Pachyballus ornatus is a species of jumping spider, a member of the family Salticidae, that was first described by the arachnologists Wanda Wesołowska, Galina Azarkina and Konrad Wiśniewski in 2020.

[4] In their 2003 phylogenetic analysis, Wayne Maddison and Marshall Hedin noted that the genus is closely related to Mantisatta, despite the large physiological differences between them, and the similarity of those spiders with a group of genera they termed Marpissoida.

[7] In 2015, Maddison listed the genus within the tribe Ballini, derived from Simon's original name, but attributed to an earlier author, Nathan Banks from 1892.

The carapace, the hard upper part of the cephalothorax, is wider than it is long with an eye field that takes up half of its area.

The spider's chelicerae have three short teeth at the front and a single tooth with serrated edges and four tips at the back.

[3] Very flat, it varies between triangular and heart-shaped and is generally wider than it is long with a front edge that is almost straight.

The male has a relatively large rounded cymbium that curves around a smaller palpal bulb, the latter with a pronounced bulge at the bottom.

[12] Some of the examples of the spider that have been found, particularly young females just after moulting, are black all over, similar to the related Pachyballus flavipes.

[14] The female spider's epigyne, or externally visible copulatory organ, is oval with a semi-circular depression to the front that is split into two by a short wide ridge.

The two copulatory openings lead to long ducts that wind their way to relatively small oval receptacles, or spermathecae.

[1] The holotype was found in Amani Nature Reserve at an altitude of 550 m (1,800 ft) above sea level in 1995.

[3] Its resemblance to beetles of the family Chrysomelidae may be a form of camouflage, enabling it to hide amongst the trees.