The complete mitochondrial genome of the millipede Epanerchodus koreanus Verhoeff, 1937 collected in limestone cave of Korea (Polydesmidae: Polydesmida)

We have determined the second mitochondrial genome of Epanerchodus koreanus Verhoeff, 1937 collected in limestone cave of Korea. The circular mitochondrial genome of E. koreanus is 15,581 bp long. It includes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Its gene order was different from the rest three Polydesmida mitochondrial genomes, resulted from relocation of tRNAs, rRNAs, and ND1. The base composition was AT-biased (75.1%). Phylogenetic trees displayed phylogenetic relationship, which is congruent to previous study, except Sphaerotheriidae sp. clustering with Helminthomorpha.

A new genus and species of narrow-range millipede (Diplopoda, Polydesmida, Dalodesmidae) from Tasmania, Australia

Kebodesmuszonarius gen. nov. et sp. nov. is only known from a small area on the Great Western Tiers in northern Tasmania, Australia, and like species of Paredrodesmus Mesibov, 2003 has no detectable paranota on the diplosegments. The gonopod telopodite of the new species is divided into a large, lateral, cowl-like structure, a solenomere and a medial branch with three processes.

HCN emission by a Polydesmid Millipede Detected Remotely by Reactive Adsorption on Gold Nanoparticles Followed by Laser Desorption/Ionization Mass Spectrometry (LDI-MS)

Hydrocyanic acid (HCN) is a well-known defensive allomone in the chemical arsenal of millipedes in the order Polydesmida. The presence of HCN in the headspace vapor of adult Xystocheir dissecta (Wood, 1867), a common millipede from the San Francisco Bay Area, was traced by laser desorption/ionization-mass spectrometry (LDI-MS). To accomplish this, the headspace vapor surrounding caged, live millipedes was allowed to diffuse passively over gold-nanoparticle (AuNP) deposits placed at various distances from the emitting source. The stainless steel plates with AuNP deposits were removed and irradiated by a 355-nm laser. The gaseous ions generated in this way were detected by time-of-flight mass spectrometry. The intensity of the mass spectrometric peak detected at m/z 249 for the Au(CN)₂^- complex anion was compared to that of the residual Au^- signal (m/z 197). Using this procedure, HCN vapors produced by the live millipedes could be detected up to 50 cm away from the source. Furthermore, the addition of H₂O₂, as an internal oxygen source for the gold cyanidation reaction that takes place in the AuNP deposits, significantly increased the detection sensitivity. Using the modified H₂O₂ addition procedure, HCN could now be detected at 80 cm from the source. Moreover, we found a decreasing intensity ratio of the Au(CN)₂^-/Au^- signals as the distance from the emitting source increased, following an exponential-decay distribution as predicted by Fick's law of diffusion. Graphical abstract.

A new, alpine species of Lissodesmus Chamberlin, 1920 from Tasmania, Australia (Diplopoda, Polydesmida, Dalodesmidae)

Lissodesmus nivalissp. n. is described from 1450-1550 m elevation on the treeless, alpine Ben Lomond plateau in northeast Tasmania, Australia. The new species is distinguished from all other Tasmanian and Victorian Lissodesmus species by a unique combination of gonopod telopodite features: solenomere without a pre-apical process, tibiotarsus Y-shaped, femoral process L-shaped with forked tips, prefemoral process with a long comb of teeth below an irregularly dentate apical margin, and a roughened "shoulder process" near the base of the prefemoral process.

Cyanogenesis in Arthropods: From Chemical Warfare to Nuptial Gifts

Chemical defences are key components in insect⁻plant interactions, as insects continuously learn to overcome plant defence systems by, e.g., detoxification, excretion or sequestration. Cyanogenic glucosides are natural products widespread in the plant kingdom, and also known to be present in arthropods. They are stabilised by a glucoside linkage, which is hydrolysed by the action of β-glucosidase enzymes, resulting in the release of toxic hydrogen cyanide and deterrent aldehydes or ketones. Such a binary system of components that are chemically inert when spatially separated provides an immediate defence against predators that cause tissue damage. Further roles in nitrogen metabolism and inter- and intraspecific communication has also been suggested for cyanogenic glucosides. In arthropods, cyanogenic glucosides are found in millipedes, centipedes, mites, beetles and bugs, and particularly within butterflies and moths. Cyanogenic glucosides may be even more widespread since many arthropod taxa have not yet been analysed for the presence of this class of natural products. In many instances, arthropods sequester cyanogenic glucosides or their precursors from food plants, thereby avoiding the demand for de novo biosynthesis and minimising the energy spent for defence. Nevertheless, several species of butterflies, moths and millipedes have been shown to biosynthesise cyanogenic glucosides de novo, and even more species have been hypothesised to do so. As for higher plant species, the specific steps in the pathway is catalysed by three enzymes, two cytochromes P450, a glycosyl transferase, and a general P450 oxidoreductase providing electrons to the P450s. The pathway for biosynthesis of cyanogenic glucosides in arthropods has most likely been assembled by recruitment of enzymes, which could most easily be adapted to acquire the required catalytic properties for manufacturing these compounds. The scattered phylogenetic distribution of cyanogenic glucosides in arthropods indicates that the ability to biosynthesise this class of natural products has evolved independently several times. This is corroborated by the characterised enzymes from the pathway in moths and millipedes. Since the biosynthetic pathway is hypothesised to have evolved convergently in plants as well, this would suggest that there is only one universal series of unique intermediates by which amino acids are efficiently converted into CNglcs in different Kingdoms of Life. For arthropods to handle ingestion of cyanogenic glucosides, an effective detoxification system is required. In butterflies and moths, hydrogen cyanide released from hydrolysis of cyanogenic glucosides is mainly detoxified by β-cyanoalanine synthase, while other arthropods use the enzyme rhodanese. The storage of cyanogenic glucosides and spatially separated hydrolytic enzymes (β-glucosidases and α-hydroxynitrile lyases) are important for an effective hydrogen cyanide release for defensive purposes. Accordingly, such hydrolytic enzymes are also present in many cyanogenic arthropods, and spatial separation has been shown in a few species. Although much knowledge regarding presence, biosynthesis, hydrolysis and detoxification of cyanogenic glucosides in arthropods has emerged in recent years, many exciting unanswered questions remain regarding the distribution, roles apart from defence, and convergent evolution of the metabolic pathways involved.

"Open access" growth histories in millipedes (Diplopoda)

A unique pattern of missing defence glands on certain body rings is described for two species of the millipede family Mongoliulidae, order Julida: Ussuriiulus pilifer Golovatch, 1980, and Koiulus interruptus Enghoff et al., 2017. Based on the patterns of missing glands observed in recently collected samples of the two species, numbers of podous and apodous body rings in successive stadia of the postembryonic development can be inferred for each individual millipede, which in turn allows the reconstruction of pathways of anamorphosis in these species. The inferred numbers of body rings in developmental stadia are compared with actual numbers observed on additional samples, including the type series, of U. pilifer. The pattern of missing glands in the two mongoliulid species is compared with the pattern of missing glands typical of the entire millipede order Polydesmida.

Complete mitochondrial genomes of two flat-backed millipedes by next-generation sequencing (Diplopoda, Polydesmida)

A lack of mitochondrial genome data from myriapods is hampering progress across genetic, systematic, phylogenetic and evolutionary studies. Here, the complete mitochondrial genomes of two millipedes, Asiomorphacoarctata Saussure, 1860 (Diplopoda: Polydesmida: Paradoxosomatidae) and Xystodesmus sp. (Diplopoda: Polydesmida: Xystodesmidae) were assembled with high coverage using Illumina sequencing data. The mitochondrial genomes of the two newly sequenced species are circular molecules of 15,644 bp and 15,791 bp, within which the typical mitochondrial genome complement of 13 protein-coding genes, 22 tRNAs and two ribosomal RNA genes could be identified. The mitochondrial genome of Asiomorphacoarctata is the first complete sequence in the family Paradoxosomatidae (Diplopoda: Polydesmida) and the gene order of the two flat-backed millipedes is novel among known myriapod mitochondrial genomes. Unique translocations have occurred, including inversion of one half of the two genomes with respect to other millipede genomes. Inversion of the entire side of a genome (trnF-nad5-trnH-nad4-nad4L, trnP, nad1-trnL2-trnL1-rrnL-trnV-rrnS, trnQ, trnC and trnY) could constitute a common event in the order Polydesmida. Last, our phylogenetic analyses recovered the monophyletic Progoneata, subphylum Myriapoda and four internal classes.

A new genus and species of dalodesmid millipede from New South Wales, Australia (Diplopoda, Polydesmida, Dalodesmidae)

Cernethiainopinata gen. n., sp. n. is described from highland New South Wales. Like other dalodesmids the new species has numerous sphaerotrichomes on the legs of adult males, but Cernethiainopinata sp. n. shares several character states with Tasmanian species in the genera Noteremus Mesibov, 2009, Paredrodesmus Mesibov, 2003 and Procophorella Mesibov, 2003, which lack sphaerotrichomes and have not yet been assigned to family within the suborder Dalodesmoidea.

Discovery of a glowing millipede in California and the gradual evolution of bioluminescence in Diplopoda

The rediscovery of the Californian millipede Xystocheir bistipita surprisingly reveals that the species is bioluminescent. Using molecular phylogenetics, we show that X. bistipita is the evolutionary sister group of Motyxia, the only genus of New World bioluminescent millipedes. We demonstrate that bioluminescence originated in the group's most recent common ancestor and evolved by gradual, directional change through diversification. Because bioluminescence in Motyxia has been experimentally demonstrated to be aposematic, forewarning of the animal's cyanide-based toxins, these results are contrary to aposematic theory and empirical evidence that a warning pattern cannot evolve gradually in unpalatable prey. However, gradual evolution of a warning pattern is plausible if faint light emission served another function and was co-opted as an aposematic signal later in the diversification of the genus. Luminescence in Motyxia stem-group taxa may have initially evolved to cope with reactive oxygen stress triggered by a hot, dry environment and was repurposed for aposematism by high-elevation crown-group taxa colonizing new habitats with varying levels of predation. The discovery of bioluminescence in X. bistipita and its pivotal phylogenetic location provides insight into the independent and repeated evolution of bioluminescence across the tree of life.

Three new species of Tasmaniosoma Verhoeff, 1936 (Diplopoda, Polydesmida, Dalodesmidae) from northeast Tasmania, Australia

The small-range millipedes Tasmaniosomaanubis sp. n., Tasmaniosomainterfluminum sp. n. and Tasmaniosomanicolaus sp. n. are described, and the colour of live Tasmaniosomabarbatulum Mesibov, 2010 is documented.

Structure and distribution of antennal sensilla in Oranmorpha guerinii (Gervais, 1837) (Diplopoda, Polydesmida)

Detailed information on sensory organs of Diplopoda especially on antennal sensilla are still sparse and fragmentary. The present study on the antennae of Oranmorpha guerinii (Polydesmida, Paradoxosomatidae) utilizing scanning electron microscopy revealed the presence of six sensillar types: (1) apical cones, (2) sensilla trichodea, (3) sensilla microtrichodea, (4) sensilla chaetica, (5) sensilla basiconica bacilliformia, and (6) sensilla basiconica spiniformia. External structure and distribution of cuticular antennal sensilla are compared with data from other diplopod species. We moreover discuss possible functions of antennal sensilla in millipedes.

New species of Agathodesmus Silvestri, 1910 from Australia (Diplopoda, Polydesmida, Haplodesmidae)

The genus Agathodesmus Silvestri, 1910 is speciose and widespread in high-rainfall parts of eastern Australia. In addition to the type species Agathodesmus steeli Silvestri, 1910 and Agathodesmus johnsi Mesibov, 2009 from New South Wales and Agathodesmus bucculentus (Jeekel, 1986) from Queensland, the following 18 new species are recognised: Agathodesmus adelphus sp. n., Agathodesmus aenigmaticus sp. n., Agathodesmus agnus sp. n., Agathodesmus anici sp. n., Agathodesmus gayundah sp. n., Agathodesmus hahnensis sp. n., Agathodesmus kerensis sp. n., Agathodesmus kirrama sp. n., Agathodesmus millaa sp. n., Agathodesmus parapholeus sp. n., Agathodesmus quintanus sp. n., Agathodesmus sagma sp. n., Agathodesmus summus sp. n. and Agathodesmus yuccabinensis sp. n. from Queensland; Agathodesmus carorum sp. n. from New South Wales and Victoria; Agathodesmus bonang sp. n. and Agathodesmus morwellensis sp. n. from Victoria; and Agathodesmus chandleri sp. n. from South Australia.

New species of Prosopodesmus Silvestri, 1910 (Diplopoda, Polydesmida, Haplodesmidae) from Queensland, Australia

Prosopodesmus cratersp. n., Prosopodesmus kirramasp. n. and Prosopodesmus monteithisp. n. are described from the Wet Tropics of north Queensland. The hothouse species Prosopodesmus panporus Blower & Rundle, 1980 is recorded from rainforest on Queensland's Cape York Peninsula, where it is likely to be native.

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

The East Asian millipede genus Riukiupeltis Verhoeff, 1939 is revised, and is restricted to a single species, Riukiupeltis jamashinai Verhoeff, 1939. Examination of the type specimens and freshly collected material from the Ryukyu Archipelago and Vietnam show that both subsequently allocated species, Riukiupeltis uenoi Murakami, 1975, and Riukiupeltis falcatus (originally Haplogonosoma falcatum Attems, 1953, reallocated by Jeekel 1968), do not belong to this genus; moreover, they are not even congeneric with each other. According to our morphological observations, including the gonopods, Riukiupeltis uenoi is closer to the widespread Chamberlinius hualienensis Wang, 1956, hence we propose the new combination Chamberlinius uenoi (Murakami, 1975), comb. n.Riukiupeltis falcatus, on the other hand, represents a separate, as yet monotypic, genus Simplogonomorphagen. n., distinct both from Haplogonosoma Brölemann, 1916 sensu Golovatch et al. (1995), and from Verhoeff's original Riukiupeltis. Additionally, Simplogonomorpha falcata (Attems, 1953), comb. n is re-described here based on fresh material from Vietnam. A key and colour habitus-illustrations to all three species are also provided here.

A remarkable case of mosaic parapatry in millipedes

The parapatric boundary between Tasmaniosoma compitale Mesibov, 2010 and Tasmaniosoma hickmanorum Mesibov, 2010 (Polydesmida: Dalodesmidae) in northwest Tasmania was mapped in preparation for field studies of parapatry and speciation. Both millipede species can be collected as adults throughout the year, are often abundant in eucalypt forest and tolerate major habitat disturbance. The parapatric boundary between the two species is ca 100 m wide in well-sampled sections and ca 230 km long. It runs from sea level to 600-700 m elevation, crosses most of the river catchments in northwest Tasmania and several major geological boundaries, and one portion of the boundary runs along a steep rainfall gradient. The location of the boundary is estimated here from scattered sample points using a method based on Delaunay triangulation.