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Provedor de dados:  Naturalis
País:  Netherlands
Título:  A Monograph on Spanish Palaeozoic Crinoidea
Autores:  Breimer, A.
Data:  1962
Ano:  1962
Resumo:  It has been the aim of this study to give a comprehensive description of the important crinoid fauna's of the Palaeozoic core of North Western Spain (provinces Palencia, León and Asturias). This was opportune since fine collections of crinoids had been made during the years 1955—1960 by students of Leiden University (Holland). Moreover, existing collections of Spanish crinoids have not recieved hitherto due attention. Up to the present day only ten species of Palaeozoic crinoids have been known from Spain. Five new genera and sixteen new species of Spanish crinoids are now described. Fourteen previously described genera are reported for the first time to occur in Spain, either from new species or from species not yet sufficiently well known to allow specific arrangement. Six previously described species are recorded for the first time from Spain. So the total number of known Spanish crinoid species has now been raised to fifty six (thirty two genera): twenty five Emsian species, nine Couvinian species, six Givetian species, one Fransnian species, one Visean species, four Namurian species and four Moscovian species. The other species, represented by museum specimens only, are of uncertain Devonian or Carboniferous age. Camerates are far more numerous than inadunates, whereas flexibles are not known with any certainty. Camerates include thirty eight species (twenty two genera); inadunates eightteen species (ten genera). Among camerates only seven species belong to the diplobathrids; stratigraphically they seem to be restricted to the Emsian. Pterinocrinus decembrachiatus, Griphocrinus ovetensis, Orthocrinus robustus and Orthocrinus elongatus are described as new species of diplobathrids. The genera Diamenocrinus, Pterinocrinus, Macarocrinus and Griphocrinus are recorded for the first time from Spain. Orthocrinus was already known. W. E. Schmidt's species Orthocrinus planus is regarded a nomen dubium, since only poor fragments are assignable to the species. Camerates further include thirty one species of monobathrids, among which periechocrinids (fourteen species) and hapalocrinids/platycrinids (nine species) are of special importance. Stratigraphical distribution of the Spanish monobathrids is from the Lower Devonian to Upper Carboniferous. Among periechocrinids (restricted to Devonian strata) Pradocrinus is held as an independent genus with the only species P. Baylii de Verneuil, 1850 as the type-species. The genus is only known to occur in Spain. The available generic names Lenneocrinus and Pyxidocrinus were used for assignment of Spanish species. Lenneocrinus is now definitely erected with L. cirratus Jaekel, 1918 as the type-species. A diagnosis has been given on p. 29. The genus is first reported to occur in Spain from the new Frasnian species L. ventanillensis. Pyxidocrinus was proposed as a conditional name but is now erected as genus with Actinocrinus prumiensis as type-species and J. Muller as the author. A diagnosis has been given on p. 35. P. collensis and P. latus are referred to it as new species. P. San-Migueli (Astre, 1925), formerly referred to Periechocrinus and Pithocrinus and P. bifrons (W. E. Schmidt, 1932, formerly referred to Megistocrinus and Pithocrinus have now been ranked under Pyxidocrinus. Although Pyxidocrinus has a German species as the type, it is essentially a Spanish genus. Strangely enough it is only now reported for the first time as occurring in Spain. The genus Pithocrinus Kirk, 1945, with P. Cooperi Kirk, 1945 as the type-species has been emended so as to include forms with globose dorsal cups, a variable number of free arms per ray and a stout subcentral anal tube. The arms are described for the first time. For emended diagnosis see p. 46. Although Pithocrinus has an American type it is essentially a Spanish genus. P. ovatus and P. spinosus are referred to this genus as new species, P. Waliszewskii Oehlert, 1896, formerly referred to Megistocrinus is kept within it, but P. intrastigmatus Schmidt, 1932, formerly referred to Saccocrinus is excluded and used as the type-species of the new genus Stamnocrinus diagnosis see p. 59 which is believed to include Dorycrinus devonicus Springer, 1911 and two more Spanish species, not yet sufficiently well known so as to allow definite description. Stamnocrinus is restricted to Devonian strata. The new Emsian species Corocrinus? grandosensis is provisionally referred to Corocrinus because it possesses characters unknown up to now from that genus. Gennaeocrinus is first recorded from Spain from a species very similar to G. nyssa. The study of the important Devonian periechocrinid fauna has revealed that no Devonian forms can be assigned to the type genus Periechocrinus, which genus must be of exclusively Silurian age. A group of Lower Carboniferous and Mississippian species, hitherto assigned to Periechocrinus, both for morphological as for stratigraphical reasons cannot belong to Periechocrinus nor to any of the Devonian periechocrinid genera. The new genus Aryballocrinus is erected for them with Periechocrinus ? Whitei Hall, 1861 as the type-species. A diagnosis for this genus is given on p. 72. The genus includes six species, four of which were formerly referred with doubt to Periechocrinus: Aryballocrinus Whitei (Hall, 1861), Aryballocrinus tenuidiscus (Hall, 1861), Aryballocrinus awthornsensis (J. Wright, 1955) and Aryballocrinus spec. 1 (Laudon & Severson, 1953). Further are included Aryballocrinus Sampsoni Miller & Gurley, 1896, formerly referred to Corocrinus and Aryballocrinus parvus Wachsmuth & Springer, 1890, formerly referred to Megistocrinus Other monobathrids include specimens of Iberocrinus multibrachiatus Sieverts Doreck, 1951, which species proved to occur in the Moscovian of Spain. Nunnacrinus ? stellaris is first reported from the Namurian of Spain. The genus Pimlicocrinus is first recorded outside Great Britain. Pimlicocrinus latus occurs in the Namurian of Spain, whereas in England it is in the Dinantian. Another two species of Pimlicocrinus are not yet fully described. One of them is of Moscovian age and probably conspecific with a specimen from the Westfalian of Marocco. A single cup is assigned to Aorocrinus. This would mean the first occurrence of this genus outside the North American continent. Platyhexacrinus Kegeli W. E. Schmidt, 1932 is mentioned because two new specimens substitute for the lost types. Trybliocrinus Flatheanus is redescribed in great detail. The species Hadrocrinus hispaniae Schmidt, 1932 is placed into synonymy with it. Much attention has been given to the ontogenetic growth. Ontogenetic phenomena are regarded as special characters of the family Polypetidae, in which family the genus Himerocrinus Springer, 1921 is placed on the ground that it is supposed to have an ontogenetic growth largely comparable to that here described for Trybliocrinus. Platycrinicae form an important part of the Spanish fauna. Besides Platycrinus spec. ex gr. bollandensis of Namurian age and Pleurocrinus spec. ex gr. coplowensis of unknown provenance, they may all be found in Lower and Middle Devonian strata. The Spanish hapalocrinids and related platycrinids are characterized by aberrant positions of the smaller basal and by differentation of the posterior interradius. The new hapalocrinid genus Cantharocrinus with C. minor spec. Nov. as the type-species (diagnosis see p. 117) and the new species C. simplex as co-type, is still only known from Spain. The new platycrinid genus Oenochoacrinus with Oe. princeps spec. Nov. as type-species (diagnosis see p. 124) and the new species Oe. pileatus and Oe. scaber as cotypes, is still known only from Spain. The genus is erected for platycrinids with a tegmen composed of five orals and five modified first axillar ambulacrals. The genus showed to posses affinity with the Permian genus Neoplatycrinus. The better understanding of modified first axillar ambulacrals, as a character consistent with the presence of but one first primibrach and two secundibrachs in trunked armbases led to a review of the morphological relations of genera in the Platycrinicae. A suggestion for their evolution is given, based on detailed morphological comparison (see textfig. 32). Among the inadunates previously described from Spain Storthingocrinus Haugi Oehlert, 1896 and Storthingocrinus labiatus W. E. Schmidt, 1932 are regarded as nomina dubia. The incomplete nature of the specimens attributed to them, forces us to do this because their cups are undistinguishable from so many other inadunate cups. The affinity of North American Devonian crinoids with the West European fauna is once more expressed by the first record from Spain of the species Vasocrinus valens Lyon, 1857; Vasocrinus turbinatus Kirk, 1929; Vasocrinus stellaris (Schultze, 1867) and spec. cf. V. sculptus Lyon, 1857. A highly interesting inadunate proved to be a form with pentalobate stem, composed of five different joint series, two anals in cup and enlarged thecal cavity by incorporation of a smalll number of interradials and the presence of a madreporite. It is described as the new genus Situlacrinus with S. costatus spec. Nov. as the type-species diagnosis see p. 153 The genus is placed provisionally among the Barycrinidae. It would be the first Devonian form of that family and the first record from Europe. The Givetian cupressocrinid fauna has largely affinitiy with Middle Devonian fauna's in the Eifel region. Cupressocrinites Townsendi, Cupressocrinites spec. cf. C. Schlotheimi, Cupressocrinites inflatus, Cupressocrinites Sampelayoi and a species not sufficiently well presented to receive full description are described from Spain. C. inflatus and C. aff. Schlotheimi have their first mention outside Germany. The genus Aviadocrinus Almela & Revilla, 1950 is put into synonymy with Cupressocrinites Goldfuss, 1831 because all the essential characters of its type-species A. Sampelayoi occur dispersedly among Cupressocrinites species. The genera Bactrocrinites, Lasiocrinus (?), Cromyocrinus and Paradelocrinus are reported for the first time from Spain. The Devonian crinoid faunas in the province of León occur in four different levels: at the top of the La Vid formation; at the base of the Santa Lucia formation; at the top of the Santa Lucia formation; and in the middle part of the Portilla formation. The first two faunas are of Emsian age. The Emsian fauna has affinities with the Lower Devonian fauna of Western Germany and with the Middle Devonian fauna of the region West-Central New York, Kentucky, Michigan, Indiana. The Spanish Emsian fauna is the richest of all known Spanish crinoid faunas.
Tipo:  Article / Letter to the editor
Formato:  application/pdf
Fonte:  Leidse Geologische Mededelingen (0075-8639) vol.27 (1962) nr.1 p.1
Direitos:  (c) Naturalis

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