During middle Paleocene 67% was dominated by reef community which then produced mainly reef complexes and also patch reef. Early Paleogene shows the low level of diversity while in middle Paleocene the diversity was moderate.
Studies showed that 14 genera resent during the time where each of them consists of 5 to 25 other species of corals. All of this include different kind of forms such as platy, branching, massive and laminar. For example, Ganiopora and Cladocora existing at the euphotic setting around Tethys. Other than that, Alpine-carpathian reef belt with fringing reef was formed at the margin of central by Tethys corals in Apulian platform. Tethys coral algal patch reef is high in diversity in the Eastern side such as Pakistan while in Pyreness extended barrier reefs was molded by the corals. In other zones, dominating by calcareous red algae the corals present as subordinate component within mounds. Corals occurred within coral-alga; patch reef and coral knobs in the high latitude area. The corals the decreased to 43% during the transition to late Paleocene.
All of the corals switch to red algae, microbes and also foraminifera as another framework builders in the low latitude. Differently in middle latitude both coral-algal patch reef and reef complexes still present in shallow and moderate water depth. Moderate diversity of corals assemblage present as knobs at low latitude.
Even though there is some obvious declining in diversity observed, in some localities the coral assemblages show diversity equivalent to that of the middle Paleocene where it is up to 13 genera. Corals fossil are usually thickly encrusted by red algae, foraminifera and microbes. For instance, rhodolith and algal mound in Egypt with rare and encrusted coral fragments are form from coral algal patch reefs. In late Paleocene, corals such as Actinacis and Ganiopoda were common as assemblages laminar and encrusting coral. The rhodolith facies then replace coral facies. Few species were resistant to high turbidity resulting a shift in coral assemblages.
56% of corals existence within high energy setting, very shallow water and moody lagoonal deposits were govern by goniopora and actinacis forming knobs. In the Cenozoic z-like corals arose for the first time as isolated knob. The concentration of central Paleocene-early Eocene corals points to the colonization of a wide variety of habitats.
In connection with this expansion of the habitat, there was a gradual reduction of the capacity to form a framework. This process is illustrated in the shift from mid-Paleocene occurrences, represented primarily by coral-algal patch reefs to coral-bearing moons common in late Paleocene and eventually to early Eocene coral knobs typical of very shallow water environments. The reduced colony dimensions usually in the range of centimeters are a general feature that characterizes the corals during the early Paleogene period.