Two new species of the millipede genus Glyphiulus Gervais, 1847 from Laos (Diplopoda, Spirostreptida, Cambalopsidae)

Comparative morphological study of the gnathochilarium of millipedes of the suborder Cambalidea (Juliformia: Spirostreptida) assessed by discrete and morphometric character approaches

Phylogenetic relationships of the suborder Cambalidea have been a well-known focus of discussion over the past 100 years. The most recent approach to the suborder is based on the morphology of the sexual structure of males and of the gnathochilarium. The phylogenetic interpretation of the gnathochilarium has been especially criticized due to the poorly understood evolution of its components since no hypothesis of homology has been put forward. This work provides a comparative study of characters of the gnathochilarium. Twenty-one characters are proposed and optimized for 34 terminals from the orders Julida and Spirostreptida. Two datasets were analysed on the basis of whether the sclerite duplomentum corresponds to a mentum fused to a promentum or only to an elongated mentum (promentum being absent). Concatenated analyses were performed with both discrete and morphometric characters to verify the variation in shape of the mentum. In all topologies obtained, Cambalidea were recovered as paraphyletic in terms of the suborder Spirostreptidea. Through constrained searches, Cambalidae, Cambalopsidae and Iulomorphidae were not recovered, while Pseudonannolenidae were recovered only when Physiostreptinae were excluded. The morphological evidence indicates the convergence of the gnathochilarium in Spirostreptidea and in some members of Cambalidea, with independent reversions of the promentum.

Revision of the javanicus species group of the millipede genus Glyphiulus Gervais, 1847, with descriptions of five new species from China (Diplopoda, Spirostreptida, Cambalopsidae)

The javanicus-group of Glyphiulus is re-assessed and its Chinese component species are presently divided between the following two newly-circumscribed species groups, i.e. the formosus- and the sinensis-group. The two can be differentiated, based on the diagnostic characters of the first pair of legs in the male. In addition, metatergal crests being complete and the carinotaxy formula on the collum being I-III+P+M are only characteristic of the formosus-group. A molecular phylogeny of the genus, based on DNA sequencing of four gene fragments of four genes, allows for Glyphiulus to be recovered as a monophyletic group, the phylogenetic relationship being ((Clade A, Clade B), Clade C). Molecular evidence is fully congruent with the morphological one. In addition, based on barcoding data, interspecific p-distances between Glyphiulus species amount to 11.2-24.9%, vs. 0-8.2% for intraspecific p-distances. Five new species of Glyphiulus, all cavernicolous, are described from China: G.sinuatoprocessus Zhao & Liu, sp. nov., G.conuliformis Zhao & Liu, sp. nov. (both from Guangdong Province), G.xiniudong Zhao & Liu, sp. nov., G.scutatus Zhao & Liu, sp. nov. and G.portaliformis Zhao & Liu, sp. nov. (all three from Guangxi Zhuang Autonomous Region). The known Chinese species of the formosus-group appear to mainly be confined to the South China region.

Two new species of the millipede genus Glyphiulus Gervais, 1847 (Diplopoda, Spirostreptida, Cambalopsidae) from caves in northern Thailand

Two new species of the genus Glyphiulus Gervais, 1847 are described and illustrated. The first species, G.longus sp. nov., is the second species of the javanicus-group to be found in Thailand. It resembles G.guangnanensis Jiang, Guo, Chen & Xie, 2018, from southern China, but is distinguished by a smaller size and the carinotaxic formula of the collum, combined with ♂ legs 1 bearing very strongly reduced telopodites, the anterior gonopods showing a pair of very long and slender apicomesal processes, and the denser plumose and stout flagella of the posterior gonopods. The second species, G.promdami sp. nov., the fifth member of the granulatus-group in Thailand, seems to be particularly similar to G.subbedosae Likhitrakarn, Golovatch & Panha, 2017, from Laos. However, it can be distinguished from the latter species mainly by showing a uniformly yellow collum and the posterior gonopod coxite bearing several strong setae in median and lateral views, coupled with the anterior gonopod coxosternum being microsetose in the anterior and medial parts in caudal view. An identification key to, and a distribution map of, all seven Glyphiulus species currently known to occur in Thailand are also provided.

A remarkable new species of the millipede genus Trachyjulus Peters, 1864 (Diplopoda, Spirostreptida, Cambalopsidae) from Thailand, based both on morphological and molecular evidence

A new, giant species of Trachyjulus from a cave in southern Thailand is described, illustrated, and compared to morphologically closely related taxa. This new species, T. magnus sp. nov., is much larger than all other congeners and looks especially similar to the grossly sympatric T. unciger Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2012, which is widespread in southern Thailand. Phylogenetic trees, both rooted and unrooted, based on a concatenated dataset of the COI and 28S genes of nine species of Cambalopsidae (Trachyjulus, Glyphiulus, and Plusioglyphiulus), strongly support the monophyly of Trachyjulus and a clear-cut divergence between T. magnus sp. nov. and T. unciger in revealing very high average p-distances of the COI gene (20.80-23.62%).

Four new species of the Glyphiulus javanicus group from southern China (Diplopoda, Spirostreptida, Cambalopsidae)

Hitherto, 24 species of the Glyphiulusjavanicus group have been recorded, all endemic to Southeast Asia, including 14 in China. Nevertheless, this species group needs further exploration. In this context, four new species of this group are described, all collected from limestone caves in Southern China: G.calceussp. n., G.foetidussp. n., G.guangnanensissp. n., and G.impletussp. n. They can be separated easily from each other and other congeners by their carinotaxic formulae, the structures of male legs I, and the gonopods. Due to the absence of any troglomorphic traits in our specimens, they may be troglophilic only.