Originally, two main species of Pterodactylus (meaning 'winged finger') were sculpted for Crystal Palace, though at the time, not a lot was known about the species, and the species have since been renamed. Pterodactyl is actually a specific type of pterosaur in the group Pterosauria ('winged lizard). Some of the original sculptures in this group have been stolen and lost over time. The Crystal Palace lake statues collectively show several species of extinct mammals, amphibians, therapsids, marine reptiles, pterosaurs and dinosaurs. They represent the first attempt to accurately reconstruct the three dinosaur species known to the scientific world by the 1850s within their geological environment and the sculptures and associated geological strata form a unique display of the state of palaeological understanding in the 1850s, opened five years before the publication of Darwin's 'Origin of Species'.