Another alien terrestrial planarian in the United Kingdom: Australopacifica atrata (Steel, 1897) (Platyhelminthes: Tricladida: Continenticola).

Black terrestrial planarians, 5 mm to 3 cm long, have been found in five locations in the United Kingdom, the earliest in 2015. They are identified as Australopacifica atrata (Steel, 1897), a species originally described from New South Wales, Australia. A detailed systematic discussion of original and later descriptions, all of which are of external features only and with no morphological details, is given in support of this identification. Sectioned specimens show partly mature ovaries and ventral testes though none show any development of the copulatory apparatus. They reproduce freely by fission. They appear to be generalist scavengers, having been found feeding on a dead slow worm, a dead mouse, an earthworm and also on rotten fruit. In captivity they feed on chicken liver, squashed slugs and earthworms. It is assumed that they have been inadvertently introduced to the UK and distributed through horticultural activity.