Hypostomes in Cambrian agnostids from the Barrandian area (Czech Republic)

Remains of agnostid hypostomes are rare and have only been reported in about fifty specimens assigned to ten Cambrian species. A large collection of several thousand specimens of a Cambrian skeletal fauna from the Barrandian area includes articulated agnostids with in situ preserved hypostomes in two species from the Pribram-Jince Basin and in one species from the Skryje-TATIN SMALL LETTER Y WITH ACUTErovice Basin. Unequivocal remains of hypostomes are described in Condylopyge rex (Barrande, 1846), Peronopsis integra (Beyrich, 1845) and Onymagnostus hybridus (Brogger, 1878). The material provides the first information on the hypostomal morphology in the superfamily Condylopygoidea Raymond, 1913 and adds new data in two other Cambrian agnostid genera. The chemical composition and placement of agnostid hypostomes are briefly discussed. center dot Key words: Agnostida, hypostomes, middle Cambrian, Jince Formation, Buchava Formation, Barrandian area, Czech Republic.