. Bulletins of American paleontology. 30 Bulletin 338 distinguished altogether (13 of which are shown on Text-fig. 16). These species were then linked into lin- eages representing single species lines using Mahala- nobis' distances among all 21 species (following the methods of Budd, 1988). In this procedure, distances between species in successive time intervals were com- pared with distances between species within time in- tervals (Text-fig. 17). Species in successive time inter- vals were linked if the distance between them was less than the minimum distance between species in each of the t
. Bulletins of American paleontology. 30 Bulletin 338 distinguished altogether (13 of which are shown on Text-fig. 16). These species were then linked into lin- eages representing single species lines using Mahala- nobis' distances among all 21 species (following the methods of Budd, 1988). In this procedure, distances between species in successive time intervals were com- pared with distances between species within time in- tervals (Text-fig. 17). Species in successive time inter- vals were linked if the distance between them was less than the minimum distance between species in each of the two intervals. In three cases, linkages appear ambiguous: (1) in M. imperatoris (Vaughan, 1919) from the Oligocene to early Miocene; (2) in M. trinitatis (Vaughan in Vaughan and Hoffmeister, 1926) from the middle Miocene to late Miocene/early Pliocene; and (3) in A4. cavernosa (Linnaeus, 1767) from the late Miocene/early Pliocene to Recent. In such cases where more than one possible linkage appears viable, Ma- halanobis' distances calculated using only the adjacent pair of intervals were used to establish linkage. Linkage reduced the 22 species to eleven (Text-fig. 17). These results suggest that two of the early Miocene types listed in Table 4 (, groups 18 and 23) may be synonymous with Dominican Republic species. Group 18, which includes the holotype oWrbicella bainbridg- ensis Vaughan, 1919, appears linked with M. endoth- ecata (Duncan, 1863). Group 23, which includes top- otypes but not the holotype of Orbicella tampaensis Vaughan, 1919, appears linked with M. canalis (Vaughan, 1919). The results provide preliminary estimates of pat- terns of speciation and extinction within Caribbean Montastraea as well as amounts of directional phyletic evolution within each Montastraea species. However, due to small sample sizes, some estimates of species durations may be reduced. The patterns found suggest that all three Oligocene species (M. endothecata, M. imperatoris, and M. canal
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