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Palaeobiogeography of the Late Cretaceous to Paleogene Larger Miliolids from tropical to subtropical Sea belt (Tethys to Caribbean)

The study of larger miliolids from the Late Cretaceous (5 genera, 8 species) and Paleogene (6 genera, 39 species) illustrates geographic, temporal and species distribution in four (Caribbean, European Tethys, North African Tethys and Indopacific) bioprovinces from the middle to late Eocene (Drobne 2002, Drobne & Hottinger 2004). The Late Cretaceous rich faunal association from the south Pyrenean shows endemic character.The Late Cretaceous rich faunal association from the south Pyrenean shows endemic character. Following the K/T event, as a consequences of the Thanetian transgression over the northern and southern margins of Neo-Tethys and renovation of the shallow marine environments (from Pyrenean to the east to Turkey, Iran, Egypt to Oman, in the SBZ3-SBZ 6) a new space for larger miliolids opened. Larger miliolids which were able to occupy new free habitats began with their restoration in the terms of species richness and abundances (Periloculina slovenica, Idalina sinjarica, I. causae, Helenalveolina rahaghii n.sp., Pseudolacazina donatae, Lacazina blumenthali, L. gracilis). The second diversification event during the Cuisian (SBZ11) is recorded in the central (European) Tethys with appearance of new species (P. dalmatina, Fabularia n. sp.). Middle Eocene radiation (SBZ 13) had a worldwide character in dispersion of fabularids (F. zitelli population in Egypt, F. ovata in Paris basin, F. colei and F. guenteri in Caribbean). The latter ones are considered as pioneers species that crossed the Atlantic to the west, and would adapt and radiate into several species. The paleoecological conditions in the late Middle Eocene (SBZ 17) resulting in morphological and abundance disparities between NE France fabularids (the largest tests of F. compressa) and those from the Pyrenean and Caribbean (sporadic occurrences of small specimens, F. roselli and F. gr. gunteri-vaughani). The uniformly dispersion over the waste area, from Caribbean to New Guinea characterized Upper Eocene age (SBZ 19, SBZ 20). It appears that the major differences between larger miliolid fauna form northern ad southern Neo-Tethys margin is distribution of Lacazinella to the southern bioprovinces. The oldest specimens are known from the Ilerdian (partly SBZ 4 – SBZ 8) from Oman, Somalia and Yemen. The representatives of the genus re-appeared further to the east (Papua, New Guinea) in the Late Eocene. The circulation pattern within Austral- pacific zone (in accordance with tectonic movements – collision in “ island arc system” ) predestinated specialized Lacazinella wichmanni to become present all over the region (along with Llle. haigi n. sp), while Lacazina reicheli is restricted to Maluku islands (westwards to New Guinea). The presented data questioned the evolutionary relationship between Lacazina and Lacazinella and allow a consideration of existence of possible refugee habitat.

Larger miliolids; Tethys; Caribbean; Cretaceous; Paleogene

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