endling

[ end ling ]
/ ˈɛnd lɪŋ /

noun

an individual living thing that is the last survivor of its species or subspecies and whose death consequently means the extinction of that species or subspecies: The endling of the once plentiful passenger pigeons was Martha, who died in a zoo in 1914.
a person who is the last living member of a family line and whose death consequently means the end of that lineage: Sadly, Kenneth, childless and himself an only child, is soon to leave this world, alone and an endling.

Origin of endling

First recorded in 1996 in the correspondence in the British journal Nature; end1 + -ling1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019