is it just me or is this article written like someone who did a few google searches for old organisms and then writes down their speculations in the form of what some would call an article?
tl;dr https://en.wikipedia.org/wiki/Pando_(tree)
"However, the oldest, precisely measured organism living on Earth today remains, for now, a Great Basin Bristlecone pine tree. Pando the quaking aspen and Antarctic glass sponges could be much older but their ages are assumed from indirect measurements and educated guesswork. "