''Suecoceras'' is an
endoceratid (a kind of nautiloid cephalopod) that lived during the
Middle Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
The ...
. It is characterised by a long, straight, slender shell with a slightly expanded tip that curves slightly downwards.
The shell is compressed from side to side in the humped apical portion, but circular in the rest. The
siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...
is proportionally large, 1/3 to 1/2 the shell diameter; ventral at the beginning, becoming subventral in the adult portion. Septal necks are holochoanitic to slightly maxichaonitic, extending back to the previous septum and sometimes beyond. Endocones are long and slender, with a narrow tube running down the middle.
The siphuncle takes up the entire apex, but is not swollen as in ''
Chazyoceras
''Chazyoceras'' ("Horn of the Chazyan") is a moderately large endocerid included in the Endoceratidae with a ''Nanno'' type apex and a ventral siphuncle with a holochoanitic (where "holo" is entire, and "choan" refers to its funnel-shaped openin ...
'' or ''
Nanno
Nanno (german: Nain, Ladin: ''Nan'') was a ''comune'' (municipality) in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about north of Trento. As of 31 December 2004, it had a population of 623 and an area of .All ...
''.
A typical species, ''S. barrande'' (Dewitz), whose fossil remains are known from Sweden (hence the name, ''Sueco-'' means "Swedish"), has a shell about long.
Distribution
Fossils of the genus have been found in:
[''Suecoceras'']
at Fossilworks
Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...
.org
*
Karmberg Formation, Tasmania, Australia
*
Kandle Formation, Estonia
*
Vaidlenai Formation, Lithuania
*
Segerstad and
Seby Limestones, Sweden
*
Rochdale Formation, New York state
References
Further reading
* Teichert, C. 1964. Endoceratoidea; Treatise on Invertebrate Paleontology, Part K, Geological Society of America and Univ. Kansas Press
* Moore, Raymond C., Lalicker, Cecil G., & Fischer, Alfred G. 1952. ''Invertebrate Fossils''. McGraw-Hill, New York. Page 355
* R. Ruedemann. 1906. Cephalopoda of the Beekmantown and Chazy formations of the Champlain Basin. Bulletin of the New York State Museum, Paleontology 14:389-611
Nautiloids
Ordovician cephalopods
Tremadocian
Floian
Dapingian
Darriwilian
Ordovician Australia
Fossils of Australia
Paleontology in Tasmania
Ordovician cephalopods of Europe
Paleozoic Estonia
Fossils of Estonia
Paleozoic Lithuania
Fossils of Lithuania
Ordovician Sweden
Ordovician cephalopods of North America
Ordovician geology of New York (state)
Paleontology in New York (state)
Fossil taxa described in 1896
{{paleo-cephalopod-stub