Prodactylioceras

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Prodactylioceras
Prodactylioceras davoei

Prodactylioceras davoei

Temporal occurrence
Pliensbachium
185.7 to 184.1 million years
Locations
Systematics
Cephalopods (cephalopoda)
Ammonites (ammonoidea)
Ammonitida
Dactylioceratidae
Prodactylioceras
Scientific name
Prodactylioceras
Spath , 1923

Prodactylioceras is a genus of evolutionary ammonites . She's index fossil in Lower Pliensbachian ( Carixium ) in the after davoei Prodactylioceras named Davoei zone .

Initial description and naming

The genus Prodactylioceras was first described by Leonard Spath in 1923 . Their name is a word creation from the Greek words δάκτυλος daktylos (finger) and κέρας keras (horn). The prefix pro (before, before, for) indicates that it was the forerunner of the genus Dactylioceras , which later appeared in the Toarcium .

characterization

Prodactylioceras is an evolutionary genus of ammonites with N ≥ 0.55. The turns develop only very slowly, so that N, for example in Prodactylioceras westgatenses, almost approaches 1. The coil cross-section is compressed, the flanks are rounded and the venter has no keel. The prorsiradiate ribs vary in density depending on the taxon and can split up in front of quite large tubercles (bullae) located laterally on the ventral side of the inner convolutions. Rib density and strength do not change during growth. Secondary and tertiary ribs can slide in on the third turn, but they disappear again on the outer turns. The lines of praise are relatively complex, with the first lobe being very large and heavily branched.

Systematics

The genus Prodactylioceras belongs to the subfamily Reynesocoeloceratinae Dommergues, 1986 within the family of Dactylioceratidae Hyatt , 1867 . The following taxa are known from her:

Synonyms are Paralytoceras Frebold, 1922 and Praedactylioceras Frentzen, 1937 .

Bettoniceras , Cetonoceras and Reynesocoeloceras act as sister taxa .

The genus Prodactylioceras developed from the genus Reynesocoeloceras , but probably via a detour via Bettoniceras .

Way of life

The individuals of the genus Prodactylioceras were fast-swimming marine carnivores that populated the shallow as well as the deeper calcareous subtidal far away from the coast and followed drifting plankton . They were also occasionally to be found in the deep shelf area and over underwater fans.

Ammonite zone

The genus Prodactylioceras is a key fossil and defines the third ammonite zone of the Pliensbachian, the Davoei zone . The Davoei zone follows the Ibex zone and is in turn overlaid by the Margaritatus zone of the Upper Pliensbachian ( Domerium ). It is in the area of Tethys from the Dilectum zone and in North America by the Freboldi zone and the base of Kunae zone replaced.

Occurrence

The Kesselspitze from the southeast. The summit is built from Adneter Kalk and leads, among other things, Prodactylioceras .

Occurrences of the genus Prodactylioceras in Germany are Bargau near Schwäbisch Gmünd , Dewangen near Aalen , Göggingen , Pliensbach and Wiesloch in Baden-Württemberg as well as Ehenfeld near Hirschau in Bavaria , Beierstedt and Gebhardshagen in Lower Saxony and Velpe in North Rhine-Westphalia . In Austria , the ammonite finds at the Kesselspitze in Tyrol are worth mentioning. In Switzerland , Prodactylioceras occurs near Seewen in the canton of Solothurn .

Finds in France are the Causses ( Aveyron and Lozère , including Rivière-sur-Tarn and Saint-Étienne-du-Valdonnez ), the eastern Corbières (in the Aude near Massac and Narbonne ), the Ardennes (near Sedan ), the Ariège department (near Foix ), the Haute-Marne department and the Hautes-Pyrénées department (near Saint-Pé-de-Bigorre ).

In the United Kingdom , the genus appears in Northern Ireland at Collin Glen and Portrush . The Almonacid-de-la-Cuba formation near Saragossa functions as a site in Spain .

Deposits outside of Europe are on Jebel Bou Rharraf in eastern Morocco , in Canada on the Queen Charlotte Islands ( Fannin Formation ) and on the mainland of British Columbia as well as in the Yukon (near Whitehorse ), in the Wrangell Mountains in Alaska and in the Clan Alpine Mountains of Nevada in the United States .

literature

  • William Joscelyn Arkell et al .: Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press, 1957.
  • Andrew H. Caruthers et al: Pliensbachian-Toarcian (Early Jurassic) Ammonoids from the Luning Embayment, West-Central Nevada, USA In: Bulletins of American Paleontology . Number 393, 2018, p. 1-84 . [1]
  • Raymond Cecil Moore : Treatise on Invertebrate Paleontology . Part L. Mollusca 4. Ammonoidea. Geological Society of America, 1957, pp. 248 .
  • Kevin N. Page: The Lower Jurassic of Europe: its subdivision and correlation . In: Geological Survey of Denmark and Greenland Bulletin . tape 1 , 2003, p. 23-59 .
  • Rudolf Schlegelmilch : The ammonites of the southern German Lias: an identification book for fossil collectors and geologists. - 2nd edition Gustav Fischer Verlag, Stuttgart, Jena, New York 1992, p. 241 .

Individual evidence

  1. ↑ JJ Sepkoski: A compendium of fossil marine animal genera . In: Bulletins of American Paleontology . tape 363 , 2002, p. 1-560 .
  2. ^ FA Wittler and R. Roth: Fauna and biostratigraphy in the Lias gamma / delta border area southwest of Lotte near Osnabrück (Jura, NW Germany) . In: Working Group Palaeontology Hanover . tape 31 , 2003, p. 14-30 .
  3. ↑ R. Fischer and F. Turinsky: Mittelias-ammoniten von der Kesselspitze (North Tyrol) . In: New Yearbook for Geology and Paleontology, monthly books . tape 10 , 1975, p. 593-605 .
  4. ^ Christian Meister: Les ammonites du Carixien des Causses (France) . In: Swiss palaeontological treatises . tape 109 , 1986, pp. 1-209 .
  5. ↑ MJ Comas-Rengifo, JJ Gomez, A. Goy, C. Herrero, N. Perilli and A. Rodrigo: El Jurasico Inferior en la seccion de Almonacid de la Cuba (sector central de la Cordillera Iberica, Zaragoza, Espana) . In: Cuadernos de Geologia Iberica . tape 25 , 1999, pp. 27-57 .
  6. ^ Christian Meister, Jean-Louis Dommergues, C. Dommergues, N. Lachkar and K. El Hariri: Les ammonites du Pliensbachien du jebel Bou Rharraf (Haut Atlas oriental, Maroc) . In: Geobios . tape 44 , 2011, p. 117 .
  7. ^ PL Smith and HW Tipper: Pliensbachian (Lower Jurassic) ammonites of the Queen Charlotte Islands, British Columbia . In: Bulletins of American Paleontology . tape 108 (348) , 1996, pp. 1-122 .
  8. ↑ M. Aberhan: Early Jurassic Bivalvia of western Canada. Part I. Subclasses Palaeotaxodonta, Pteriomorpha, and Isofilibranchia. In: Beringeria . tape 21 , 1998, pp. 57-150 .
  9. ↑ Ralph W. Imlay: Early Jurassic Ammonites from Alaska . In: Geological Survey Professional Paper 1148 . United States Government Printing Office, Washington 1981.
  10. ^ Andrew H. Caruthers et al.: Pliensbachian-Toarcian (Early Jurassic) Ammonoids from the Luning Embayment, West-Central Nevada, USA In: Bulletins of American Paleontology . Number 393, 2018, p. 1-84 .