess Shale, Middle Cambrian) possess eyes, paired nasal capsules and well-developed branchial arches, the latter derived from cranial neural crest in extant vertebrates, indicating that placodes and neural crest evolved over 500 million years ago. Since that time the vertebrate craniofacial skeleton has evolved, including different types of bone, of potential neural crest or mesodermal origin. One problematic part of the craniofacial skeleton concerns the evolution of the nasal organs, with evidence for both paired and unpaired nasal sacs being the primitive state for vertebrates.
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6
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The Development of the Chimaeroid Pelvic Skeleton and the Evolution of Chondrichthyan Pelvic Fins. J Dev Biol 2022; 10:jdb10040053. [PMID: 36547475 PMCID: PMC9782884 DOI: 10.3390/jdb10040053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/11/2022] [Accepted: 11/01/2022] [Indexed: 12/14/2022] Open
Abstract
Pelvic girdles, fins and claspers are evolutionary novelties first recorded in jawed vertebrates. Over the course of the evolution of chondrichthyans (cartilaginous fish) two trends in the morphology of the pelvic skeleton have been suggested to have occurred. These evolutionary shifts involved both an enlargement of the metapterygium (basipterygium) and a transition of fin radial articulation from the pelvic girdle to the metapterygium. To determine how these changes in morphology have occurred it is essential to understand the development of extant taxa as this can indicate potential developmental mechanisms that may have been responsible for these changes. The study of the morphology of the appendicular skeleton across development in chondrichthyans is almost entirely restricted to the historical literature with little contemporary research. Here, we have examined the morphology and development of the pelvic skeleton of a holocephalan chondrichthyan, the elephant shark (Callorhinchus milii), through a combination of dissections, histology, and nanoCT imaging and redescribed the pelvic skeleton of Cladoselache kepleri (NHMUK PV P 9269), a stem holocephalan. To put our findings in their evolutionary context we compare them with the fossil record of chondrichthyans and the literature on pelvic development in elasmobranchs from the late 19th century. Our findings demonstrate that the pelvic skeleton of C. milii initially forms as a single mesenchymal condensation, consisting of the pelvic girdle and a series of fin rays, which fuse to form the basipterygium. The girdle and fin skeleton subsequently segment into distinct components whilst chondrifying. This confirms descriptions of the early pelvic development in Scyliorhinid sharks from the historical literature and suggests that chimaeras and elasmobranchs share common developmental patterns in their pelvic anatomy. Alterations in the location and degree of radial fusion during early development may be the mechanism responsible for changes in pelvic fin morphology over the course of the evolution of both elasmobranchs and holocephalans, which appears to be an example of parallel evolution.
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7
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Jobbins M, Rücklin M, Ferrón HG, Klug C. A new selenosteid placoderm from the Late Devonian of the eastern Anti-Atlas (Morocco) with preserved body outline and its ecomorphology. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.969158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Placoderms are an extinct group of early jawed vertebrates that play a key role in understanding the evolution of the gnathostome body plan, including the origin of novelties such as jaws, teeth, and pelvic fins. As placoderms have a poorly ossified axial skeleton, preservation of the mainly cartilaginous axial and fin elements is extremely rare, contrary to the heavily mineralized bones of the skull and thoracic armor. Therefore, the gross anatomy of the animals and body shape is only known from a few taxa, and reconstructions of the swimming function and ecology are speculative. Here, we describe articulated specimens preserving skull roofs, shoulder girdles, most fins, and body outlines of a newly derived arthrodire. Specimens of the selenosteid Amazichthys trinajsticae gen. et sp. nov. display a skull roof with reticular ornamentation and raised sensory lines like Driscollaspis, a median dorsal plate with a unique sharp posterior depression, the pelvic girdle, the proportions and shape of the pectoral, dorsal, and caudal fins as well as a laterally enlarged region resembling the lateral keel of a few modern sharks and bony fishes. Our new phylogenetic analyses support the monophyly of the selenosteid family and place the new genus in a clade with Melanosteus, Enseosteus, Walterosteus, and Draconichthys. The shape of its body and heterocercal caudal fin in combination with the pronounced “lateral keel” suggest Amazichthys trinajsticae was an active macropelagic swimmer capable of reaching high swimming speeds.
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8
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Trinajstic K, Long JA, Sanchez S, Boisvert CA, Snitting D, Tafforeau P, Dupret V, Clement AM, Currie PD, Roelofs B, Bevitt JJ, Lee MSY, Ahlberg PE. Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte. Science 2022; 377:1311-1314. [DOI: 10.1126/science.abf3289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The origin and early diversification of jawed vertebrates involved major changes to skeletal and soft anatomy. Skeletal transformations can be examined directly by studying fossil stem gnathostomes; however, preservation of soft anatomy is rare. We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and bilobed liver from arthrodire placoderms, stem gnathostomes from the Late Devonian Gogo Formation in Western Australia. The application of synchrotron and neutron microtomography to this material shows evidence of a flat S-shaped heart, which is well separated from the liver and other abdominal organs, and the absence of lungs. Arthrodires thus show the earliest phylogenetic evidence for repositioning of the gnathostome heart associated with the evolution of the complex neck region in jawed vertebrates.
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Affiliation(s)
- Kate Trinajstic
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
- Western Australian Museum, Welshpool, WA 6106, Australia
| | - John A. Long
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Museum Victoria, Melbourne, VIC 3001, Australia
| | - Sophie Sanchez
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, 75236 Uppsala, Sweden
- European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - Catherine A. Boisvert
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Daniel Snitting
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, 75236 Uppsala, Sweden
| | - Paul Tafforeau
- European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - Vincent Dupret
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, 75236 Uppsala, Sweden
| | - Alice M. Clement
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Peter D. Currie
- Australian Regenerative Medicine Institute and EMBL Australia, Monash University, Clayton, VIC 3800, Australia
| | - Brett Roelofs
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Joseph J. Bevitt
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Michael S. Y. Lee
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Earth Sciences Section, South Australian Museum, Adelaide, SA 5000, Australia
| | - Per E. Ahlberg
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, 75236 Uppsala, Sweden
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9
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Zhu YA, Li Q, Lu J, Chen Y, Wang J, Gai Z, Zhao W, Wei G, Yu Y, Ahlberg PE, Zhu M. The oldest complete jawed vertebrates from the early Silurian of China. Nature 2022; 609:954-958. [PMID: 36171378 DOI: 10.1038/s41586-022-05136-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 07/22/2022] [Indexed: 11/09/2022]
Abstract
Molecular studies suggest that the origin of jawed vertebrates was no later than the Late Ordovician period (around 450 million years ago (Ma))1,2. Together with disarticulated micro-remains of putative chondrichthyans from the Ordovician and early Silurian period3-8, these analyses suggest an evolutionary proliferation of jawed vertebrates before, and immediately after, the end-Ordovician mass extinction. However, until now, the earliest complete fossils of jawed fishes for which a detailed reconstruction of their morphology was possible came from late Silurian assemblages (about 425 Ma)9-13. The dearth of articulated, whole-body fossils from before the late Silurian has long rendered the earliest history of jawed vertebrates obscure. Here we report a newly discovered Konservat-Lagerstätte, which is marked by the presence of diverse, well-preserved jawed fishes with complete bodies, from the early Silurian (Telychian age, around 436 Ma) of Chongqing, South China. The dominant species, a 'placoderm' or jawed stem gnathostome, which we name Xiushanosteus mirabilis gen. et sp. nov., combines characters from major placoderm subgroups14-17 and foreshadows the transformation of the skull roof pattern from the placoderm to the osteichthyan condition10. The chondrichthyan Shenacanthus vermiformis gen. et sp. nov. exhibits extensive thoracic armour plates that were previously unknown in this lineage, and include a large median dorsal plate as in placoderms14-16, combined with a conventional chondrichthyan bauplan18,19. Together, these species reveal a previously unseen diversification of jawed vertebrates in the early Silurian, and provide detailed insights into the whole-body morphology of the jawed vertebrates of this period.
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Affiliation(s)
- You-An Zhu
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Qiang Li
- Research Center of Natural History and Culture, Qujing Normal University, Qujing, China.,Chongqing Institute of Geology and Mineral Resources, Chongqing, China
| | - Jing Lu
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yang Chen
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,Chongqing Institute of Geology and Mineral Resources, Chongqing, China
| | - Jianhua Wang
- Research Center of Natural History and Culture, Qujing Normal University, Qujing, China
| | - Zhikun Gai
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Wenjin Zhao
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Guangbiao Wei
- Chongqing Institute of Geological Survey, Chongqing, China
| | - Yilun Yu
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Per E Ahlberg
- Department of Organismal Biology, Uppsala University, Uppsala, Sweden.
| | - Min Zhu
- Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), Beijing, China. .,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China. .,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China.
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10
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Clement AM, Challands TJ, Cloutier R, Houle L, Ahlberg PE, Collin SP, Long JA. Morphometric analysis of lungfish endocasts elucidates early dipnoan palaeoneurological evolution. eLife 2022; 11:e73461. [PMID: 35818828 PMCID: PMC9275822 DOI: 10.7554/elife.73461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
The lobe-finned fish, lungfish (Dipnoi, Sarcoptergii), have persisted for ~400 million years from the Devonian Period to present day. The evolution of their dermal skull and dentition is relatively well understood, but this is not the case for the central nervous system. While the brain has poor preservation potential and is not currently known in any fossil lungfish, substantial indirect information about it and associated structures (e.g. labyrinths) can be obtained from the cranial endocast. However, before the recent development of X-ray tomography as a palaeontological tool, these endocasts could not be studied non-destructively, and few detailed studies were undertaken. Here, we describe and illustrate the endocasts of six Palaeozoic lungfish from tomographic scans. We combine these with six previously described digital lungfish endocasts (4 fossil and 2 recent taxa) into a 12-taxon dataset for multivariate morphometric analysis using 17 variables. We find that the olfactory region is more highly plastic than the hindbrain, and undergoes significant elongation in several taxa. Further, while the semicircular canals covary as an integrated module, the utriculus and sacculus vary independently of each other. Functional interpretation suggests that olfaction has remained a dominant sense throughout lungfish evolution, and changes in the labyrinth may potentially reflect a change from nektonic to near-shore environmental niches. Phylogenetic implications show that endocranial form fails to support monophyly of the 'chirodipterids'. Those with elongated crania similarly fail to form a distinct clade, suggesting these two paraphyletic groups have converged towards either head elongation or truncation driven by non-phylogenetic constraints.
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Affiliation(s)
- Alice M Clement
- College of Science and Engineering, Flinders UniversityAdelaideAustralia
| | - Tom J Challands
- School of Geosciences, University of EdinburghEdinburghUnited Kingdom
| | - Richard Cloutier
- Département de Biologie, Chimie et Géographie, Université du Québec à RimouskiRimouskiCanada
| | - Laurent Houle
- Département de Biologie, Chimie et Géographie, Université du Québec à RimouskiRimouskiCanada
| | - Per E Ahlberg
- Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala UniversityUppsalaSweden
| | - Shaun P Collin
- School of Life Sciences, La Trobe UniversityMelbourneAustralia
| | - John A Long
- College of Science and Engineering, Flinders UniversityAdelaideAustralia
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11
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Alesci A, Capillo G, Fumia A, Messina E, Albano M, Aragona M, Lo Cascio P, Spanò N, Pergolizzi S, Lauriano ER. Confocal Characterization of Intestinal Dendritic Cells from Myxines to Teleosts. BIOLOGY 2022; 11:biology11071045. [PMID: 36101424 PMCID: PMC9312193 DOI: 10.3390/biology11071045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/01/2022] [Accepted: 07/07/2022] [Indexed: 12/11/2022]
Abstract
Dendritic cells (DCs) are antigen-presenting cells (APCs) that regulate the beginning of adaptive immune responses. The mechanisms of tolerance to antigens moving through the digestive tract are known to be regulated by intestinal DCs. Agnatha and Gnathostoma are descendants of a common ancestor. The Ostracoderms gave rise to Cyclostomes, whereas the Placoderms gave rise to Chondrichthyes. Sarcopterygii and Actinopterygii are two evolutionary lines of bony fishes. Brachiopterygii and Neopterygii descend from the Actinopterygii. From Neopterygii, Holostei and Teleostei evolved. Using immunohistochemistry with TLR-2, Langerin/CD207, and MHC II, this study aimed to characterize intestinal DCs, from myxines to teleosts. The findings reveal that DCs are positive for the antibodies tested, highlighting the presence of DCs and DC-like cells phylogenetically from myxines, for the first time, to teleosts. These findings may aid in improving the level of knowledge about the immune system’s evolution and these sentinel cells, which are crucial to the body’s defense.
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Affiliation(s)
- Alessio Alesci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
- Correspondence: (A.A.); (G.C.)
| | - Gioele Capillo
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy;
- Institute of Marine Biological Resources and Biotechnology, National Research Council (IRBIM, CNR), 98164 Messina, Italy;
- Correspondence: (A.A.); (G.C.)
| | - Angelo Fumia
- Department of Clinical and Experimental Medicine, University of Messina, Padiglione C, A. O. U. Policlinico “G. Martino”, 98124 Messina, Italy;
| | - Emmanuele Messina
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
| | - Marco Albano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
| | - Marialuisa Aragona
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy;
| | - Patrizia Lo Cascio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
| | - Nunziacarla Spanò
- Institute of Marine Biological Resources and Biotechnology, National Research Council (IRBIM, CNR), 98164 Messina, Italy;
- Department of Biomedical, Dental and Morphological and Functional Imaging, University of Messina, 98125 Messina, Italy
| | - Simona Pergolizzi
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
| | - Eugenia Rita Lauriano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy; (E.M.); (M.A.); (P.L.C.); (S.P.); (E.R.L.)
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Wang Y, Zhu M. Squamation and scale morphology at the root of jawed vertebrates. eLife 2022; 11:76661. [PMID: 35674421 PMCID: PMC9177148 DOI: 10.7554/elife.76661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Placoderms, as the earliest branching jawed vertebrates, are crucial to understanding how the characters of crown gnathostomes comprising Chondrichthyes and Osteichthyes evolved from their stem relatives. Despite the growing knowledge of the anatomy and diversity of placoderms over the past decade, the dermal scales of placoderms are predominantly known from isolated material, either morphologically or histologically, resulting in their squamation being poorly understood. Here we provide a comprehensive description of the squamation and scale morphology of a primitive taxon of Antiarcha (a clade at the root of jawed vertebrates), Parayunnanolepis xitunensis, based on the virtual restoration of an articulated specimen by using X-ray computed tomography. Thirteen morphotypes of scales are classified to exhibit how the morphology changes with their position on the body in primitive antiarchs, based on which nine areas of the post-thoracic body are distinguished to show their scale variations in the dorsal, flank, ventral, and caudal lobe regions. In this study, the histological structure of yunnanolepidoid scales is described for the first time based on disarticulated scales from the type locality and horizon of P. xitunensis. The results demonstrate that yunnanolepidoid scales are remarkably different from their dermal plates as well as euantiarch scales in lack of a well-developed middle layer. Together, our study reveals that the high regionalization of squamation and the bipartite histological structure of scales might be plesiomorphic for antiarchs, and jawed vertebrates in general.
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Affiliation(s)
- Yajing Wang
- School of Earth Sciences and Engineering, Nanjing University
| | - Min Zhu
- School of Earth Sciences and Engineering, Nanjing University
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences
- CAS Center for Excellence in Life and Paleoenvironment
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