Neogene marine fossils from the eastern Canary Islands

Abstract

In the eastern Canary Islands: Gran Canaria, Fuerteventura and Lanzarote are located mio-pliocene marine deposits. These deposits consist in a reddish fossiliferous conglomerate and sandstones with structures and bioturbation, which are interpreted as belonging to a shallow environment. In some sites, these marine deposits appear below lava flows. In Salinas del Janubio (Lanzarote) are under basalts from Tías-Janubio Formation, dated about 6.6 Myr and 8.9 Myr. In the Barranco de Ajuí (Fuerteventura) dated about 4.8 Myr and in the Barranco de Los Dolores and Tamaraceite (Gran Canaria) are associated with pillow lava flows dated as 4.1 Myr. The study of the fossil fauna shows more than 136 taxa and ichnotaxa, many currently extinct, which provide valuable stratigraphic, paleoclimate and paleoceanographic information. In this list stand up some Upper Miocene and Lower Pleistocene characteristic fossil taxa as the coral Siderastraea micoenica Osasco, 1897; the gastropods Rothpletzia rudista Simonelli, 1890; Ancilla glandiformis (Lamarck, 1822), Strombus coronatus Defrance, 1827; Nerita emiliana Mayer, 1872 or the bivalve Gryphaea virleti Deshayes, 1832. Among fossil swimmers vertebrates list, several species correspond to large predators with migratory capacity and in some cases with pan-oceanic distribution such as Carcharodon megalodon Agassiz, 1843; Carcharodon carcharias Linné, 1758; Isurus hastalis (Agassiz, 1843) and Galeocerdo aduncus Agassiz, 1843. Their presence is associated with marine mammals existence that constituted their preferred prey. Other fossil taxa only had migratory capacity in their larval stage as the fish Diodon sigma Martin, 1887; the gastropod Columbella mercatoria Linné, 1758 and the balanus Tetraclita aff. rubescens Darwin 1854. T. rubescens Darwin 1854 is characteristic of the Pacific coast of North America from Cabo San Lucas, Baja California, Mexico, to San Francisco Bay. Its presence in the Canaries was only possible before the closure of Panama isthmus circa 3 Myr.