As a member of the Onychophora phylum, O. roseus has a chitin-covered body with numerous papillae that give it hydrophobic qualities and velvety appearance.

[7] Velvet worms have two antennae on the head, two simple-lensed eyes, and touch and smell sensitive hairs on their papillae.

[8] A pair of modified legs from which they squirt sticky protein-based slime to ensnare prey is called the oral tubes.

[6] O. roseus is endemic to the Ngele mistbelt forest, near the town of Kokstad in the KwaZulu-Natal province of South Africa.

[6] The genetic voucher specimen was collected by Savel R. Daniels in 2012 and is housed in the Museum of Comparative Zoology at Harvard University.

[15] Because of the threat of desiccation due to their spiracles being constantly open,[7] velvet worms live in saproxylic environments, like decaying wood logs and leaf litter.

[10] Although all extant onychophorans are terrestrial, the fossil record shows that they were likely aquatic in the past, transitioning to land in the Ordovician period.

[8] Notably, both marine Cambrian[16] and terrestrial Pennsylvanian[17] fossils are remarkably similar to extant velvet worms.

[18] Once potential prey has been localized using the sensory antennae, the hunter secretes sticky slime, which is produced and stored in large glands, to entangle it.

[18] The velvet worm then injects the prey with digestive saliva and sucks in the softened body parts using its pharynx.

[18] The slime is also used in self-defense, startling the potential predators, like birds, centipedes, and spiders[8] to give the worm time to escape.

[20] Newborn velvet worms resemble the adults morphologically, but are smaller in size and have weaker integument pigmentation.

[31] This genetic clade also includes some velvet worms with 16 leg pairs that would traditionally be considered specimens of O. cinctipes.

This broader understanding of O. roseus features intraspecific variation in leg number, ranging from 16 to 18 pairs, includes a range of colors from blood red or indigo to pearl white, and entails a broader geographic distribution in the southern part of the Drakensberg Mountains in Kwa-Zulu Natal province of South Africa.