Treemap graphical representation of HELLAS-ALIENS taxa origin. Colours of tiles are consistent within each group of organisms. A terrestrial taxa B freshwater taxa C marine taxa. C-IP: Central Indo-Pacific; W-IP: Western Indo-Pacific; CT: Circumtropical; T-NP: Temperate Northern Pacific; T-NWP: Temperate Northern Western Atlantic; TR-A: Tropical Atlantic; T-AA: Temperate Australo-Asia.