{{Short description|Species of mollusc}} {{Speciesbox | image = Faunus_ater_01.JPG | image_caption = A shell of ''Faunus ater'' | status = LC | status_system = IUCN3.1 | status_ref = <ref>{{cite iucn |author=Rintelen, T. |year=2011 |title=''Faunus ater'' |volume=2011 |article-number=e.T175104A7097356 |doi=10.2305/IUCN.UK.2011-2.RLTS.T175104A7097356.en |language=en |access-date=5 April 2026}}</ref> | genus = Faunus | species = ater | authority = (Linnaeus, 1758) }} thumb|''Faunus ater'' (Linnaeus, 1758). Museum specimens.

'''''Faunus ater''''' is a species of brackish water snail with an operculum, an aquatic gastropod mollusc in the family Pachychilidae.<ref name="Lok 2011"/>

''Faunus ater'' is the only extant species within the genus ''Faunus''.<ref name="Lok 2011">Lok A. F. S. L., Ang W. F., Ng P. X., Ng B. Y. Q. & Tan S. K. (2011). "Status and distribution of ''Faunus ater'' (Linnaeus, 1758) (Mollusca: Cerithioidea) in Singapore". ''Nature in Singapore'' '''4''': 115-121. [http://rmbr.nus.edu.sg/nis/bulletin2011/2011nis115-121.pdf PDF] {{Webarchive|url=https://web.archive.org/web/20120331094327/http://rmbr.nus.edu.sg/nis/bulletin2011/2011nis115-121.pdf |date=2012-03-31 }}.</ref> == Distribution == The distribution of ''Faunus ater'' includes: * India<ref name="Lok 2011"/> * Sri Lanka<ref name="Lok 2011"/> * Andaman Islands<ref name="Lok 2011"/> * Malaysia * Myanmar<ref name="Lok 2011"/> * Thailand<ref name="Lok 2011"/> * Singapore<ref name="Lok 2011"/> * Indonesia<ref name="Lok 2011"/> * Philippines<ref name="Lok 2011"/> * New Guinea<ref name="Lok 2011"/> * western and southern Pacific Islands:<ref name="Lok 2011"/> Solomon Islands<ref>Solem A. (1953). "Marine and fresh-water mollusks of the Solomon Islands". ''Fieldiana Zoology'' '''34'''(22): 213-227. [https://archive.org/stream/marinefreshwater3422sole#page/220/mode/2up page 220].</ref> * northern Australia<ref name="Lok 2011"/> * China<ref name="Lok 2011"/>

== Description == The periostracum is thick, and the color of the periostracum is dark brown or black.<ref name="Lok 2011"/> The shell has about 20 whorls.<ref name="Lok 2011"/> The apical whorls may be eroded in older snails.<ref name="Lok 2011"/> The aperture is ovate and white.<ref name="Lok 2011"/> The shell is unique among Cerithioidea, because it has two deep sinuses: an anal sinus which is close to the suture and an anterior sinus more forward in the aperture.<ref name="Lok 2011"/> The height of the aperture is about one-fifth of the height of the shell.<ref name="Lok 2011"/>

The height of the shell is usually 50–60&nbsp;mm, but can be up to 90&nbsp;mm.<ref name="Lok 2011"/>

The operculum is oval, corneous and dark brown in color.<ref name="Lok 2011"/> The snail has a broad snout.<ref name="Lok 2011"/> The radula is large and is located in a correspondingly large buccal mass.<ref name="Lok 2011"/>

== Ecology == This snail lives in slightly brackish water.<ref name="Lok 2011"/> It has also been reported from freshwater.<ref name="Lok 2011"/> It is the only pachychilid species that lives in brackish water; the other species in the family are freshwater snails.

The population density can reach up to 6700 snails per&nbsp;m<sup>2</sup>.<ref name="Lok 2011"/>

This snail probably feeds by grazing.<ref name="Lok 2011"/>

It is oviparous.<ref name="Lok 2011"/> It probably has free-swimming larvae.<ref name="Lok 2011"/>

== Human use == This snail is used as a food source for humans in the Philippines and in Thailand.<ref name="Lok 2011"/>

==References== {{Reflist}}

== Further reading == * Gray J. E. (1867). "On the species of the genera ''Latiaxis'', ''Faunus'' and ''Melanatria''". ''American Journal of Conchology'' '''3''': [https://archive.org/stream/americanjournalo03amer#page/330/mode/2up 330]. * Houbrick R. S. (1991). "Anatomy and systematic placement of ''Faunus'' Montfort 1810 (Prosobranchia: Melanopsinae)". ''Malacological Review'' '''24''': 35–54. * Yap C. K., Hisyam M. N. D., Edward F. B., Cheng W. H. & Tan S. G. (2010). "Concentrations of heavy metal in different parts of the gastropod, ''Faunus ater'' (Linnaeus), collected from intertidal areas of Peninsular Malaysia". ''Pertanika Journal of Tropical Agricultural Science'' '''33'''(1): 45–60.

== External links == {{Commons category-inline||''Faunus ater''}}

{{Taxonbar|from=Q5438244}}

Category:Pachychilidae Category:Gastropods described in 1758 Category:Animal taxa named by Carl Linnaeus