Iowatrypa rotundicollis n. sp., brachiopode atrypidé de la fin du Frasnien

The specimens belonging to the new species Iowatrypa rotundicollis have been collected in the limestone lentils (bioherms) developed during the late Frasnian on the southern border of the Dinant Synclinorium and in the Roly "massif".The species is one of the latest atrypid brachiopods of which the history ends near the close of Frasnian times. It is an uncommon example of inverse vaulting (ventribiconvex shell) in atrypid shells. The genus Iowatrypa , distributed over several localities of the northern hemisphere, is recorded from Belgium for the first time.