Shallow-water organisms recovered from drilling four guyots in the western Pacific (from the southern Marshall Islands to the Japanese Seamounts) allow the recognition of changes in bioprovinces through time. The Tethyan low-latitude bioprovince characterizes the early Aptian worldwide. In the late Albian, however, shallow-water floral and f aunal assemblages from the drilled guyots, although predominantly composed of cosmopolitan forms, yielded few elements with an areal distribution more restricted to either the Caribbean-central American region or the Mediterranean, suggesting that two bioprovinces had already differentiated at low latitude at that time. During the late Campanian-Maastrichtian, the guyots' area was under the influence of the Caribbean bioprovince, but foraminifer assemblages also include some Mediterranean elements, suggesting that colonization occurred both westward and eastward. In the latest Paleocene-early middle Eocene, the direction of colonization reversed, with prevalent migration from the Mediterranean toward the Pacific.

Shallow-water larger foraminifers have been recovered at two drill sites on the eastern Maldive Ridge. Despite the poor recovery in Hole 715A, a rather diversified larger benthic foraminifer assemblage allowed us to date the initiation of a carbonate platform, resting on volcanic basement, as late early Eocene. Several age-diagnostic species belonging to the genera Alveolina, Nummulites, Orbitolites, and Discocyclina have been identified. The assemblages may be attributable to the upper part of the Nummulites burdigalensis cantabricus Zone and/or to the lower part of the Nummulites campesinus Zone and to the Alveolina dainellii (upper part) and/or to the A. violae (lower part) zones. The carbonate platform had a very short life (a few hundred thousand years) and rapidly sank below the euphotic zone, as testified by the occurrence of several species of planktonic foraminifers associated with redeposited reef-derived skeletal debris, especially discocyclinids, in the upper part of the sequence. Among the planktonic foraminifers, the presence of Planorotalites palmeri, which has a range confined to the lower portion of the late early Eocene Zone P9, implies that the platform was drowned before the end of the early Eocene.At Hole 714A, the occurrence of several shallow-water foraminifer genera, such as Nummulites (TV. fabianii gr.), Discocyclina, Fabiania, Heterostegina, and Operculina (O. gomezi), in pebbles derived from turbidite beds interbedded within late Oligocene pelagic sediments, allows us to suggest that a carbonate platform, possibly reduced in size, was still growing in the Maldive Ridge area after the late early Eocene time. The erosional event, responsible for the redeposition of middle to late Eocene reef-derived skeletal debris, is apparently coeval with the global sea-level fall recorded in late Oligocene Zone P22.