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PETTITT (1950) erected the species Cretirhynchia magna for a rhynchonellide brachiopod collected from the Upper Chalk of Trimingham, Norfolk, England. On the basis of specimens of this species made available to the authors, serial transverse sections and SEM examination of the shell microstructure were performed. Macro-morphological characters observed assign this material to the genus Septatoechia LOBATSCHEVA & TITOVA, 1977. The early Maastrichtian Cyclothyris elegans (VON HANSTEIN, 1879) collected from Ciply (Hainaut, Belgium) is reappraised and its generic allocation is also changed due to the macromorphological characteristics fitting the genus Septatoechia. The shell microstructure pattern of the secondary shell layer of both species is ‘fine fibrous’ (leptinoid). The discrepancy in the shell microstructure patterns between western representatives (S. magna and S. elegans) and the eastern representatives (S. inflate and S. amudariensis) stimulated revision of previous published information. Careful re-examination of unpublished results revealed problems with the original description of the shell microstructure of S. inflate and S. amudariensis due to the use of oblique lateral sections of the fibres. Emended description of the shell microstructure of S. inflate and S. amudariensis is herein provided. Thus all four species belonging to the genus Septatoechia have ‘fine fibrous’ (leptinoid) shell microstructure, typical of superfamily Hemithiridoidea. |
