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Hou JB, Hughes NC, Hopkins MJ. The trilobite upper limb branch is a well-developed gill. SCIENCE ADVANCES 2021; 7:eabe7377. [PMID: 33789898 PMCID: PMC8011964 DOI: 10.1126/sciadv.abe7377] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
Whether the upper limb branch of Paleozoic "biramous" arthropods, including trilobites, served a respiratory function has been much debated. Here, new imaging of the trilobite Triarthrus eatoni shows that dumbbell-shaped filaments in the upper limb branch are morphologically comparable with gill structures in crustaceans that aerate the hemolymph. In Olenoides serratus, the upper limb's partial articulation to the body via an extended arthrodial membrane is morphologically comparable to the junction of the respiratory book gill of Limulus and differentiates it from the typically robust exopod junction in Chelicerata or Crustacea. Apparently limited mechanical rotation of the upper branch may have protected the respiratory structures. Partial attachment of the upper branch to the body wall may represent an intermediate state in the evolution of limb branch fusion between dorsal attachment to the body wall, as in Radiodonta, and ventral fusion to the limb base, as in extant Euarthropoda.
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Affiliation(s)
- Jin-Bo Hou
- Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA.
| | - Nigel C Hughes
- Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA
- Geological Studies Unit, Indian Statistical Institute, Kolkata 700108, India
| | - Melanie J Hopkins
- Division of Paleontology (Invertebrates), American Museum of Natural History, New York, NY 10024, USA
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2
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Wang H, Matzke-Karasz R, Horne DJ, Zhao X, Cao M, Zhang H, Wang B. Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods. Proc Biol Sci 2020; 287:20201661. [PMID: 32933445 PMCID: PMC7542813 DOI: 10.1098/rspb.2020.1661] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/19/2020] [Indexed: 11/12/2022] Open
Abstract
The bivalved crustacean ostracods have the richest fossil record of any arthropod group and display complex reproductive strategies contributing to their evolutionary success. Sexual reproduction involving giant sperm, shared by three superfamilies of living ostracod crustaceans, is among the most fascinating behaviours. However, the origin and evolution of this reproductive mechanism has remained largely unexplored because fossil preservation of such features is extremely rare. Here, we report exceptionally preserved ostracods with soft parts (appendages and reproductive organs) in a single piece of mid-Cretaceous Kachin amber (approximately 100 Myr old). The ostracod assemblage is composed of 39 individuals. Thirty-one individuals belong to a new species and genus, Myanmarcypris hui gen. et sp. nov., exhibiting an ontogenetic sequence from juveniles to adults (male and female). Seven individuals are assigned to Thalassocypria sp. (Cypridoidea, Candonidae, Paracypridinae) and one to Sanyuania sp. (Cytheroidea, Loxoconchidae). Our micro-CT reconstruction provides direct evidence of the male clasper, sperm pumps (Zenker organs), hemipenes, eggs and female seminal receptacles with giant sperm. Our results reveal that the reproduction behavioural repertoire, which is associated with considerable morphological adaptations, has remained unchanged over at least 100 million years-a paramount example of evolutionary stasis. These results also double the age of the oldest unequivocal fossil animal sperm. This discovery highlights the capacity of amber to document invertebrate soft parts that are rarely recorded by other depositional environments.
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Affiliation(s)
- He Wang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
| | - Renate Matzke-Karasz
- Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Ludwig-Maximilians-Universität München, Richard-Wagner-Strasse 10, 80333 München, Germany
| | - David J. Horne
- School of Geography, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Xiangdong Zhao
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Meizhen Cao
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
| | - Haichun Zhang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
| | - Bo Wang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
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3
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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.
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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
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Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD. A well-preserved respiratory system in a Silurian ostracod. Biol Lett 2018; 14:rsbl.2018.0464. [PMID: 30404865 PMCID: PMC6283931 DOI: 10.1098/rsbl.2018.0464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/12/2018] [Indexed: 11/13/2022] Open
Abstract
Ostracod crustaceans are diverse and ubiquitous in aqueous environments today but relatively few known species have gills. Ostracods are the most abundant fossil arthropods but examples of soft-part preservation, especially of gills, are exceptionally rare. A new ostracod, Spiricopia aurita (Myodocopa), from the marine Silurian Herefordshire Lagerstätte (430 Mya), UK, preserves appendages, lateral eyes and gills. The respiratory system includes five pairs of gill lamellae with hypobranchial and epibranchial canals that conveyed haemolymph. A heart and associated vessels had likely evolved in ostracods by the Mid-Silurian.
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Affiliation(s)
- David J Siveter
- School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK
| | - Derek E G Briggs
- Department of Geology and Geophysics, and Yale Peabody Museum of Natural History, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA
| | - 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
| | - Mark D Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK
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5
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Arenz AL, Tran T, Koyama KH, Marin Gomez AM, Rivera AS. Sexually Dimorphic Eye-Loss Driven by Ecological Selection in an Ostracod Crustacean: Support for the Reproductive Role Hypothesis. Integr Comp Biol 2018; 58:431-440. [PMID: 30107507 DOI: 10.1093/icb/icy077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Euphilomedes carcharodonta ostracods exhibit sex-specific eye-loss, with females lacking image-forming compound eyes compared with males and related species. The standard assumption is that sexual dimorphism is driven by sexual selection. However, previous work in E. carcharodonta suggests that male eyes are used to evade predators in the male-specific ecological niche, and that male-eyes lack the resolution to search for females. In this study, we examine whether sexual selection or ecological selection drives the retention of male eyes. Ecological niche differentiation was hypothesized by Darwin (1871) to be an alternative selective force for sexual dimorphism either through food competition or through dimorphic sex-role behavior, the reproductive role hypothesis. As of yet, there is little experimental evidence supporting this hypothesis. Here, we experimentally blindfold male E. carcharodonta to mimic the female phenotype and examine the effects on sex-specific niches and behavior. Blindfolding does not appear to grossly change male behavior, nor do females behave differently when exposed to blindfolded males. This lead us to conclude that the development of complex eyes in male E. arises from ecological selection rather than sexual selection.
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Affiliation(s)
- Alexis L Arenz
- Department of Biological Sciences, University of the Pacific, 601 Pacific Avenue, Stockton, CA 95211, USA
| | - Tiffanie Tran
- Department of Biological Sciences, University of the Pacific, 601 Pacific Avenue, Stockton, CA 95211, USA
| | - Kristina H Koyama
- Department of Biological Sciences, University of the Pacific, 601 Pacific Avenue, Stockton, CA 95211, USA
| | - Astrid M Marin Gomez
- Department of Biological Sciences, University of the Pacific, 601 Pacific Avenue, Stockton, CA 95211, USA
| | - Ajna S Rivera
- Department of Biological Sciences, University of the Pacific, 601 Pacific Avenue, Stockton, CA 95211, USA
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6
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Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD, Legg D. A three-dimensionally preserved lobopodian from the Herefordshire (Silurian) Lagerstätte, UK. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172101. [PMID: 30224988 PMCID: PMC6124121 DOI: 10.1098/rsos.172101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 07/06/2018] [Indexed: 06/08/2023]
Abstract
The Herefordshire (Silurian) Lagerstätte (approx. 430 Myr BP) has yielded, among many exceptionally preserved invertebrates, a wide range of new genera belonging to crown-group Panarthropoda. Here, we increase this panarthropod diversity with the lobopodian Thanahita distos, a new total-group panarthropod genus and species. This new lobopodian preserves at least nine paired, long, slender appendages, the anterior two in the head region and the posterior seven representing trunk lobopods. The body ends in a short post-appendicular extension. Some of the trunk lobopods bear two claws, others a single claw. The body is covered by paired, tuft-like papillae. Thanahita distos joins only seven other known three-dimensionally preserved lobopodian or onychophoran (velvet worm) fossil specimens and is the first lobopodian to be formally described from the Silurian. Phylogenetic analysis recovered it, together with all described Hallucigenia species, in a sister-clade to crown-group panarthropods. Its placement in a redefined Hallucigeniidae, an iconic Cambrian clade, indicates the survival of this clade to Silurian times.
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Affiliation(s)
- Derek J. Siveter
- Earth Collections, University Museum of Natural History, Oxford OX1 3PW, UK
- Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3AN, UK
| | - Derek E. G. Briggs
- Department of Geology and 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
| | - Mark D. Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK
| | - David Legg
- School of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK
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7
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A gigantic marine ostracod (Crustacea: Myodocopa) trapped in mid-Cretaceous Burmese amber. Sci Rep 2018; 8:1365. [PMID: 29358761 PMCID: PMC5778021 DOI: 10.1038/s41598-018-19877-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/09/2018] [Indexed: 11/29/2022] Open
Abstract
The mid-Cretaceous Burmese amber (~99 Ma, Myanmar), widely known for exquisite preservation of theropods, also yields microfossils, which can provide important contextual information on paleoenvironment and amber formation. We report the first Cretaceous ostracod in amber—the gigantic (12.9 mm) right valve of an exclusively marine group (Myodocopa: Myodocopida) preserved in Burmese amber. Ostracods are usually small (0.5–2 mm), with well-calcified carapaces that provide an excellent fossil record extending to at least the Ordovician (~485 million years ago), but they are rarely encountered in amber. The new specimen effectively doubles the age of the ostracod amber record, offering the first representative of the Myodocopa, a weakly calcified group with a poor fossil record. Its carapace morphology is atypical and likely plesiomorphic. The preserved valve appears to be either a moulted exuvium or a dead and disarticulated specimen, and subsequent resin flows contain forest floor inclusions with terrestrial arthropods, i.e., fragmentary remains of spiders, and insect frass. These features resolve an enigmatic taphonomic pathway, and support a marginal marine setting for resin production.
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8
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Sorek M, Douek J, Guy-Haim T, Simon-Blecher N, Rinkevich B, Achituv Y. Population genetics and reproductive strategies of two Notostraca (Crustacea) species from winter ponds in Israel. ZOOLOGY IN THE MIDDLE EAST 2016. [DOI: 10.1080/09397140.2016.1257404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Michal Sorek
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Jacob Douek
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Tamar Guy-Haim
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Noa Simon-Blecher
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Baruch Rinkevich
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Yair Achituv
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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9
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Vogt G. Structural specialties, curiosities, and record-breaking features of crustacean reproduction. J Morphol 2016; 277:1399-1422. [DOI: 10.1002/jmor.20582] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/18/2016] [Accepted: 07/06/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Günter Vogt
- Faculty of Biosciences; University of Heidelberg; Im Neuenheimer Feld 230 69120 Heidelberg Germany
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10
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Schön I, Martens K. Ostracod (Ostracoda, Crustacea) genomics - Promises and challenges. Mar Genomics 2016; 29:19-25. [PMID: 27020380 DOI: 10.1016/j.margen.2016.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/11/2016] [Accepted: 03/15/2016] [Indexed: 01/18/2023]
Abstract
Ostracods are well-suited model organisms for evolutionary research. Classic genetic techniques have mostly been used for phylogenetic studies on Ostracoda and were somewhat affected by the lack of large numbers of suitable markers. Genomic methods with their huge potential have so far rarely been applied to this group of crustaceans. We provide relevant examples of genomic studies on other organisms to propose future avenues of genomic ostracod research. At the same time, we suggest solutions to the potential problems in ostracods that the application of genomic techniques might present.
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Affiliation(s)
- Isa Schön
- Royal Belgian Institute of Natural Sciences, OD Nature, ATECO, Freshwater Biology, Vautierstraat 29, B-1000 Brussels, Belgium; University of Hasselt, Research Group Zoology, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Koen Martens
- Royal Belgian Institute of Natural Sciences, OD Nature, ATECO, Freshwater Biology, Vautierstraat 29, B-1000 Brussels, Belgium; University of Ghent, Department of Biology, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
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11
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Daley AC, Drage HB. The fossil record of ecdysis, and trends in the moulting behaviour of trilobites. ARTHROPOD STRUCTURE & DEVELOPMENT 2016; 45:71-96. [PMID: 26431634 DOI: 10.1016/j.asd.2015.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/01/2015] [Accepted: 09/14/2015] [Indexed: 06/05/2023]
Abstract
Ecdysis, the process of moulting an exoskeleton, is one of the key characters uniting arthropods, nematodes and a number of smaller phyla into Ecdysozoa. The arthropod fossil record, particularly trilobites, eurypterids and decapod crustaceans, yields information on moulting, although the current focus is predominantly descriptive and lacks a broader evolutionary perspective. We here review literature on the fossil record of ecdysis, synthesising research on the behaviour, evolutionary trends, and phylogenetic significance of moulting throughout the Phanerozoic. Approaches vary widely between taxonomic groups, but an overall theme uniting these works suggests that identifying moults in the palaeontological record must take into account the morphology, taphonomy and depositional environment of fossils. We also quantitatively analyse trends in trilobite ecdysis based on a newly generated database of published incidences of moulting behaviour. This preliminary work reveals significant taxonomic and temporal signal in the trilobite moulting fossil record, with free cheek moulting being prevalent across all Orders and throughout the Phanerozoic, and peaks of cephalic moulting in Phacopida during the Ordovician and rostral plate moulting in Redlichiida during the Cambrian. This study and a review of the literature suggest that it is feasible to extract large-scale evolutionary information from the fossil record of moulting.
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Affiliation(s)
- Allison C Daley
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom; Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PZ, United Kingdom.
| | - Harriet B Drage
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom; Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PZ, United Kingdom
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12
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Siveter D, Briggs D, Siveter D, Sutton M. A 425-Million-Year-Old Silurian Pentastomid Parasitic on Ostracods. Curr Biol 2015; 25:1632-7. [DOI: 10.1016/j.cub.2015.04.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 04/11/2015] [Accepted: 04/15/2015] [Indexed: 10/23/2022]
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13
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Matzke-Karasz R, Neil JV, Smith RJ, Symonová R, Mořkovský L, Archer M, Hand SJ, Cloetens P, Tafforeau P. Subcellular preservation in giant ostracod sperm from an early Miocene cave deposit in Australia. Proc Biol Sci 2015; 281:rspb.2014.0394. [PMID: 24827442 DOI: 10.1098/rspb.2014.0394] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cypridoidean ostracods are one of a number of animal taxa that reproduce with giant sperm, up to 10 000 µm in length, but they are the only group to have aflagellate, filamentous giant sperm. The evolution and function of this highly unusual feature of reproduction with giant sperm are currently unknown. The hypothesis of long-term evolutionary persistence of this kind of reproduction has never been tested. We here report giant sperm discovered by propagation phase contrast X-ray synchrotron micro- and nanotomography, preserved in five Miocene ostracod specimens from Queensland, Australia. The specimens belong to the species Heterocypris collaris Matzke-Karasz et al. 2013 (one male and three females) and Newnhamia mckenziana Matzke-Karasz et al. 2013 (one female). The sperm are not only the oldest petrified gametes on record, but include three-dimensional subcellular preservation. We provide direct evidence that giant sperm have been a feature of this taxon for at least 16 Myr and provide an additional criterion (i.e. longevity) to test hypotheses relating to origin and function of giant sperm in the animal kingdom. We further argue that the highly resistant, most probably chitinous coats of giant ostracod sperm may play a role in delaying decay processes, favouring early mineralization of soft tissue.
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Affiliation(s)
- Renate Matzke-Karasz
- Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Ludwig-Maximilian-University and GeoBio-Center, Richard-Wagner-Strasse 10, 80333 Munich, Germany
| | - John V Neil
- School of Civil Engineering and Physical Sciences, La Trobe University, PO Box 199, Bendigo, Victoria 3552, Australia
| | - Robin J Smith
- Lake Biwa Museum, Oroshimo 1091, Kusatsu, Shiga 525-0001, Japan
| | - Radka Symonová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12844 Praha, Czech Republic
| | - Libor Mořkovský
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12844 Praha, Czech Republic
| | - Michael Archer
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Suzanne J Hand
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Peter Cloetens
- European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France
| | - Paul Tafforeau
- European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France
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14
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Exceptionally Preserved 450-Million-Year-Old Ordovician Ostracods with Brood Care. Curr Biol 2014; 24:801-6. [DOI: 10.1016/j.cub.2014.02.040] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 12/17/2013] [Accepted: 02/15/2014] [Indexed: 11/30/2022]
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15
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Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD, Legg D, Joomun S. A Silurian short-great-appendage arthropod. Proc Biol Sci 2014; 281:20132986. [PMID: 24452026 PMCID: PMC3906945 DOI: 10.1098/rspb.2013.2986] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A new arthropod, Enalikter aphson gen. et sp. nov., is described from the Silurian (Wenlock Series) Herefordshire Lagerstätte of the UK. It belongs to the Megacheira (=short-great-appendage group), which is recognized here, for the first time, in strata younger than mid-Cambrian age. Discovery of this new Silurian taxon allows us to identify a Devonian megacheiran representative, Bundenbachiellus giganteus from the Hunsrück Slate of Germany. The phylogenetic position of megacheirans is controversial: they have been interpreted as stem chelicerates, or stem euarthropods, but when Enalikter and Bundenbachiellus are added to the most comprehensive morphological database available, a stem euarthropod position is supported. Enalikter represents the only fully three-dimensionally preserved stem-group euarthropod, it falls in the sister clade to the crown-group euarthropods, and it provides new insights surrounding the origin and early evolution of the euarthropods. Recognition of Enalikter and Bundenbachiellus as megacheirans indicates that this major arthropod group survived for nearly 100 Myr beyond the mid-Cambrian.
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Affiliation(s)
- Derek J Siveter
- Earth Collections, University Museum of Natural History, , Parks Road, Oxford OX1 3PW, UK, Department of Earth Sciences, University of Oxford, , South Parks Road, Oxford OX1 3PR, UK, Department of Geology and Geophysics and Yale Peabody Museum of Natural History, Yale University, , PO Box 208109, New Haven, CT 06520-8109, USA, Department of Geology, University of Leicester, , Leicester LE1 7RH, UK, Department of Earth Sciences and Engineering, Imperial College London, , London SW7 2BP, UK
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16
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Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD, Joomun SC. A Silurian myodocope with preserved soft-parts: cautioning the interpretation of the shell-based ostracod record. Proc Biol Sci 2012; 280:20122664. [PMID: 23235709 DOI: 10.1098/rspb.2012.2664] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ostracod crustaceans are the most abundant fossil arthropods. The Silurian Pauline avibella gen. et sp. nov., from the Herefordshire Lagerstätte, UK, is an extremely rare Palaeozoic example with soft-part preservation. Based on its soft-part morphology, especially the exceptionally preserved limbs and presence of lateral eyes, it is assigned to the myodocopid myodocopes. The ostracod is very large, with an epipod on the fifth limb pair, as well as gills implying the presence of a heart and an integrated respiratory-circulatory system as in living cylindroleberidid myodocopids. Features of its shell morphology, however, recall halocyprid myodocopes and palaeocopes, encouraging caution in classifying ostracods based on the carapace alone and querying the interpretation of their shell-based fossil record, especially for the Palaeozoic, where some 500 genera are presently assigned to the Palaeocopida.
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Affiliation(s)
- David J Siveter
- Department of Geology, University of Leicester, Leicester LE1 7RH, UK.
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Karanovic I, Lörz AN. A new subfamily and species of Ostracoda (Cylindroleberididae, Myodocopa) from the Chatham Rise (New Zealand). NEW ZEALAND JOURNAL OF ZOOLOGY 2012. [DOI: 10.1080/03014223.2011.648200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Oakley TH, Wolfe JM, Lindgren AR, Zaharoff AK. Phylotranscriptomics to Bring the Understudied into the Fold: Monophyletic Ostracoda, Fossil Placement, and Pancrustacean Phylogeny. Mol Biol Evol 2012; 30:215-33. [DOI: 10.1093/molbev/mss216] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Rodriguez-Lazaro J, Ruiz-Muñoz F. A General Introduction to Ostracods. OSTRACODA AS PROXIES FOR QUATERNARY CLIMATE CHANGE 2012. [DOI: 10.1016/b978-0-444-53636-5.00001-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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20
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Williams M, Vannier J, Corbari L, Massabuau JC. Oxygen as a driver of early arthropod micro-benthos evolution. PLoS One 2011; 6:e28183. [PMID: 22164241 PMCID: PMC3229522 DOI: 10.1371/journal.pone.0028183] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/02/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND We examine the physiological and lifestyle adaptations which facilitated the emergence of ostracods as the numerically dominant Phanerozoic bivalve arthropod micro-benthos. METHODOLOGY/PRINCIPAL FINDINGS The PO(2) of modern normoxic seawater is 21 kPa (air-equilibrated water), a level that would cause cellular damage if found in the tissues of ostracods and much other marine fauna. The PO(2) of most aquatic breathers at the cellular level is much lower, between 1 and 3 kPa. Ostracods avoid oxygen toxicity by migrating to waters which are hypoxic, or by developing metabolisms which generate high consumption of O(2). Interrogation of the Cambrian record of bivalve arthropod micro-benthos suggests a strong control on ecosystem evolution exerted by changing seawater O(2) levels. The PO(2) of air-equilibrated Cambrian-seawater is predicted to have varied between 10 and 30 kPa. Three groups of marine shelf-dwelling bivalve arthropods adopted different responses to Cambrian seawater O(2). Bradoriida evolved cardiovascular systems that favoured colonization of oxygenated marine waters. Their biodiversity declined during intervals associated with black shale deposition and marine shelf anoxia and their diversity may also have been curtailed by elevated late Cambrian (Furongian) oxygen-levels that increased the PO(2) gradient between seawater and bradoriid tissues. Phosphatocopida responded to Cambrian anoxia differently, reaching their peak during widespread seabed dysoxia of the SPICE event. They lacked a cardiovascular system and appear to have been adapted to seawater hypoxia. As latest Cambrian marine shelf waters became well oxygenated, phosphatocopids went extinct. Changing seawater oxygen-levels and the demise of much of the seabed bradoriid micro-benthos favoured a third group of arthropod micro-benthos, the ostracods. These animals adopted lifestyles that made them tolerant of changes in seawater O(2). Ostracods became the numerically dominant arthropod micro-benthos of the Phanerozoic. CONCLUSIONS/SIGNIFICANCE Our work has implications from an evolutionary context for understanding how oxygen-level in marine ecosystems drives behaviour.
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Affiliation(s)
- Mark Williams
- Department of Geology, University of Leicester, Leicester, United Kingdom.
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21
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Syme AE, Oakley TH. Dispersal between Shallow and Abyssal Seas and Evolutionary Loss and Regain of Compound Eyes in Cylindroleberidid Ostracods: Conflicting Conclusions from Different Comparative Methods. Syst Biol 2011; 61:314-36. [PMID: 21865337 DOI: 10.1093/sysbio/syr085] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Anna E. Syme
- Ecology, Evolution, Marine Biology and Marine Science Institute, University of California-Santa Barbara, Santa Barbara, CA 93106, USA; and
| | - Todd H. Oakley
- Ecology, Evolution, Marine Biology and Marine Science Institute, University of California-Santa Barbara, Santa Barbara, CA 93106, USA; and
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Olempska E, Horne DJ, Szaniawski H. First record of preserved soft parts in a Palaeozoic podocopid (Metacopina) ostracod, Cytherellina submagna: phylogenetic implications. Proc Biol Sci 2011; 279:564-70. [PMID: 21733903 DOI: 10.1098/rspb.2011.0943] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The metacopines represent one of the oldest and most important extinct groups of ostracods, with a fossil record from the Mid-Ordovician to the Early Jurassic. Herein, we report the discovery of a representative of the group with three-dimensionally preserved soft parts. The specimen--a male of Cytherellina submagna--was found in the Early Devonian (416 Ma) of Podolia, Ukraine. A branchial plate (Bp) of the cephalic maxillula (Mx), a pair of thoracic appendages (walking legs), a presumed furca (Fu) and a copulatory organ are preserved. The material also includes phosphatized steinkerns with exceptionally preserved marginal pore canals and muscle scars. The morphology of the preserved limbs and valves of C. submagna suggests its relationship with extant Podocopida, particularly with the superfamilies Darwinuloidea and Sigillioidea, which have many similar characteristic features, including a large Bp on the Mx, the morphology of walking legs, Fu with two terminal claws, internal stop-teeth in the left valve, adductor muscle scar pattern, and a very narrow fused zone along the anterior and posterior margins. More precise determination of affinities will depend on the soft-part morphology of the cephalic segment, which has not been revealed in the present material.
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Affiliation(s)
- E Olempska
- Institute of Paleobiology, Polish Academy of Sciences, 00-818 Warszawa, Poland.
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Hou X, Williams M, Siveter DJ, Siveter DJ, Aldridge RJ, Sansom RS. Soft-part anatomy of the Early Cambrian bivalved arthropods Kunyangella and Kunmingella: significance for the phylogenetic relationships of Bradoriida. Proc Biol Sci 2010; 277:1835-41. [PMID: 20181565 DOI: 10.1098/rspb.2009.2194] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bradoriids are small bivalved marine arthropods that are widespread in rocks of Cambrian to Early Ordovician age. They comprise seven families and about 70 genera based on shield ('carapace') morphology. New bradoriid specimens with preserved soft-part anatomy of Kunmingella douvillei (Kunmingellidae) are reported from the Early Cambrian Chengjiang Lagerstätte of China together with, for the first time to our knowledge, a second bradoriid species with preserved soft parts, Kunyangella cheni (Comptalutidae). Kunmingella douvillei has a 10-segmented limb-bearing body with uniramous ninth and tenth appendages and a series of homogeneous, apparently (proximal parts not preserved) unspecialized post-antennal biramous limbs with setose leaf-shaped exopods. Each endopod consists of five podomeres. A presumed penultimate instar of Ky. cheni preserves remnants of three head and two trunk appendages, and the adult is reconstructed as having four head appendages. This material allows testing of the affinity of the Bradoriida. Kunmingella is identified as a stem crustacean in character-based analyses, through both morphological comparisons and cladistic reconstructions. Global parsimony analysis recovers a monophyletic Bradoriida as the sister group to crown crustaceans.
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Affiliation(s)
- Xianguang Hou
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming, Yunnan Province, People's Republic of China.
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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.
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Affiliation(s)
- David J Siveter
- Department of Geology, University of Leicester, Leicester, UK.
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Tanaka G, Smith RJ, Siveter DJ, Parker AR. Three-Dimensionally Preserved Decapod Larval Compound Eyes from the Cretaceous Santana Formation of Brazil. Zoolog Sci 2009; 26:846-50. [DOI: 10.2108/zsj.26.846] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Williams M, Siveter DJ, Ashworth AC, Wilby PR, Horne DJ, Lewis AR, Marchant DR. Exceptionally preserved lacustrine ostracods from the Middle Miocene of Antarctica: implications for high-latitude palaeoenvironment at 77 degrees south. Proc Biol Sci 2008; 275:2449-54. [PMID: 18647723 PMCID: PMC2603191 DOI: 10.1098/rspb.2008.0396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A newly discovered Konservat-Lagerstätte from the Middle Miocene of the western Olympus Range, Dry Valleys, Antarctica, yields cypridoidean ostracods complete with preserved body and appendages. This is the first record of three-dimensionally fossilized animal soft tissues from the continent. The ostracods are preserved in goethite, secondary after pyrite, representing a novel mode of exceptional preservation. They signal a high-latitude (greater than 77 degrees south) lake setting (Palaeolake Boreas) viable for benthic animal colonization prior to 14 Myr ago. Their presence supports the notion of warmer, tundra-like environmental conditions persisting in the Dry Valleys until the Middle Miocene.
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Affiliation(s)
- Mark Williams
- Department of Geology, University of Leicester, Leicester LE1 7RH, UK.
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27
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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.
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Affiliation(s)
- Mark D Sutton
- Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK.
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Tinn O, Oakley TH. Erratic rates of molecular evolution and incongruence of fossil and molecular divergence time estimates in Ostracoda (Crustacea). Mol Phylogenet Evol 2008; 48:157-67. [DOI: 10.1016/j.ympev.2008.03.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/23/2008] [Accepted: 03/02/2008] [Indexed: 11/16/2022]
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Williams M, Siveter DJ, Salas MJ, Vannier J, Popov LE, Ghobadi Pour M. The earliest ostracods: the geological evidence. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/bf03043974] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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30
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Oakley TH, Plachetzki DC, Rivera AS. Furcation, field-splitting, and the evolutionary origins of novelty in arthropod photoreceptors. ARTHROPOD STRUCTURE & DEVELOPMENT 2007; 36:386-400. [PMID: 18089117 DOI: 10.1016/j.asd.2007.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 08/28/2007] [Indexed: 05/25/2023]
Abstract
Arthropod photoreceptor evolution is a prime example of how evolution has used existing components in the origin of new structures. Here, we outline a comparative approach to understanding the mutational origins of novel structures, describing multiple examples from arthropod photoreceptor evolution. We suggest that developmental mechanisms have often split photoreceptors during evolution (field-splitting) and we introduce "co-duplication" as a null model for the mutational origins of photoreceptor components. Under co-duplication, gene duplication events coincide with the origin of a higher level structure like an eye. If co-duplication is rejected for a component, that component probably came to be used in a new photoreceptor through regulatory mutations. If not rejected, a gene duplication mutation may have allowed the component to be used in a new structure. In multiple case studies in arthropod photoreceptor evolution, we consistently reject the null hypothesis of co-duplication of genetic components and photoreceptors. Nevertheless, gene duplication events have in some cases occurred later, allowing divergence of photoreceptors. These studies provide a new perspective on the evolution of arthropod photoreceptors and provide a comparative approach that generalizes to the study of any evolutionary novelty.
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Affiliation(s)
- Todd H Oakley
- Ecology Evolution and Marine Biology, University of California-Santa Barbara, Santa Barbara, CA 93106, USA.
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Siveter DJ, Fortey RA, Sutton MD, Briggs DEG, Siveter DJ. A Silurian 'marrellomorph' arthropod. Proc Biol Sci 2007; 274:2223-9. [PMID: 17646139 PMCID: PMC2287322 DOI: 10.1098/rspb.2007.0712] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Xylokorys chledophilia, a new arthropod with three-dimensionally preserved soft tissues, is described from the Herefordshire (Silurian) Lagerstätte of England. The head and trunk are covered by a relatively featureless ovoid carapace, which comprises a domed central part and a flange-like border. The head bears five pairs of appendages. The first is uniramous, with dorsal and ventral projections distally. Appendages two to four are biramous and each endopod terminates in two projections. Appendage five is possibly biramous. The hypostome is very long and subrectangular in outline. There are approximately 35 pairs of biramous trunk appendages. Each exopod comprises a long slender shaft bearing numerous fine filaments; each endopod comprises a ribbon-like shaft bearing paddle-like endites. Morphological comparisons and cladistic analyses of X. chledophilia indicate affinity with Vachonisia rogeri from the Lower Devonian Hunsrück Slate, within the marrellomorphs, but assignment to Marrellomorpha is provisional pending revision of other members of this clade. Xylokorys is the first 'marrellomorph' to be reported from the Silurian. It is interpreted as a benthic particle filter feeder, which may also have consumed prey items.
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Affiliation(s)
- Derek J Siveter
- Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK.
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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.
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Affiliation(s)
- Derek J Siveter
- Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK.
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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.
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Affiliation(s)
- David J Siveter
- Department of Geology, University of Leicester, Leicester LE1 7RH, UK.
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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.
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Affiliation(s)
- M D Sutton
- Department of Earth Sciences and Engineering, South Kensington Campus, Imperial College London, SW7 2AZ, UK.
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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.
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Affiliation(s)
- Derek E G Briggs
- Yale University, Department of Geology and Geophysics, PO Box 208109, New Haven, CT 06520-8109, USA.
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38
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Sutton MD, Briggs DEG, Siveter DJ, Siveter DJ. Silurian brachiopods with soft-tissue preservation. Nature 2005; 436:1013-5. [PMID: 16107847 DOI: 10.1038/nature03846] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 05/23/2005] [Indexed: 11/09/2022]
Abstract
'Articulated' rhynchonelliformean brachiopods are abundant shelly fossils, but the direct fossil record of their soft parts was hitherto confined to a single pyritized trace possibly representing a lophophore. Anatomical knowledge of extinct rhynchonelliformeans relies heavily on analogies to extant species; these analogies are untested for stem-group clades. The Silurian Herefordshire (UK) Konservat-Lagerstätte (about 425 Myr bp) yields exceptionally preserved three-dimensional fossils that provide unrivalled insights into the palaeobiology of a variety of invertebrates. The fossils are preserved as calcitic void in-fills in carbonate concretions within a volcaniclastic horizon, and are reconstructed digitally. Here we describe a stem-group rhynchonelliformean specimen from this deposit; it most probably belongs in the order Orthida. A robust ridged pedicle with distal rootlets is preserved, together with a lophophore and other soft-tissue structures. The pedicle morphology is novel, urging caution in inferring stem-group rhynchonelliformean anatomy from that of crown-group species. Smaller brachiopods are attached to the specimen; these include a probable atrypide, with pedicle and marginal setae preserved.
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Affiliation(s)
- Mark D Sutton
- Department of Earth Science and Engineering, Imperial College, London SW7 2AZ, UK.
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Sutton MD, Briggs DEG, Siveter DJ, Siveter DJ, Gladwell DJ. A starfish with three-dimensionally preserved soft parts from the Silurian of England. Proc Biol Sci 2005; 272:1001-6. [PMID: 16024357 PMCID: PMC1599871 DOI: 10.1098/rspb.2004.2951] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Palaeozoic asteroids represent a stem-group to the monophyletic post-Palaeozoic Neoasteroidea, but many aspects of their anatomy are poorly known. Using serial grinding and computer reconstruction, we describe fully articulated Silurian (ca 425 Myr) specimens from the Herefordshire Lagerstätte, preserved in three dimensions complete with soft tissues. The material belongs to a species of Bdellacoma, a genus previously assigned to the ophiuroids, but has characters that suggest an asteroid affinity. These include a pyloric system in the gut, and the presence of large bivalved pedicellariae, the latter originally described under the name Bursulella from isolated valves. Ampullae are external and occur within podial basins; the radial canal is also external. Podia are elongate and lack terminal suckers. The peristome is large relative to the mouth. Aspects of the morphology are comparable to that of the extant Paxillosida, supporting phylogenetic schemes that place this order at the base of the asteroid crown group.
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Affiliation(s)
- M D Sutton
- Department of Earth Sciences and Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, UK.
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Ogoh K, Ohmiya Y. Biogeography of luminous marine ostracod driven irreversibly by the Japan current. Mol Biol Evol 2005; 22:1543-5. [PMID: 15858206 DOI: 10.1093/molbev/msi155] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The biogeography of the luminous marine ostracod Vargula hilgendorfii, also called "Umihotaru," shows that this organism may have arrived relatively recently on the Japanese islands during the final glacier period approximately 10,000 years ago. Phylogenetic relationships also strongly indicate that the Japan Current drove the Umihotaru ostracod northward. It is evident that the Umihotaru ostracod spread rapidly to the major Japanese islands 3,000 km north, whereas its spread was slow in the southwest of the Japanese islands, covering a distance of 400 km. The meandering of the Japan Current, where it passes by the Tokara Gap at 28 degrees N latitude, may be a barrier to Umihotaru ostracod extension.
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Siveter DJ, Sutton MD, Briggs DEG, Siveter DJ. A Silurian sea spider. Nature 2004; 431:978-80. [PMID: 15496921 DOI: 10.1038/nature02928] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Accepted: 08/12/2004] [Indexed: 11/08/2022]
Abstract
Pycnogonids (sea spiders) are marine arthropods numbering some 1,160 extant species. They are globally distributed in depths of up to 6,000 metres, and locally abundant; however, their typically delicate form and non-biomineralized cuticle has resulted in an extremely sparse fossil record that is not accepted universally. There are two opposing views of their phylogenetic position: either within Chelicerata as sister group to the euchelicerates, or as a sister taxon to all other euarthropods. The Silurian Herefordshire Konservat-Lagerstatte in England (approximately 425 million years (Myr) bp) yields exceptionally preserved three-dimensional fossils that provide unrivalled insights into the palaeobiology of a variety of invertebrates. The fossils are preserved as calcitic void in-fills in carbonate concretions within a volcaniclastic horizon, and are reconstructed digitally. Here we describe a new pycnogonid from this deposit, which is the oldest adult sea spider by approximately 35 Myr and the most completely known fossil species. The large chelate first appendage is consistent with a chelicerate affinity for the pycnogonids. Cladistic analyses place the new species near the base of the pycnogonid crown group, implying that the latter had arisen by the Silurian period.
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Affiliation(s)
- Derek J Siveter
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Briggs DEG, Sutton MD, Siveter DJ, Siveter DJ. A new phyllocarid (Crustacea: Malacostraca) from the Silurian Fossil-Lagerstätte of Herefordshire, UK. Proc Biol Sci 2004; 271:131-8. [PMID: 15058388 PMCID: PMC1691579 DOI: 10.1098/rspb.2003.2593] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A new three-dimensionally preserved arthropod, Cinerocaris magnifica, from the Wenlock Series (Silurian) of Herefordshire, UK, is described and assigned to the Phyllocarida (Crustacea). The description and reconstruction are based on specimens that have been serially ground, reconstructed by computer and rendered in three dimensions as coloured virtual models. Cinerocaris magnifica displayed the tagmosis characteristic of phyllocarids, with eight thoracic and seven abdominal somites, terminating in a telson with furca. The remarkable preservation of the appendages makes this the earliest completely known malacostracan crustacean. Two pairs of antennae (the first with two flagella) were followed by a mandible and first maxilla, each with a slender palp-like ramus. The second maxilla consisted of a limb stem with endites and an endopod that tapered distally. There was no exopod. The thoracopods comprised a limb stem with six or seven endites, an arrangement previously known only in entomostracans, and an endopod with about five endites. Flap-like outer rami correspond to an exopod and epipods. The pleopods bore two long slender oar-blade-like rami. Cladistic analysis places C. magnifica as a plesion within the Echinocaridina. It provides critical evidence of the limb morphology of an early malacostracan, which will be important in understanding crustacean evolution.
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Affiliation(s)
- Derek E G Briggs
- Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA.
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