Taxonomy of the enigmatic genus Acanthoniscus Gosse, 1851 (Isopoda: Oniscidea: Armadillidae), from Jamaica, with the description of a new species

Abstract A body entirely covered with long and sharp-pointed spines makes Acanthoniscus spiniger Gosse, 1851, one of the rarest and most ornamented terrestrial isopods in the world. The original description of this species was based on a single specimen collected by the British naturalist Philip Henry Gosse in Jamaica in 1845 and deposited in the British Museum (currently The Natural History Museum, London). A second specimen, presumably of this species, was collected by the American entomologist Henry Guernsey Hubbard in 1877 and deposited in the United States National Museum, Smithsonian Institution, which served as the basis for a further description by Richardson (1909). After Gosse and Hubbard specimens, no additional material appears to have reached any museum collection. Due to the scarce available information on this genus, it has been indistinctly placed in at least four different families through history, without a consensus on its definitive placement to date. Herein, we describe a new species of Acanthoniscus Gosse, 1851, based on a population discovered in the Blue Mountains, Jamaica, above 1,200 m elevation and more than 150 km eastward of A. spiniger’s type locality. We also emend the authorship and diagnoses of the genus Acanthoniscus and its type species. Finally, we discuss the possible relationships of Acanthoniscus at the family level, concluding that, despite some putative autapomorphies, it belongs to Armadillidae, as its present-day status.