A revision of the millipede genus Riukiupeltis Verhoeff, 1939 (Diplopoda, Polydesmida, Paradoxosomatidae), with comments on the status of related species

Occurrence of the millipede genus Tonkinosoma Jeekel, 1953 in China, with the description of the first presumed troglobitic species of this genus (Diplopoda, Polydesmida, Paradoxosomatidae)

The genus Tonkinosoma Jeekel, 1953 has hitherto been known to contain only two species, both from northern Vietnam. T.flexipes Jeekel, 1953, the type species of the genus, is recorded from Guangxi, southern China, for the first time. T.tianisp. n., a presumed troglobite, is described from caves in Guizhou, southwestern China. A key is presented to all three species of the genus.

Is geography an accurate predictor of evolutionary history in the millipede family Xystodesmidae?

For the past several centuries, millipede taxonomists have used the morphology of male copulatory structures (modified legs called gonopods), which are strongly variable and suggestive of species-level differences, as a source to understand taxon relationships. Millipedes in the family Xystodesmidae are blind, dispersal-limited and have narrow habitat requirements. Therefore, geographical proximity may instead be a better predictor of evolutionary relationship than morphology, especially since gonopodal anatomy is extremely divergent and similarities may be masked by evolutionary convergence. Here we provide a phylogenetics-based test of the power of morphological versus geographical character sets for resolving phylogenetic relationships in xystodesmid millipedes. Molecular data from 90 species-group taxa in the family were included in a six-gene phylogenetic analysis to provide the basis for comparing trees generated from these alternative character sets. The molecular phylogeny was compared to topologies representing three hypotheses: (1) a prior classification formulated using morphological and geographical data, (2) hierarchical groupings derived from Euclidean geographical distance, and (3) one based solely on morphological data. Euclidean geographical distance was not found to be a better predictor of evolutionary relationship than the prior classification, the latter of which was the most similar to the molecular topology. However, all three of the alternative topologies were highly divergent (Bayes factor >10) from the molecular topology, with the tree inferred exclusively from morphology being the most divergent. The results of this analysis show that a high degree of morphological convergence from substantial gonopod shape divergence generated spurious phylogenetic relationships. These results indicate the impact that a high degree of morphological homoplasy may have had on prior treatments of the family. Using the results of our phylogenetic analysis, we make several changes to the classification of the family, including transferring the rare state-threatened species Sigmoria whiteheadi Shelley, 1986 to the genus Apheloria Chamberlin, 1921-a relationship not readily apparent based on morphology alone. We show that while gonopod differences are a premier source of taxonomic characters to diagnose species pairwise, the traits should be viewed critically as taxonomic features uniting higher levels.

Three new cavernicolous species of dragon millipedes, genus Desmoxytes Chamberlin, 1923, from southern China, with notes on a formal congener from the Philippines (Diplopoda, Polydesmida, Paradoxosomatidae)

The large Southeast Asian genus Desmoxytes is slightly rediagnosed. A number of troglomorphic, most likely troglobitic, species occur in southern China. A key is provided to all 10 Desmoxytes spp. currently known from China, including three new presumed troglobites: Desmoxytes eupterygotasp. n. from Hunan Province, as well as Desmoxytes spinissimasp. n. and Desmoxytes luisp. n. from Guangxi Province. "Desmoxytes" philippina Nguyen Duc & Sierwald, 2010, from the Philippines, is formally removed from Desmoxytes, but not assigned to another genus. It probably belongs in a new genus in the subfamily Australiosomatinae, tribe Antichiropodini, close to the Bornean Euphyodesmus Attems, 1931 and Borneochiropus Golovatch, 1996.