Dungeons and dragons: two new species and records of Kinorhyncha from anchialine cenotes and marine lava tubes

Abstract

Caves are natural laboratories to investigate evolutionary processes in the ocean. In contrast to the many described lineages of cave exclusive crustaceans and annelids, very little is known about cave scalidophorans. We here describe two new species of kinorhynchs from a lava tube in the Canary Islands and a cenote in the Yucatan Peninsula. Leiocanthus bretti sp. nov., from Tenerife, is mainly characterized by the lack of middorsal structure specializations on all trunk segment, middorsal line covered by hairs on segments 3e9, unpaired paradorsal setae on segments 2e9, middorsal seta on segment 10, and laterodorsal setae on segments 2e9 and 11. Pycnophyes kukulkan sp. nov. from Yucatan is defined by the strong denticulation in the tergal anterior margin, as a barbed comb, followed by the autapomorphic presence a pool of depressed and perforated cuticular annuli on the anterior half of the plate. The species is also defined by the combination of the following features: very long lateral terminal spines (LTS/TL above 38%), middorsal elevations on segments 2e9, unpaired paradorsal setae on segments 4, 6, 8, paired laterodorsal setae on segments 2e9, lateroventral setae on segments 2, 4, 6e8, 10 (two pairs on segment 10), ventrolateral setae on segment 5 plus ventrolateral or ventromedial setae on segments 3e8, and ventromedial ones on segment 9. The new species are discussed in reference to the diversity of cave scalidophorans, including possible adaptations to the ecological conditions found in some caves. A checklist with all the records of scalidophorans in caves is provided.