Proterovaginoceras

Proterovaginoceras (Ancient Greek for "earlier shield horn") is a medium to large sized endocerid (endocone-bearing orthoconic nautiliod) from the Early and Middle Ordovician included in the family Endoceratidae.

Proterovaginoceras
Temporal range: Darriwilian
~
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Nautiloidea
Order: †Endocerida
Family: †Endoceratidae
Genus: †Proterovaginoceras
Reudemann, 1905
Type species
Proterovaginoceras belemnitiforme
(Holm, 1885)
Species
  • P. belemnitiforme (Holm, 1885)
  • P. incognitum (Schröder, 1882)
  • P. rapidum Fang, 2022[1]
Synonyms
  • P. belemnitiforme
  • P. incognitum
    • Dideroceras amplum Balashov 1968
    • Dideroceras brevispiculum Balashov 1968
    • Dideroceras kundense Balashov 1968
    • Dideroceras longispicum Balashov 1968
    • Dideroceras pribalticum Balashov 1968
    • Endoceras duplex Wahlenberg 1821
    • Orthoceras duplex Wahlenberg 1821
    • Schmidtoceras estonicum Balashov 1968
    • Schmidtoceras kundense Balashov 1968
    • Vaginoceras endoseptum Chang 1957

Proterovaginoceras has a straight shell with a circular cross section, straight sutures, and a ventral to central, nanno-type, siphuncle which fills the entire apical part of the shell. Septal necks are macrochoanitic, up to two camerae (chambers) long; connecting rings, one chamber in length line the inside of the necks. Endocones are long and slender, fill the entire bulbous, nanno-end, of the siphuncle.

Proterovaginoceras was named by Reudemann in 1905. Dideroceras Flower 1950 and Chisloceras Gortani 1934 are probably synonymous equivalents.

Distribution

Fossils of the genus have been found in:[2]

  • Loobu Formation, Estonia
  • Abastu Formation, Iran
  • Pivorjaiskaja Formation, Lithuania
  • Huk and Stein Formations, Norway
  • Gillberga, Holen and Komstad Formations, Sweden
  • China

References
  1. Fang, X.; Chen, T.; Wang, W.; Zhang, Y. (2022). "Middle–Late Ordovician cephalopod faunas from western Hunan and Hubei provinces, South China". Acta Palaeontologica Sinica. 61 (2): 197–216. doi:10.19800/j.cnki.aps.2021040.
  2. Proterovaginoceras at Fossilworks.org

Further reading
  • O. K. Bogolepova, B. Kröger, M. Falahatgar and M. Javidan. 2014. Middle Ordovician cephalopods from the Abarsaj area, northern Iran. GFF - Geological Society of Sweden 136(1):34-37
  • B. Kröger. 2014. Middle Ordovician cephalopod biofacies and palaeoenvironments of Baltoscandia. Lethaia
  • B. Kröger. 2012. The 'Vaginaten': the dominant cephalopods of the Baltoscandian Mid Ordovician endocerid limestone. Geologiska Föreningen i Stockholm Förhandlingar 134(2):115-132
  • H. Mutvei. 1997. Siphuncular structure in Ordovician endocerid cephalopods. Acta Palaeontologica Polonica 42(3):375-390
  • J. Laskovas, V. Marcinkevicius, and J. Paskevicius. 1993. The Stratigraphy and Structure of Ordovician Rocks of the South - East Part of the Baltic Basin (Druksiu Area). Geologija, Detailed Stratigraphy (14)81-98
  • Tiechert,C. 1964. Endoceratoidea. Treatise on Invertebrate Paleontology, Part K. Endoceratoidea, Actinoceratoidea, Nautiloidea. Geological Soc. of America and Univ Kansas Press
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