Onoba semicostata

Onoba semicostata is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Rissoidae.^[1]

Onoba semicostata
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Family:	Rissoidae
Genus:	Onoba
Species:	O. semicostata
Binomial name
Onoba semicostata (Montagu, 1803)
Synonyms[1]
Cingula semicostata (Montagu, 1803) Cingula striata (Adams, 1797) (nomen dubium) Odostomia marionae MacGillivray, 1843 (dubious synonym) Onoba candida (Brown, 1844) Onoba scotiana (Melvill & Standen, 1907) Onoba striata (J. Adams, 1797) (non da Costa, 1778) Pyramis candidus Brown, 1827 (dubious synonym) Pyramis decussatus Brown, 1827 (dubious synonym) Pyramis discors Brown, 1827 (dubious synonym) Rissoa communis Forbes, 1838 (dubious synonym) Rissoa ecostata Michaud, 1830 Rissoa gracilis MacGillivray, 1843 Rissoa minutissima Michaud, 1830 Rissoa peticularis Menke, 1830 Rissoa scotiana Melvill & Standen, 1907 Rissoa striata J. Adams, 1797 Rissoia scotiana Melvill & Standen, 1907 Turbo semicostatus Montagu, 1803 (original combination) Turbo shepeianus J. Adams, 1798 Turbo striatus J. Adams, 1797 (Invalid: junior secondary homonym of Rissoa striata Da Costa, 1778)

Classification

Turbo semicostatus Montagu, 1803 is probably another species than those which is mostly understand by that name. According to Warén Turbo shepeianus could be the valid name for this species found off Belgium. Further research is necessary, therefore we use the more commonly used name Onoba semicostata.^[1]

Taxonomy

Janssen (1975) mentioned two subspecies: O. s. semicostata and O. s. aculeus (Gould, 1841). Thorson (1941), Warén (1973, 1974) and Fretter & Graham (1978) are followed who both consider O. s. semicostata and O. s. aculeus as separate species.^[1]

Description

Distribution

This marine species occurs in the Baltic Sea, the North Sea, the Northern and Northeast Atlantic Ocean and in the Mediterranean Sea.