. Bulletins of American paleontology. 300 CO CO 300 200 100. 100 AXIS1 200 300 Text-figure 10.—Scatterplots of DCA scores for 27 Costa Rican localities determined using relative abundance code data. Each point represents a locality, the abbreviations for which are given in Table 1. Shaded areas encompass localities within the Buenos Aires (BA). Empalme (EM), and Lomas del Mar (LM) reef trends. The Lomas del Mar localities are divided into two subsets based on cluster anal- ysis results: (1) 10 tightly clustered localities (LE2. LE3, LE4, LE5, LEV, LE8, LE9, LEIO, LW2, LW3) that are scattered a
. Bulletins of American paleontology. 300 CO CO 300 200 100. 100 AXIS1 200 300 Text-figure 10.—Scatterplots of DCA scores for 27 Costa Rican localities determined using relative abundance code data. Each point represents a locality, the abbreviations for which are given in Table 1. Shaded areas encompass localities within the Buenos Aires (BA). Empalme (EM), and Lomas del Mar (LM) reef trends. The Lomas del Mar localities are divided into two subsets based on cluster anal- ysis results: (1) 10 tightly clustered localities (LE2. LE3, LE4, LE5, LEV, LE8, LE9, LEIO, LW2, LW3) that are scattered across the top of the topographic ridge formed by the Lomas del Mar trend, and (2) three localities (LEI. PI. P2) along the northern margin of that ridge. The results of DCA analyses using relative abun- dance codes (Text-fig. 10) suggest that, with the ex- ception of locality E3 and three northern localities within the Lomas del Mar trend (LEI, PI, P2), the localities within the three better-sampled reef trends group together The two clusters of localities within the Lomas del Mar trend are separated by a pro- nounced discontinuity; whereas localities within the Buenos Aires trend and Santa Rosa patch appear to overlap slightly. The Quebrada Chocolate locality is isolated in the plot of axis 1 vs. axis 2, but groups with the Buenos Aires locality in the plot of axis 1 vs. axis 3. These findings are consistent with those of the cluster analyses (Text-fig. 9). Visual examination of the two DCA plots (Text-fig. 10) suggests that axis 1 corresponds with relative stratigraphic position and geologic age. Possible ex- ceptions exist for locality E3 and the three northern localities within the Lomas del Mar trend. Neverthe- less, older localities generally have high values along axis 1; whereas younger localities tend to have low values. DCA scores for species (Text-fig. 11) are also generally higher for extinct species than for living spe- cies along axis 1. In contrast, axes 2 and
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