Miniaceoliva mascarena (Tursch & Greifeneder, 1996)

"General aspect. The rather cylindrical shell is of medium to large size, (40 to probably 80 mm), with an average ratio of diameter (D) to lip length (L) of D/L = 0.49. The spire is flat conical to onion-shaped. The average height of the spire is 7% of the total shell length (H). In adult shells, the posterior parietal callus reaches (or more often protrudes above) the level of the channel of the previous whorl. The protoconch and the width of the filament channel are similar to those of the other large Oliva species of the Indian Ocean, such as O. miniacea tremulina and O. ponderosa. The columellar plaits are flat and smooth in adult shells, whereas 20 distinct plaits were counted on an immature specimen. The upper margin of the suprafasciolarian band meets the columella outline at an average relative height of 0.49 of the lip length (L). The uppermost callus zone of the fasciolar band has a mean breadth of 8.3% of the lip length (L). This zone is thus generally broader than in O. miniacea tremulina (mean 5.6%) or in O. miniacea (mean 6.0%). In large, adult specimens the inner part of the lip is thickened over a large stretch, in which the lip runs straight, parallel to the shell axis. The siphonal notch is mostly more oblique than in O.miniacea tremulina. For an equal size, the shell of O. mascarena n. sp. is generally much heavier than O. miniacea tremulina or O. miniacea, but lighter than O. atalina and O. ponderosa. Colour pattern. The ground colour of all parts of the shell is ivory white or brilliant white, the latter mainly in populations from Aldabra, the Seychelles or Tanzania. The columella and the fasciolar band can show a touch of cream. Prevalent blurred and diffuse pattern elements are purplish-grey, the additional blotches are brown, dark brown or even black. The whorls of the spire show few tangential strokes or chevrons. The subchannel rim has 9 to 17 faint oblique chevrons. Then follows a small zone with a reduced density of pattern elements. On the body whorl, the blurred purplish-grey pattern elements (mostly degenerated chevrons and strokes) are arranged more or less axially. There are two darker spiral bands, which are mainly formed by additional dark blotches. Occasionally, the shells are partly ovrlaid with dark chocolate brown. In the upper zone of the suprafasciolarian band, the pattern density is reduced. The lower part of the same band is decorated with 6 to 12 dark blotches or oblique strokes, forming in some cases a "tiger pattern".". Recent. Aldabra.