The Last Interglacial (LIG; ca. 125,000 y ago) resulted from rapid global warming and reached global mean temperatures exceeding those of today. The LIG thus offers the opportunity to study how life may respond to future global warming. Using global occurrence databases and applying sampling-standardization, we compared reef coral diversity and distributions between the LIG and modern. Latitudinal diversity patterns are characterized by a tropical plateau today but were characterized by a pronounced equatorial trough during the LIG. This trough is governed by substantial range shifts away from the equator. Range shifts affected both leading and trailing edges of species range limits and were much more pronounced in the Northern Hemisphere than south of the equator. We argue that interglacial warming was responsible for the loss of equatorial diversity. Hemispheric differences in insolation during the LIG may explain the asymmetrical response. The equatorial retractions are surprisingly strong given that only small temperature changes have been reported in the LIG tropics. Our results suggest that the poleward range expansions of reef corals occurring with intensified global warming today may soon be followed by equatorial range retractions.biodiversity | climate change | paleobiology C urrent global warming triggers substantial range shifts in both terrestrial and marine ecosystems (1-3). Scleractinian reef corals, like many other marine organisms, are currently experiencing poleward range expansions (4-7), but there is little evidence for range retractions in low latitudes. Whether this trend will persist into the future is difficult to predict, partly because of the lack of well-studied examples on past responses to rapid global warming. Range expansions of fossil reef corals with climate warming have been observed in the early to mid-Holocene (10 to 6 ky ago) (7) and during the Last Interglacial (LIG; ca. 125 ky ago) (8, 9). These previous studies highlighted particular taxa and regions, but the generality of the observations remains uncertain. Moreover, the balance between leading-edge range expansions (defined as species ranges moving toward the poles) and trailingedge contractions (defined as species ranges moving away from the equator) in these past warming phases is unexplored.Here we compare latitudinal patterns of global reef coral distributions and diversity (number of species) from raised reef terraces of the LIG [Marine Isotope Stage 5 (MIS 5)] with modern-day distributions to highlight the impact of past global warming. During most of the Pleistocene, global temperatures were colder than today (10-12), but glacial episodes are not well documented in reef corals because coral reefs of those times are largely submerged today (but see ref. 13). Interglacial warming led to polar ice melting and sea levels substantially higher than today (12, 14-16), leaving fossil coral reefs accessible on land. Tectonic uplift on some Pacific islands may also leave a record outside the peak interglacials, but not of p...

Understanding historical patterns of diversity dynamics is of paramount importance for many evolutionary questions. The fossil record has long been the only source of information on patterns of diversification, but the molecular record, derived from timecalibrated phylogenies, is becoming an important additional resource. Both fossil and molecular approaches have shortcomings and biases. These have been well studied for fossil data but much less so for molecular data and empirical comparisons between approaches are lacking. Here, we compare the patterns of diversification derived from fossil and molecular data in scleractinian reef coral species. We also assess the robustness of molecular diversification rates to poor taxon sampling. We find that the temporal pattern of molecular diversification rates is robust to incomplete sampling when rates are calculated per interval. The major obstacle of molecular methods is that rate estimates are distorted because diversification rates can never be negative, whereas the fossil record suffers from incomplete preservation and inconsistent taxonomy. Nevertheless, the molecular pattern of diversification is comparable to the pattern we observe in the fossil record, with the timing of major diversification pulses coinciding in each dataset. For example, both agree that the end-Triassic coral extinction was a catastrophic bottleneck in scleractinian evolution. K E Y W O R D S : Diversification, extinction, fossils, molecular phylogenies, reef corals, speciation.Although historical patterns of diversity dynamics are most commonly inferred from the fossil record, it is possible to infer at least diversification rate from the molecular record using timecalibrated molecular phylogenies. If the patterns of diversification estimated with molecular methods can be trusted, then macroevolutionary questions can be asked in groups with poor fossil records and, perhaps more usefully, diversification rates can be inferred independent from potential biases in the fossil record. But how reliable are molecularly derived estimates of diversification dynamics and how do they compare to estimates derived from the fossil record? Both of these questions have received little empirical investigation.Even though the methods for estimating diversification rates from fossils or molecules are quite similar (Alroy 2009), there is a drastic difference in analytical protocols. In paleobiology, we accept that taxonomic turnover rates in fact vary substantially over time. The major goal of paleobiological research into taxonomic rates has been to develop methods for quantifying the historical pattern rates while minimizing bias (Foote

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