Shell morphology: The species exhibits a thin, oblong-ovate, flatly convex shell with between four and seven open respiratory pores. The exterior has fine, smooth spiral cording, with a shallow post-syphonic groove, infrequently found with lamellae at shell sizes smaller than 25 mm. The exterior shell coloration is variegated olive green, brown, and beige with an occasional totally orange form. The shell exterior often forms a fine radial tenting pattern of the other colors against the beige background.
Epipodium: The species has a thick epipodial structure with an elongated dorsal margin and smaller ventral margin. The ventral surface is covered with small wartlike papillae and is pigmented. The mid-epipodial region, also pigmented, is covered with large, highly ramified projections, which often subdivide into complex non-symmetrical branching structures. The number and spacing of these large projections vary from one specimen to the next. The basic color of pigmented areas is brown to almost black.

When examining the soft body parts of Haliotis mykonosensis and Haliotis tuberculata lamellosa, anatomical differences between the species are most evident in the epipodium. The side-by-side comparison of live specimens of these two species in Figure 1 clearly shows that the large, highly ramified epipodial projections between the upper and lower epipodial margins of H. mykonosensis are very different from the small digiform projections of H. t. lamellose. In H. mykonosensis, the projections subdivide into complex non-symmetrical branching structures, which give the living animal a unique appearance. Larger specimens (> 25 mm) have highly developed projections, which can be more than 6 mm in length. Haliotis tuberculata lamellosa has small digiform projections, which are simple, blunt, and seldom more than 1 mm. Infrequently, a specimen will have longer projections (up to 1.5 mm) with a small stellate structure visible at the tip when viewed under a hand magnifier. In addition, the lower epipodial margin of H. mykonosensis is not visible from the top view in contrast to the clearly visible lower epipodial margin of H. t. lamellosa.
Differences in the epipodium can also be seen in the comparison of alcohol-preserved specimens of Haliotis mykonosensis and H. t. lamellose. Haliotis mykonosensis has an elongated dorsal margin and the presence of papillae and pigment on the ventral surface. Haliotis tuberculata lamellosa has a more elongated ventral margin, with a smooth unpigmented ventral surface. The pigmented areas of the epipodium of Haliotis mykonosensis are brown to almost black, whereas those of H. t. lamellosa are grayish green, dispersed in a series of vertical bands.

Greece. Thus far found only on five of the 11 islands surveyed. Most common at the more northern Greek islands studied, particularly Corfu. Less common at Mykonos (type locality) and rare at Paros, Chios, and Samos. Thus far found only in areas of Poisidenea oceanica.