Pseudunela marteli is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Pseudunelidae.

The specific name marteli is in honour of author's "big-hearted friend and colleague" biologist Martin “Martl” Heß from Ludwig Maximilian University of Munich, because the species has a large heart-bulb.

[2] The type locality is beach of “Art Gallery”, Honiara, Guadalcanal, Solomon Islands.

[2] Subepidermal spicules are more abundant in cephalic tentacles, foot and visceral hump.

[2] Pseudunela marteli is a minute species that lives in the spaces between sand grains in saltwater habitats, and it is thus considered to be a mesopsammic, marine interstitial animal that is part of the meiofauna of marine sands.