The fossil echinoids of Santa Maria Island, Azores (Northern Atlantic Ocean)

Abstract

In the relatively young archipelago of the Azores, fossiliferous deposits are restricted to the oldest island (Santa Maria), mainly from late Miocene–early Pliocene deposits, and a few from the Pleistocene. echinoid material collected from these deposits comprises mainly disarticulated skeletal material (primary spines and coronal fragments) and a few complete tests. The taxa present in the Upper Miocene to lower Pliocene beds comprise Eucidaris tribuloides, Echinoneus cf. cyclostomus, Clypeaster altus, Echinocyamus pusillus, Echinocardium sp. 1, Echinocardium sp. 2, Schizobrissus sp. and undetermined spatangoids. The spatangoids and E. cf. cyclostomus, are new records for the Miocene– Pliocene strata of the island. The material collected from Upper Pleistocene outcrops (MISS 5e) included three regular echinoid species, Sphaerechinus granularis, Arbacia lixula and Paracentrotus lividus. The two latter species are recorded for the first time from the Pleistocene deposits of the island. compared to the older deposits, the Pleistocene record represents a very narrow range of environments and is basically restricted to deposits associated with an ancient rocky shore. Moreover, the conspicuous presence of taxa typical of tropical seas in the Mio-Pliocene sediments contrasts with the Pleistocene and modern echinoid fauna, which is warm temperate in composition.