| A new northeastern Pacific limpet species common in the mid-intertidal of southern California is described as Lottia polyfacies sp. nov. (type locality: Anacapa Island, Channel Islands National Park, California). It is distinguished from its sister species to the south, L. strigatella (Carpenter 1864), and a morphologically similar species to the north, L. paradigitalis (Fritchman 1960). Morphological comparisons herein reveal substantial plasticity and overlap; however, all these species can be unambiguously distinguished based on analyses of 16S and COI mitochondrial DNA markers. Moreover, L. polyfacies and L. strigatella are resolved in a phylogeny as reciprocally monophyletic sister species. At its southern and northern range limits, L. polyfacies populations overlap with L. strigatella and L. paradigitalis, respectively, with no evidence for genetic exchange. The ecological and biogeographical implications of these range transitions are explored, and these help support the Southern California Bight as part of the distinctive San Diegan biogeographic province. |
