Achanarella
Achanarella was a genus of jawless fish from the Middle Devonian. Its type and only known species is A. trewini. Its known specimens were found in the Achanarras Quarry of Scotland. Despite being known since the 1980s, it was not formally named until 2002.
Its name Achanarella refers to its locality, the Achanarras Quarry. The species name trewini refers to Nigel Trewin, a paleontologist that has done a great amount of work at the quarry for decades.
Achanarella is known from many specimens, though their preservation quality is usually quite poor. The holotype is the best-preserved fossil that has been found to date that has many distinguishable anatomical features. However, the slab the holotype is on has a plant stem crossing through the center, leaving some features unidentifiable.
In life, Achanarella would be a slender and small fish. The largest specimens are about 90mm and the smallest reach about 20mm. The eyes are large and conspicuous, especially with the small head. The mouth appears on the fossils as just a round hole without any obvious features inside. A caudal fin and anal fin are present, and possibly a dorsal fin. There are at least 13, or possibly more than 20, branchial (gill) openings beginning right behind an eye. Achanarella was likely similar looking to a modern lamprey.
Though no notochord is visible, it's likely Achanarella was a vertebrate due to its overall appearance and the presence of epichordal fin supports, a feature many other primitive vertebrates from the time period share. The exact taxonomy of Achanarella beyond that is uncertain, but it was placed into its own family Achanarellidae, which is under Jamoytiiformes.
Sources: Newman 2002