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ABSTRACT--Compared to their Recent counterparts, fossil abalone are rare and poorly known. Their taxonomy is problematic, because most of the 35 fossil species have been described from single specimens and shell characteristics of Recent species are extremely plastic. Thus, the use of fossil species in phylogeny is questionable. Abalone first appear in the Upper Cretaceous (Maastrichian) with one species each in California and the Caribbean, are unknown in the Paleocene, and appear again in the late Eocene and Oligocene of New Zealand and Europe. They are regularly found from the late Miocene to the Recent in tropical to temperate regions worldwide. Most records are from intensely studied areas: SW North America, Caribbean, Europe, South Africa, Japan, and Australia. Despite their highest present-day diversity being found in the Indo-Pacific, their scarcity in the fossil record in this region is remarkable. The family may have originated in the central Indo-Pacific, Pacific Rim, or Tethys. An extensive list of all known fossil records including new ones from Europe and western North America is given. Fossil and Recent abalone both apparently lived in the shallow, rocky sublittoral in tropical and temperate climates. No on-shore/off-shore pattern is detected.
INTRODUCTION
RECENT MEMBERS of the family Haliotidae, with "abalone" as their common name. are well-known. Due to their economic value, living species have received much scientific attention; e.g., Shepherd et al. (1992, 1995a) and Fleming and Hone (1996). However, only relatively few and isolated accounts of fossil abalone are found in the literature, with Lindberg (1992) supplying a limited overview. We present here a more extensive review on what little is known about fossil abalone to stimulate further work.
DIAGNOSTIC CHARACTERS OF THE FAMILY
Shell morphological characters clearly separate abalone from any other family of fossil as well as extant gastropod (Fig. 1). Abalone shells are easily recognized by their flat, limpetlike shape and row of tremata toward the left periphery. This row of tremata represents the subdivided selenizone found in Pleurotomaroidea, Scissurelloidea, and Fissurelloidea (Knight et al., 1960; Bandel, 1998; Geiger, 1998a; McLean and Geiger, 1998). The extremely hypertrophied epipodium is a key diagnostic character for the anatomy of the Haliotidae, but such characters do not apply to fossil representatives, and are not further discussed here (see Geiger, 1998a). Some...