Could it have been multiple spiders moving into the same burrow after the first one died?
from the first reference in the article:
There is a high level of certainty that #16 lived for 43 years.
Neither males nor females re-use the defunct burrow of another
spider. Adult spiders do not relocate if their burrow
is damaged, but repair their existing burrow.
Could it have been multiple spiders moving into the same burrow after the first one died?from the first reference in the article: