Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e....Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e.g., mural pores） and rugose corals （e.g., welldeveloped septa）. Septal patterns have long been considered to be indicative of the origin of corals, and the pattern of septal insertion in Agetolites has been known to be typical of rugosans. This study, however, reveals that the patterns in Ageto lites are rather random and cannot be an indication of its rugosan affinity. It is suggested that Agetolites probably has a closer phylogenetic relation with tabulates than with either rugosans or scleractinians. Two insertion patterns of the first six septa were detected （Types I and II）. Type I is interpreted as scleractinian pattern whereas Type II as typical pattern of rugosans. Types 1 and 2 are septal patterns of the second stage recognized in this study. Type 1 insertion occurs in six sectors located in the center of each interseptal space, suggesting scleractinian pattern of insertion. Type 2 insertion occurs in four sectors that are comparable with alar and counter sectors in rugose corals. Four patterns of the third （Types AD） and fourth stages （Types ad） of septal insertion have also been recognized in Agetolites. Type A only occurs in two adjacent sectors possibly due to the in completeness of septal development. Type B presents rugosan pattern. Types C and D resemble scleractinian pattern in most aspects. Types a, b, and c present no clear attribution to rugosan or scleractinian pattern probably due to the incompleteness of septal development whereas Type d is observable in rugose corals.展开更多
基金supported by the Invitation and Training of Outstanding Overseas Student Researcher Program by Korea Science and Engineering Foundation(Grant No.KOSEF 211-2007-1-C00047)Korea Research Foundation funded by the Korean Government(MOEHRD)to DJL(Grant No.KRF-2006-312-C00690)
文摘Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e.g., mural pores） and rugose corals （e.g., welldeveloped septa）. Septal patterns have long been considered to be indicative of the origin of corals, and the pattern of septal insertion in Agetolites has been known to be typical of rugosans. This study, however, reveals that the patterns in Ageto lites are rather random and cannot be an indication of its rugosan affinity. It is suggested that Agetolites probably has a closer phylogenetic relation with tabulates than with either rugosans or scleractinians. Two insertion patterns of the first six septa were detected （Types I and II）. Type I is interpreted as scleractinian pattern whereas Type II as typical pattern of rugosans. Types 1 and 2 are septal patterns of the second stage recognized in this study. Type 1 insertion occurs in six sectors located in the center of each interseptal space, suggesting scleractinian pattern of insertion. Type 2 insertion occurs in four sectors that are comparable with alar and counter sectors in rugose corals. Four patterns of the third （Types AD） and fourth stages （Types ad） of septal insertion have also been recognized in Agetolites. Type A only occurs in two adjacent sectors possibly due to the in completeness of septal development. Type B presents rugosan pattern. Types C and D resemble scleractinian pattern in most aspects. Types a, b, and c present no clear attribution to rugosan or scleractinian pattern probably due to the incompleteness of septal development whereas Type d is observable in rugose corals.
