Phylogeny and evolution of ontogeny of the family Oxytomidae Ichikawa, 1958 (Mollusca: Bivalvia)

The Berriasian–Valanginian (Early Cretaceous) boundary transition at Santa Catarina Ticuá, Oaxaca state, southern Mexico: Ammonites, bivalves, calpionellids and their paleobiogeographic significance

“…The genus Arctotis is abundant in northern Siberia in strata from the Early Jurassic to Hauterivian (e.g., Zakharov, 1966;Crame, 1985;Lutikov, 2010), and in the Kimmeridgian-early Tithonian of the northern Antarctic Peninsula (Crame, 1985;Doyle, 1991). An isolated occurrence of Arctotis was documented from the lower Tithonian of England (Kelly, 1984) and the genus possibly occurs in Canada and in the Manihiki (South Pacific Ocean) and Falkland plateaux (Jeletzky, 1963(Jeletzky, , 1983Kauffman, 1976;Crame, 1985).…”

“…Specimens described here were collected from the late Berriasian Calpionellopsis oblonga Subzone (assemblage I) and the early Valanginian Calpionellites darderi Subzone (assemblages III, IV, V). The high latitude taxon Arctotis is abundant in Lower Jurassic to Hauterivian strata of the Arctic (e.g., Lutikov, 2010) and in Kimmeridgian-early Tithonian sediments of the Antarctic region (e.g., Doyle, 1991). Identification of the genus in Mexico provides the first record in low latitudes.…”