| Summary: | Taxonomically, the Mollusca of the southern end of South America are moderately well known, but the literature is scattered, there is little information on their habitats, and distributional records are scarce for the Chilean archipelago lying between Chiloé Island (42° S) and Tierra del Fuego (55° S). Although much is known about the biology and ecology of of some species of Nacellidae, the taxonomy of the group have been partially neglected, particularly in remote areas of the world such as the Chilean fjords. Therefore, this study aims to clarify the nomenclatural status, and establish the morphological characteristics and distribution of the Chilean Nacellidae. Especially, the following three objectives are pursued: (i) to clarify the correct identity of existing species; (ii) to describe of morphological details, highlighting the clear diagnostic characters of each species, and (iii) to delimitate and discuss their geographical range in Chile. The examination of the Nacellidae of the Chilean fiords has resulted in the recognition of one species of Nacella (Nacella) and seven species of Nacella (Patinigera), wherein the principal specific differences are in the shell (shape, thickness and color) and in radular teeth morphology. The genus Nacella and its subgenus Patinigera are cold-water limpets, and are exclusively inhabitants of Subantarctic and Antarctic waters. The greater part of their range being subantarctic, but extending to the Antarctic by way of the Scotia Arc, and also ranging northward up the Chilean coast to at least Valparaiso at 33° S (only N. (P.) clypeater). They apparently have their centre of distribution in the Magellanic Province of southern South America, corresponding to an area with a high degree of diversification (N. (N.) mytilina, N. (P.) chiloensis, N. (P.) deaurata, N. (P.) delicatissima, N. (P.) flammea, N. (P.) magellanica, N. (P.) venosa), wherefrom the species tends to spread eastward, with a larval transport probably assisted to a considerable extent by the prevailing West ...
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