Search results for "Crinoid"
showing 10 items of 12 documents
First report of Gogia (Eocrinoidea, Echinodermata) from the Early-Middle Cambrian of Sonora (Mexico), with biostratigraphical and palaeoecological co…
2009
10 pages; International audience; The blastozoan echinoderm genus Gogia is reported for the first time in the Early and the Middle Cambrian of Mexico. Reports in different members of the section of San José de Gracia (Sonora State, northwestern Mexico) extend the palaeogeographical range of the genus to the South Laurentia, and the stratigraphic range of Gogia granulosa to the whole first half of middle Middle Cambrian. Isolated plates occur in rocks deposited in detrital inner platform and complete specimens, in carbonate outer platform, confirming their ability to live in diverse environments. Their presence in these different environments through the Early-Middle Cambrian on Laurentia ag…
Athenacrinus n. gen. and other early echinoderm taxa inform crinoid origin and arm evolution
2020
AbstractIntermediate morphologies of a new fossil crinoid shed light on the pathway by which crinoids acquired their distinctive arms. Apomorphies originating deep in echinoderm history among early nonblastozoan pentaradiate echinoderms distinguish Tremadocian (earliest Ordovician) crinoid arms from later taxa. The brachial series is separated from the ambulacra, part of the axial skeleton, by lateral plate fields. Cover plates are arrayed in two tiers, and floor plates expressed podial basins and pores. Later during the Early Ordovician, floor plates contacted and nestled into brachials, then were unexpressed as stereom elements entirely and cover plates were reduced to a single tier. Inco…
Revision of the pentacrinid stalked crinoids of the genus Endoxocrinus (Echinodermata, Crinoidea), with a study of environmental control of character…
2006
A revision of the stalked crinoid species attributed to the genus Endoxocrinus A.H. Clark, 1908 (Diplocrininae, Pentacrinitidae, Crinoidea, Echinodermata) is conducted using studies on phenotype variation and its relation with environment. Specimens collected via submersible at five sites in the Bahamas exhibit distinct phenotypes that correlate with different apparent ecological niches and serve as references for interpreting specimens dredged in Atlantic and Pacific Oceans where detailed information on their benthic environment is unknown. Documentation of ecophenotypic convergences or divergences allows us to distinguish between adaptive characters and those revealing genetic affinities,…
Echinodermata: The complex immune system in echinoderms
2018
View references (418) The Echinodermata are an ancient phylum of benthic marine invertebrates with a dispersal-stage planktonic larva. These animals have innate immune systems characterized initially by clearance of foreign particles, including microbes, from the body cavity of both larvae and adults, and allograft tissue rejection in adults. Immune responsiveness is mediated by a variety of adult coelomocytes and larval mesenchyme cells. Echinoderm diseases from a range of pathogens can lead to mass die-offs and impact aquaculture, but some individuals can recover. Genome sequences of several echinoderms have identified genes with immune function, including expanded families of Toll-like r…
Microcrinoids from the lower and middle Albian of the Anglo-Paris Basin (southern England, UK, Seine Maritime, Pas de Calais and Aube, France).
2021
16 pages; International audience; Microcrinoids of the family Roveacrinidae Peck, 1943 are described from lower and middle Albian clays of the Anglo-Paris Basin (Seine Maritime, Pas de Calais and Aube, France; Kent and Bedfordshire, UK). They are referred to two subfamilies - the Orthogonocrininae Gale, 2019 and the Plotocrininae Gale, 2020. Orthogonocrinines include the long-ranging (middle Albian-lower Cenomanian) species Orthogonocrinus apertus Peck, 1943, and Styracocrinus peracutus (Peck, 1955), known from Texas, USA, Morocco, the UK and France, and two stratigraphically successive species of the genus Hyalocrinus, H. magniezii Destombes, 1984 and H. bulliensis Destombes, 1984, known o…
Correction to: Echinodermata: The complex immune system in echinoderms (Advances in Comparative Immunology, 10.1007/978-3-319-76768-0_13)
2018
This chapter was inadvertently published with an incorrect spelling of the author's name as V. Arriza whereas it should be V. Arizza. In addition to this the affiliation of one of the chapter authors Elisse Sutton was published incorrectly and it has now been corrected to read as Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
Late Cretaceous echinoderm ‘odds and ends’ from the Low Countries
2018
From various levels within the Gulpen and Maastricht formations (upper lower to upper upper Maastrichtian, c. 69.5–66 Ma) in the extended type area of the Maastrichtian Stage (southeast Netherlands, northeast Belgium and the Aachen area in Germany), a few recent additions to echinoderm faunas are illustrated and briefly discussed. Added are some erratic, flint-preserved, pre-Maastrichtian echinoid taxa from Pleistocene fluvial gravel deposits; these are of palaeogeographical interest. Crinoids include the comatulid Semiometra saskiae with traces of sublethal predation and several bourgueticrinines. Amongst the latter, the species Dunnicrinus aequalis is found preserved in biocalcarenites as…
Controls of mud mound formation: The Early Devonian Kess-Kess carbonates of the Hamar Laghdad, Antiatlas, Morocco
1992
The origin and development of Early Devonian (late Pragian to late Zlichovian; predominantly uppermost Zlichovian as indicated by conodont faunas) mud mounds of the Hamar Laghdad area in the eastern Antiatlas, Morocco, are controlled by extrinsic and intrinsic factors. Extrinsic factors include the existence of a paleohigh (Lochkovian volcaniclastics), unidirectional currents and repeated storm events as well as sea level fluctuations. Intrinsic, biologically induced factors are the preferred growth of organisms on the top and the flanks of the mounds because of more favourable ecological conditions, and a rapid synsedimentary lithification of the steep mound flanks by interskeletal cementa…
A Middle Cambrian edrioasteroid from the Murero biota (NE Spain) with Australian affinities
2007
Abstract A Middle Cambrian edrioasteroid belonging to the genus Cambraster is described from the Middle Cambrian Murero biota (Cadenas Ibericas, NE Spain). Up to now, this genus was known only from Australia and France. This represents the first record of the class Edrioasteroidea in the Cambrian of Spain. Moreover, preliminary results on the diversity and biostratigraphic position of Cincta, Eocrinoidea and Edrioasteroidea from this area are reported.
New specimens of Lingulocystis Thoral, 1935 (Eocrinoidea, Blastozoa) from the Arenig (Lower Ordovician) of Montagne noire (southern France): Intraspe…
2007
16 pages; The genus Lingulocystis Thoral, 1935 is a preponderant component of the echinoderm fauna of the Lower Ordovician of Montagne noire (France), as suggested by its abundant remains. Its morphology is characterized by a flattened theca, composed of a frame enclosing numerous small polygonal central plates. The new specimens have been determined partly as Lingulocystis elongata Thoral, 1935 and partly as Lingulocystis aff. deani Ubaghs, 1994. This study is the first report of Lingulocystis in the Foulon Formation. New stratigraphic ranges have been defined for both species: L. elongata from the early Tremadoc (Saint- Chinian Formation) to the middle Arenig (lower part of the Landeyran …