1. Spix's Macaw (_Cyanopsitta spixii_): This vibrant blue parrot is native to Brazil. Only one confirmed individual remains in the wild.
2. Yangtze Giant Softshell Turtle (_Rafetus swinhoei_): This enormous freshwater turtle is endemic to China. There are only three known individuals left in captivity.
3. Northern White Rhino (_Ceratotherium simum cottoni_): Only two northern white rhinos, both female, are known to exist in captivity in Kenya.
4. Sumatran Rhino (_Dicerorhinus sumatrensis_): This rhinoceros species is critically endangered with an estimated population of fewer than 80 individuals in fragmented habitats across Southeast Asia.
5. Javan Rhino (_Rhinoceros sondaicus_): With fewer than 80 individuals remaining in western Java, the Javan rhino is one of the rarest large mammals on Earth.
6. Black Rhinoceros (_Diceros bicornis_): Subspecies of black rhino, including the critically endangered western black rhino (_Diceros bicornis longipes_) and eastern black rhino (_Diceros bicornis michaeli_), are on the brink of extinction.
7. Hawksbill Turtle (_Eretmochelys imbricata_): This marine turtle is highly threatened due to illegal trade for its beautiful shell patterns.
8. Amur Leopard (_Panthera pardus orientalis_): This subspecies of leopard is native to the remote forests of the Russian Far East and China, where fewer than 100 individuals are believed to remain.
9. Tapanuli Orangutan (_Pongo tapanuliensis_): Discovered as a distinct species in 2017, the Tapanuli orangutan is endemic to the Batang Toru forest in Sumatra and critically endangered with only 800 individuals left.
10. Mountain Gorilla (_Gorilla beringei beringei_): Endemic to the Virunga Mountains in Central Africa, mountain gorillas are critically endangered with only around 1,000 individuals remaining due to habitat loss and poaching.
These species are facing severe declines in their populations due to habitat loss, hunting, poaching, climate change, and other threats. Conservation efforts, including international collaboration, habitat protection, anti-poaching measures, and breeding programs, are essential to prevent the extinction of these critically endangered species.