Haplophthalmus danicus

Haplophthalmus danicus, also known as the terrestrial cave isopod or spurred ridgeback isopod, is a species of woodlouse in the family Trichoniscidae. It is naturally found in Europe, Southern Asia, and temperate Asia, however it has been introduced to North America. This species was likely introduced during original European settlement, and therefore has been well established in terrestrial communities.

Subspecies
These seven subspecies belong to the species Haplophthalmus danicus:
 * Haplophthalmus danicus armenius Collinge, 1918
 * Haplophthalmus danicus bagnalli Collinge, 1946
 * Haplophthalmus danicus danicus Budde-Lund, 1880
 * Haplophthalmus danicus rufus Arcangeli, 1960
 * Haplophthalmus danicus tauricus Frankenberger, 1950
 * Haplophthalmus danicus transsilvanicus Verhoeff, 1908
 * Haplophthalmus danicus virescens Collinge, 1918