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Shirley B, Leonhard I, Murdock DJE, Repetski J, Świś P, Bestmann M, Trimby P, Ohl M, Plümper O, King HE, Jarochowska E. Increasing control over biomineralization in conodont evolution. Nat Commun 2024; 15:5273. [PMID: 38902270 PMCID: PMC11190287 DOI: 10.1038/s41467-024-49526-0] [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: 10/12/2022] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
Vertebrates use the phosphate mineral apatite in their skeletons, which allowed them to develop tissues such as enamel, characterized by an outstanding combination of hardness and elasticity. It has been hypothesized that the evolution of the earliest vertebrate skeletal tissues, found in the teeth of the extinct group of conodonts, was driven by adaptation to dental function. We test this hypothesis quantitatively and demonstrate that the crystallographic order increased throughout the early evolution of conodont teeth in parallel with morphological adaptation to food processing. With the c-axes of apatite crystals oriented perpendicular to the functional feeding surfaces, the strongest resistance to uniaxial compressional stress is conferred along the long axes of denticles. Our results support increasing control over biomineralization in the first skeletonized vertebrates and allow us to test models of functional morphology and material properties across conodont dental diversity.
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Affiliation(s)
- Bryan Shirley
- Fachgruppe Paläoumwelt, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
| | - Isabella Leonhard
- Department of Palaeontology, University of Vienna, Vienna, Austria
- Institute of Evolutionary Biology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - John Repetski
- US Geological Survey-Emeritus, MS 926 A National Center, Reston, USA
| | - Przemysław Świś
- Institute of Evolutionary Biology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, Warsaw, Poland
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Michel Bestmann
- Department of Geology, University of Vienna, Vienna, Austria
| | - Pat Trimby
- Oxford Instruments, High Wycombe, UK
- Carl Zeiss Ltd., Cambridge, UK
| | - Markus Ohl
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
| | - Oliver Plümper
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
| | - Helen E King
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
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Souquet L, Guenser P, Girard C, Mazza M, Rigo M, Goudemand N. Temperature-driven heterochrony as a main evolutionary response to climate changes in conodonts. Proc Biol Sci 2022; 289:20220614. [PMID: 36259210 PMCID: PMC9579755 DOI: 10.1098/rspb.2022.0614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 09/27/2022] [Indexed: 01/17/2023] Open
Abstract
Can we predict the evolutionary response of organisms to climate changes? The direction of greatest intraspecific phenotypic variance is thought to correspond to an 'evolutionary line of least resistance', i.e. a taxon's phenotype is expected to evolve along that general direction, if not constrained otherwise. In particular, heterochrony, whereby the timing or rate of developmental processes are modified, has often been invoked to describe evolutionary trajectories and it may be advantageous to organisms when rapid adaptation is critical. Yet, to date, little is known empirically as to which covariation patterns, whether static allometry, as measured in adult forms only, or ontogenetic allometry, the basis for heterochrony, may be prevalent in what circumstances. Here, we quantify the morphology of segminiplanate conodont elements during two distinct time intervals separated by more than 130 Myr: the Devonian-Carboniferous boundary and the Carnian-Norian boundary (Late Triassic). We evidence that the corresponding species share similar patterns of intraspecific static allometry. Yet, during both crises, conodont evolution was decoupled from this common evolutionary line of least resistance. Instead, it followed heterochrony-like trajectories that furthermore appear as driven by ocean temperature. This may have implications for our interpretation of conodonts' and past marine ecosystems' response to environmental perturbations.
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Affiliation(s)
- Louise Souquet
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| | - Pauline Guenser
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
- Univ. Lyon, Université Claude Bernard Lyon 1, LEHNA, CNRS UMR 5023, 3-6 rue Raphaël Dubois – Bâtiments Forel, 69622 Villeurbanne Cedex 43
| | | | | | - Manuel Rigo
- Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padova, Italy
| | - Nicolas Goudemand
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
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Leonhard I, Shirley B, Murdock DJE, Repetski J, Jarochowska E. Growth and feeding ecology of coniform conodonts. PeerJ 2021; 9:e12505. [PMID: 34993015 PMCID: PMC8679908 DOI: 10.7717/peerj.12505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/26/2021] [Indexed: 01/04/2023] Open
Abstract
Conodonts were the first vertebrates to develop mineralized dental tools, known as elements. Recent research suggests that conodonts were macrophagous predators and/or scavengers but we do not know how this feeding habit emerged in the earliest coniform conodonts, since most studies focus on the derived, 'complex' conodonts. Previous modelling of element position and mechanical properties indicate they were capable of food processing. A direct test would be provided through evidence of in vivo element crown tissue damage or through in vivo incorporated chemical proxies for a shift in their trophic position during ontogeny. Here we focus on coniform elements from two conodont taxa, the phylogenetically primitive Proconodontus muelleri Miller, 1969 from the late Cambrian and the more derived Panderodus equicostatus Rhodes, 1954 from the Silurian. Proposing that this extremely small sample is, however, representative for these taxa, we aim to describe in detail the growth of an element from each of these taxa in order to the test the following hypotheses: (1) Panderodus and Proconodontus processed hard food, which led to damage of their elements consistent with prey capture function; and (2) both genera shifted towards higher trophic levels during ontogeny. We employed backscatter electron (BSE) imaging, energy-dispersive X-ray spectroscopy (EDX) and synchrotron radiation X-ray tomographic microscopy (SRXTM) to identify growth increments, wear and damage surfaces, and the Sr/Ca ratio in bioapatite as a proxy for the trophic position. Using these data, we can identify whether they exhibit determinate or indeterminate growth and whether both species followed linear or allometric growth dynamics. Growth increments (27 in Pa. equicostatus and 58 in Pr. muelleri) were formed in bundles of 4-7 increments in Pa. equicostatus and 7-9 in Pr. muelleri. We interpret the bundles as analogous to Retzius periodicity in vertebrate teeth. Based on applied optimal resource allocation models, internal periodicity might explain indeterminate growth in both species. They also allow us to interpret the almost linear growth of both individuals as an indicator that there was no size-dependent increase in mortality in the ecosystems where they lived e.g., as would be the case in the presence of larger predators. Our findings show that periodic growth was present in early conodonts and preceded tissue repair in response to wear and damage. We found no microwear and the Sr/Ca ratio, and therefore the trophic position, did not change substantially during the lifetimes of either individual. Trophic ecology of coniform conodonts differed from the predatory and/or scavenger lifestyle documented for "complex" conodonts. We propose that conodonts adapted their life histories to top-down controlled ecosystems during the Nekton Revolution.
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Affiliation(s)
- Isabella Leonhard
- Institute of Evolutionary Biology, University of Warsaw, Warsaw, Poland
| | - Bryan Shirley
- Paläoumwelt, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Bavaria, Germany
| | | | - John Repetski
- US Geological Survey-Emeritus, Reston, Virginia, United States of America
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Atakul-Özdemir A, Warren X, Martin PG, Guizar-Sicairos M, Holler M, Marone F, Martínez-Pérez C, Donoghue PCJ. X-ray nanotomography and electron backscatter diffraction demonstrate the crystalline, heterogeneous and impermeable nature of conodont white matter. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202013. [PMID: 34386244 PMCID: PMC8334826 DOI: 10.1098/rsos.202013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Conodont elements, microfossil remains of extinct primitive vertebrates, are commonly exploited as mineral archives of ocean chemistry, yielding fundamental insights into the palaeotemperature and chemical composition of past oceans. Geochemical assays have been traditionally focused on the so-called lamellar and white matter crown tissues; however, the porosity and crystallographic nature of the white matter and its inferred permeability are disputed, raising concerns over its suitability as a geochemical archive. Here, we constrain the characteristics of this tissue and address conflicting interpretations using ptychographic X-ray-computed tomography (PXCT), pore network analysis, synchrotron radiation X-ray tomographic microscopy (srXTM) and electron back-scatter diffraction (EBSD). PXCT and pore network analyses based on these data reveal that while white matter is extremely porous, the pores are unconnected, rendering this tissue closed to postmortem fluid percolation. EBSD analyses demonstrate that white matter is crystalline and comprised of a single crystal typically tens of micrometres in dimensions. Combined with evidence that conodont elements grow episodically, these data suggest that white matter, which comprises the denticles of conodont elements, grows syntactically, indicating that individual crystals are time heterogeneous. Together these data provide support for the interpretation of conodont white matter as a closed geochemical system and, therefore, its utility of the conodont fossil record as a historical archive of Palaeozoic and Early Mesozoic ocean chemistry.
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Affiliation(s)
- Ayse Atakul-Özdemir
- Department of Geophysical Engineering, Yuzuncu Yil University, 65180 Van, Turkey
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
| | - Xander Warren
- Interface Analysis Centre, School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | - Peter G. Martin
- Interface Analysis Centre, School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | | | - Mirko Holler
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Carlos Martínez-Pérez
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/Catedrático José Beltrán Martínez no 2, Paterna Valencian 46980, Spain
| | - Philip C. J. Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
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Petryshen W, Henderson CM, De Baets K, Jarochowska E. Evidence of parallel evolution in the dental elements of Sweetognathus conodonts. Proc Biol Sci 2020; 287:20201922. [PMID: 33203328 DOI: 10.1098/rspb.2020.1922] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The repeated emergence of similar morphologies in the dental elements of Permian Sweetognathus conodonts has been a hypothesized example of parallel evolution. To test if morphological parallelisms occur between isolated Sweetognathus lineages, this study uses two-dimensional-based geometric morphometrics combined with a revised and expanded phylogeny of Permian Sweetognathus conodonts to quantify dental element trait distributions and compare the phenotypic trajectories between lineages. A hierarchical clustering method was used to identify recurrent species pairs based on principal component scores describing their morphological variation, with the further incorporation of widely used ecological metrics such as limiting similarity and morphological overlap. Our research implies that a major contributor to conodont diversity in Palaeozoic marine trophic networks is the emergence of recurrent parallel morphologies via disruptive and directional selection. This study illustrates the mechanisms through which conodonts achieved their status as hyper-diverse predators and scavengers, contributing substantially to the complexity of Palaeozoic marine communities.
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Affiliation(s)
- W Petryshen
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
| | - C M Henderson
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
| | - K De Baets
- Department of Paleontology, Friedrich-Alexander University Erlangen-Nürnberg, GeoZentrum Nordbayern, Erlangen, Germany
| | - E Jarochowska
- Department of Paleontology, Friedrich-Alexander University Erlangen-Nürnberg, GeoZentrum Nordbayern, Erlangen, Germany
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Shohel M, McAdams NEB, Cramer BD, Forbes TZ. Ontogenetic variability in crystallography and mosaicity of conodont apatite: implications for microstructure, palaeothermometry and geochemistry. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200322. [PMID: 32874630 PMCID: PMC7428274 DOI: 10.1098/rsos.200322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
X-ray diffraction data from Silurian conodonts belonging to various developmental stages of the species Dapsilodus obliquicostatus demonstrate changes in crystallography and degree of nanocrystallite ordering (mosaicity) in both lamellar crown tissue and white matter. The exclusive use of a single species in this study, combined with systematic testing of each element type at multiple locations, provided insight into microstructural and crystallographic differentiation between element type (Sa , Sb -c , M) as well as between juveniles and adults. A relative increase in the unit cell dimensions a/c ratio of nanocrystallites during growth was apparent in areas demonstrating single-crystal behaviour, but no such relationship was seen in dominantly polycrystalline areas. Systematic variations in mosaicity were identified, with mosaicity (as a proxy for disorder) increasing during growth, as well as along elements from tip to base. These results provide potential insight into the integrity of conodont apatite as a recorder of palaeoseawater chemistry, as well as demonstrate the need to consider the influence of ontogeny and element type on the use of conodonts in palaeothermometry and geochemical investigations.
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Affiliation(s)
- Mohammad Shohel
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Neo E. B. McAdams
- Department of Geosciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Bradley D. Cramer
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Tori Z. Forbes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
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Shirley B, Grohganz M, Bestmann M, Jarochowska E. Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging. Proc Biol Sci 2018; 285:rspb.2018.1614. [PMID: 30185642 DOI: 10.1098/rspb.2018.1614] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 08/14/2018] [Indexed: 11/12/2022] Open
Abstract
Conodont elements are the earliest mineralized vertebrate dental tools and the only ones capable of extensive repair. Two models of conodont growth, as well as the presence of a larval stage, have been hypothesized. We analysed normally and pathologically developed elements to test these hypotheses and identified three ontogenetic stages characterized by different anisometric growth and morphology. The distinction of these stages is independently corroborated by differences in tissue strontium (Sr) content. The onset of the last stage is marked by the appearance of wear resulting from mechanical food digestion. At least five episodes of damage and repair could be identified in the normally developed specimen. In the pathological element, function was compromised by the development of abnormal denticles. This development can be reconstructed as addition of new growth centres out of the main growth axis during an episode of renewed growth. Our findings support the model of periodic retraction of elements and addition of new growth centres. Changes in Sr content coincident with distinct morphology and lack of wear in the early life stage indicate that conodonts might have assumed their mature feeding habit of predators or scavengers after an initial larval stage characterized by a different feeding mode.
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Affiliation(s)
- Bryan Shirley
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Madleen Grohganz
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Michel Bestmann
- Fachgruppe Strukturgeologie, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Emilia Jarochowska
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
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