PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 116(2):308-316. 2003. A new species of penguin (Spheniscidae: Spheniscus) and other birds from the late Pliocene of Chile Steven D. Emslie and Carlos Guerra Correa (SDE) Department of Biological Sciences, University of North Carolina, Wilmington, North Carolina 28403, U.S.A., email:
[email protected]; (CGC) Instituto de Investigaciones Oceanologicas, Universidad de Antofagasta, Casilla 170, Antofagasta, Chile, email:
[email protected] Abstract. — We describe a new species of penguin, Spheniscus chilensis, from Cuenca del Tiburon, late Pliocene, northern Chile. This species was found in association with a small species of cormorant, Phalacrocorax sp., and a cara-cara, Milvago sp., and is the first Pliocene penguin to be described from South America. Other vertebrates at this site include fish, sharks, and cetaceans. An extensive invertebrate fauna, including the late Pliocene muricid gastropod Herminespina mirabilis, also is present. The avifauna suggests a low diversity of seabirds existed in northern Chile from the late Pliocene to the present, unlike the much higher diversity found in Patagonia in the late Oligocene/early Miocene. The coastal region of southern Peru and northern Chile is well known for its mas-sive layers of marine shell beds exposed in cliffs. Geologic studies of these beds have provided considerable information on ma-rine faunas in the Miocene through late Pleistocene of this region. Previous inves-tigations in Chile have concentrated on the age and structure of the invertebrate faunas, and eustatic changes in sea level in corre-lation with tectonic uplift (Herm 1969, 1970; Tsuchi et al. 1988; Padilla & Elgueta 1992). Deposition of these beds occurred over a period of millions of years in coastal forearc basins, the eastern sections of which were later uplifted during crustal deforma-tions of the continental margin (Dunbar et al. 1990). Extensive and diverse deposits of late Pleistocene marine mollusks also occur throughout this region (Ortleib et al. 1994). In 1994, we visited an exposure of ma-rine shell beds on the Peninsula de Mejil-lones and approximately 14 km northwest of the Antofagasta airport and 6 km from the coast (Fig. 1). Here, over 10 m of ma-rine sediments are exposed on eroded slopes of valleys and hills that contain abundant marine mollusks. The upper lay-ers of these exposed sediments also contain numerous sharks' teeth, fish bones, and fragmentary and complete bones of marine mammals and birds. This fossil exposure lies within the upper beds of the Caleta Herradura de Mejillones Formation (23°21.453"S; 70°32.06r'W), dating to the late Pliocene (Tsuchi et al. 1988). In addi-tion, the fossils were found in association with the muricid gastropod Herminespina mirabilis, which is only known from the late Pliocene of Peru and Chile (DeVries & Vermeij 1997). The area of concentration of the verte-brate fossils, known locally as Cuenca del Tiburon, is particularly rich in birds. Doz-ens of disarticulated bones of a single spe-cies of penguin (Spheniscidae) and a small cormorant (Phalacrocoracidae) are scattered on the surface, having eroded from exposed layers of shell beds nearby. Fossils of this penguin originally were found by one of us (CGC) at the locahty in 1980. We visited the site twice in 1994 and once in 1997 to
Specimen codes extracted from OCR text.
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