DOCSLIB.ORG

An Unusual Echinoderm Assemblage from the Earliest Bajocian of Luxembourg

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Unusual Echinoderm Assemblage from the Earliest Bajocian of Luxembourg L.D. Numberger-Thuy & B. Thuy An unusual echinoderm assemblage from the earliest Bajocian of Luxembourg An unusual echinoderm assemblage from the earliest Bajocian (middle Jurassic) of Luxembourg, with special emphasis on the ophiuroids (Echinodermata: Ophiuroidea) Lea D. Numberger-Thuy1, 2 & Ben Thuy1 1 Musée national d'histoire naturelle du Luxembourg, section paléontologie, 25, rue Münster, L-2160 Luxembourg 2 [email protected] Zusammenfassung Die Mehrheit der Stachelhäutervergesellschaftungen Balanocrinus, ein Balanocidaris-artiger Psychocidaride, aus dem Bajocium wurden aus Ablagerungen von und benthopectinide und korethrasteride/pterasteride Karbonatplattformen beschrieben. Im Nordwesten der Seesterne, welche allesamt in Karbonatplattformsedi- Tethys haben diese Ablagerungen aussergewöhnlich menten des nordwestlichen Tethysrandes entweder häufige Funde von artikulierten Resten geliefert, was ganz fehlen oder nur sehr selten vorkommen. Im eine starke Habitat-bezogene Verzerrung des Fossilbe- Gegenzug deuten sie auf einen stärkeren offen-oze- richts der Stachelhäuter im Bajocium bewirkt. Siliziklas- anischen Einfluss hin. Die Schlangensternreste, hier tische Ablagerungen hingegen haben bisher wesentlich ausführlich beschrieben, umfassen fünf Arten, wovon weniger Beachtung bezüglich ihrer möglichen Echino- eine als neu (Lapidaster hellersi sp. nov.) beschrieben wird. dermenfunde erhalten. In der vorliegenden Arbeit wird Letztere gehört zu einer ophiacanthiden Gattung, die im eine Vergesellschaftung von Echinodermen aus einer Bajocium bisher nur aus Tiefwasserablagerungen der dünnen, lateral begrenzten Schicht aus sandigem Ton westlichen Tethys bekannt war und somit die offen-oze- mit Phosphoritknollen beschrieben, die in Rumelange, anischen Affinitäten der restlichen Echinodermen unter- Luxemburg, am nordöstlichen Rand der jungen mauert. Die vorliegende Arbeit bekräftigt das Beachten Burgund Plattform aufgeschlossen sind und auf das von Ablagerungsräumen bei Untersuchungen der früheste Bajocium datiert wird. Die Vergesellschaftung Paläobiodiversität, die ungewöhnlich oder Lagerstätten umfasst den rätselhaften Cyclocrinus, den Isocriniden gegenüber weniger attraktiv erscheinen. Abstract The vast majority of Bajocian echinoderm assemblages pectinid and korethrasterid/pterasterid asteroids, which have been reported from carbonate platform settings. In lack from or only very rarely occur in Bajocian carbonate the northwestern Tethys, these deposits have produced platform deposits of the northwestern Tethys margin. exceptionally abundant articulated remains, thus intro- Instead, they point to a more open ocean affinity. The ducing a strong palaeo-habitat bias in the Bajocian ophiuroid assemblage, described in detail, includes echinoderm fossil record. Siliciclastic deposits, in five species, one of which is formally described as new contrast, have received surprisingly little attention with (Lapidaster hellersi sp. nov.). The latter belongs to the respect to their potential echinoderm content. Here, ophiacanthid genus Lapidaster which is known only we describe an echinoderm fauna from a thin, laterally discontinuous sandy clay bed rich in phosphorite from deep-water deposits of the western Tethys in the nodules exposed in Rumelange, Luxembourg, on the Bajocian, thus corroborating the open ocean affinities of northeast margin of the incipient Burgundy Platform, the other echinoderms. Our study endorses the inclusion and dated to the earliest Bajocian. The assemblage in palaeo-biodiversity surveys of depositional settings includes the enigmatic Cyclocrinus, the isocrinid Balano- which might seem unusual or less promising than crinus, a Balanocidaris-like psychocidarid, and bentho- Lagerstätten. Résumé La majorité des collections d'échinodermes du Bajocien ont fourni des fossiles d'échinodermes articulés excep- proviennent de sédiments de plateformes carbonatées. tionnellement abondants, ce qui a créé un fort biais dans Au nord-ouest de la Téthys, les gisements en question le registre fossile bajocien des échinodermes pour les Ferrantia • 71 / 2015 39 L.D. Numberger-Thuy & B. Thuy An unusual echinoderm assemblage from the earliest Bajocian of Luxembourg types d'habitats correspondants. Les gisements siliciclas- très rarement trouvés dans les gisements bajociens de tiques par contre n'ont reçu que peu d'attention quant au plateforme carbonatée de la bordure nord-ouest de la potentiel de fournir des fossiles d'échinodermes. Dans le Téthys. Les ophiures, décrites en détail, comprennent présent travail, une collection d'échinodermes provenant un total de cinq espèces, dont une nouvelle (Lapidaster d'une couche lenticulaire d'argile sableuse de faible hellersi sp. nov.) appartenent au genre ophiacanthide épaisseur riche en concrétions phosphoritiques, exposée Lapidaster qui n'est connu au Bajocien que de sédiments à Rumelange, Luxembourg, sur la bordure nord-est de la de mer profonde de la Téthys de l'Ouest. Cette obser- plateforme de Bourgogne naissante et datée du Bajocien vation corrobore le charactère plutôt océanique des autres basal. La collection inclut le crinoïde énigmatique Cyclo- groupes d'échinodermes de la collection. Le présent crinus, l'isocrinide Balanocrinus, un psychocidaride proche travail met l'accent sur l'inclusion dans les analyses de de Balanocidaris ainsi que des astérides benthopectinides paléo-biodiversité de gisements qui, à première vue, et korethrasterides/pterasterides, qui ne sont pas ou que semblent moins prometteurs que les Lagerstätten. Introduction Bajocian (Thuy, this volume), which is well in line with the general trend observed in the survey of Bajocian echinoderms. Dissociated ophiuroid The Bajocian is among the stages that have lateral arm plates, which are known to allow produced outstandingly well known and diverse for much more exhaustive palaeobiodiversity echinoderm remains. Most noteworthy are the assessments than the patchy record of articu- exceptionally preserved and abundant, intact lated skeletons, have only recently come into the layers of echinoderms on the Bahama-type focus of taxonomic surveys (Thuy 2013; Thuy this Burgundy carbonate platform deposits such as volume). the widespread Hauptrogenstein Formation, including remains of all five extant classes (Hess Here, we present a new echinoderm assemblage, 1972; Hess & Holenweg 1985; Hess & Meyer comprising disarticulated remains of crinoids, 2008; Thuy & Meyer 2012). Echinoderms are echinoids, asteroids and ophiuroids, retrieved only preserved intact under certain sedimento- from sieving residues of a sandy clay bed rich in logical and taphonomic conditions (Ausich 2001). phosphorite nodules exposed on the northeast Therefore, although these articulated assemblages margin of the incipient Burgundy Platform. The gained a lot of interest in the past, they represent aim is to contribute to a more complete picture of just a small part of the total echinoderm diversity shallow-water echinoderm biodiversity during during the Bajocian. the Bajocian by focusing on siliciclastic deposi- tional settings which, compared to carbonate The exceptionally preserved echinoderm assem- platform deposits, are strongly undersampled. blages from the Burgundy Platform Lagerstätten The faunal spectrum is highly unusual, comprising originate from a limited number of depositional echinoderm taxa which are only very rarely, settings (Hess & Meyer 2008). In fact, almost all if at all, found in the coeval and later carbonate published records in this respect originate from platform settings. We provide a very brief general oolithic to detrital sand wave obrution deposits overview on the echinoid, crinoid and asteroid (Hess 1972; Hess & Meyer 2008). The abundance taxa with the aim to spark more detailed investi- and exceptional preservation of the echinoderm gations, and provide a detailed assessment of the fossils in question makes them particularly ophiuroid assemblage. attractive for both collectors and researchers, and thus introduces a strong bias in the Bajocian echinoderm fossil record towards shallow-water, high energy carbonate platform assemblages. Geological context Reefal, peri-reefal and, in particular, siliciclastic settings are heavily underrepresented, at least for The here described assemblage was predomi- the non-echinoid echinoderms. nantly retrieved from sieving residues of a 0,10 m In the particular case of the ophiuroids, it is thin, laterally discontinuous bed of grey sandy clay noteworthy that, until recently, only species based with pea- to walnut-sized phosphorite nodules on articulated skeletons were known from the and numerous abraded and encrusted belemnite 40 Ferrantia • 71 / 2015 L.D. Numberger-Thuy & B. Thuy An unusual echinoderm assemblage from the earliest Bajocian of Luxembourg rostra, approximately 1 m above the base of the Material and methods Micaceous Marls. The sand size fraction of the sandy clay predominantly consists of quartz More than 200 echinoderm plates and spines, grains and iron ooids. The bed was dated to the assignable to echinoids, asteroids, crinoids and earliest Bajocian Discites Zone (Walkeri Subzone) ophiuroids, were examined in the present study. based on ammonite evidence (Guérin-Franiatte & Some of the larger remains were picked in the field Weis 2010). It is exposed on the shores of a pond from the weathered surface of the sandy claybed. on an artificial plateau in the former "Hutbierg" The vast majority of the specimens, however, was opencast mine in Rumelange, Luxembourg. retrieved from sieving
Load more

Recommended publications
  • Brittle-Star Mass Occurrence on a Late Cretaceous Methane Seep from South Dakota, USA Received: 16 May 2018 Ben Thuy1, Neil H
    www.nature.com/scientificreports OPEN Brittle-star mass occurrence on a Late Cretaceous methane seep from South Dakota, USA Received: 16 May 2018 Ben Thuy1, Neil H. Landman2, Neal L. Larson3 & Lea D. Numberger-Thuy1 Accepted: 29 May 2018 Articulated brittle stars are rare fossils because the skeleton rapidly disintegrates after death and only Published: xx xx xxxx fossilises intact under special conditions. Here, we describe an extraordinary mass occurrence of the ophiacanthid ophiuroid Brezinacantha tolis gen. et sp. nov., preserved as articulated skeletons from an upper Campanian (Late Cretaceous) methane seep of South Dakota. It is uniquely the frst fossil case of a seep-associated ophiuroid. The articulated skeletons overlie centimeter-thick accumulations of dissociated skeletal parts, suggesting lifetime densities of approximately 1000 individuals per m2, persisting at that particular location for several generations. The ophiuroid skeletons on top of the occurrence were preserved intact most probably because of increased methane seepage, killing the individuals and inducing rapid cementation, rather than due to storm-induced burial or slumping. The mass occurrence described herein is an unambiguous case of an autochthonous, dense ophiuroid community that persisted at a particular spot for some time. Thus, it represents a true fossil equivalent of a recent ophiuroid dense bed, unlike other cases that were used in the past to substantiate the claim of a mid-Mesozoic predation-induced decline of ophiuroid dense beds. Brittle stars, or ophiuroids, are among the most abundant and widespread components of the marine benthos, occurring at all depths and latitudes of the world oceans1. Most of the time, however, ophiuroids tend to live a cryptic life hidden under rocks, inside sponges, epizoic on corals or buried in the mud (e.g.2) to such a point that their real abundance is rarely appreciated at frst sight.
    [Show full text]
  • Phylogenomic Resolution of the Class Ophiuroidea Unlocks a Global Microfossil Record
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Current Biology 24, 1874–1879, August 18, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2014.06.060 Report Phylogenomic Resolution of the Class Ophiuroidea Unlocks a Global Microfossil Record Timothy D. O’Hara,1,* Andrew F. Hugall,1 Ben Thuy,2 We used a phylogenomic approach to address these defi- and Adnan Moussalli1 ciencies, obtaining 52 de novo ophiuroid transcriptomes and 1Museum Victoria, GPO Box 666, Melbourne, VIC 3001, three from other echinoderm classes, in addition to three pub- Australia lically available transcriptomes and three genomes (see Table 2Section Pale´ ontologie, Muse´ e National d’Histoire Naturelle du S1 available online). Twenty-nine of the ophiuroid transcrip- Luxembourg, 24 Rue Mu¨ nster, 2160 Luxembourg tomes were obtained from deep-sea (>500 m) samples, to ensure adequate taxonomic representation across the class. We identified and aligned 425 orthologous genes that could Summary be annotated using available sea urchin, hemichordate, or actinopterygian genomes (Table S2). After trimming, we used Our understanding of the origin, evolution, and biogeog- 102,143 amino acid positions to reconstruct a phylogeny of raphy of seafloor fauna is limited because we have insuf- the Echinodermata, with a focus on the ophiuroids (Figure 1). ficient spatial and temporal data to resolve underlying The resulting sequence matrix is 85% complete (Figure S1) processes [1]. The abundance and wide distribution of mod- and is the largest genetic data set ever assembled to analyze ern and disarticulated fossil Ophiuroidea [2], including brittle phylogenetic relationships within echinoderms.
    [Show full text]
  • Crinoids from the Middle Jurassic (Bajocian–Lower Callovian) of Arde`Che, France
    Swiss J Palaeontol (2012) 131:211–253 DOI 10.1007/s13358-012-0044-9 Crinoids from the Middle Jurassic (Bajocian–Lower Callovian) of Arde`che, France Hans Hess Received: 24 February 2012 / Accepted: 25 April 2012 / Published online: 6 June 2012 Ó Akademie der Naturwissenschaften Schweiz (SCNAT) 2012 Abstract Several Middle Jurassic outcrops in the Arde`che results demonstrate that the Middle Jurassic crinoids from Department near La Voulte-sur-Rhoˆne and St-E´tienne-de- the Arde`che are one of the important and diverse Mesozoic Boulogne are rich in the remains of crinoids, but these were crinoid faunas. Some forms bridge the gap between the known from surface collections only and were not descri- Early Jurassic and the Late Jurassic hardground faunas of bed using present standards of systematics. This paper cyrtocrinids. Cyrtocrinus praenutans n. sp., a form similar brings the taxonomic status of the previously described to Cyrtocrinus nutans (GOLDFUSS) from the Oxfordian, is crinoids up to date, reassesses the systematic position of described as a separate species despite some overlapping some of the species based on cups and describes new phenotypic variability of cups and columnals. Pathological forms. Sampling and washing of bulk material from the deformations on all types of ossicles of C. praenutans n. sp. Lower Bathonian of the La Pouza locality yielded nearly are ascribed to the epizoan commensal Oichnus para- 100,000 crinoid ossicles. Among them are rare comatulids boloides BROMLEY. Different species are dominant at the with the following recognized as new: Andymetra galei n. different Bathonian localities, namely C. praenutans n.
    [Show full text]
  • Echinodermata, Asteroidea) and Ophiuroids (Echino Dermata, Ophiuroidea) from the Late Jurassic (Volgian / Tithonian) of Central Spitsbergen
    European Journal of Taxonomy 411: 1–26 ISSN 2118-9773 https://doi.org/10.5852/ejt.2018.411 www.europeanjournaloftaxonomy.eu 2018 · Rousseau J. et al. This work is licensed under a Creative Commons Attribution 3.0 License. Research article urn:lsid:zoobank.org:pub:20D7A744-CE8B-4E6C-92DA-71A9B8C3D805 New articulated asteroids (Echinodermata, Asteroidea) and ophiuroids (Echino dermata, Ophiuroidea) from the Late Jurassic (Volgian / Tithonian) of central Spitsbergen Julie ROUSSEAU 1,*, Andrew Scott GALE 2 & Ben THUY 3 1 1111 Belle Pre Way, Apt. 537, Alexandria, VA, 22314, United States of America. 2 School of Earth & Environmental Sciences, University of Portsmouth, Burnaby Building, Burnaby Road, Portsmouth, PO1 3QL, United Kingdom. 3 Department of Palaeontology, Natural History Museum Luxembourg, Luxembourg-City, Luxembourg. * Corresponding author: [email protected] 2 Email: [email protected] 3 Email: [email protected] 1 urn:lsid:zoobank.org:author:C58AF561-3A85-4615-B5A4-BA3D323F7A25 2 urn:lsid:zoobank.org:author:092855B9-CBE4-41F9-9861-3BEA1FDE50F1 3 urn:lsid:zoobank.org:author:04186A8C-3F0D-485E-834A-08414A217ACA Abstract. The Late Jurassic–Early Cretaceous Slottsmøya Member of the Agardhfjellet Formation in central Spitsbergen has yielded two new species of asteroids and two species of ophiuroids, one of which is described as new. Polarasterias janusensis Rousseau & Gale gen. et sp. nov. is a forcipulatid neoasteroid with elongated arms, small disc and very broad ambulacral grooves with narrow adambulacrals. Savignaster septemtrionalis Rousseau & Gale sp. nov. is a pterasterid with well- developed interradial chevrons. The Spitsbergen specimens are the fi rst described articulated material of Savignaster and reveal the overall arrangement of the ambulacral groove ossicles.
    [Show full text]
  • Accepted Manuscript
    Accepted Manuscript Predation in the marine fossil record: Studies, data, recognition, environmental factors, and behavior Adiël A. Klompmaker, Patricia H. Kelley, Devapriya Chattopadhyay, Jeff C. Clements, John W. Huntley, Michal Kowalewski PII: S0012-8252(18)30504-X DOI: https://doi.org/10.1016/j.earscirev.2019.02.020 Reference: EARTH 2803 To appear in: Earth-Science Reviews Received date: 30 August 2018 Revised date: 17 February 2019 Accepted date: 18 February 2019 Please cite this article as: A.A. Klompmaker, P.H. Kelley, D. Chattopadhyay, et al., Predation in the marine fossil record: Studies, data, recognition, environmental factors, and behavior, Earth-Science Reviews, https://doi.org/10.1016/j.earscirev.2019.02.020 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Predation in the marine fossil record: studies, data, recognition, environmental factors, and behavior Adiël A. Klompmakera,*, Patricia H. Kelleyb, Devapriya Chattopadhyayc, Jeff C. Clementsd,e, John W. Huntleyf, Michal Kowalewskig aDepartment of Integrative Biology & Museum of Paleontology, University of California, Berkeley, 1005 Valley Life
    [Show full text]
  • New Articulated Asteroids (Echinodermata, Asteroidea) and Ophiuroids (Echinodermata, Ophiuroidea) from the Late Jurassic (Volgian / Tithonian) of Central Spitsbergen
    European Journal of Taxonomy 411: 1–26 ISSN 2118-9773 https://doi.org/10.5852/ejt.2018.411 www.europeanjournaloftaxonomy.eu 2018 · Rousseau J. et al. This work is licensed under a Creative Commons Attribution 3.0 License. Research article urn:lsid:zoobank.org:pub:20D7A744-CE8B-4E6C-92DA-71A9B8C3D805 New articulated asteroids (Echinodermata, Asteroidea) and ophiuroids (Echinodermata, Ophiuroidea) from the Late Jurassic (Volgian / Tithonian) of central Spitsbergen Julie ROUSSEAU 1,*, Andrew Scott GALE 2 & Ben THUY 3 1 1111 Belle Pre Way, Apt. 537, Alexandria, VA, 22314, United States of America. 2 School of Earth & Environmental Sciences, University of Portsmouth, Burnaby Building, Burnaby Road, Portsmouth, PO1 3QL, United Kingdom. 3 Department of Palaeontology, Natural History Museum Luxembourg, Luxembourg-City, Luxembourg. * Corresponding author: [email protected] 2 Email: [email protected] 3 Email: [email protected] 1 urn:lsid:zoobank.org:author:C58AF561-3A85-4615-B5A4-BA3D323F7A25 2 urn:lsid:zoobank.org:author:092855B9-CBE4-41F9-9861-3BEA1FDE50F1 3 urn:lsid:zoobank.org:author:04186A8C-3F0D-485E-834A-08414A217ACA Abstract. The Late Jurassic–Early Cretaceous Slottsmøya Member of the Agardhfjellet Formation in central Spitsbergen has yielded two new species of asteroids and two species of ophiuroids, one of which is described as new. Polarasterias janusensis Rousseau & Gale gen. et sp. nov. is a forcipulatid neoasteroid with elongated arms, small disc and very broad ambulacral grooves with narrow adambulacrals. Savignaster septemtrionalis Rousseau & Gale sp. nov. is a pterasterid with well- developed interradial chevrons. The Spitsbergen specimens are the first described articulated material of Savignaster and reveal the overall arrangement of the ambulacral groove ossicles.
    [Show full text]
  • Echinodermata) Records in the Palaeontological Collection of the Museo Di Storia Naturale “Antonio Stoppani” (Venegono Inferiore, Varese, Italy)
    TO L O N O G E I L C A A P I ' T A A T L E I I A Bollettino della Società Paleontologica Italiana, 55 (3), 2016, 183-192. Modena C N O A S S. P. I. Description of the ophiuroid (Echinodermata) records in the Palaeontological Collection of the Museo di Storia Naturale “Antonio Stoppani” (Venegono Inferiore, Varese, Italy) Luca JASELLI L. Jaselli, Museo di Storia Naturale “Antonio Stoppani”, via Papa Pio XI 32, I-21040 Venegono Inferiore (VA), Italy; [email protected] KEY WORDS - Ophiuroidea, Museum Collection, Stoppani, morphology, taxonomy. ABSTRACT - The Palaeontological Collection of the Museo di Storia Naturale “Antonio Stoppani” (Venegono Inferiore, Varese, Italy), consists of more than 4000 specimens that are housed in its store and partially on display to the public. The ophiuroid series is represented by a considerable number of specimens of extant and fossil ophiuroids. The aim of the present study is to provide a catalogue of these ophiuroids together with their taxonomic assignment and illustrations of their anatomical features. RIASSUNTO - [Descrizione degli esemplari di ofiuroidi presenti nella Collezione Paleontologica del Museo di Storia Naturale “Antonio Stoppani” (Venegono Inferiore, Varese, Italia)] - La Collezione Paleontologica del Museo di Storia Naturale “Antonio Stoppani” di Venegono Inferiore, in provincia di Varese, conta più di quattromila esemplari custoditi nel suo deposito e parzialmente esposti al pubblico. Fra questi reperti si annoverano, nelle serie zoologiche e paleontologiche, alcuni esemplari di ofiuroidi, sia attuali che fossili. Lo scopo del presente studio è quello di fornire un catalogo degli esemplari facenti parte di questa classe di echinodermi, assegnarli alla categoria tassonomica di riferimento e di illustrarne le particolarità anatomiche.
    [Show full text]
  • Predation in the Marine Fossil Record Studies, Data, Recognition
    Earth-Science Reviews 194 (2019) 472–520 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Predation in the marine fossil record: Studies, data, recognition, T environmental factors, and behavior ⁎ Adiël A. Klompmakera, , Patricia H. Kelleyb, Devapriya Chattopadhyayc, Jeff C. Clementsd,e, John Warren Huntleyf, Michal Kowalewskig a Department of Integrative Biology & Museum of Paleontology, University of California, Berkeley, 1005 Valley Life Sciences Building #3140, Berkeley, CA 94720,USA b Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC 28403-5944, USA c Department of Earth Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur WB-741246, India d Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway e Department of Biological and Environmental Sciences, University of Gothenburg, Sven Lovén Centre for Marine Sciences – Kristineberg, Fiskebäckskil 45178, Sweden f Department of Geological Sciences, University of Missouri, 101 Geology Building, Columbia, MO 65211, USA g Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, FL 32611, USA ARTICLE INFO ABSTRACT Keywords: The fossil record is the primary source of data used to study predator-prey interactions in deep time and to Behavior evaluate key questions regarding the evolutionary and ecological importance of predation. Here, we review the Fossil record types of paleontological data used to infer predation in the marine fossil record, discuss strengths and limitations Mollusks of paleontological lines of evidence used to recognize and evaluate predatory activity, assess the influence of Parasitism environmental gradients on predation patterns, and review fossil evidence for predator behavior and prey de- Predation fense.
    [Show full text]
  • Exceptionally Well-Preserved Brittle Stars from the Pliensbachian
    [Palaeontology, Vol. 54, Part 1, 2011, pp. 215–233] EXCEPTIONALLY WELL-PRESERVED BRITTLE STARS FROM THE PLIENSBACHIAN (EARLY JURASSIC) OF THE FRENCH ARDENNES by BEN THUY Department of Geobiology, Geoscience Centre, University of Go¨ttingen, Goldschmidtstraße 3, D-37077 Germany; e-mail [email protected] Typescript received 22 May 2009; accepted in revised form 2 July 2010 Abstract: Two new genera and species of ophiuroid, Inex- of different sizes, with some of the most delicate skeletal pectacantha acrobatica new gen. et sp. and Eirenura papillata structures left intact, together with completely disarticulated new gen et sp., are described on the basis of 39 articulated skeletons of the same species suggests that the ophiuroids specimens and several hundreds of arm fragments and were preserved as autochthonous faunule among an in situ isolated skeletal parts. The material was extracted from a population of Modiolus sp. during a period of more favourable lumachellic bed in a late early Pliensbachian succession of bottom water conditions in an otherwise largely hostile argillites at Sedan, French Ardennes. The material is unusually near-shore soft-bottom environment. Based on its small size, well preserved with even finest structures of the skeleton the highly flexible arms and the presence of well-developed discernible. Despite the exceptionally detailed morphological hooks on distal arm segments, an epizoic way of life is data extractable from the material, the higher taxonomic inferred for I. acrobatica while E. papillata, with its rigid arm classification in the system of recent ophiuroids could only be structure and the conspicuously large tentacle pores, is inter- tentatively attained.
    [Show full text]
  • Late Triassic (Rhaetian) Ophiuroids from Winterswijk, the Netherlands; with Com- Ments on the Systematic Position of Aplocoma (Echinodermata, Ophiolepididae)*
    Zoosymposia 7: 163–172 (2012) ISSN 1178-9905 (print edition) www.mapress.com/zoosymposia/ ZOOSYMPOSIA Copyright © 2012 · Magnolia Press ISSN 1178-9913 (online edition) urn:lsid:zoobank.org:pub:1682E191-10B1-4C71-87BC-31EF246963F1 Late Triassic (Rhaetian) ophiuroids from Winterswijk, the Netherlands; with com- ments on the systematic position of Aplocoma (Echinodermata, Ophiolepididae)* BEN THUY1,4, ADIËL A. KLOMPMAKER2, JOHN W.M. JAGT3 1 Geoscience Centre, University of Göttingen, Department of Geobiology, Göttingen, Germany 2 Department of Geology, Kent State University, Kent, Ohio, USA; and Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA 3 Natuurhistorisch Museum Maastricht, Maastricht, the Netherlands 4 Corresponding author, E-mail: [email protected] *In: Kroh, A. & Reich, M. (Eds.) Echinoderm Research 2010: Proceedings of the Seventh European Conference on Echinoderms, Göttingen, Germany, 2–9 October 2010. Zoosymposia, 7, xii + 316 pp. Abstract An ophiuroid assemblage from Rhaetian dark shales in a subrosion pipe (or sinkhole) penetrating middle Triassic (Muschel- kalk) strata, and, outside the subrosion pipe, disconcordantly overlying middle Triassic strata, east of Winterswijk, the Netherlands, is described, discussed and assessed taxonomically. The material consists of nearly intact and articulated as well as wholly disintegrated skeletons, almost all of which are pyritised, yet so well preserved that the diagnostic char- acters could be studied in detail. All specimens belong to Aplocoma agassizi (von Münster, 1839). Examination of the type material of Ophiolepis damesii Wright, 1874 (housed at the Roemer and Pelizäus Museum in Hildesheim, Germany, collection numbers NKP 7821 to NKP 7828) from Rhaetian strata at Hildesheim, Germany, comparable to those exposed at Winterswijk, has revealed that O.
    [Show full text]
  • Paedomorphosis As an Evolutionary Driving Force: Insights from Deep-Sea Brittle Stars
    RESEARCH ARTICLE Paedomorphosis as an Evolutionary Driving Force: Insights from Deep-Sea Brittle Stars Sabine StoÈ hr1*, Alexander Martynov2* 1 Swedish Museum of Natural History, Department of Zoology, Stockholm, Sweden, 2 Zoological Museum, Moscow State University, Moscow, Russia * [email protected] (SS); [email protected] (AM) a11111 Abstract Heterochronic development has been proposed to have played an important role in the evo- lution of echinoderms. In the class Ophiuroidea, paedomorphosis (retention of juvenile characters into adulthood) has been documented in the families Ophiuridae and Ophiolepi- didae but not been investigated on a broader taxonomic scale. Historical errors, confusing juvenile stages with paedomorphic species, show the difficulties in correctly identifying the OPEN ACCESS effects of heterochrony on development and evolution. This study presents a detailed anal- Citation: StoÈhr S, Martynov A (2016) ysis of 40 species with morphologies showing various degrees of juvenile appearance in Paedomorphosis as an Evolutionary Driving Force: late ontogeny. They are compared to a range of early ontogenetic stages from paedomor- Insights from Deep-Sea Brittle Stars. PLoS ONE 11 (11): e0164562. doi:10.1371/journal. phic and non-paedomorphic species. Both quantitative and qualitative measurements are pone.0164562 taken and analysed. The results suggest that strongly paedomorphic species are usually Editor: Michael Schubert, Laboratoire de Biologie larger than other species at comparable developmental stage. The findings support recent du DeÂveloppement de Villefranche-sur-Mer, notions of polyphyletic origin of the families Ophiuridae and Ophiolepididae. The impor- FRANCE tance of paedomorphosis and its correct recognition for the practice of taxonomy and phy- Received: April 25, 2016 logeny are emphasized.
    [Show full text]
  • S-236548 COMPLETO.Pdf
    saglS?!?,ift»ensrw.'»K»» » d' i Dr. R. Hartmje k H^M CATALOGUE OF THE BRITISH ECHINODERMS rN THE BRITISH MUSEUM (NATURAL HISTOBY). BY F. JEFFREY BELL, M.A. LONDON: PRINTED BY ORDER OF THE TRUSTEES. SOLD BY LONGMANS & Co., S9 PATERNOSTER ROW; B. QUARITCH, 15 PICCADILLY; DULAU & Co., 37 SOHO SQUARE; KEGAN PAUL & Co., PATERNOSTER HOUSE, CHARING CROSS ROAD; AND AT THE BRITISH MUSEUM (NATURAL HISTORY), CROMWELL ROAD, S.W. 1892. PRINTED BY TAYLOR AND FRANCIS, KED HON COURT, FLEET STEEET. PREFACE. THE efforts which have been made of recent years to investigate the Fauna of the seas surrounding the British Islands have supplied ft large and important contributions to the Collection of Echinoderms in the British Museum, which previously was singularly poor in specimens of this part of the indigenous Fauna. Much time and labour has been given to the study and arrangement of these additions; and it seemed to be expedient to prepare, together with the nominal list of the specimens, a complete account of all the species hitherto found in British seas—descriptive so far as to define the limits of a species as understood by the author, and to supply at the same time the means by which the collector could identify his specimens. As no such guide exists, it is expected that much encouragement will be given to the study of Echinoderms by the present volume, and especially that the deficiencies which still exist in the series of specimens in the National Collection will be supplied by those who may use, and profit by, this work.
    [Show full text]