''Proterovaginoceras'' (

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

for "earlier shield horn") is a medium to large sized

endocerid Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian ...

(endocone-bearing orthoconic nautiliod) from the Early and Middle Ordovician included in the family

Endoceratidae Endoceratidae is a family of large to very large straight shelled nautiloid cephalopods belonging to the order Endocerida that lived during the Middle and Late Ordovician. They include the largest known Paleozoic invertebrates, represented by '' ...

. ''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:''Proterovaginoceras''
at Fossilworks.org * Loobu Formation, Estonia * Abastu Formation, Iran * Pivorjaiskaja Formation, Lithuania * Huk and Stein Formations, Norway * Gillberga, Holen and Komstad Formations, Sweden * China

References

* 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

External links

''Proterovaginoceras''
in th
Paleobiology Database
{{Taxonbar, from=Q7251578 Nautiloids Darriwilian Ordovician cephalopods Ordovician animals of Asia Paleozoic Iran Fossils of Iran Ordovician animals of Europe Paleozoic Estonia Fossils of Estonia Paleozoic Lithuania Fossils of Lithuania Ordovician Norway Fossils of Norway Ordovician Sweden Fossils of Sweden Fossil taxa described in 1905 Ordovician China

Distribution

References

Further reading

External links