Relationships of Henicopidae (Chilopoda: Lithobiomorpha): New molecular data, classification and biogeography

Abstract

Phylogenetic relationships in the lithobiomorph family Henicopidae are analysed based on sequence data for five molecular markers and 58 morphological characters. The character sample includes two nuclear ribosomal genes (complete 18S rRNA and the D3 region of 28S rRNA) and three mitochondrial genes, two ribosomal (16S rRNA and 12S rRNA) and one protein-coding (cytochrome c oxidase subunit I). Terminal taxa include six outgroup species of Lithobiidae and 41 exemplars of Henicopidae representing 33 species. Analysis of the combined dataset using Direct Optimization and exploring stability of clades to a range of gap:substitution and transversion:transition costs yields a most congruent (minimal ILD) cladogram that is largely congruent with the shortest molecular cladogram. Morphology, however, contributes additional nodes to the strict consensus of all explored parameters. The morphological cladogram resolves the Oriental Shikokuobius as sister to a gondwanan clade of Anopsobiinae, whereas the sequence data place Shikokuobius as sister to Henicopinae or all Henicopidae. Henicopinae sensu Attems is monophyletic for combined analyses for all parameters, being retrieved amongst the shortest morphological cladograms and by all molecular parameter sets, but the traditionally defined Zygethobiini is polyphyletic for several parameter sets. For the most congruent parameters, the nearctic Zygethobius is resolved in the expected position as sister to Henicopini, but the oriental Cermatobius nests within the Henicopini. Henicopini divides into two clades: one unites Henicops and Lamyctes (stable for all combined analyses as well as for morphological and molecular data alone) and the other unites the four gondwanan subgenera of Paralamyctes. In most analyses, South African species of Paralamyctes unite as a clade, with Cape endemics each others’ closest relatives. Most parameter sets for the molecular and combined data resolve a group that includes the Australasian Paralamyctes (Thingathinga) and P. (Haasiella) together with Patagonian species formerly placed in P. (Nothofagobius).