DISTRIBUTION Caribbean, Guadeloupe, Martinique. MATERIAL EXAMINED Paratype 3 (MNHN-IM-2000-34872) dim. 4.60 × 1.60 mm. Protoconch 0.35 × 0.37 mm. stn AS576. Paratype 4 (MNHN-IM-2000-34873) dim. 3.75 x 1.33 mm. Protoconch 0.38 0.28 mm. stn AB155. Paratype 5 (MNHN-IM-2000-34874) dim. 3.40 x 1.27 mm. Protoconch 0.39 × 0.28 mm. stn AB117. TYPE LOCALITY Caribbean: Martinique, Baie de Fort-de-France, Caye de Gros Îlet, 6 m. .
DESCRIPTION Shell medium in size, perfectly conical with flat sides, sutures not very discernible. Protoconch short, conical of 2 smooth slightly convex whorls, apex small acuminate. Particularly the suture that surmounts the embryonic whorl (under ESEM with some obsolete spiral cords) is highlighted by a subsequent noticeable constriction. Color orange. Teleoconch of 12.5 flat whorls with a sculpture of 3 smooth, equal spiral keels, intervals almost equal. Seen under ESEM: clearly visible, fine very close- set axial lamellae in the intervals between the spirals; suture marked by a very thin thread. A fourth narrow smooth spiral is emerging from the suture at the base of the last whorl followed by another significantly thinner one. Columella short, obliquely truncate; border between last whorl and columella highlighted by an angulation. Color orange.
COLOR OF THE LIVING MOLLUSK The animal is colorless, transparent with white dots; black eyes .
COMPARISON Seila tissieri n. sp. differs from Seila adamsii (H. C. Lea, 1845) mainly by its more conical and acute protoconch with straighter whorls. REMARKS The color of Seila tissieri n. sp. is orange in the holotype, in other specimens it varies from dark orange with whitish patches (see paratype 4), to whitish with dark orange patches (see paratype 3). The protoconch shows a certain variability in size. ETYMOLOGY Named after Colonel Alain Tissier, education officer with the French Forces Armées des Antilles, for his support to the outreach and education program during the MADIBENTHOS expedition.