The periostracum is thick, and the color of the periostracum is dark brown or black.[1] The shell has about 20 whorls.[1] The apical whorls may be eroded in older snails.[1] The aperture is ovate and white.[1] 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.[1] The height of the aperture is about one-fifth of the height of the shell.[1]
The height of the shell is usually 50–60 mm, but can be up to 90 mm.[1]
This snail lives in slightly brackish water.[1] It has also been reported from freshwater.[1] It is the only pachychilid species that lives in brackish water; the other species in the family are freshwater snails.
^ abcdefghijklmnopqrstuvwxyzaaabacadaeLok 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 Singapore4: 115-121. PDF.
Houbrick R. S. (1991). "Anatomy and systematic placement of Faunus Montfort 1810 (Prosobranchia: Melanopsinae)". Malacological Review24: 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 Science33(1): 45-60.