Haliotis marmorata geigeri Owen, 2014
Distribution: São Tomé & Príncipe
Size to 43,97mm (2014).

Deep red specimens from São Tomé. The sculpture is smoother than in the neighbour continental marmorata s.s. 3-5m deep, under rocks, Gamboa beach. 34-41mm.
12-20m deep, on rocks, Ilhéu das Cabras, off Lobata. 24mm.
Shells from São Tomé look very different from specimens living on continental Africa.
Gamboa beach again, N. of São Tomé city. 30mm.
As many Haliotidae have a very short swimming larval stage, the dispersion of the ancestors of H. marmorata geigeri may have been mostly leaning against the continental coast, with sporadic excursions into the offshore islands. So, one can imagine that these animals have been existing in the archipelago for a very long time, genetically fed by successive supplies from the continent, and could have been definitively isolated from its african source during the rising of ocean level consecutive to the end of a heavy glaciation. Then, insular conditions could have predominated, restricting the variability of the population around some characteristics as the small size and the lengthened shape, which are two features that are typical of the populations of H. tuberculata tuberculata living in Mediterranean.
2-3m deep, on rocks, Espraihna, São Tomé. 35,2mm.
Original picture: © P. Ryall (AU).

All pics © Olivier Caro