Diversity and Extinction of Tropical American Mollusks and Emergence of the Isthmus of Panama

Abstract

The gradual closure of the Panamanian seaway and the resulting environmental change stimulated an increase in Caribbean molluscan diversity rather than the mass extinction hypothesized previously on the basis of inadequate data. Upheaval of molluscan faunas did occur suddenly throughout tropical America at the end of the Pliocene as a result of more subtle, unknown causes. There is no necessary correlation between the magnitude of regional shifts in abiotic conditions and the subsequent biological response.

Phylogeography of the sand dollar genus Mellita: Cryptic speciation along the coasts of the Americas

“…Origination rates of many marine taxa are reported to have peaked at this time, in response to increasing habitat heterogeneity in shallow-water marine environments (Jackson et al, 1993;Cheetham and Jackson, 1996;Collins, 1996;Knowlton and Weigt, 1998;Budd and Johnson, 1999;Marko, 2002;Smith and Jackson, 2009;Jagadeeshan and O'Dea, 2011).…”

Diversity and extinction in the Cenozoic history of Caribbean reefs

“…Increased upwelling and associated turbidity and cooling have been inferred for the Caribbean during the Early Miocene Risk 1994, 1995). Drops in sea surface temperature associated with the onset of northern hemisphere glaciation a ected many di erent marine organisms (including molluscs and bryozoans) in the Caribbean during the Late Pliocene (Stanley 1986;Jackson et al 1993. Studies of extinction selectivity Risk 1994, 1995) indicate that cold-tolerant, eurytopic reef coral species that brood larvae were more likely to survive extinction during the Late Oligocene to Early Miocene; whereas reef coral species with large maximum colony sizes and longer generation times were more likely to survive extinction during the Plio-Pleistocene .…”

Molecular phylogeny and phylogeography of free-living Bryozoa (Cupuladriidae) from both sides of the Isthmus of Panama

“…These differences are not all one-way; some taxa, e.g., molluscs (Jones and Hasson, 1985), are more diverse in the eastern Pacific, whereas others, e.g., sponges (Soest, 1994) and corals (Glynn, 1982) are more diverse in the Caribbean. The diversity inequalities are generally attributed to differential speciation and extinction on the two sides of the isthmus (Budd, 1989;Jackson et al, 1993Jones and Hasson, 1985;Vermeij, 1978;Vermeij and Petuch, 1986). However, these evolutionary patterns do not explain why taxa responded differently to environmental changes in the two oceans associated with closure of the isthmus.…”

“…Furthermore, both diversity inequalities and rates of origination and extinction have varied through time, also in a taxon-specific manner. For example, strombinid gastropods were more diverse in the Caribbean than the eastern Pacific until the late Pliocene, when a reversal occurred due to a decline in origination and increase in extinction in the Caribbean, whereas the opposite occurred in the Pacific (Jackson et al, 1993. In contrast, corals underwent declines in both the eastern Pacific and Caribbean during the late Pliocene, but there was no subsequent Pacific radiation (Budd, 1989;Budd et al, 1996).…”