Underestimated diversity and range size of diving beetles in tank bromeliads—Coleoptera of ‘hygrofloric’ lifestyle (Dytiscidae)

Abstract

Tank bromeliads provide a vast amount of stagnant water high up in the Neotropical forest canopy. However, the aquatic macroinvertebrate diversity in this specialized habitat remains poorly explored. Here, we study obligatorily bromeliadicolous species of the diving beetle genus Copelatus Erichson, 1832. We review the known species Copelatus bromeliarum Scott, 1912 (Trinidad and Venezuela) and Copelatus bimaculatus Resende & Vanin, 1991 (Brazil). We describe three new species: Copelatus espinhasso sp. nov. (Brazil), Copelatus florae sp. nov. (Brazil, Colombia, Costa Rica, Ecuador and Panama) including its larva, and Copelatus panguana sp. nov. (Peru). Based on their male genital morphology, these species form a distinct clade within the genus. Other shared characters such as compact drop-shaped habitus, shortened appendages, and reduction of natatory setae on legs are interpreted as adaptations for what we call the ‘hygrofloric’ lifestyle. We document the thin water layer between leaf axils as the preferred habitat of both Copelatus adults and larvae, and not necessarily the central tank.