{{Short description|Species of gastropod}} {{Speciesbox | image = Alvania obeliscus 001.jpg | image_caption = Shell of ''Alvania obeliscus'' (holotype) | taxon = Alvania obeliscus | authority = Harmer, 1920 | extinct=yes |synonyms_ref= |synonyms= |display_parents= 3 }}
'''''Alvania obeliscus''''' is an extinct species of minute sea snail, a marine gastropod mollusc or micromollusk in the family Rissoidae.<ref name="WoRMS">MolluscaBase eds. (2024). MolluscaBase. Alvania obeliscus Harmer, 1920 †. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1027567 on 2024-02-07</ref>
==Description== The length of the shell is {{cvt|4|mm}}, and its diameter is {{cvt|0.3|mm}}.
(Original description) The small shell is conical. It contains about 7 whorls, nearly flat. The shell is ornamented by strong longitudinal ribs, 15 or 16 on the body whorl, and by well-marked spiral ridges, especially conspicuous near the base. The suture is distinct but not deep. The spire is somewhat elongate, regularly diminishing upwards. The aperture is ovate, compressed and angulated above and rounded below. The outer lip is thin.<ref>[https://www.biodiversitylibrary.org/page/36960258 Harmer F. W. (1920-1925). The Pliocene Mollusca of Great Britain, being supplementary to S.V. Wood's monograph of the Crag Mollusca. Vol. 2. Monographs of the Palaeontographical Society. 72(344): 485-652, pl. 45-52 (part 1, December 1920); 73(346): 653-704, pl. 53-56 (part 2, July 1921); 75(352): 705-856, pl. 57-64 (part 3, December 1923); 76(354): i-xiv, 857-900, pl. 65 (part 4, January 1925)]{{source-attribution}}</ref>
==Distribution== Fossils of this species were found in late Pliocene strata at St. Erth, Cornwall, Great Britain.
==References== {{Reflist}}
{{Taxonbar|from=Q106108817}}
Category:Gastropods described in 1920 obeliscus {{Improve categories|date=February 2024}}
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