''Oxystele'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

, the top snails. Although previously suggested as a subgenus of ''

Diloma ''Diloma'' is a genus of medium-sized sea snails, marine gastropod mollusks in the family Trochidae, the top snails.Bouchet, P. (2010). Diloma Philippi, 1845. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aph ...

'', genetic analysis has shown it to be more appropriate as its own genus.

Description

The depressed conical shell is dark or variegated in color. The large

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is oblique. The concave

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

is arcuate, thin-edged, perfectly simple and curved below. It is above spread over the umbilical area as a rounded, well-defined pad of callus. Patterns of the variegated shell color within the genus ''Oxystele'' are shown in the image : A–C ''Oxystele variegata'' from Namibia, 5 km north of Swakopmund, diameter 22.2 mm (NMSA E6038) D–F ''Oxystele impervia'' from the Western Cape, Groen Rivier, diameter 22.3 mm (NMSA E7353) G–I ''Oxystele'' sp. from the Eastern Cape, Tsitsikamma National Park, diameter 16.5 mm (HVDBM058-10, NMSA W7371); the colour pattern of these specimens suggests ''Oxystele variegata'', but these specimens group within the unit of ''Oxystele impervia'' J–L ''Oxystele'' sp. from the Northern Cape, Noup, diameter 18.0 mm (HVDBM185-10, NMSA W7608); the colour pattern suggests ''Oxystele impervia'', but they group with ''Oxystele variegata''

Distribution

These marine species occur off

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

and

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Species

Patterns of shell colour within the genus Oxystele - ZooKeys-365-337-g004

Phylogram A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

(weighted maximum parsimony based on 16S, COI and

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...

sequence data) of the species in the genus ''Oxystele'': Other species in the genus not included in this tree are: * '' Oxystele fulgurata'' (Philippi, 1848) * ''

Oxystele merula The pink-lipped topshell (''Oxystele sinensis'') also known as the rosy-base topsnail, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Description The pink-lipped topshell has monomorphic purplish- ...

'' (Dillwyn, 1817) Species brought into synonymy: * ''Oxystele capensis'' (Gmelin, 1791): synonym of '' Oxystele sinensis'' (Gmelin, 1791) * ''Oxystele depressa'' Granata-Grillo, 1877: synonym of ''

Tomura depressa ''Tomura'' is a genus of sea snails, marine gastropod mollusks in the family Cornirostridae.MolluscaBase eds. (2022). MolluscaBase. Tomura Pilsbry & McGinty, 1946. Accessed through: World Register of Marine Species at: https://www.marinespecies. ...

'' (Granata-Grillo, 1877) * ''Oxystele impervius'' Menke, Schwarz, 1910: synonym of '' Oxystele variegata'' (Anton, 1838) * ''Oxystele inflata'' Turton, 1932: synonym of '' Oxystele sinensis'' (Gmelin, 1791) * ''Oxystele romettensis'' Granata-Grillo, 1877: synonym of '' Cirsonella romettensis'' (Granata-Grillo, 1877) * ''Oxystele sagittifera'' Lamarck, Smith, 1903: synonym of '' Oxystele variegata'' (Anton, 1838) * ''Oxystele sagittifera'' var. ''perdix'' Koch in Turton, 1932: synonym of ''

Oxystele tigrina ''Oxystele tigrina'', common name the tiger top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Description The size of an adult shell varies between 25 mm and 43 mm. The more or l ...

'' (Anton, 1838) * ''Oxystele sagittifera'' var. ''rufanensis'' Turton, 1932: synonym of '' Oxystele variegata'' (Anton, 1838) * ''Oxystele tabularis'' var. ''pulchra'' Turton, 1932: synonym of '' Oxystele variegata'' (Anton, 1838) * ''Oxystele tigrinus'' Turton 1932: synonym of ''

'' (Anton, 1838) * ''Oxystele variegata'' (Anton, 1838) accepted as ''Oxystele antoni'' D. G. Herbert, 2015 MolluscaBase eds. (2023). MolluscaBase. ''Oxystele'' R. A. Philippi, 1847. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=204998 on 2023-10-28 * ''Oxystele zonata'' Wood, Sowerby, 1892: synonym of '' Gibbula zonata'' (Wood, 1828)

References

* Williams S.T., Donald K.M., Spencer H.G. & Nakano T. (2010) ''Molecular systematics of the marine gastropod families Trochidae and Calliostomatidae (Mollusca: Superfamily Trochoidea)''. Molecular Phylogenetics and Evolution 54:783-809 {{Taxonbar, from=Q7116153 Trochidae Taxa named by Rodolfo Amando Philippi Gastropod genera