1
|
The role of volcanic-derived clays in the preservation of Ediacaran biota from the Itajaí Basin (ca. 563 Ma, Brazil). Sci Rep 2021; 11:5013. [PMID: 33658558 PMCID: PMC7930025 DOI: 10.1038/s41598-021-84433-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/05/2021] [Indexed: 11/22/2022] Open
Abstract
The early evolution of metazoans has been reconstructed by studies on exceptionally preserved molds in siliciclastic rocks from the Ediacaran Period. However, there remains considerable controversy regarding the formation mechanisms of this unusual ‘Ediacaran-style’ preservation. Proposed hypotheses usually include early authigenesis of minerals, but evidence for this is scarce. In a recently discovered deposit of Ediacaran biota in Brazil, we show that the classic moldic preservation is related to clay mineral authigenesis. Specifically, these clays originated from the alteration of original pyroclastic sediments, likely enhanced by microbial activity, leading to early illitization and morphological templating of the fossiliferous surfaces at a micrometric scale. Such high-fidelity preservation was made possible by rapid burial during volcanic events and the in-situ templating of tissue by clays via microbially-mediated mineralization. This newly described Lagerstätte demonstrates that a number of minerals can facilitate preservation, and that perhaps ‘Ediacaran-style’ preservation result from different processes leading to the same broad style of preservation.
Collapse
|
2
|
Nadhira A, Sutton MD, Botting JP, Muir LA, Gueriau P, King A, Briggs DEG, Siveter DJ, Siveter DJ. Three-dimensionally preserved soft tissues and calcareous hexactins in a Silurian sponge: implications for early sponge evolution. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190911. [PMID: 31417767 PMCID: PMC6689616 DOI: 10.1098/rsos.190911] [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: 05/17/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
Sponges (Porifera), as one of the earliest-branching animal phyla, are crucial for understanding early metazoan phylogeny. Recent studies of Lower Palaeozoic sponges have revealed a variety of character states and combinations unknown in extant taxa, challenging our views of early sponge morphology. The Herefordshire Konservat-Lagerstätte yields an abundant, diverse sponge fauna with three-dimensional preservation of spicules and soft tissue. Carduispongia pedicula gen. et sp. nov. possesses a single layer of hexactine spicules arranged in a regular orthogonal network. This spicule type and arrangement is characteristic of the reticulosans, which have traditionally been interpreted as early members of the extant siliceous Class Hexactinellida. However, the unusual preservation of the spicules of C. pedicula reveals an originally calcareous composition, which would be diagnostic of the living Class Calcarea. The soft tissue architecture closely resembles the complex sylleibid or leuconid structure seen in some modern calcareans and homoscleromorphs. This combination of features strongly supports a skeletal continuum between primitive calcareans and hexactinellid siliceans, indicating that the last common ancestor of Porifera was a spiculate, solitary, vasiform animal with a thin skeletal wall.
Collapse
Affiliation(s)
- Ardianty Nadhira
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK
| | - Mark D. Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK
| | - Joseph P. Botting
- Nanjing Institute of Geology and Palaeontology, 39 East Beijing Road, Nanjing 210008, People's Republic of China
- Department of Natural Sciences, Amgueddfa Cymru—National Museum Wales, Cathays Park, Cardiff CF10 3NP, UK
| | - Lucy A. Muir
- Department of Natural Sciences, Amgueddfa Cymru—National Museum Wales, Cathays Park, Cardiff CF10 3NP, UK
| | - Pierre Gueriau
- IPANEMA, CNRS, Ministère de la Culture, UVSQ, USR 3461, Université Paris-Saclay, 91192 Gif-sur-Yvette, France
- Institute of Earth Sciences, University of Lausanne, Géopolis, CH-1015 Lausanne, Switzerland
| | - Andrew King
- SOLEIL synchrotron, 91192 Gif-sur-Yvette, France
| | - Derek E. G. Briggs
- Department of Geology & Geophysics, and Yale Peabody Museum of Natural History, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA
| | - David J. Siveter
- School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK
| | - Derek J. Siveter
- Earth Collections, University Museum of Natural History, Oxford OX1 3PW, UK
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| |
Collapse
|
3
|
Audo D, Robin N, Luque J, Krobicki M, Haug JT, Haug C, Jauvion C, Charbonnier S. Palaeoecology of Voulteryon parvulus (Eucrustacea, Polychelida) from the Middle Jurassic of La Voulte-sur-Rhône Fossil-Lagerstätte (France). Sci Rep 2019; 9:5332. [PMID: 30926859 PMCID: PMC6441058 DOI: 10.1038/s41598-019-41834-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 03/18/2019] [Indexed: 11/08/2022] Open
Abstract
Exceptional and extremely rare preservation of soft parts, eyes, or syn-vivo associations provide crucial palaeoecological information on fossil-rich deposits. Here we present exceptionally preserved specimens of the polychelidan lobster Voulteryon parvulus, from the Jurassic of La Voulte-sur-Rhône Fossil-Lagerstätte, France, bearing eyes with hexagonal and square facets, ovaries, and a unique association with epibiont thecideoid brachiopods, giving insights onto the palaeoenvironment of this Lagerstätte. The eyes, mostly covered in hexagonal facets are interpreted as either apposition eyes (poorly adapted to low-light environment) or, less likely, as refractive or parabolic superposition eyes (compatible with dysphotic palaeoenvironments). The interpretation that V. parvulus had apposition eyes suggests an allochthonous, shallow water origin. However, the presence of thecideoid brachiopod ectosymbionts on its carapace, usually associated to dim-light paleoenvironments and/or rock crevices, suggests that V. parvulus lived in a dim-light setting. This would support the less parsimonious interpretation that V. parvulus had superposition eyes. If we accept the hypothesis that V. parvulus had apposition eyes, since the La Voulte palaeoenvironment is considered deep water and had a soft substrate, V. parvulus could have moved into the La Voulte Lagerstätte setting. If this is the case, La Voulte biota would record a combination of multiple palaeoenvironments.
Collapse
Affiliation(s)
- Denis Audo
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, North Cuihu road 2#, 650091, Kunming, China.
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.
| | - Ninon Robin
- Centre de Recherche en Paléontologie - Paris (UMR 7207), CNRS-MNHN-Sorbonne Université, Muséum national d'Histoire naturelle, Département Origines & Evolution, (CP 38), 8, rue Buffon, F-75005, Paris, France
| | - Javier Luque
- Department of Geology and Geophysics, Yale University, New Haven, CT, 06520-8109, USA
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Michal Krobicki
- Department of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Mickiewicza 30, 30-059, Kraków, Poland
| | - Joachim T Haug
- LMU Munich, Department of Biology II and GeoBio-Center, Großhaderner Str. 2, 82152, Martinsried-Planegg, Germany
| | - Carolin Haug
- LMU Munich, Department of Biology II and GeoBio-Center, Großhaderner Str. 2, 82152, Martinsried-Planegg, Germany
| | - Clément Jauvion
- Centre de Recherche en Paléontologie - Paris (UMR 7207), CNRS-MNHN-Sorbonne Université, Muséum national d'Histoire naturelle, Département Origines & Evolution, (CP 38), 8, rue Buffon, F-75005, Paris, France
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC, UMR 7590), Muséum National d'Histoire Naturelle, Sorbonne Université, CNRS, IRD, 57 rue Cuvier, F-75005, Paris, France
| | - Sylvain Charbonnier
- Centre de Recherche en Paléontologie - Paris (UMR 7207), CNRS-MNHN-Sorbonne Université, Muséum national d'Histoire naturelle, Département Origines & Evolution, (CP 38), 8, rue Buffon, F-75005, Paris, France
| |
Collapse
|
4
|
Briggs DEG, Siveter DJ, Siveter DJ, Sutton MD, Legg D. Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care. Proc Natl Acad Sci U S A 2016; 113:4410-5. [PMID: 27044103 PMCID: PMC4843443 DOI: 10.1073/pnas.1600489113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The ∼430-My-old Herefordshire, United Kingdom, Lagerstätte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities-that the tethered individuals represent a different epizoic or parasitic arthropod-appear less likely.
Collapse
Affiliation(s)
- Derek E G Briggs
- Department of Geology and Geophysics, Yale University, New Haven, CT 06520-8109; Yale Peabody Museum of Natural History, Yale University, New Haven, CT 06520-8109;
| | - Derek J Siveter
- Oxford University Museum of Natural History, Oxford OX1 3PW, United Kingdom; Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, United Kingdom
| | - David J Siveter
- Department of Geology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Mark D Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, United Kingdom
| | - David Legg
- Oxford University Museum of Natural History, Oxford OX1 3PW, United Kingdom
| |
Collapse
|
5
|
Brachiopods hitching a ride: an early case of commensalism in the middle Cambrian Burgess Shale. Sci Rep 2014; 4:6704. [PMID: 25330795 PMCID: PMC4204044 DOI: 10.1038/srep06704] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 10/02/2014] [Indexed: 11/25/2022] Open
Abstract
Ecological interactions, including symbiotic associations such as mutualism, parasitism and commensalism are crucial factors in generating evolutionary novelties and strategies. Direct examples of species interactions in the fossil record generally involve organisms attached to sessile organisms in an epibiont or macroboring relationship. Here we provide support for an intimate ecological association between a calcareous brachiopod (Nisusia) and the stem group mollusc Wiwaxia from the Burgess Shale. Brachiopod specimens are fixed to Wiwaxia scleritomes, the latter showing no signs of decay and disarticulation, suggesting a live association. We interpret this association as the oldest unambiguous example of a facultative ectosymbiosis between a sessile organism and a mobile benthic animal in the fossil record. The potential evolutionary advantage of this association is discussed, brachiopods benefiting from ease of attachment, increased food supply, avoidance of turbid benthic conditions, biofoul and possible protection from predators, suggesting commensalism (benefiting the symbiont with no impact for the host). While Cambrian brachiopods are relatively common epibionts, in particular on sponges, the association of Nisusia with the motile Wiwaxia is rare for a brachiopod species, fossil or living, and suggests that symbiotic associations were already well established and diversified by the “middle” (Series 3, Stage 5) Cambrian.
Collapse
|
6
|
Sutton MD, Briggs DEG, Siveter DJ, Siveter DJ. A soft-bodied lophophorate from the Silurian of England. Biol Lett 2010; 7:146-9. [PMID: 20685698 DOI: 10.1098/rsbl.2010.0540] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Soft-bodied taxa comprise an important component of the extant lophophorate fauna, but convincing fossils of soft-bodied lophophorates are extremely rare. A small fossil lophophorate, attached to a brachiopod dorsal valve, is described from the Silurian (Wenlock Series) Herefordshire Lagerstätte of England. This unmineralized organism was bilaterally symmetrical and comprised a subconical body attached basally to the host and partially enclosed by a broad 'hood'; the body bore a small, coiled lophophore. Where the hood attached laterally, there is a series of transverse ridges and furrows. The affinities of this organism probably lie with Brachiopoda; the hood is interpreted as the homologue of a dorsal valve/mantle lobe, and the attachment as the homologue of the ventral valve and/or pedicle. The ridges are arranged in a manner that suggests constructional serial repetition, indicating that they are unlikely to represent mantle canals. Extant brachiopods are not serially structured, but morphological and molecular evidence suggests that their ancestors were. The new organism may belong to the brachiopod stem group, and might also represent a significant element of the Palaeozoic lophophorate fauna.
Collapse
Affiliation(s)
- M D Sutton
- Department of Earth Sciences and Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, UK.
| | | | | | | |
Collapse
|
7
|
Garwood RJ, Rahman IA, Sutton MD. From clergymen to computers-the advent of virtual palaeontology. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1365-2451.2010.00753.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
8
|
Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD. An exceptionally preserved myodocopid ostracod from the Silurian of Herefordshire, UK. Proc Biol Sci 2010; 277:1539-44. [PMID: 20106847 DOI: 10.1098/rspb.2009.2122] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An exceptionally preserved new ostracod crustacean from the Silurian of Herefordshire, UK, represents only the third fully documented Palaeozoic ostracod with soft-part preservation. Appendages, gills, gut system, lateral compound eyes and even a medial eye with a Bellonci organ are preserved, allowing assignment of the fossil to a new genus and species of cylindroleberidid myodocope (Myodocopida, Cylindroleberididae). The Bellonci organ is recorded for the first time in fossil ostracods. The find also represents a rare occurrence of gills in fossil ostracods and confirms the earliest direct evidence of a respiratory-cum-circulatory system in the group. The species demonstrates remarkably conserved morphology within myodocopes over a period of 425 Myr. Its shell morphology more closely resembles several families of myodocopes other than the Cylindroleberididae, especially the Cypridinidae and Sarsiellidae, thus questioning the utility of the carapace alone in establishing the affinity of fossil ostracods.
Collapse
Affiliation(s)
- David J Siveter
- Department of Geology, University of Leicester, Leicester, UK.
| | | | | | | |
Collapse
|
9
|
Zhang Z, Han J, Wang Y, Emig CC, Shu D. Epibionts on the lingulate brachiopod Diandongia from the Early Cambrian Chengjiang Lagerstatte, South China. Proc Biol Sci 2009; 277:175-81. [PMID: 19439439 DOI: 10.1098/rspb.2009.0618] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The classic Chengjiang Lagerstätte (Lower Cambrian, Atdabanian stage: Yu'anshan Formation) Yunnan, southwestern China, has yielded, besides the exceptional and often controversial soft-bodied fossils, a fauna of primitive/early lingulid brachiopods. Diandongia pista (Rong 1974) is one of the commonest and most strongly mineralized of the phosphatic brachiopods from the Lagerstätte. The shells of this species have been found to commonly serve as a basibiont host. Epibionts comprise the coeval brachiopod Longtancunella chengjiangensis and the cone-shaped cnidarian-related Archotuba conoidalis, as well as rounded smaller-sized epizoans (lesser than 2 mm). A principle morphological analysis demonstrates that the ovoid and rounded organisms that often occur along the commissure of D. pista resemble small juvenile or immature brachiopods. Epibiont-bearing shells of D. pista with soft-tissue preservation demonstrate that the host brachiopods were overgrown while alive, and provide an argument for D. pista having a semi-infaunal life style with only the slim pedicle embedded in sediment. The epibiotic association sheds direct light on the ecology of Cambrian brachiopods in soft-substrate marine environments. The Chengjiang fossils demonstrate that the Early Cambrian brachiopods, as compared with recent lingulids, occupied different and a wider spectrum of ecological niches and tiers of space.
Collapse
Affiliation(s)
- Zhifei Zhang
- Early Life Institute, State Key Laboratory of Continental Dynamics, Northwest University, Xi'an 710069, People's Republic of China.
| | | | | | | | | |
Collapse
|
10
|
Sutton MD. Tomographic techniques for the study of exceptionally preserved fossils. Proc Biol Sci 2008; 275:1587-93. [PMID: 18426749 DOI: 10.1098/rspb.2008.0263] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Three-dimensional fossils, especially those preserving soft-part anatomy, are a rich source of palaeontological information; they can, however, be difficult to work with. Imaging of serial planes through an object (tomography) allows study of both the inside and outside of three-dimensional fossils. Tomography may be performed using physical grinding or sawing coupled with photography, through optical techniques of serial focusing, or using a variety of scanning technologies such as neutron tomography, magnetic resonance imaging and most usefully X-ray computed tomography. This latter technique is applicable at a variety of scales, and when combined with a synchrotron X-ray source can produce very high-quality data that may be augmented by phase-contrast information to enhance contrast. Tomographic data can be visualized in several ways, the most effective of which is the production of isosurface-based 'virtual fossils' that can be manipulated and dissected interactively.
Collapse
Affiliation(s)
- Mark D Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK.
| |
Collapse
|
11
|
Abstract
Problematica are taxa that defy robust phylogenetic placement. Traditionally the term was restricted to fossil forms, but it is clear that extant taxa may be just as difficult to place, whether using morphological or molecular (nucleotide, gene or genomic) markers for phylogeny reconstruction. We discuss the kinds and causes of Problematica within the Metazoa, as well as criteria for their recognition and possible solutions. The inclusive set of Problematica changes depending upon the nature and quality of (homologous) data available, the methods of phylogeny reconstruction and the sister taxa inferred by their placement or displacement. We address Problematica in the context of pre-cladistic phylogenetics, numerical morphological cladistics and molecular phylogenetics, and focus on general biological and methodological implications of Problematica, rather than presenting a review of individual taxa. Rather than excluding Problematica from phylogeny reconstruction, as has often been preferred, we conclude that the study of Problematica is crucial for both the resolution of metazoan phylogeny and the proper inference of body plan evolution.
Collapse
Affiliation(s)
- Ronald A Jenner
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
| | | |
Collapse
|
12
|
Siveter DJ, Sutton MD, Briggs DEG, Siveter DJ. A new probable stem lineage crustacean with three-dimensionally preserved soft parts from the Herefordshire (Silurian) Lagerstätte, UK. Proc Biol Sci 2007; 274:2099-107. [PMID: 17609185 PMCID: PMC2706188 DOI: 10.1098/rspb.2007.0429] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A new arthropod with three-dimensionally preserved soft parts, Tanazios dokeron, is described from the Wenlock Series (Silurian) of Herefordshire, England, UK. Serial grinding, digital photographic and computer rendering techniques yielded 'virtual fossils' in the round for study. The body tagmata of T. dokeron comprise a head shield and a long trunk. The head shield bears six pairs of horn-like spines and the head bears five pairs of appendages. The antennule, antenna and mandible are all uniramous, and the mandible includes a gnathobasic coxa. Appendages four and five are biramous and similar to those of the trunk: each comprises a limb base with an endite, an enditic membrane, and two epipodites, plus an endopod and exopod. The hypostome bears a large cone-like projection centrally, and there may be a short labrum. The trunk has some 64 segments and at least 60 appendage pairs. A very small telson has the anus sited ventrally in its posterior part and also bears a caudal furca. Comparative morphological and cladistic analyses of T. dokeron indicate a crustacean affinity, with a probable position in the eucrustacean stem group. As such the epipodites in T. dokeron are the first recorded in a eucrustacean stem taxon. The new species is interpreted as a benthic or nektobenthic scavenger.
Collapse
Affiliation(s)
- Derek J Siveter
- Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK.
| | | | | | | |
Collapse
|
13
|
Siveter DJ, Siveter DJ, Sutton MD, Briggs DEG. Brood care in a Silurian ostracod. Proc Biol Sci 2007; 274:465-9. [PMID: 17476765 PMCID: PMC1766388 DOI: 10.1098/rspb.2006.3756] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 10/13/2006] [Indexed: 11/12/2022] Open
Abstract
An exceptionally preserved new ostracod crustacean from the Silurian of Herefordshire, England, preserves eggs and possible juveniles within its carapace, providing an unequivocal and unique view of parental brood care in the invertebrate fossil record. The female fossil is assigned to a new family and superfamily of myodocopids based on its soft-part anatomy. It demonstrates a remarkably conserved egg-brooding reproductive strategy within these ostracods over 425 Myr. The soft-tissue anatomy urges extreme caution in classifying 'straight-hinged' Palaeozoic ostracods based on the carapace alone and fundamentally questions the nature of the shell-based Palaeozoic ostracod record.
Collapse
Affiliation(s)
- David J Siveter
- Department of Geology, University of Leicester, Leicester LE1 7RH, UK.
| | | | | | | |
Collapse
|
14
|
Zhang Z, Han J, Zhang X, Liu J, Guo J, Shu D. Note on the gut preserved in the Lower Cambrian Lingulellotreta (Lingulata, Brachiopoda) from southern China. ACTA ZOOL-STOCKHOLM 2006. [DOI: 10.1111/j.1463-6395.2007.00252.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
15
|
Sutton MD, Briggs DEG, Siveter DJ, Siveter DJ. Fossilized soft tissues in a Silurian platyceratid gastropod. Proc Biol Sci 2006; 273:1039-44. [PMID: 16600878 PMCID: PMC1560260 DOI: 10.1098/rspb.2005.3403] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Gastropod shells are common in the fossil record, but their fossil soft tissues are almost unknown, and have not been reported previously from the Palaeozoic. Here, we describe a Silurian (approx. 425 Myr) platyceratid gastropod from the Herefordshire Lagerstätte that preserves the oldest soft tissues yet reported from an undoubted crown-group mollusc. The digestive system is preserved in detail, and morphological data on the gonads, digestive gland, pedal muscle, radula, mouth and foot are also available. The specimen is preserved three-dimensionally, and has been reconstructed digitally following serial grinding. Platyceratids are often found attached to echinoderms, and have been interpreted as either commensal coprophages or kleptoparasites. The new data provide support for an attached mode of life, and are suggestive of a coprophagous feeding strategy. The affinities of the platyceratids are uncertain; they have been compared to both the patellogastropods and the neritopsines. Analysis of the new material suggests that a patellogastropod affinity is the more plausible of these hypotheses.
Collapse
Affiliation(s)
- M D Sutton
- Department of Earth Sciences and Engineering, South Kensington Campus, Imperial College London, SW7 2AZ, UK.
| | | | | | | |
Collapse
|
16
|
Abstract
Exceptionally preserved fossils from the Wenlock Series (Silurian) of Herefordshire, UK, provide unique evidence of metamorphosis from free-swimming cyprid larva to attached juvenile in a Palaeozoic barnacle. The larva had large brush-like anterior limbs. The juvenile shows the head transformed into a stalk and the development of the primordial condition of five mineralized plates within the carapace. The discovery of a cyprid larva indicates that crown group cirripedes had evolved by the Silurian.
Collapse
Affiliation(s)
- Derek E G Briggs
- Yale University, Department of Geology and Geophysics, PO Box 208109, New Haven, CT 06520-8109, USA.
| | | | | | | |
Collapse
|