Abstract
Lateral arm plates, the spine-bearing plates of the ophiuroid arm skeleton, have long been assumed to display sufficient morphological diversity to be used for species identifications in ophiuroid micropalaeontology. As a consequence, many new brittle-star species have been described on the basis of isolated fossil lateral arm plates. A substantial lack of information on the morphological variability of lateral arm plates in respect of taxon concepts, however, has led to increasing confusion over species limits and excessive extensions of stratigraphic species ranges. In this study, we therefore performed a detailed assessment of the variability of lateral arm plate morphology within and between species in order to test to what extent isolated lateral arm plates can be used for species identifications. To this end, we investigated the morphological variability of lateral arm plates within species according to ontogenetic changes and according to the position of the plates along the arm. Furthermore, we examined the lateral arm plates of 56 Recent species, belonging to 27 genera and 10 families, and systematically assessed their morphology in the light of currently accepted taxon concepts. The results of this study demonstrate that lateral arm plate morphology is in accordance with most family, genus and species limits. Some of the currently accepted taxon concepts, including the affinities between the Ophiacanthidae and Ophiocomidae, however, are challenged by lateral arm plate morphology. Differences in lateral arm plate morphology between taxa are the most conspicuously displayed by adult proximal lateral arm plates, as a consequence of their high degree of differentiation compared to distal or juvenile lateral arm plates. Differences at species level, often pertain to characters which were considered to be within-species variation in previous micropalaeontological works, suggests that species identifications based on isolated fossil lateral arm plates require a much more detailed and careful morphological assessment. Some of the species studied herein displayed indistinguishable lateral arm plate morphologies, but belonged to the same genus in all cases. Our study endorses the use of isolated fossil lateral arm plates for taxonomic interpretations in ophiuroid micropalaeontology, including species identifications and the creation of new taxa, providing that descriptions are based on pristinely preserved adult proximal LAPs, described and illustrated using SEM-pictures of both the external and internal sides of the plate.References
Abildgaard, P.C. (1789) In: Müller, O. F., Zoologica Danica seu animalium Daniae et Norvegiae rariorum, ac minus notorum, descriptiones et historia, 3. N. Molleri, Hauniae, 1–71.
Ayres, W.O. (1851) An account of the structure of the Ophiuridae and a description and drawings of a new species belonging to the genus Ophiolepis. Proceedings of the Boston Society of Natural History, 4, 133–135.
Bell, F.J. (1902) Echinoderms. Report on the collections of natural history made in the Antarctic regions during the voyage of the “Southern Cross”, 214–220.
Berry, C.T. (1938) Ophiurans from the Upper Senonian of South Limburg, Holland. Journal of Paleontology, 12, 61–71.
Bruzelius, N. (1805) Dissertatio sistens species cognitas asteriarum, quamr. sub praesidio A.J. Retzii, pro laurea modeste exhibit Nicolaus Bruzelius. Lund, 1–37.
Clark, H.L. (1911) North Pacific Ophiurans in the collection of the Unites States National Museum. Bulletin of the United States National Museum, 75, 1–302.
Danielssen, C. & Koren, J. (1877) Fra den norske Nordhavs Expedition. Nyt Magazin for Naturvidenskaberne, 32, 1–39.
Devaney, D.M. (1970) Studies on ophiocomid brittlestars. I. A new genus (Clarkcoma) of Ophiocominae with a re-evaluation of the genus Ophiocoma. Smithsonian Contributions to Zoology, 51, 1–41.
Düben, M.W. & Koren, J. (1846) Ofversigt af Skandinaviens Echinodermer. Kungliga Svenska Wetenskapsakademiens Handlingar, 1844, 229–328.
Forbes, E. (1839) On the Asteriadae of the Irish Sea. Memoirs of the Wernerian Society, 8, 114–129.
Forbes, E. (1843) On the Radiata of the Eastern Mediterranean. Part I., Ophiuridae. Transactions of the Linnean Society of London, 19, 143–153.
Forbes, E. (1852) Notes on animals of the class Echinodermata collected by Dr. Sutherland in Assistance Bay. Sutherland’s Journal of a voyage to Baffin’s Bay, 2, 214–216.
Hendler, G. (1998) Implications of the remarkable ontogenetic changes in some deep-sea brittle stars. In: Mooi, R. & Telford M. (Eds.), Echinoderms: San Francisco. Rotterdam, Balkema, pp. 353–358.
Hendler, G., Miller, J.E., Pawson, D.L. & Kier, P.M. (1995) Sea Stars, Sea Urchins, and Allies. Washington (Smithsonian Institution Press), 390 pp.
Hertz, M. (1927) Die Ophiuroiden der Deutschen Südpolar-Expedition 1901–1903. Deutsche Südpolar-Expedition 1901–1903, 19, 1–56.
Hess, H. (1960) Ophiurenreste aus dem Malm des Schweizer Juras und des Departements Haut-Rhin. Eclogae Geologicae Helvetiae, 53/1, 385–421.
Hess, H. (1962a) Mikropaläontologische Untersuchungen an Ophiuren I: Einleitung. Eclogae Geologicae Helvetiae, 55/2, 595–608.
Hess, H. (1962b) Mikropaläontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae Geologicae Helvetiae, 55/2, 609–656.
Hess, H. (1963) Mikropaläontologische Untersuchungen an Ophiuren III: Die Ophiuren aus dem Callovien-Ton von Liesberg (Berner Jura). Eclogae Geologicae Helvetiae, 56/2, 1141–1164.
Hess, H. (1965) Mikropaläontologische Untersuchungen an Ophiuren IV: Die Ophiuren aus dem Renggeri-Ton (Unter-Oxford) von Chapois (Jura) und Longecombe (Ain). Eclogae Geologicae Helvetiae, 58/2, 1059–1082.
Hess, H. (1966) Mikropaläontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dépt. Jura). Eclogae Geologicae Helvetiae, 59/2, 1025–1063.
Hess, H. (1975a) Mikropaläontologische Untersuchungen an Ophiuren VI: Die Ophiuren aus den Günsberg-Schichten (oberes Oxford) vom Guldental (Kt. Solothurn). Eclogae Geologicae Helvetiae, 68/3, 591–601.
Hess, H. (1975b) Mikropaläontologische Untersuchungen an Ophiuren VII: Die Ophiuren aus den Humeralis-Schichten (Ober-Oxford) von Raedersdorf (Ht-Rhin). Eclogae Geologicae Helvetiae, 68/3, 603–612.
Hess, H. & Palain, C. (1975) Ophiures de l’Hettangien du nord du Portugal. Communications du service géologique du Portugal, 59, 5–13.
Hotchkiss, F.H.C. & Haude, R. (2004) Observations on Aganaster gregarius and Stephanoura belgica (Ophiuroidea: Ophiolepididae) (Early Carboniferous and Late Devonian age). In: Heinzeller, T. & Nebelsick, J.H. (Eds.), Echinoderms München. London (Taylor & Francis), pp. 425–431.
Hunter, R.L. (2007) Morphological cladistic analysis of Ophiurolepis Matsumoto, 1915 (Ophiurida: Ophiuridae) from the Southern Ocean. Zootaxa, 1401, 33–51.
Jagt, J.W.M. (2000) Late Cretaceous-Early Palaeogene echinoderms and the K/T boundary in the southeast Netherlands and nordeast Belgium – Part 3: Ophiuroids. With a chapter on Early Maastrichtian ophiuroids from Rügen (northeast Germany) and Møn (Denmark) by Manfred Kutscher & John W. M. Jagt. Scripta Geologica, 121, 1–179.
Kerr, T.J.V. & Twitchett, R.J. (2004) Experimental decay and disintegration of Ophiura texturata: implications for the fossil record of ophiuroids. In: Heinzeller, T. & Nebelsick, J.H. (Eds.), Echinoderms München. London (Taylor & Francis), pp. 439–446.
Koehler, R. (1896) Résultats scientifiques de la compagne du Caudan dans le Golfe de Gascogne. Echinodermes. Annales de l’Université de Lyon, 26, 33–122.
Koehler, R. (1900) Echinides et Ophiures. Résultats du voyage du S.Y. Belgicae en 1897–1899. Anvers, 1–42.
Koehler, R. (1904) Ophiures des mers profondes. Siboga-Expeditie, 45, 1–176.
Koehler, R. (1922a) Ophiurans of the Philippine Seas and adjacent waters. Smithsonian Institution United States National Museum, 100/5, 1–486.
Koehler, R. (1922b) Ophiuroidea. Scientific Reports of the Australasian Antarctic Expedition 1911–1914, 8, 1–98.
Kutscher, M. (1987) Die Echinodermen der Callovien-Geschiebe. Der Geschiebesammler, 21/2–3, 53–104.
Kutscher, M. (1988) Zur Invertebratenfauna und Stratigraphie des oberen Pliensbachium von Grimmen, Echinodermata. Freiberger Forschungshefte, C, 419, 62–70.
Kutscher, M. (1996) Echinodermata aus dem Ober-Toarcium und Aalenium Deutschlands II. Ophiuroidea. Stuttgarter Beiträge zur Naturkunde, Serie B, 242, 1–33.
Kutscher, M. & Hary, A. (1991) Echinodermen im Unteren Lias (Bucklandi- und Semicostatum-Zone) zwischen Ellange und Elvange (SE-Luxemburg). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 182/1, 37–72.
Kutscher, M. & Villier, L. (2003) Ophiuroid remains from the Toarcian of Sainte-Verge (Deux-Sèvres, France): paleobiological perspectives. Geobios, 36, 179–194.
Lamarck, J.B. de (1816) Histoire naturelle des animaux sans vertèbres. Volume 2. Verdière, Paris, 522–568.
Ljungman, (1872) Förteckning öfver uti Vestindien af Dr. A Goës samt under korvetten Josefinas expedition i Atlantiska Oceanen samlade Ophiurider. Öfversigt af Kungliga Vetenskaps-Akademiens Förhandlingar, Stockholm, 28, 615–658.
Linnaeus, C. (1758) Systema naturae per regna tria naturae secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decimal, reformata. Holmiae, 1–824.
Linnaeus, C. (1767) Systema Naturae, seu per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Holmiae, Laurentii Salvii, 533–1327.
Litvinova, N.M. (1991) [Revision of the Genus Ophiotholia (Echinodermata, Ophiuroidea)]. Zoologichesky Zhurnal, 71(3), 47–57. (In Russian)
Lütken, C.F. (1855) Bidrag til Kundskab om Slangestjernerne. I. Forelöbig Oversigt over Grönlandshavets Ophiurer. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 95–104.
Lütken, C.F. (1856) Oversigt over de Vestindiske Ophiurer. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 1856/1–2, 1–26.
Lütken, C.F. (1858) Systematisk oversigt over Gronlands echinodermer. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening i Kjobenhavn, 1–7, 1–109.
Lyman, T. (1869) Preliminary report on the Ophiuridea and Astrophytidae dredged in deep water between Cuba and the Florida Reef, by L.F. de Pourtales, Assist. U.S. Coast Survey. Bulletin of the Museum of Comparative Zoology, Harvard University, 1, 309–354.
Lyman, T. (1874) Ophiuridae and Astrophytidae, old and new. Bulletin of the Museum of Comparative Zoology, Harvard, 3/10, 221–272.
Lyman, T. (1878) Ophiuridae and Astrophytidae of the exploring voyage of H.M.S. Challenger, under Prof. Sir Wyville Thomson, F.R.S. Part 1. Bulletin of the Museum of Comparative Zoology, Harvard, 5, 65–168.
Lyman, T. (1883) Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Carribbean Sea (1878–79), and on the east coast of the United States, during the summer of 1880, by the U.S. coast survey steamer “Blake”, commander J.R. Bartlett, U.S.N., commanding. XX. Report on the Ophiuroidea. Bulletin of the Museum of Comparative Zoology at Harvard College, 10, 227–287.
Madsen, F.J. (1970) West African ophiuroids. Atlantide Report, 11, 151–243.
Martynov, A. (2010a) Structure of the arm spine articulation ridges as a basis for taxonomy of Ophiuroidea (a preliminary report). – In: Harris, L.G., Böttger, A.S., Walker, C.W. & Lesser, M.P. (Eds.), Echinoderms: Durham. Proceedings of the 12th International Echinoderm Conference, Durham, New Hampshire, USA, 7–11 August 2006. London (Taylor & Francis Group), pp. 233–239.
Martynov, A. (2010b) Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa, 2697, 1–154.
Martynov, A. & Litvinova, N.M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76–111.
Matsumoto, H. (1915) A new classification of the Ophiuroidea. Proceedings of the Academy of Natural Sciences of Philadelphia, 67, 43–92.
Matsumoto, H. (1917) A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College Science, Imperial University Tokyo, 38, 1–408.
Meek, F.B. & Worthen, A.W. (1869) Descriptions of new Carboniferous fossils from the Western States. Proceedings of the Academy of Natural Sciences of Philadelphia, 21, 137–172.
Mortensen, T. (1927) Handbook of the Echinoderms of the British Isles. Backhuys: Rotterdam, 471 pp.
Mortensen, T. (1936) Echinoidea and Ophiuroidea. Discovery Reports, 12, 199–348.
Mortensen, T. (1937) Some echinoderm remains from the Jurassic of Württemberg. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab Kobenhavn, 13, 1–28.
Müller, A.H. (1950) Die Ophiuroideenreste aus dem Mucronatensenon von Rügen. Geologica, 5, 4–35.
Müller, J. & Troschel, F.H. (1840) Über die Gattungen der Ophiuren. Archiv fur Naturgeschichte, Berlin, 6, 327–330.
Müller, O.F. (1776) Zoologiae danicae prodromus. Havniae, 1–282.
O’Hara, T.D. & Stöhr, S. (2006) Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer De Forges, B. & Justine, J.-L. (Eds.), Tropical Deep-Sea Benthos. Volume 24. Mémoires du Muséum national d’Histoire Naturelle, 193, pp. 33–141.
Paterson, G.L.J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49, 1–162.
Philippi, R.A. (1858) Beschreibung einiger neuer Seesterne aus dem Meere von Chiloe. Archiv für Naturgeschichte, 24/2, 264–268.
Rasmussen, H.W. (1950) Cretaceous Asteroidea and Ophiuroidea with special reference to the species found in Denmark. Danmarks Geologiske Undersogelse, 77, 1–134.
Rasmussen, H.W. (1951) Cretaceous Ophiuroidea from Germany, Sweden, Spain and New Jersey. Meddelelser fra Dansk Geologisk Forening, 12, 47–57.
Sars, G.O. (1871) Nye Echinodermer fra den Norske kyst. Videnskabelige Selskabs Forhandlingar, 1871, 1–31.
Sars, M. (1861) Oversigt af Norges Echinodermer. Christiania, Videnskabs-selskabet, 1–166.
Say, T. (1825) On the species of the Linnean genus Asterias, inhabiting the coast of the United States. Journal of the Academy of Natural Sciences of Philadelphia, 5, 141–154.
Smith, A.B., Paterson, G.L.J. & Lafay, B. (1995) Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives. Zoological Journal of the Linnean Society, 114, 213–243.
Smith, E.A. (1876) Diagnosis of new species of Mollusca and Echinodermata from the Island of Rodriguez. Annals and Magazine of Natural History, series 4, 17, 404–406.
Stöhr, S. (2005) Who’s who among baby brittle stars (Echinodermata: Ophiuroidea): postmetamorphic development of some North Atlantic forms. Zoological Journal of the Linnean Society, 143, 543–576.
Stöhr, S. & Hansson, H. (2011) Ophiura Lamarck, 1801. In: Stöhr, S., O’Hara, T. (Eds) (2011). World Ophiuroidea database. Accessed through: Stöhr, S., O’Hara, T. (Eds) (2011). World Ophiuroidea database at http://www.marinespecies.org/ophiuroidea/aphia.php?p=taxdetails&id=123574 (accessed on 2011-04-08)
Stöhr, S. & Segonzac, M. (2005) Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean. Journal of the Marine Biological Association of the UK, 85, 383–402.
Studer, T. (1885) Die Seesterne Süd-Georgiens, nach der Ausbeute der deutschen Polarstation in 1882 und 1883. Jahrbuch der Wissenschaftlichen Anstalten zu Hamburg, 2, 141–166.
Sumida, P.Y.G., Tyler, P.A., Gage, J.D. & Nørrevang, A. (1998) Postlarval development in shallow and deep-sea ophiuroids (Echinodermata: Ophiuroidea) of the NE–Atlantic Ocean. Zoological Journal of the Linnean Society, 124, 267–300.
Štorc, R. & Žítt, J. (2008) Late Turonian ophiuroids (Echinodermata) from the Bohemian Cretaceous Basin, Czech Republic. Bulletin of Geosciences, 83/2, 123–140.
Thomson, W. (1840) Contributions towards a knowledge of the Mollusca Nudibranchia and Mollusca Tunnicata of Ireland with a description of some apparently new species of invertebrates. Annals and Magazine of Natural History, 5, 84–102.
Thuy, B. (2005) Les Ophiures de l’Hettangien inférieur de Vance (B), Bereldange/Bridel et Bourglinster (L). Memoirs of the Geological Survey of Belgium, 51, 33–57.
Ubaghs, G. (1941) Description de quelques ophiures du Famennien de la Belgique. Bulletin du Musée royal d’Histoire naturelle de Belgique, 17/44, 1–31.
Vadon, C. (1990) Ophiozonella novaecaledoniae n.sp. (Ophiuroidea, Echinodermata): description, ontogeny and phyletic position. Journal of Natural History, 24, 165–179.
Verrill, A.E. (1879) Notice of recent additions to the marine invertebrates of the northeastern coast of America. Proceedings of the United States National Museum, 2, 165–205.
Verrill, A.E. (1885) Results of the explorations made by the Steamer Albatross off the northern coast of the United States. Report United States Commissioner of Fisheries, 1883, 517.
Wilkie, I.C. (1980) The systematic position of Ophiocomina Koehler and a reconsideration of certain interfamilial relationships within the Ophiuroidea. In: Jangoux, M. (ed.), Proceedings of the European Colloquium on Echinoderms, Brussels, 3–8 September 1979, Rotterdam, Balkema, pp. 151–157.
Wolburg, J. (1939) Skelettreste von Ophiuren aus dem deutschen Lias, ihre systematische Zugehörigkeit und Bedeutung als Mikrofossilien. Paläontologische Zeitschrift, 21, 20–42.
Wyville-Thomson, C. (1873) The depths of the sea. London (Macmillan & Co.), 527 pp.