| Fossil echinoderms from the Middle Eocene through Pleistocene in Florida are described here in detail, including any previously reported species as well as taxa that are new records as a result of this study. Twenty-three formations from the state produced fossils belonging to four classes of echinoderms, including echinoids, asteroids, crinoids, and ophiuroids. Echinoids are distinctly more diverse and documented than the other classes in the state.; The diversity of echinoderms from the Cenozoic in Florida has increased significantly as a result of examination of fragmented skeletal debris and small size fractions of the sedimentary rock. Echinoid species diversity generated herein resulted in an increase from 68 species (reported in publications before 1994) to a current diversity of 97 species. These new additions include both newly reported stratigraphic records of a species from the state and new taxonomic records (i.e., undescribed species). An important result of the additional taxa recorded is the change in the echinoid diversity pattern over time. Most newly reported taxa were found in Miocene (14 new records) and Pliocene (eight new records) formations. The diversity pattern thereby shows a dramatic increase in diversity from the Oligocene to the Miocene, rather than a drop in diversity as formerly documented.; Changes in the diversity pattern may be attributed to multiple biases in addition to species extinction and origination. Such biases include stratigraphic resolution of data, changes in stratigraphic nomenclature, amount of outcrop exposure and topographic relief, varying preservation potential in carbonate versus siliciclastic strata, unequal epoch duration in the Cenozoic units, taxonomic nomenclature changes (i.e., species versus subspecies identifications), fossil collector preferences favoring unbroken specimens, and substrate grain-size preferences of the echinoderm taxa. Analysis of such biases indicated collector bias, strata composition, and substrate texture were the most important factors ultimately controlling the diversity pattern in Florida's Cenozoic echinoderm record.; Finally, an analysis of allometric heterochrony patterns completed for echinoid species in the family Mellitidae showed the predominance of paedomorphic patterns of evolution. Such trends closely matched previously proposed models for r-selection styles in higher energy environments where descendant species ultimately inhabited. |
