Helcionopsis is an extinct genus of paleozoic monoplacophoran in the family Tryblidiidae.
| Helcionopsis Temporal range:
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| Drawing of dorsal view of the shell of Helcionopsis radiatum. Head region is on the left. | |
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| Drawing of lateral view of the shell of Helcionopsis radiatum. Head region is on the left. | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Monoplacophora |
| Order: | Tryblidiida |
| Family: | †Tryblidiidae |
| Genus: | †Helcionopsis Ulrich & Scofield, 1897[1] |
The generic name is from the external resemblance which the genus bear to the recent species of the genus Helcion in family Patellidae.[1]
Species
editSpecies in the genus Helcionopsis include:[2]
- Helcionopsis radiatum (Lindström, 1884)
- Helcionopsis reticulatus Easton, 1943[3]
- Helcionopsis striata Ulrich, 1897[4]
- Helcionopsis subcarinata Ulrich & Scofield, 1897[5]
Shell description
editGeneral form and position of apex is as in Tryblidium, from which Helcionopsis differ in having the surface marked by fine radiating striae.[1] Muscular scars of this genus Helcionopsis unknown in 1897, when the genus was described.[1]
References
editThis article incorporates public domain text from reference.[1]
- ^ a b c d e Ulrich E. O. & Scofield W. H. 1897. The Lower Silurian Gastropoda of Minnesota. In: Ulrich E. O., Scofield W. H., Clarke J. M. & Winchell N. H. The Geological and Natural History Survey of Minnesota, volume 3(2), Harrison and Smith, Minneapolis, 48 plates. Pages 813-1081, plates 61-82. Helcionopsis is on the page 821 and on pages 826-827.
- ^ Helcionopsis. The Paleobiology Database, accessed 25 August 2009.
- ^ Easton W. H. 1943. The Fauna of the Pitkin Formation of Arkansas. Journal of Paleontology 17(2):125-154.
- ^ Ulrich E. O. & Scofield W. H. 1897. The Lower Silurian Gastropoda of Minnesota. page 827, plate VXI, figure 29-30.
- ^ Ulrich E. O. & Scofield W. H. 1897. The Lower Silurian Gastropoda of Minnesota. page 827-828, plate VXI, figure 28.
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