Bacterial distribution evaluated at the phylum taxonomical level. (a) The gut microbiota of herbivorous reptiles was predominated by Firmicutes, unclassified Bacteria and Bacteroidetes. (b) The low-abundance phyla were grouped together as ‘others', and their specific abundances were listed. *denotes that Archaea were detected in all herbivorous reptiles, at abundance ranging from 0.1 to 0.2% of total microbial community, except in MI. LI, land iguanas; MI, marine iguanas; GI, green iguanas; GT, giant tortoises.