Fig. 6. Protacrodus vetustus Jaekel, 1921. A in Chondrichthyan fauna of the Frasnian-Famennian boundary beds in Poland

Fig. 6. Protacrodus vetustus Jaekel, 1921. A. Tooth−whorl composed of three teeth, right side incomplete, IGPUW/Ps/1/222, sample Md−I/1, Late Pa. triangularis Zone, occlusal view, × 30. B–D. Large, almost completely preserved tooth, IGPUW/Ps/4/13, sample Ko−SF, Pa. linguiformis Zone, oblique lingual, oblique labial and lingual views, × 17. All SEM micrographs.