Millipedes from Australia, 6: Australiosomatini from Victoria (Diplopoda: Polydesmida: Paradoxosomatidae)

Abstract

Redescriptions of Hoplatria clavigera Verhoeff, 1941, and Hoplatessara pugiona Verhoeff, 1941. Descriptions of: Somethus biramus n.sp., characterized by the length of the tibiotarsal branch of the gonopods, and the small size of the femoral branch, which is reduced to a tiny lappet emanating from near the apex of the seminiferous branch; Australiosoma laminatum n.sp., characterized by the laminate expansion of the femoral process of the gonopods; and Hoplatessara nigrocingulata n.sp., particularly characterized by the relative length and shape of the femoral process of the gonopods. Two new genera are proposed: Archicladosoma and Isocladosoma. Archicladosoma, type species A. magnum n.sp., is of particular interest since it is characterized by what may be regarded as the most ancestral type of gonopods yet recorded in the Australiosomatini, with a distinctly demarcated femoral section, and the tibiotarsus, femoral process and solenomerite unmodified. Isocladosoma, type species I. guttatum n.sp., has the gonopods split into three branches, all of which emanate almost directly from the prefemur. The genus suggests Cladethosoma Chamberlin, 1920, but differs in having the femoral process elongate lanceolate, and in having only a single tibiotarsal branch, which in some species bears an additional spine. A second and third species, I. pallidulum n.sp. and I. maculatum n.sp., substantiate the characters of the genus. The three species are distinguished mainly by the structure of the tibiotarsus of the gonopods and by their colour pattern.