Millipede Order Research Articles

First record of the millipede order Polydesmida (Diplopoda) in the Kamchatka Peninsula

The millipede order Polydesmida Pocock, 1887, family Polydesmidae Leach, 1815, genus Polydesmus Latreille, 1802-1803 and Polydesmus denticulatus C. L. Koch, 1847 are new to the fauna of the Kamchatka Peninsula.

Atlas of European millipedes 3: Order Chordeumatida (Class Diplopoda)

For each of the 534 species of the millipede order Chordeumatida known from Europe, available information on taxonomy, distribution and habitat is summarized, and the distribution in 50 × 50 km UTM/MGRS squares is shown on a map. Comparisons between Chordeumatida and the equally-sized order Julida are made with respect to distribution patterns and history of exploration.

Structure of the midgut epithelium in four diplopod species: histology, histochemistry and ultrastructure

Abstract The middle region of the digestive system of millipedes, the midgut, is responsible for all processes connected with digestion, but also takes part in homeostasis maintenance thanks to the ability to activate many mechanisms which neutralize changes occurring at different levels of the animal’s body. Numerous millipede species are treated as bioindicators of the natural environment and they are exposed to different stressors which originate from external environment. To obtain all data on the functioning of midgut of millipedes as the barrier against stressors, it is necessary to have a precise and general description of the midgut epithelium. Members from four millipede orders were selected for the studies: Polydesmus angustus (Polydesmida), Epibolus pulchripes (Spirobolida), Unciger transsilvanicus (Julida) and Glomeris tetrasticha (Glomerida). The structure and ultrastructure of their midgut epithelial cells (the digestive, secretory and regenerative cells) were documented using transmission electron microscopy and histochemical methods. The obtained results have been compared and discussed to previous ones, to present the general and structural organization of the midgut in Diplopoda. Our studies revealed that the ultrastructure of all cells which form the midgut epithelium in millipedes is general for all the species studied up to now and it resembles the cell ultrastructure observed in Chilopoda and Hexapoda, including the digestive, secretory and stem cells.

No Tömösváry organ in flat backed millipedes (Diplopoda, Polydesmida).

The Tömösváry organ is a sensory structure of the head in myriapods and some other terrestrial arthropods. Due to its variable shape, size, and position in millipedes (Diplopoda) the Tömösváry organ is commonly used as diagnostic character in taxonomic descriptions and often included in phylogenetic analyses. For the Polydesmida, the largest millipede order, the Tömösváry organ is inconsistently stated as being either absent or present as a pear-shaped pit covered by a membrane or cuticular disc. In order to resolve this inconsistency, we investigated the morphology of the presumable Tömösváry organ in four polydesmidan species based on paraffin-histology, semi-thin sections and micro-computed tomography. Our results unambiguously favor the view that the articulation of the cephalic tentorium with the head capsule was misidentified as the Tömösváry organ in previous studies, and thus that the Tömösváry organ indeed is absent in the Polydesmida. The pear-shaped pit proved to represent the distal roundish expansion of the incisura lateralis, to which – similarly as in julidan millipedes – the tentorial transverse bar is articulated. The absence of the Tömösváry organ in the Polydesmida does not affect the topology of the interrelationships among the millipede orders retrieved in previous cladistic analyses based on morphology. As a character shared by Colobognatha and Juliformia, however, absence of a Tömösváry organ in Polydesmida favors the optimization of its presence in nematophoran millipedes as a reversal. Further studies are needed to clarify whether among chilognathan millipedes a Tömösváry organ really exists in taxa such as Stemmiulida, and whether the Tömösváry organs are homologous across millipedes.

Check list of the Venezuelan millipedes species.

Here we provide a checklist of millipedes described or recorded in the literature from Venezuela. The diplopod fauna is comprised of eight orders, 18 families, 54 genera, and 157 species. The millipede orders Glomerida, Chordeumatida, Julida, Siphoniulida, and Platydesmida (known elsewhere in the Western Hemisphere) are not, as of yet, reported from the Venezuelan fauna. Two widely distributed invasive species, Asiomorpha coarctata and Oxidus gracilis, were recorded from Venezuela. All species records listed here contain comprehensive citation and synonymy lists. Numerous locality data are questionable and are discussed. For most species, the supposed deposition of the type specimens is given. However, the museum and gender information is taken mostly from the literature as the type specimen themselves were not examined. An analysis of records extracted from GBIF in 2016 and in 2018 was conducted and compared to the data captured from the published taxonomic literature. The data in this checklist are summarized online at the MilliBase website.

One hundred million years of stasis: Siphonophora hui sp. nov., the first Mesozoic sucking millipede (Diplopoda: Siphonophorida) from mid-Cretaceous Burmese amber

Fossil records of the ancient and less studied millipede order Siphonophorida are rare and only known from Oligocene-Miocene Dominican amber to date. Here, we describe a Mesozoic species of this order, Siphonophora hui sp. nov., based on two well-preserved specimens from mid-Cretaceous Burmese amber. The new species can be placed in the family Siphonophoridae by having mouthparts strongly modified into a long beak, straight antennae, the separation of tergites, pleurites and sternites, leg-like gonopods derived from 9th and 10th leg pairs, and absence of ommatidia. This discovery pushes back the fossil record of Siphonophorida by more than 60 Ma. It also demonstrates that the details of the siphonophorid body plan have remained virtually unchanged for nearly 100 million years. An enigmatic structure on the antennae of the paratype may represent either the ancestral form of the circular sensory pits, or more unlikely, the earliest occurrence of a fungus parasitic or commensal on an arthropod.

Multifaceted activity of millipede secretions: Antioxidant, antineurodegenerative, and anti-Fusarium effects of the defensive secretions of Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) (Diplopoda: Julida).

Members of the millipede order Julida rely on dominantly quinonic defensive secretions with several minor, non-quinonic components. The free radical-scavenging activities of ethanol, methanol, hexane, and dichloromethane extracts of defensive secretions emitted by Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) were investigated using the ABTS, DPPH, and total reducing power (TRP) tests. The obtained extracts were also tested for inhibition of acetylcholinesterase and tyrosinase activity. Finally, the antifungal potential of both julid extracts was evaluated against seven Fusarium species. Secretions of both species showed activity against free radicals, acetylcholinesterase, tyrosinase, and all of the selected fungal species. The secretions of P. hungaricus exhibited a more potent antioxidative effect than did those of M. unilineatum, while there were no significant differences of antiacetylcholinesterase activity between the tested extracts. Only the hexane extract of M. unilineatum showed an effect on tyrosinase activity stronger than that of P. hungaricus. Fusarium sporotrichioides, F. graminearum, and F. verticillioides were the fungi most resistant to secretions of both julids. The Fusarium species most susceptible to the secretion of P. hungaricus was F. avenaceum, while the concentrations of M. unilienatum extracts needed to inhibit and completely suppress fungal growth were lowest in the case of their action on F. lateritium. Our data support previous findings that julid defensive secretions possess an antimicrobial potential and reveal their antioxidative and antineurodegenrative properties. Bearing in mind the chemical complexity of the tested defensive secretions, we presume that they can also exhibit other biological activities.

Novelty upon novelty visualized by rotational scanning electron micrographs (rSEM): Laboulbeniales on the millipede order Chordeumatida.

Laboulbeniales are highly specific ectoparasitic fungi of arthropods (insects, millipedes, and arachnids). The first Laboulbeniales parasitizing the millipede order Chordeumatida (Diplopoda) were discovered and described as a new dioecious genus of Laboulbeniales, Thaxterimyces, to accommodate the new species T. baliensis. Also the millipede host is a new species and is described as Metopidiothrix sheari. This is the first time Laboulbeniales fungus and its millipede host are described as new together. Males of Metopidiothrix have the most extensive secondary sexual modifications in the entire class Diplopoda. Although nothing is known about the function of these modifications, the unique pattern of Laboulbeniales infection in the new millipede species is obviously related to host sexual behavior. Rotational Scanning Electron Micrographs (rSEM) are used to create a 3D comprehensive model to examine the fungal-host interaction, a more advanced visualization of the ectoparasitic fungus on its host. Laboulbeniales diversity on millipedes is still understudied, and a consistent effort is needed to unveil and understand the extent and diversity of this biological interaction. Due to their minute size and apparently non-detrimental effect on their hosts, Laboulbeniales in general have been largely ignored by mycologists and neglected by generations of entomologists. As a result a significant component of global biodiversity has been strongly underestimated, and a wealth of new discoveries is still to be made both in the field and in existing museum collections.

An apparently non-swinging tentorium in the Diplopoda (Myriapoda): comparative morphology of the tentorial complex in giant pill-millipedes (Sphaerotheriida).

The presence of a swinging tentorium is a key apomorphy of Myriapoda, but this character has been studied in detail in only few species. Here the tentorium, i.e., the peristomatic skeleton of the preoral chamber, is comparatively studied in three species of the millipede order Sphaerotheriida Brandt, 1833. Since dissections of the fragile tentorial components proved to be difficult, despite the large head size, they were analysed mainly in situ via micro-computed tomography. Our results confirm previous observations of large differences in the tentorial construction in the giant pill-millipedes compared to chilognathan diplopods. The tentorium of Sphaerotheriida consists of a curved, plate-like epipharyngeal bar with distal projections, an elongate and thin hypopharyngeal bar, and a plate-like triangular posterior process; a transverse bar is absent. Only seven muscles attach at the tentorium in giant pill-millipedes, including two antennal muscles and two muscles of the gnathochilarium. Within the order Sphaerotheriida, the composition of the tentorium and its muscular equipment seems to be conserved, except for some variability in the shape of the epipharyngeal bar. As the transverse bar has been considered essential for the mobility of the tentorium in myriapods, its absence in Sphaerotheriida may indicate that their tentorium is not capable of performing a swing. Loss of tentorial mobility may also pertain to the order Glomerida Brandt, 1833, inferred here from the absence of a posterior process. An apparently immobile tentorium in Glomerida and Sphaerotheriida can straightforwardly be correlated with transformations of the head related to their ability of volvation. The different transformations of the tentorium, here hypothesised to cause immobility, may support current assumptions that the ability of volvation evolved convergently in Glomerida and Sphaerotheriida. This conclusion, however, still requires more detailed studies of the head anatomy in Glomerida and Glomeridesmida Cook, 1895.

The ultrastructure of the hepatic cells in millipedes (Myriapoda, Diplopoda)

The hepatic cells are characteristic cells that occur in millipede body where they form a continuous layer which surrounds the midgut epithelium. The following species, which represent five millipede orders were selected: Julus scandinavius (Julida), Polyxenus lagurus (Polyxenida), Polydesmus angustus (Polydesmida, Polydesmidae), Strongylosoma stigmatosum (Polydesmida, Paradoxosomatidae), Epibolus pulchripes (Spirobolida, Pachybolidae), and two species of the order Spirostreptida, Archispirostreptus gigas and Telodeinopus aoutii. The hepatic cells are absent in P. lagurus in which the midgut epithelium is surrounded by the visceral muscles. In the other species they were arranged around the midgut as coherent hepatic cells of mesenchymal character. Each hepatic cell possessed its own basal lamina and formed the cellular processes which protrude into the basal lamina of the midgut to make contact with midgut digestive cells. Accumulation of reserve material in different millipede taxa has been described with the special emphasis on the process of autophagy in the cytoplasm of the hepatic cells. The lack of hepatic cells may represent an ancestral condition within millipedes.

“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.

The complete mitochondrial genome of the Korean endemic millipede Anaulaciulus koreanus (Verhoeff, 1937), with notes on the gene arrangement of millipede orders.

The millipede Anaulaciulus koreanus (Verhoeff, 1937), belonging to the family Julidae, is an endemic species of the Korean fauna. In this study, we sequence and annotate the mitochondrial genome of A. koreanus. The complete mitochondrial genome of this species is 14,916 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes (16S and 12S rRNA), and a large non-coding region. The genome has a very high A+T content (71.1%), less than of the species Brachycybe lecontii Wood, 1864 (order Platydesmida; 76.6%) and Sphaerotheriidae sp. (order Sphaerotheriida; 71.2%). In comparison with the mitochondrial gene arrangement of eight other millipede species, the whole mitochondrial gene arrangement of A. koreanus is most similar to the nemasomatid species, Antrokoreana gracilipes Verhoeff, 1938, but differs from those of the other diplopod orders. The absence of tRNACys between the ND2 and COI regions is unique to the order Polydesmida, whereas the translocation of tRNATyr to between ND2 and COI is exclusive to the Sphaerotheriida. It is also shown that the translocation of tRNAThr between ND4L and ND1 may be a synapomorphy to support a close relationship of two orders Spirobolida and Spirostreptida.

Atlas of European millipedes 2: Order Julida (Class Diplopoda)

For each of the 593 species of the millipede order Julida known from Europe, available information on taxonomy, distribution and habitat is summarized, and the distribution in 50 × 50 km UTM squares is shown on a map.

Convergent Evolution of Unique Morphological Adaptations to a Subterranean Environment in Cave Millipedes (Diplopoda).

Animal life in caves has fascinated researchers and the public alike because of the unusual and sometimes bizarre morphological adaptations observed in numerous troglobitic species. Despite their worldwide diversity, the adaptations of cave millipedes (Diplopoda) to a troglobitic lifestyle have rarely been examined. In this study, morphological characters were analyzed in species belonging to four different orders (Glomerida, Polydesmida, Chordeumatida, and Spirostreptida) and six different families (Glomeridae, Paradoxosomatidae, Polydesmidae, Haplodesmidae, Megalotylidae, and Cambalopsidae) that represent the taxonomic diversity of class Diplopoda. We focused on the recently discovered millipede fauna of caves in southern China. Thirty different characters were used to compare cave troglobites and epigean species within the same genera. A character matrix was created to analyze convergent evolution of cave adaptations. Males and females were analyzed independently to examine sex differences in cave adaptations. While 10 characters only occurred in a few phylogenetic groups, 20 characters were scored for in all families. Of these, four characters were discovered to have evolved convergently in all troglobitic millipedes. The characters that represented potential morphological cave adaptations in troglobitic species were: (1) a longer body; (2) a lighter body color; (3) elongation of the femora; and (4) elongation of the tarsi of walking legs. Surprisingly, female, but not male, antennae were more elongated in troglobites than in epigean species. Our study clearly shows that morphological adaptations have evolved convergently in different, unrelated millipede orders and families, most likely as a direct adaptation to cave life.

A look with μCT technology into a treasure trove of fossils: The first two fossils of the millipede order Siphoniulida discovered in Cretaceous Burmese amber (Myriapoda, Diplopoda)

Millipedes (Diplopoda) are an important fossil group of land arthropods in the Palaeozoic. However, there is a gap in the Mesozoic, with only slightly more than a dozen fossils being known, until the much more recent fossil records mainly from Cenozoic Dominican and Baltic ambers become available. Burmese amber, precisely dated to the Late Cretaceous, is known for an apparently rich but still undescribed millipede fauna, and might represent the ideal bridge to close this gap in the millipede fossil record. In addition, modern micro-computed tomography (μCT) technology allows complex 3D reconstructions of objects fossilized in amber. Here we utilize μCT technology to describe the first millipedes from Burmese amber, which are also the first two fossil representatives of the order Siphoniulida. Siphoniulida, with two known species and just nine recorded specimens, are the rarest and least known of the 16 extant orders of the Diplopoda. Records are known from Sumatra, Guatemala and Mexico. The two new fossils described here represent two distinct species, Siphoniulus muelleri sp. nov. and S. preciosus sp. nov., and indicate a wider distribution of this order in the Cretaceous. The holotype of S. muelleri sp. nov. was well-enough preserved so that characters of the head, such as the incisura lateralis, not investigated before in extant representatives of the order, could be studied. This study highlights the possibilities and challenges provided by μCT technology in investigating Diplopoda fossilized in amber.

Methane production and methanogenic Archaea in the digestive tracts of millipedes (Diplopoda).

Methane production by intestinal methanogenic Archaea and their community structure were compared among phylogenetic lineages of millipedes. Tropical and temperate millipedes of 35 species and 17 families were investigated. Species that emitted methane were mostly in the juliform orders Julida, Spirobolida, and Spirostreptida. The irregular phylogenetic distribution of methane production correlated with the presence of the methanogen-specific mcrA gene. The study brings the first detailed survey of methanogens’ diversity in the digestive tract of millipedes. Sequences related to Methanosarcinales, Methanobacteriales, Methanomicrobiales and some unclassified Archaea were detected using molecular profiling (DGGE). The differences in substrate preferences of the main lineages of methanogenic Archaea found in different millipede orders indicate that the composition of methanogen communities may reflect the differences in available substrates for methanogenesis or the presence of symbiotic protozoa in the digestive tract. We conclude that differences in methane production in the millipede gut reflect differences in the activity and proliferation of intestinal methanogens rather than an absolute inability of some millipede taxa to host methanogens. This inference was supported by the general presence of methanogenic activity in millipede faecal pellets and the presence of the 16S rRNA gene of methanogens in all tested taxa in the two main groups of millipedes, the Helminthophora and the Pentazonia.

Sternites and spiracles – The unclear homology of ventral sclerites in the basal millipede order Glomeridesmida (Myriapoda, Diplopoda)

We report the discovery of a ventral plate in the basal and little-known chilognath millipede order Glomeridesmida. This ventral plate, interpreted here as a ‘true sternite’, is clearly separate from both the coxa and the more lateral stigma-carrying plates commonly referred to as ‘diplopod sternites’. Therefore, the lateral, stigma-carrying plates of the Diplopoda, previously referred to as sternites, are not sternal elements, but subcoxal elements associated with the limb base. This discovery changes the nomenclature used for the ventral plates in Diplopoda, with the formerly named ‘sternite’ better referred to as ‘stigma-carrying plate’. In helminthomorph Diplopoda, the stigma-carrying plates are apparently secondarily fused with the sternite.The main argument for the independent evolution of tracheae in insects and myriapods, the different location of their respective spiracles, no longer holds true. In all Myriapoda and Hexapoda the spiracles associated with subcoxal elements are located lateral to the limb base. This discovery shows that the arguments for an independent origin of tracheae in insects and myriapods are not uncontestable.

Ordinal-level phylogenomics of the arthropod class Diplopoda (millipedes) based on an analysis of 221 nuclear protein-coding loci generated using next-generation sequence analyses.

BackgroundThe ancient and diverse, yet understudied arthropod class Diplopoda, the millipedes, has a muddled taxonomic history. Despite having a cosmopolitan distribution and a number of unique and interesting characteristics, the group has received relatively little attention; interest in millipede systematics is low compared to taxa of comparable diversity. The existing classification of the group comprises 16 orders. Past attempts to reconstruct millipede phylogenies have suffered from a paucity of characters and included too few taxa to confidently resolve relationships and make formal nomenclatural changes. Herein, we reconstruct an ordinal-level phylogeny for the class Diplopoda using the largest character set ever assembled for the group.MethodsTranscriptomic sequences were obtained from exemplar taxa representing much of the diversity of millipede orders using second-generation (i.e., next-generation or high-throughput) sequencing. These data were subject to rigorous orthology selection and phylogenetic dataset optimization and then used to reconstruct phylogenies employing Bayesian inference and maximum likelihood optimality criteria. Ancestral reconstructions of sperm transfer appendage development (gonopods), presence of lateral defense secretion pores (ozopores), and presence of spinnerets were considered. The timings of major millipede lineage divergence points were estimated.ResultsThe resulting phylogeny differed from the existing classifications in a number of fundamental ways. Our phylogeny includes a grouping that has never been described (Juliformia+Merocheta+Stemmiulida), and the ancestral reconstructions suggest caution with respect to using spinnerets as a unifying characteristic for the Nematophora. Our results are shown to have significantly stronger support than previous hypotheses given our data. Our efforts represent the first step toward obtaining a well-supported and robust phylogeny of the Diplopoda that can be used to answer many questions concerning the evolution of this ancient and diverse animal group.

Revival of forgotten characters and modern imaging techniques help to produce a robust phylogeny of the Diplopoda (Arthropoda, Myriapoda)

The external and internal anatomy of millipedes (Diplopoda) is poorly known compared to some of the other myriapod and arthropod groups. Due to both language barriers, which hindered the assessment of the character-rich older literature, and non-phylogenetic thinking, our knowledge of morphological characters useful for phylogenetic work diminished over the last decades. Here, a new character matrix with 64 characters, mainly derived from old literature data, is used to reconstruct a phylogeny of Diplopoda. As a tool to further our knowledge about the morphology of the different millipede orders, we show how micro-computer tomography (μCT) can be used to assess and illustrate specific parts of the Platydesmida. With the advent of μCT it is now possible to analyse many taxa and characters in a comparatively short time. A focus is put on potential phylogenetically useful characters. Our results support a Verhoeffian classification of the Diplopoda: Polyxenida + Chilognatha. Pentazonia are the sistergroup to the Helminthomorpha. Colobognatha form the sistergroup to Eugnatha, the latter split into monophyletic Juliformia and Polydesmida + Nematophora.

The millipede order Chordeumatida (Diplopoda) in Kazakhstan, with descriptions of three new species.

The order Chordeumatida is represented in Kazakhstan by five species in three genera and three families. All species are recorded in the Altai and Dzhungarskii Alatau Mountains. Three species are described here as new to science: Altajosoma arshaty sp. nov., Altajosoma bukhtarma sp. nov. and Tarbagataya zaisanica sp. nov. The family Diplomaragnidae and the genus Altajosoma Gulička, 1972 are formally new to the fauna of Kazakhstan. Diagnosis of the genus Tarbagataya has been supplemented. All currently known Chordeumatida from Kazakhstan are keyed, including the new species. The distributions of all Kazakhstan chordeumatidan species are mapped.