H. concolor occurs in the Indian Ocean off of Mozambique and South Africa, where the water typically ranges between 20-25°C (68-77°F)
Description
H. concolor typically ranges between 30mm and 60mm. Coloration varies widely; individual shells may be white, yellow, russet, or black and may feature spots or rays of various widths. Coloration does not appear to vary with distribution or zonation. The cusps of the radula teeth are sharply pointed.
Dorsal view.
Ventral view.
Behavior and Ecology
In a 1975 paper, South African cnidariologist George Branch noted a tendency for larger individuals to migrate further upshore and space out further than their smaller counterparts. Larger individuals (over 35mm) were noted to return to a "home scar" after feeding with the majority of studied specimens remaining in or returning to the same scar over a 10-day observation period. Smaller individuals (under 20mm) did not have a fixed scar but tended to return to a general area when not feeding.
H. concolor is a non-territorial broswer. An examination of the gut contents of fifty individuals of the species noted that most had consumed large quantities of sand along with smaller quantities of diatoms, sponge spicules, algae fragments, lichens, and detritus.
Relationship with humans
H. concolor is one of a number of limpet species commonly eaten by humans. In his 1975 paper, Branch noted that the mollusc featured in the diets of indigenous people of southeastern South Africa, particularly in instances of drought and crop failure when other food became scarce. He recounts that H. concolor (then called Patella concolor) and Cellana capensis were favored "because they yield a reasonable quantity of meat and the flesh is easily removed. The entire animal is eaten, after removal of the radula from larger specimens." Branch noted that both species were at particular risk of being harvested as their tendency to reside in the balanoid zone made them easily accessible. He recorded a decrease in both size and number of some populations which he attributed to human predation.
Kalk, M. (1958). The fauna of the intertidal rocks at Inhaca Island, Delagoa Bay. Ann. Natal Mus. 14: 189–242.
Kilburn, R. N. 1972. Taxonomic notes on South African marine Mollusca (2), with the description of new species and subspecies of Conus, Nassarius, Vexillum and Demoulia. Annals of the Natal Museum 21(2):391–437, 15 figs.
Kilburn, R.N. & Rippey, E. (1982) Sea Shells of Southern Africa. Macmillan South Africa, Johannesburg, xi + 249 pp. page(s): 37
Steyn, D.G. & Lussi, M. (1998) Marine Shells of South Africa. An Illustrated Collector’s Guide to Beached Shells. Ekogilde Publishers, Hartebeespoort, South Africa, ii + 264 pp. page(s): 16
Koufopanou et al. (1999). A molecular phylogeny of the patellid limpets (Gastropoda: Patellidae) and its implications for the origins of their antitropical distribution Mol. Phylogenet. Evol. 11(1):138–156
Nakano & Ozawa (2007). Worldwide phylogeography of limpets of the order Patellogastropoda: Molecular, morphological and palaeontological evidence. Journal of Molluscan Studies 73(1) 79–99.
Petit R.E. (2009) George Brettingham Sowerby, I, II & III: their conchological publications and molluscan taxa. Zootaxa 2189: 1–218
