First described in 2000 by Wanda Wesołowska and Anthony Russell-Smith, the species was originally known as Lilliput pusillus but was renamed in 2008. it is a very small spider, which is recalled in its species name, a Latin word meaning diminutive, with a carapace and abdomen between 0.8 and 0.9 mm (0.03 and 0.04 in) long.

The spider is generally yellow apart from the dark brown eye field and grey top to its abdomen.

Tanzania pusillus is a species of jumping spider, a member of the family Salticidae, that was first described by Wanda Wesołowska and Anthony Russell-Smith in 2000.

[2] They allocated it to the genus Lilliput, first circumscribed by Wesolowska and Anthony Russell-Smith in 2000 after the nation in Gulliver's Travels.

[6] In Wayne Maddison's 2015 study of spider phylogenetic classification, the genus Tanzania was placed in the tribe Euophryini [7] This is a member of the clade Saltafresia.

It is covered in delicate hairs and has an indistinct brown stripe running down its middle.

The abdomen has a vague darker pattern that is reminiscent of that on the related Tanzania mkomaziensis.