The quantitative reconstruction presented in this paper documents paleoecological trends of the northern Maracaibo basin (western Venezuela), during the Early Miocene, through pollen analysis of drill core samples from the La Rosa (shallow marine) and Lagunillas (coastal plain) formations. Palynological assemblages were grouped statistically into three assemblages representing mangroves, herbaceous back-mangrove swamps, and inland palm/fern swamps. Mangroves were the local vegetation during the deposition of La Rosa Formation and, after a regressive event, were replaced by herbaceous back-mangroves during the sedimentation of Lagunillas Formation. The palynological assemblage representing palm/fern swamps dominates the entire sequence and is interpreted as a large background signal reflecting transport by rivers. Mangrove communities had few species, and represented a transitional phase in the mangrove community evolution, after the terminal Eocene biotic crisis.