Two new stygophilic tanaidomorphs (Peracarida, Tanaidacea) from Canary Islands and southeastern Iberian Peninsula

Two new species of stygophilic tanaidomorphs are described from El Hierro (Canary Islands) and the Spanish Mediterranean coast from samples collected both at caves and open marine environments. Both species lack autapomorphies but are described based on their unique combination of characters. Pseudotanais isabelae sp. nov. is characterized by the presence of eyes and forcipate chelas, absence of outer seta in article 2 of maxilliped, absence of tubercles on the endite of the maxilliped, presence of 2–6 blade-like spines on the pereopods and presence of one segment on the endopod of the uropod. Zeuxo bimbache sp. nov. is diagnosed by the presence of three aesthetascs on the terminal article of the antennule, laccinia mobilis not articulated on the right mandible, wide and crenulated on the left one; basis of the maxilliped with serrated margin, article 1 of the palp without outer seta, anterior process of the coxa naked, unique chaetotaxy of the pleopods, and endopod of the uropod with three articles. These two species represent the first stygophilic members of the genera Pseudotanais and Zeuxo. Araphura brevimanus (Lilljeborg 1864) and Chondrochelia savignyi (Krøyer 1842) are also reported from our cave samples. An updated checklist of all 24 tanaidaceans recorded in caves is provided, with data on their ecological characterization and degree of troglomorphism. The ecological preferences and affinities of all tanaidaceans present in caves is briefly discussed, and compared with those of other peracarids.