Cyrtospirifer sp. A
publication ID |
https://doi.org/ 10.5281/zenodo.13748813 |
persistent identifier |
https://treatment.plazi.org/id/255287DC-FFE4-FF9D-FF94-CBEDFCE305CE |
treatment provided by |
Felipe |
scientific name |
Cyrtospirifer sp. A |
status |
|
Fig. 10F View Fig .
0.3
Material.—Two complete shells and ten incomplete single valves collected from Schelon' river basin.
Description.—Shell small sized (up to 20 mm in width) with maximum width at hinge line; cardinal extremities acute and short; anterior commissure uniplicate. Pyramidal ventral valve weakly convex with a small slightly curved beak; ventral interarea catacline to apsacline. Sulcus shallow originates at the umbo. Dorsal valve moderately convex with weakly developed fold. Radial ornament with up to 18 simple low ribs separated by narrow interspaces on each flank. Ventral sulcus and dorsal fold with up to 9 bifurcating ribs along the anterior margin.
Ventral interior with a delthyrial plate and divergent extrasinal dental plates. Dorsal interior with a ctenophoridium.
Remarks.—This is small−sized Cyrtospirifer with pyramidal ventral valve similar to Cyrtospirifer tenticulum . It differs from the latter by more rounded lateral margins and less convex ventral valve.
Cyrtospirifer sp. A is similar to Tenticospirifer lagovensis ( Gürich, 1896) from the Late Givetian of the Holy Cross Mountains, Poland, but differs in having thinner ribs, narrower and less sharply bounded sulcus and fold. C. sp. A is somewhat suggestive of the Late Frasnian North American Cyrtospirifer pyramidalis Cooper and Dutro, 1982 but it differs in generally weakly convex ventral valve and finer ribs. Sorokin (1978) listed this form from Porkhov Beds of the Schelon river basin as Cyrtospirifer schelonicus var. tenticula .
Occurrence.—Middle Frasnian, Palmatolepis punctata Zone, Porkhov Beds, Main Devonian Field.
1.3
2.3
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
Kingdom |
|
Phylum |
|
Class |
|
Order |
|
Family |
|
Genus |
Cyrtospirifer sp. A
Sokiran, Elena V. 2006 |
Cyrtospirifer pyramidalis
Cooper and Dutro 1982 |