Diagnosis: Shell with rounded or weakly shouldered whorls, sutures weak, last whorl with numerous ribs and threads of unequal size, of which 3-7 are slightly enlarged but not carinate or nodulose; surface of ribs shiny and lacking spiral microstriae; black to brown with white dashes, spots or flames.
Shell: Mature shell height 3.9-16.9 mm. Shape turbinate to high turbinate (H/B = 1.25-1.64, SH = 1.34-1.72); spire whorls rounded or slightly angled at shoulder, suture distinct but weakly impressed; spire profile slightly convex; last whorl angled at shoulder and slightly at periphery, often swollen or slightly square in profile. Columella long, straight, slightly hollowed at base; inner lip of aperture slightly rounded and con¬tinuous with eroded pseudumbilical and parietal area. Sculpture of last whorl: surface covered by low spiral ribs and threads of unequal size, 11-19 at and above periphery and 4-6 below, with narrow grooves between; usually 3-7 ribs at and above periphery are slightly enlarged; ribs sometimes made finely granulose by intersection with growth lines, especially on spire, but granules often faint or absent; fine spiral microstriae in grooves only, surface of ribs shiny if well preserved. Protoconch 0.28 mm diameter, 2.5 whorls. Colour: blackish brown, paler at suture and on base; ribs and suture marked by prominent white dashes or spots, rarely fusing to form axial flames of brown and white or a finely marbled pattern; aperture dark brown, pale band at base; columella dark purple-brown, inner lip purplish.

Analysis of both 28S rRNA and COI sequence data confirm that the sister species of E. leucosticta is E. biangulata (Williams & Reid 2004). The latter, in Sumatra and Java, is geographically the closest of this group to E. leucosticta, although the shells of E. biangulata are more similar to those of E. tricincta. The shortest distance between the known ranges of E. leucosticta and E. biangulata is almost 2000 km (Sri Lanka to Nias I.), while the extralimital records of the former in Burma suggest that transport of pelagic larvae can occur over distances of at least 1500 km across the Bay of Bengal. The consistent morphological differences in the shells of these two, and their genetic distance (COI K2P distance = 7.8%), support their recognition as distinct species.
The members of the E. leucosticta group cannot be distinguished from each other by unique anatomical features, but their distributions are allopatric and their shells are mostly distinctive. The pair E. biangulata and E. tricincta are most similar to E. leucosticta, but in the latter the profile is only slightly shouldered, the ribs are never carinate or nodulose, and the ribs lack microstriae and are therefore shiny.

Range: Oman, Pakistan, India, Sri Lanka, Burma.
On the Indian coast this species is abundant between Mumbai and Chennai. In Sri Lanka it is restricted to the south and west coasts (Atapattu 1972). Occurrence in Burma is based on a single specimen from Cape Negrais, a distance of 1500 km across the Bay of Bengal from the closest known population in Chennai.

Habitat: On exposed or moderately exposed rocky shores, in the littoral fringe and mid to upper eulit-toral; recorded from granite, beach rock and limestone. There are various, sometimes conflicting, records of the zonation of this species: in the upper eulittoral, down to high water of neap tides (Starmuhlner 1974); in the littoral fringe on a sandstone reef, with black lichens (Arudpragasam & Ranatunga 1966); at and below mean high water of spring tides (Rao & Sundaram 1974); in large numbers among weed in the lower eulittoral (Atapattu 1972). It always occupies a zone below the sympatric E. malaccana (Rao & Sundaram 1974; Pillai & Appukuttan 1980). According to Atapattu (1969) settlement occurs in the mid-eulittoral zone among oysters, while adults occupy the littoral fringe in the monsoon season and the mid-eulittoral at other times.