Waclaw Tworzydlo received his PhD from the Jagiellonian University in 2006 and is currently Associate Professor in zoology and developmental biology at the Jagiellonian University in Krakow. Szczepan M. Bilinski received his PhD from the Jagiellonian University in 1975 and is currently Secretary General of the Polish Academy of Arts and Sciences and Professor of zoology, cell and developmental biology at the Jagiellonian University in Krakow.