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Kočí T, Gašparič R, Buckeridge J, Kočová Veselská M, Šoster A. The first record of a Konservat-Lagerstätten in which early post-settlement stages of fossil archaeobalanids (Cirripedia: Balanomorpha) are preserved. Integr Zool 2024; 19:200-223. [PMID: 37248329 DOI: 10.1111/1749-4877.12728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A diverse sessile barnacle fauna from a Miocene shallow-water deposit at Dolnja Stara vas in Slovenia is described. It includes the first descriptions of early post settlement juveniles of Actinobalanus sloveniensis attached to mangrove leaves. These represent three distinct growth phases, the earliest being interpreted as being less than 24 h post settlement, the others being 1 to 2 days post settlement. An assessment of their taphonomy is provided. Associated adult balanomorphs are attached to a variety of organic substrates, including mangrove leaves and branches, fragments of the conifers ?Taxodioxylon, Carapoxylon, pine cones, molluscs, and cetacean bones. The barnacles include A. sloveniensis, Amphibalanus venustus, and Perforatus perforatus-many with opercula retained within the shells. A. venustus retains some of the original shell color. This is the second record of barnacle-plant associations from the Central Paratethys from Kamnik and Trbovlje. The paleoecology and paleogeography of the site are discussed.
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Affiliation(s)
- Tomáš Kočí
- Ivančická 581, Prague, Czech Republic
- Palaeontological Department, Natural History Museum, National Museum, Prague, Czech Republic
| | - Rok Gašparič
- Oertijdmuseum, Bosscheweg 80, Boxtel, 5293 WB, The Netherlands
- Institute for Palaeobiology and Evolution, Novi Trg, Kamnik, Slovenia
| | - John Buckeridge
- Earth and Oceanic Systems Group, RMIT University, Melbourne, Australia
- Museums Victoria, Carlton, Victoria, Australia
| | - Martina Kočová Veselská
- Department of Paleobiology and Paleoecology, Institute of Geology of the Czech Academy of Sciences, Prague, Czech Republic
- Institute of Geology and Palaeontology, Charles University, Prague, Czech Republic
| | - Aleš Šoster
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Ljubljana, Slovenia
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2
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Chan BKK, Dreyer N, Gale AS, Glenner H, Ewers-Saucedo C, Pérez-Losada M, Kolbasov GA, Crandall KA, Høeg JT. The evolutionary diversity of barnacles, with an updated classification of fossil and living forms. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlaa160] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Abstract
We present a comprehensive revision and synthesis of the higher-level classification of the barnacles (Crustacea: Thecostraca) to the genus level and including both extant and fossils forms. We provide estimates of the number of species in each group. Our classification scheme has been updated based on insights from recent phylogenetic studies and attempts to adjust the higher-level classifications to represent evolutionary lineages better, while documenting the evolutionary diversity of the barnacles. Except where specifically noted, recognized taxa down to family are argued to be monophyletic from molecular analysis and/or morphological data. Our resulting classification divides the Thecostraca into the subclasses Facetotecta, Ascothoracida and Cirripedia. The whole class now contains 14 orders, 65 families and 367 genera. We estimate that barnacles consist of 2116 species. The taxonomy is accompanied by a discussion of major morphological events in barnacle evolution and justifications for the various rearrangements we propose.
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Affiliation(s)
- Benny K K Chan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Niklas Dreyer
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
- Biodiversity Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
- Natural History Museum of Denmark, Invertebrate Zoology, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Andy S Gale
- School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, UK
- Department of Earth Sciences, The Natural History Museum, London, UK
| | - Henrik Glenner
- Marine Biodiversity Group, Department of Biology, University of Bergen, Bergen, Norway
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Marcos Pérez-Losada
- Computational Biology Institute, Department of Biostatistics and Bioinformatics, George Washington University, Washington, DC, USA
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Gregory A Kolbasov
- White Sea Biological Station, Biological Faculty of Moscow State University, Moscow, Russia
| | - Keith A Crandall
- Computational Biology Institute, Department of Biostatistics and Bioinformatics, George Washington University, Washington, DC, USA
- Department of Invertebrate Zoology, US National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Jens T Høeg
- Marine Biology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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3
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Haug JT, Haug C. Beetle larvae with unusually large terminal ends and a fossil that beats them all (Scraptiidae, Coleoptera). PeerJ 2019; 7:e7871. [PMID: 31632854 PMCID: PMC6796959 DOI: 10.7717/peerj.7871] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/11/2019] [Indexed: 01/02/2023] Open
Abstract
Larvae, and especially fossil larvae, are challenging to deal with from a purely taxonomic view. Often one cannot determine which species the larvae belong to. Yet, larvae can still contribute to various scientific questions. Especially morphological traits of a fossil larva can be highly informative for reconstructing character evolution. Also the occurrence of specific larval types and larval characters in time and the disappearance of such forms can well be reconstructed also without being able to narrow down the phylogenetic relationship of a larva very far. Here, we report two new beetle larvae preserved in Baltic amber which are identified as representatives of Scraptiidae, based on an enlarged terminal end ('9th abdomen segment'); this is only the third record of such larvae. In comparison to modern forms, the terminal ends of the two new fossil larvae is even larger in relation to the remaining body than in any known larva. Unfortunately, our knowledge of such larvae in the modern fauna is very limited. Still, one of the two already known fossil larvae of Scraptiidae also has a very long terminal end, but not as long as those of the two new fossils. These three fossil larvae therefore seem to possess a specific morphology not known from the modern fauna. This might either mean that they (1) represent a now extinct larval morphology, a phenomenon well known in other euarthropodan lineages, or that (2) these forms represent a part of the larval phase not known from modern day species as they have not been described yet; such cases occur in closely related lineages. In any case, the fossils expand the known diversity of larval morphologies.
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Affiliation(s)
- Joachim T Haug
- Department of Biology II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.,GeoBio-Center at LMU, München, Germany
| | - Carolin Haug
- Department of Biology II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.,GeoBio-Center at LMU, München, Germany
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4
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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.
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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
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5
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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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6
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Wolfe JM, Hegna TA. Testing the phylogenetic position of Cambrian pancrustacean larval fossils by coding ontogenetic stages. Cladistics 2013; 30:366-390. [DOI: 10.1111/cla.12051] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2013] [Indexed: 01/14/2023] Open
Affiliation(s)
- Joanna M. Wolfe
- Department of Geology and Geophysics; Yale University; 210 Whitney Avenue New Haven CT 06520 USA
- Division of Invertebrate Zoology & Sackler Institute of Comparative Genomics; American Museum of Natural History; Central Park West at 79th Street New York NY 10024 USA
| | - Thomas A. Hegna
- Department of Geology and Geophysics; Yale University; 210 Whitney Avenue New Haven CT 06520 USA
- Department of Geology; Western Illinois University; Tillman Hall 1 University Circle Macomb IL 61455 USA
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7
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On the Unique Perspective of Paleontology in the Study of Developmental Evolution and Biases. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13752-013-0115-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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8
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Wheat CW, Wahlberg N. Phylogenomic Insights into the Cambrian Explosion, the Colonization of Land and the Evolution of Flight in Arthropoda. Syst Biol 2012; 62:93-109. [DOI: 10.1093/sysbio/sys074] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Christopher W. Wheat
- Department of Biosciences, PL 65, Viikinkaari 1, 00014 University of Helsinki, Finland; 2 Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden; 3 Laboratory of Genetics, Department of Biology, University of Turku, FI-20014 Turku, Finland
- Department of Biosciences, PL 65, Viikinkaari 1, 00014 University of Helsinki, Finland; 2 Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden; 3 Laboratory of Genetics, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Niklas Wahlberg
- Department of Biosciences, PL 65, Viikinkaari 1, 00014 University of Helsinki, Finland; 2 Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden; 3 Laboratory of Genetics, Department of Biology, University of Turku, FI-20014 Turku, Finland
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9
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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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10
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O'Brien LJ, Caron JB. A new stalked filter-feeder from the middle Cambrian Burgess Shale, British Columbia, Canada. PLoS One 2012; 7:e29233. [PMID: 22279532 PMCID: PMC3261148 DOI: 10.1371/journal.pone.0029233] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 11/22/2011] [Indexed: 11/18/2022] Open
Abstract
Burgess Shale-type deposits provide invaluable insights into the early evolution of body plans and the ecological structure of Cambrian communities, but a number of species, continue to defy phylogenetic interpretations. Here we extend this list to include a new soft-bodied animal, Siphusauctum gregarium n. gen. and n. sp., from the Tulip Beds (Campsite Cliff Shale Member, Burgess Shale Formation) of Mount Stephen (Yoho National Park, British Columbia). With 1,133 specimens collected, S. gregarium is clearly the most abundant animal from this locality.This stalked animal (reaching at least 20 cm in length), has a large ovoid calyx connected to a narrow bilayered stem and a small flattened or bulb-like holdfast. The calyx is enclosed by a flexible sheath with six small openings at the base, and a central terminal anus near the top encircled by indistinct openings. A prominent organ, represented by six radially symmetrical segments with comb-like elements, surrounds an internal body cavity with a large stomach, conical median gut and straight intestine. Siphusauctum gregarium was probably an active filter-feeder, with water passing through the calyx openings, capturing food particles with its comb-like elements. It often occurs in large assemblages on single bedding planes suggesting a gregarious lifestyle, with the animal living in high tier clusters. These were probably buried en masse more or less in-situ by rapid mud flow events.Siphusauctum gregarium resembles Dinomischus, another Cambrian enigmatic stalked animal. Principal points of comparison include a long stem with a calyx containing a visceral mass and bract-like elements, and a similar lifestyle albeit occupying different tiering levels. The presence in both animals of a digestive tract with a potential stomach and anus suggest a grade of organization within bilaterians, but relationships with extant phyla are not straightforward. Thus, the broader affinities of S. gregarium remain largely unconstrained.
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Affiliation(s)
- Lorna J O'Brien
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
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11
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Abstract
A longstanding question in paleontology has been the influence of calcite and aragonite seas on the evolution of carbonate skeletons. An earlier study based on 21 taxa that evolved skeletons during the Ediacaran through Ordovician suggested that carbonate skeletal mineralogy is determined by seawater chemistry at the time skeletons first evolve in a clade. Here I test this hypothesis using an expanded dataset comprising 40 well-defined animal taxa that evolved skeletons de novo in the last 600 Myr. Of the 37 taxa whose mineralogy is known with some confidence, 25 acquired mineralogies that matched seawater chemistry of the time, whereas only two taxa acquired non-matching mineralogies. (Ten appeared during times when seawater chemistry is not well constrained.) The results suggest that calcite and aragonite seas do have a strong influence on carbonate skeletal mineralogy, however, this appears to be true only at the time mineralized skeletons first evolve. Few taxa switch mineralogies (from calcite to aragonite or vice versa) despite subsequent changes in seawater chemistry, and those that do switch do not appear to do so in response to changing aragonite-calcite seas. This suggests that there may be evolutionary constraints on skeletal mineralogy, and that although there may be increased costs associated with producing a mineralogy not favored by seawater, the costs of switching mineralogies are even greater.
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Affiliation(s)
- S M Porter
- Department of Earth Science, University of California at Santa Barbara, Santa Barbara, California, USA.
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12
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Sanders KL, Lee MSY. Arthropod molecular divergence times and the Cambrian origin of pentastomids. SYST BIODIVERS 2010. [DOI: 10.1080/14772000903562012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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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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14
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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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16
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Pérez-Losada M, Harp M, Høeg JT, Achituv Y, Jones D, Watanabe H, Crandall KA. The tempo and mode of barnacle evolution. Mol Phylogenet Evol 2007; 46:328-46. [PMID: 18032070 DOI: 10.1016/j.ympev.2007.10.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 09/26/2007] [Accepted: 10/06/2007] [Indexed: 10/22/2022]
Abstract
Previous phylogenetic attempts at resolving barnacle evolutionary relationships are few and have relied on limited taxon sampling. Here we combine DNA sequences from three nuclear genes (18S, 28S and H3) and 44 morphological characters collected from 76 thoracican (ingroup) and 15 rhizocephalan (outgroup) species representing almost all the Thoracica families to assess the tempo and mode of barnacle evolution. Using phylogenetic methods of maximum parsimony, maximum likelihood, and Bayesian inference and 14 fossil calibrations, we found that: (1) Iblomorpha form a monophyletic group; (2) pedunculated barnacles without shell plates (Heteralepadomorpha) are not ancestral, but have evolved, at least twice, from plated forms; (3) the ontogenetic pattern with 5-->6-->8-->12+ plates does not reflect Thoracica shell evolution; (4) the traditional asymmetric barnacles (Verrucidae) and the Balanomorpha are each monophyletic and together they form a monophyletic group; (5) asymmetry and loss of a peduncle have evolved twice in the Thoracica, resulting in neither the Verrucomorpha nor the Sessilia forming monophyletic groups in their present definitions; (6) the Scalpellomorpha are not monophyletic; (7) the Thoracica suborders evolved since the Early Carboniferous (340mya) with the final radiation of the Sessilia in the Upper Jurassic (147mya). These results, therefore, reject many of the underlying hypotheses about character evolution in the Cirripedia Thoracica, stimulate a variety of new thoughts on thoracican radiation, and suggest the need for a major rearrangement in thoracican classification based on estimated phylogenetic relationships.
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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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18
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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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