dichotomization:

“Endling” might just be the loneliest term in the English language. An endling is the last member of a species or subspecies, and when this lone individual dies its species is extinct. Several endlings have been recorded in recent times. Martha, the last passenger pigeon, died in 1914 in Cincinnatti Zoo. She was the last of a species that had numbered several billion before Europeans arrived in North America. Human actions are a oft-repeated theme in the story of endlings. The animal in the photo is Benjamin, the last thylacine (or Tasmanian Tiger). Benjamin - who may have actually been female - lived out his days in Hobart Zoo. On the 7th of September, 1936, Benjamin died due to neglect. Other species endlings have included the last quagga and the Caspian tiger, though there are certainly more we don’t know of.  Perhaps the most well-known recent endling is the Pinta Island giant tortoise Lonesome George, who died on 24th June last year. George’s status as an endling may be rescinded in time; DNA from 17 hybrid tortoises indicates that they have some genetic material from George’s subspecies. Given tortoises’ long lifespans, the researchers have hope that the hybrids’ parents may still be alive somewhere on the Galápagos islands. Unless these purebred specimens are found (if they are still alive), Lonesome George holds a special place as our most famous and recent endling.