A review of Pseudorygmodus (Coleoptera: Hydrophilidae), with notes on the classification of the Anacaenini and on distribution of genera endemic to southern South America
Abstract
The morphology and taxonomy of the genus Pseudorygmodus Hansen, 1999 endemic to Chile is reviewed based on freshly collected material and museum specimens. Two species are recognized: P flintispangleri (Moroni, 1985) widespread from Los Lagos Region to Magallanes Region, and P versicolor sp. nov. which is only known from Parque Nacional Nahuelbuta in La Araucania Region.
A phylogenetic analysis is performed to reveal the position of the genus within Hydrophilidae, based on four genes (cox1, cox2, 18S and 28S). The results reveal that Pseudorygmodus is a member of the tribe Anacaenini of the subfamily Chaetarthriinae, which is supported by both adult and larval morphology.
Within Anacaenini, it was placed in the Anacuena Thomson, 1859 clade, which is supported by the morphology of the nasale of the larva. The phylogenetic analysis performed here as well as the morphological comparison of larvae of the Anacaenini brought additional evidence supporting the internal topology of the tribe, including the polyphyly of Anucaena in the current sense.