Smallest spider

The smallest spiders are from the family Symphytognathidae, which occurs in every continent except Antarctica. There is a debate over which species from this family should be considered the smallest overall. Two contenders are from the genus Patu: males of Patu digua described in Colombia had a body length of 0.37 millimetres (0.014 inches), while the Samoan moss spider (P. marplesi) could be as small as 0.4 millimetres (0.011 inches) long. Another genus eligible for the title is Anapistula: a female Frade cave spider Anapistula ataecina – a critically endangered species endemic to a cave system in Portugal – had a body length of 0.43 millimetres (0.016 inches); males of this species are yet to be discovered but are expected to be even smaller. Similarly, with only females measured to date, a dwarf orb weaver (Anapistula caecula) from the Ivory Coast was 0.48 millimetres (0.018 inches) long.

Note that the male of P. marplesi has a prosoma length of 0.22 mm, and an abdomen of 0.21 mm (Forster, 1959), in contrast to 0.15 mm and 0.25 mm (prosoma and abdomen, respectively) in P. digua (Forster & Platnick, 1977).