Publication Date

Fall 2015

Degree Type


Degree Name

Master of Science (MS)




Jonathan Hendricks


Community Structure, Diversity, Invertebrate, Neogene

Subject Areas

Geology; Paleontology; Paleoecology


River valleys in the Cibao Valley Basin, located in the northern Dominican Republic, expose three fossiliferous Neogene-aged strata (the Cercado, Gurabo, and Mao formations) that show evidence for shifting marine paleo-habitats. This study system is ideal for analyzing the relationships between environmental changes and faunal community stability through time. A new database was developed from the published literature to examine changing diversity patterns and to determine if the Cibao Valley communities exhibited stasis over a 3 My time span (6.5 Ma to 3.5 Ma) across shallow- to very deep-water environments. This database includes spatio-temporal occurrence data for 179 species of gastropods, bivalves, and corals. Analyses of diversity patterns reveal a high diversity of species in shallow- to deep-water depths, and a low diversity of species in very deep-water depths, as well as a low similarity of species through time across the different paleoenvironmental settings. An R-mode hierarchical cluster analysis illustrates two major clusters that were based mostly on the different paleoenvironments in which these species lived, while a Q-mode cluster analysis shows two major clusters, one consisting mostly of mollusk and the other of corals. Finally, a detrended correspondence analysis indicates higher species richness in intermediate-water depths and lower species richness in very deep-water depths. In total, these results indicate faunal instability though changing habitats across time in this study system.

Abdollahian_Nina_Database_Supplementary.xls (1116 kB)

Abdollahian_Nina_Plate1_Supplementary.pdf (282 kB)