Notes on type material of the family Pectinidae (Mollusca: Bivalvia). 1. Pecten limatula Reeve, 1853, a new synonym of Chlamys irregularis (Sowerby, 1842)

Recently the author was able to examine the holotype of Pecten limatula Reeve, 1853: species/fig. 124, pl. XXVIII [British Museum (Natural History), London, no. 1981246]; the measurements are height 28 mm x width 24 mm and the locality is unknown. There are no differences in microsculpture of both juvenile and adult parts of the shell when compared to the holotype of Pecten irregularis Sowerby, 1842: 69, pl. xiii figs. 51-52, also kept in the London museum (no. 1950.11.14.39). The latter shell measures height 36 mm x width 32.5 mm, locality ‘Eastern Seas’. The type specimens of both nominal taxa are adult shells. A comparison of the situation of the more pronounced ribs with respect to the less pronounced ribs failed to reveal significant differences between the two species. Unfortunately it was impossible to compare the muscle scars on the inside of the shells.