''Oxystele'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is oblique. The concave columella 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.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
/ref> 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 southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Species

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

Phylogram A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

(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 over ...

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 ''Oxystele merula'' is a species of sea snail, a marine gastropod mollusk in the family (biology), family Trochidae, the top snails.Bouchet, P. (2013). Oxystele merula (Dillwyn, 1817). Accessed through: World Register of Marine Species at http: ...

'' (Dillwyn, 1817) Species brought into synonymy: * ''Oxystele capensis'' (Gmelin, 1791): synonym of ''

Oxystele sinensis ''Oxystele sinensis'', common name the pink-lipped topshell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Description The size of the shell varies between 18 mm and 51 mm. Distribut ...

'' (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.o ...

'' (Granata-Grillo, 1877) * ''Oxystele impervius'' Menke, Schwarz, 1910: synonym of ''

Oxystele variegata ''Oxystele variegata'', common name the variegated topshell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Description The size of the shell varies between 15 mm and 20 mm. Distributi ...

'' (Anton, 1838) * ''Oxystele inflata'' Turton, 1932: synonym of ''

'' (Gmelin, 1791) * ''Oxystele romettensis'' Granata-Grillo, 1877: synonym of '' Cirsonella romettensis'' (Granata-Grillo, 1877) * ''Oxystele sagittifera'' Lamarck, Smith, 1903: synonym of ''

'' (Anton, 1838) * ''Oxystele sagittifera'' var. ''perdix'' Koch in Turton, 1932: synonym of '' Oxystele tigrina'' (Anton, 1838) * ''Oxystele sagittifera'' var. ''rufanensis'' Turton, 1932: synonym of ''

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

'' (Anton, 1838) * ''Oxystele tigrinus'' Turton 1932: synonym of '' Oxystele tigrina'' (Anton, 1838) * ''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