In defence of the calcichordates

The cornutes and mitrates, collectively known as stylophorans or calcichordates, are the most controversial members of the traditional group of the 'carpoid echinoderms'. In a recent review, Philip has rejected Ubaghs' interpretation of them as aberrant echinoderms with a single feeding arm, has also rejected my own interpretation of diem as primitive chordates, and has made some tentative proposals of his own. The present paper answers Philip's criticisms of the calcichordate interpretation and discusses his own proposals and his comments on Ubaghs' views.     

Middle Cambrian cystoid (sensu lato) stem columnals from Bornholm, Denmark

A rich material of echinoderm fragments from two Middle Cambrian stratigraphical levels on Bornholm are preserved due to phosphatization of the original calcitic stereom. Preservation of echinoderms in this way - not previously recorded from the Middle Cambrian - permits detailed analysis of the three-dimensional stereom structure. Identifiable are fragments of stylophorans and eocrinoids. Stem columnals, most likely from eocrinoids, show a wide and advanced morphological variation indicating articulation similar to that of crinoids. The material from the Exsulans Limestone/Kalby marl ( Ptychagnostus gibbus Zone) represents stem-bearing cystoids older than Akadocrinus from Bohemia. The Andrarum Limestone ( Sole-nopleura brachymetopa Zone) contains echinoderm fragments from a higher stratigraphical level, a level correlatable with that from which the oldest North American stem–bearing cystoid, Eustypocystis , has been recorded.