Number 16 (c. 1974 – 2016), also known as #16,[1] was a wild female trapdoor spider (Gaius villosus, family Idiopidae) that lived in North Bungulla Reserve near Tammin, Western Australia.

She lived an estimated 43 years and became the longest-lived spider on record, beating a 28-year-old tarantula who previously held the title.

She marked off ten spiders and returned the following year to find new spiderlings, including Number 16, that had likely been born after the first autumn rain of 1974.

[4] For her 40th birthday, research assistant Leanda Mason wanted to give the spider a mealworm, but Main denied the request since it would interfere with the study.

[1] Based on the burrow fidelity of females of her species, the researchers concluded with a "high level of certainty" that Number 16 was 43 years old at the time of her death.