Two new species of Phryssonotus (Diplopoda : Synxenidae) from southern and western Australia

Abstract

For many years Phryssonotus novaehollandiae Silvestri, 1923 was thought to be the only species of this genus present in Australia. Specimens collected from three geographically separated populations had similar taxonomically important morphological characters and body lengths. However, their body scale trichomes exhibited three distinctive patterns: a trapezoid, T-shape, or dark banding, and the length-to-width ratios of their trichomes also differed. These differences, as well as results of phylogenetic analysis using 18S and COI gene regions from representatives of the three populations, suggested that more than one Phryssonotus species were present. Specimens of Phryssonotus preserved in ethanol can prove difficult to distinguish because the colour patterning gradually fades. Examination of the colour patterns of live specimens, other morphological characters and DNA analysis together, were found to be the most reliable method of correctly distinguishing between these three species. P. novaehollandiae Silvestri, 1923, the first described species collected from South Australia, remains, with its range extended to inland Victoria, and two new species (P. australis, sp. nov. and P. occidentalis, sp. nov.) are described.