A new record of Caudammina (Foraminiferida) from the upper Rupelian of Madonie Mts. (Sicily)

The systematic assignment of two populations of Caudammina from deep-water agglutinated foraminifera (DWAF) assemblages from the upper Rupelian of the Madonie Mts. (Benedetti & Pignatti, in press), cropping out near Portella Colla (NW Sicily), is discussed. Biometrical data of diameter of the neck (a), width (b), length (c) and factor b/a (Bubík, 1997; Geroch, 1959; Rögl, 1995) allow us to compare them with other species from the Cretaceous to the Middle Eocene. The ratio c/b is proposed to define the degree of increase in size in the different species. Two statistical populations of Caudammina from Portella Colla (n=27 and 35) are compared with data for C. ovulum (Grzybowski, 1896), C. gigantea (Geroch, 1960), C. ovuloides (Grzybowski, 1901), and C. crassa (Geroch, 1966). The biometrical parameters considered indicate that C. ovulum is smaller and has less pyriform chambers; C. crassa has a thicker neck, whereas C. ovuloides has smaller b/a values. The populations of Caudammina from Portella Colla represent probably the first record of this genus for the Rupelian, because the last recorded occurrence of C. ovulum and C. ovuloides is referred to the Middle Eocene (Kaminski & Gradstein, 2005). A significant pattern in the genus is a trend towards increase in size in Late Cretaceous times, up to the extinction of C. gigantea at the K/T boundary. A similar trend, following Cope’s rule, can be hypothesized for the Paleocene-Oligocene, in which the large-sized Caudammina from Portella Colla represent the end members of this evolutionary trend.