The colony regeneration and life habitat of free-living bryozoans, Cupuladria canariensis (Busk) and C. haidingeri (Reuss), from the Korytnica Clays (Middle Miocene; Holy Cross Mountains, Poland)

Abstract

The colony regeneration of free-living· cheilostome bryozoans from the Korytnica Clays (Middle Miocene, Holy Cross Mountains, Central Poland) is revealed by two cupuladriid species, Cupuladria canariensis (Busk) and C. haidingeri (Reuss), the first of which is extant. In these species, the regeneration is for the first time recorded from ancient environments, the phenomenon itself being formerly known in the present-day forms. The regeneration in colonies from the Korytnica Clays often happened from very tiny fragments, some of which were composed of only one zooid that survived the breakage of the primary colony and remained alive. Contrary to previous views, the investigated specimens were well adopted to the clay-bottom environment if the water-circulation conditions were favorable for their life requirements (bottom currents in action, no setting of clay particles from turbid waters). It is also shown that these cupuladriid species are indicative of tropical and/or subtropical conditions prevailing in the Korytnica basin.