''Helcionopsis'' is an extinct genus of paleozoic
monoplacophora
Monoplacophora , meaning "bearing one plate", is a polyphyletic superclass of molluscs with a cap-like shell inhabiting deep sea environments . Extant representatives were not recognized as such until 1952; previously they were known only from ...
n in the family
Tryblidiidae
Tryblidiidae is an extinct family of paleozoic monoplacophorans in the superfamily Tryblidioidea.
Genera
Genera in the family Tryblidiidae include:
* ''Tryblidium'' Gustaf Lindström, Lindström, 1880. From Ordovician and Silurian.W. H. Dall ...
.
The
generic name is from the external resemblance which the genus bear to the recent species of the genus ''
Helcion
''Helcion'' is a genus of sea snails, true limpets, marine gastropod mollusks in the family Patellidae.
Species
Species within the genus ''Helcion'' include:
Subgenus ''Ansates'' : accepted as ''Ansates'' G.B. Sowerby II x Klein 1839
* ''Helci ...
'' in family
Patellidae
Patellidae is a taxonomic family of sea snails or true limpets, marine gastropod molluscs in the clade Patellogastropoda.
(The superfamily Patelloidea should not be confused with the similar-sounding genus of true limpets ''Patelloida'' which ...
.
Species
Species in the genus ''Helcionopsis'' include:
* ''
Helcionopsis radiatum'' (Lindström, 1884)
* ''
Helcionopsis reticulatus'' Easton, 1943
* ''
Helcionopsis striata'' Ulrich, 1897
* ''
Helcionopsis subcarinata'' Ulrich & Scofield, 1897
[Ulrich E. O. & Scofield W. H. 1897. ''The Lower Silurian Gastropoda of Minnesota'']
page 827
828
plate VXI
figure 28.
Shell description
General form and position of
apex is as in ''
Tryblidium'', from which ''Helcionopsis'' differ in having the surface marked by fine radiating striae.
Muscular scars of this genus ''Helcionopsis'' unknown in 1897, when the genus was described.
References
This article incorporates public domain text from reference.
{{paleo-mollusc-stub