Fact-checked by Grok 2 weeks ago

Polydesmida

Polydesmida is the largest order of s in the class Diplopoda, comprising approximately 5,500 described that account for nearly half of all known millipede , and is characterized by flattened, wedge-shaped bodies with distinctive lateral extensions of the tergites called paranota, which often bear spines or keels for defense. These lack eyes, have short antennae with eight articles, and typically exhibit 20 body rings in adults, adapting them for life in moist, terrestrial environments such as leaf litter and . Polydesmida are in , with the highest in tropical and subtropical regions, though they occur worldwide in forests, gardens, and under decaying wood. Taxonomically, Polydesmida belongs to the subclass Chilognatha and superorder Merocheta (or sometimes proposed within an "eighth gonopod clade" alongside orders like Callipodida and Chordeumatida), encompassing over 30 families, more than 500 genera, and a vast array of morphological variations in paranota shape and gonopod structure that aid in species identification. The order's evolutionary history traces back to ancient lineages, with phylogenetic analyses placing it variably as sister to groups like Colobognatha or Julida based on genetic data. Notable families include Xystodesmidae and Polydesmidae, the latter predominantly Holarctic with over 60 genera and nearly 300 species. Ecologically, polydesmid millipedes play key roles as decomposers in forest ecosystems, feeding primarily on decaying plant matter and fungi while contributing to nutrient cycling. They are uniquely equipped with chemical defenses, including cyanogenic compounds that produce (HCN) upon threat, alongside like cresols and , and , making them unpalatable to predators. Some species exhibit specialized adaptations, such as semi-aquatic habits allowing submersion tolerance or arboricolous lifestyles on bark, and a few are troglobitic cave-dwellers. Their abundance in regions like underscores their ecological significance, though habitat loss poses ongoing threats to many populations.

Taxonomy and Overview

Classification and Phylogeny

Polydesmida is an order of millipedes within the subclass Chilognatha and class Diplopoda, encompassing approximately 5,500 described species distributed across over 500 genera and about 30 families as of 2025. This order represents the largest and most diverse group of millipedes, characterized by their keeled or flat-backed body form, and is placed in the superorder Merocheta (also known as Merochaeta). The species are classified into four suborders—Dalodesmidea, Leptodesmidea, Paradoxosomatidea, and Polydesmidea—with the latter two being particularly species-rich. Key families include Paradoxosomatidae, the largest with over 1,000 species primarily in tropical regions; Xystodesmidae, with over 500 species mainly in North America; and Chelodesmidae, noted for its diversity in the Neotropics. Phylogenetically, Polydesmida occupies a basal position among eugnathan millipedes, supported by both molecular and morphological analyses that highlight its early divergence within the subclass. Molecular phylogenomics, including multi-locus studies, recover polydesmidans as to other major eugnathan lineages such as , with morphological traits like the gnathochilarium and reduced tracheal systems reinforcing this placement. The order's is well-established, though internal relationships among suborders remain under revision through integrative approaches combining and . The taxonomic history of Polydesmida dates to its establishment as an order by in 1815, initially based on European species with distinctive body keels. Major revisions occurred in the , notably by Carl Attems, who expanded the in his 1937 monograph on myriapods, and Richard L. Hoffman, whose 1976 and 1999 works refined family-level boundaries and synonymies. Contemporary updates incorporate integrative , blending morphological, molecular, and ecological data to address cryptic diversity, particularly in cyanogenic clades that produce as a . Recent developments have accelerated species discovery, with hundreds of new taxa described since 2020, driven by targeted surveys in biodiversity hotspots. Notable examples include seven new species of Xystodesmus (Xystodesmidae) from southwestern in 2025, expanding the genus's known range in , and two new species of Inodesmus (Haplodesmidae) from Colombian oak forests in 2025, marking the first records of that family in the country. Earlier contributions include the genus Nagaxytes, established in 2018 for Southeast Asian species with extended paranota, highlighting ongoing refinements in suborder Paradoxosomatidea. These additions underscore the emphasis on cyanogenic lineages, which dominate phylogenetic studies of the order. Evolutionary insights portray Polydesmida as an ancient lineage, with fossil records from the suggesting origins in the . The group's is evident in its diversification across humid tropical and subtropical environments, where ecological specialization in leaf litter and niches has driven , particularly in the suborders Paradoxosomatidea and Polydesmidea. This radiation is supported by estimates placing key divergences in the late to early .

Distribution and Diversity

Polydesmida exhibit a , occurring on all continents except and being absent from extreme desert environments, with their presence documented across a wide array of temperate, subtropical, and tropical habitats worldwide. The order's range spans from boreal forests in and to humid rainforests in the Neotropics and Indo-Malaya, reflecting adaptations to diverse climatic conditions but with a clear preference for moist, vegetated areas. Highest species diversity is concentrated in tropical regions, particularly , , and , where environmental stability and habitat complexity support elevated richness. Biogeographic patterns within Polydesmida suggest pantropical origins, with subsequent radiations leading to temperate extensions, such as in where the family Xystodesmidae dominates forest assemblages. Island endemism is prominent in isolated systems like and the , where unique evolutionary trajectories have produced regionally restricted lineages, including chelodesmid millipedes in the . These patterns underscore the order's historical dispersal via vicariance and overwater colonization, with tropical hotspots serving as centers of . The comprises approximately 5,500 described , with estimates suggesting significantly more undescribed taxa, making it the most diverse . Biodiversity hotspots include , home to numerous of dragon millipedes in the genus Desmoxytes (), and the Colombian , where Cryptodesmidae exhibit high local amid Andean cloud forests. The majority of are endemic to . Recent discoveries, such as 18 new in the Polydesmidae from in 2021, illustrate ongoing revelations of cryptic diversity in temperate zones. Threats to Polydesmida diversity primarily stem from tropical loss due to , , and , which disproportionately affect undescribed species in biodiversity hotspots. Most species remain unassessed, with conservation statuses classified as under IUCN criteria, underscoring the urgent need for expanded surveys and protection to mitigate extinction risks in vulnerable ecosystems.

Morphology

General Body Structure

Polydesmida exhibit a distinctive body form that ranges from cylindrical to dorsoventrally flattened, primarily due to the presence of paranota, which are lateral keels or wing-like extensions on the surface of most body segments. These paranota serve protective and possibly functions, contributing to the order's characteristic flat-backed appearance in many species, while in others they are reduced, resulting in a more cylindrical shape. The body comprises a head followed by typically 20 rings: the legless collum (ring 1), three thoracic rings (2–4) each bearing one pair of legs, 14 diplosegments (rings 5–18) each with two pairs of legs, a legless anal ring (19), and the (20), which includes the preanal ring and anal plates. The head is eyeless, lacking ocelli, and relies on other sensory structures for in dark or humid environments. A pair of antennae, each with eight segments, protrudes from the head and plays a key role in chemosensation and mechanoreception, enabling detection of food, mates, and environmental cues. The is hardened by deposits, particularly in the tergites, providing structural rigidity while allowing flexibility for movement. Coloration is often aposematic, featuring bold patterns in red, yellow, orange, or black to signal to predators, a linked to their chemical defenses. Body length varies from approximately 3 mm to over 130 mm, with most species falling between 5 and 50 mm. Internally, Polydesmida possess a simple tubular gut adapted for detritivory, consisting of , , and regions that facilitate the breakdown of decaying plant material and fungi through microbial . Repugnatorial glands, arranged segmentally, produce (HCN) from cyanogenic precursors, which can be released as a defensive ; these glands open via ozopores on the paranota or body sides. In males, the eighth leg pair is modified into gonopods for transfer, resulting in 30 pairs of walking legs, while females have 31 pairs.

Segmental and Appendage Variations

While most Polydesmida exhibit a typical with 20 segments (including the collum and ), notable variations occur across , with adult segment counts ranging from 18 to 21 rings in many families. This range often shows sex-specific differences, such as females having one more segment than males in certain taxa, reflecting modifications associated with reproductive structures. Extreme deviations include the Brazilian cave-dwelling Dobrodesmus mirabilis, discovered in 2016, which possesses 40 segments in adult males, far exceeding the norm and accompanied by 79 pairs of legs, highlighting evolutionary adaptations in isolated subterranean environments. Such supernumerary segmentation underscores the plasticity in polydesmidan trunk development, potentially linked to habitat-specific selective pressures. Appendage diversity in Polydesmida is particularly evident in the male gonopods, derived from the eighth leg pair, which display intricate morphologies crucial for species recognition during . These structures vary widely in branching patterns, lengths, and ornamentation even within , serving as primary diagnostic traits for and enabling precise mate discrimination among closely related . A rare exception is Aenigmopus alatus, a Central American in the Tridontomidae, where males lack gonopods entirely and retain 31 pairs of unmodified walking legs, an anomaly unique among helminthomorph millipedes that may imply alternative reproductive mechanisms. Paranota, the lateral extensions of the tergites often functioning as keels, exhibit significant morphological , ranging from simple flanges to elaborate, spine-like crests that enhance body width and possibly aid in locomotion or defense. In the Southeast Asian genus Desmoxytes, known as dragon millipedes, paranota can form striking, ornate projections, such as the long, thin, spiniform types in cave-adapted like D. spinissima, which may facilitate navigation in confined spaces. Some families display in paranota, with males featuring more pronounced or differently shaped extensions compared to females, contributing to attraction or isolation. Miniaturization represents another key variation, with some Holarctic Polydesmidae attaining lengths under 2 mm, such as certain members of oligotypic genera measuring 1.4–5.0 mm and possessing only 18 or 19 segments. These diminutive forms, often found in litter, contrast with elongated cave-adapted taxa in families like , where troglobitic evolve longer bodies, extended legs, and antennae to traverse dark, narrow habitats, as seen in elongated forms from karst caves. Intraspecific variation further diversifies Polydesmida morphology, with color morphs—such as pale grayish versus dark brown patterns in Xystodesmus species—influenced by environmental factors like and humidity, potentially serving adaptive roles in or warning signaling. Similarly, keel (paranota) shapes show , with broader or more rounded forms in humid dwellers versus narrower ones in drier microhabitats, reflecting responses to local ecological conditions.

Development and Reproduction

Life Cycle Stages

Polydesmida exhibit teloanamorphic , a post-embryonic pattern in which segment addition ceases after a fixed number of , culminating in the form with no subsequent molts. This process typically involves 8 , during which the progressively adds pairs of segments and legs from the posterior end until reaching the definitive segment count, which varies by species but often totals around 19–20 leg-bearing diplosegments. occurs in Stadium I with 7 body rings, including 3 pairs of walking legs on the initial diplosegments, followed by the collum and a few apodous rings. Subsequent stadia build on this foundation: Stadium II adds the first additional segment pair, Stadium III adds another, and so on, with segments incorporated behind the until Stadium VIII, when the final adult morphology is achieved. In species like Poratia salvator, development progresses through 7 post-hatching stages (equivalent to 8 including the hatching ), with juveniles in early stadia showing high mortality rates (up to 54% between stages) as they molt to incorporate new segments. Growth occurs via gradual size increases across molts, triggered by environmental cues such as , temperature, and photoperiod, which regulate the timing of ; maturity is typically reached after 1–2 years in natural conditions. Juveniles in initial stadia possess reduced paranota (lateral projections on the tergites) that are shorter and less developed compared to adults, along with simpler appendages lacking full . The transition to adult form happens during the final molt, where paranota expand fully, appendages mature, and gonopods form in males, marking the end of segment addition. In the wild, Polydesmida spans 2–5 years, with individuals capable of iteroparity, producing multiple broods over successive reproductive seasons after reaching maturity. For instance, in Polydesmus angustus, late-season cohorts extend their to 2 years to align with optimal breeding windows, supporting repeated reproduction.

Reproductive Strategies

Polydesmida primarily reproduce sexually through indirect sperm transfer, where males use their specialized gonopods—modified legs on the seventh body ring—to collect from the gonopores on the second ring and insert it into the female's cyphopods on the third ring, often in the form of spermatophores for precise . This mechanism ensures targeted deposition, with the gonopods locking into the female's reproductive openings during copulation, which typically lasts several minutes to hours depending on species and density. Mating in Polydesmida involves chemical and behavioral cues, including pheromone attraction to draw partners, particularly during humid seasons when activity peaks from June to September in temperate regions. In some species, males engage in precopulatory struggles or with rivals, involving coiling, pushing, and coercion to secure mating access, while mate-guarding post-copulation can last days to prevent remating. Females exhibit ranging from 7–24 eggs per , which are buried in nests constructed from fecal material and ; incubation periods last 10–21 days before hatching. is rare in Polydesmida but documented in certain populations, such as the thelytokous form in Poratia salvator, where unfertilized eggs develop into females, potentially aiding survival in isolated habitats. Sex ratios in Polydesmida populations are typically near 1:1, though some exhibit slight bias during seasons; females are generally larger than males, reflecting sexual size dimorphism that supports higher egg production, with maintained through obligatory in most species.

Ecology and Behavior

Habitats and Feeding

Polydesmida millipedes predominantly inhabit moist microhabitats that provide high humidity and , such as , layers, and under loose on trees or logs. In temperate regions, like those in the family Xystodesmidae thrive in humus-rich deciduous or mixed forests, including the U.S. Midwest and woodlands, where they into or riparian zones with coniferous cover. Tropical species exhibit greater vertical stratification, occupying not only the but also extending into canopy layers of rainforests, where decaying epiphytes and accumulate. As detritivores, Polydesmida primarily consume decomposing organic material, including decaying wood, leaf , and fungi, contributing to nutrient cycling in their ecosystems. Some species engage in mycophagy, selectively feeding on fungal hyphae or spores within , while gut microbial symbionts assist in breaking down and for nutrient extraction. For example, temperate Xystodesmidae in forests target lichens, alongside fungi in bark and litter habitats. Foraging in Polydesmida is characterized by slow, deliberate crawling, often nocturnal to avoid and predation, with activity peaking during periods of high such as after rainfall or in the . Seasonal patterns vary by region; temperate populations show fall abundance in moist , while tropical forms maintain year-round activity in consistently humid environments. Microhabitat adaptations include lifestyles on the surface for many species, contrasted with geophilous burrowing in soil, and specialized troglomorphic forms in caves, such as cavernicolous Polydesmidae in Vietnamese systems, which rely on limited detrital inputs in dark, stable subterranean niches.

Defenses and Interactions

Polydesmida employ sophisticated chemical defenses primarily through repugnatorial glands located on their lateral body segments, which eject noxious secretions when threatened. These glands store cyanogenic precursors such as mandelonitrile or , which, upon release, are enzymatically degraded by hydroxynitrile lyase to produce (HCN) and . The biosynthesis pathway derives from aromatic like , with potentially aiding in maintaining acidity for precursor stability, particularly in immature stages. HCN is highly toxic, proving fatal to arthropods and small vertebrates in confined spaces, while benzaldehyde contributes irritating odors and tastes that deter a broad spectrum of predators, including , , spiders, and vertebrates. Some species also incorporate quinones or , enhancing overall repellency against and microbial threats. In addition to chemical mechanisms, Polydesmida utilize behavioral defenses to evade predation. Many species coil their bodies into tight spirals or balls, shielding vulnerable undersides and directing secretions outward from the exposed dorsum. This is often accompanied by thanatosis, where individuals feign death by remaining immobile, reducing attractiveness to visually hunting predators. Aposematic coloration, featuring bold patterns of red, yellow, or black, serves as a visual signal in several families like Xystodesmidae and Chelodesmidae, unpalatability and promoting avoidance learning in predators. Polydesmida serve as primary prey for various predators in forest litter and soil ecosystems, influencing co-evolutionary dynamics. They are commonly consumed by centipedes, ground-dwelling spiders (including Atypidae funnel-web spiders), , and amphibians, with predation often occurring in moist leaf habitats where these millipedes . Specialized predators like phengodid larvae circumvent chemical defenses by injecting digestive fluids to subdue and consume them. These interactions have driven adaptations in both millipedes and predators, such as enhanced in litter arthropods. Ecological interactions of Polydesmida extend to mutualistic, competitive, and parasitic relationships. They engage in with fungi by dispersing spores through fecal pellets, which aids fungal propagation while millipedes benefit from nutrient-rich . As detritivores, they compete with other invertebrates like isopods and earthworms for decomposing , influencing rates. is relatively rare but documented, with nematodes of the orders Rhigonematomorpha and Oxyuridomorpha inhabiting their hindguts, such as Rhigonema naylae in xystodesmid hosts. In human contexts, Polydesmida contribute to by enhancing nutrient cycling and microbial activity through detritivory, supporting ecosystem fertility. Certain , such as Oxidus gracilis (Paradoxosomatidae), act as minor pests in greenhouses, damaging seedlings and requiring management in controlled environments.

References

  1. [1]
    Polydesmida - an overview | ScienceDirect Topics
    Polydesmida refers to an order of millipedes characterized by species that often possess lateral extensions of the dorsal surface known as paranota, ...Missing: taxonomy | Show results with:taxonomy
  2. [2]
    FLAT BACKED MILLIPEDE: Identification, Damage & Control
    Sep 18, 2025 · Found worldwide, with the highest diversity in tropical and subtropical regions. Prefer moist soils, forest litter, gardens, and agricultural ...
  3. [3]
    The millipede family Polydesmidae Leach, 1816 ... - ZooKeys
    Jan 30, 2024 · The millipede family Polydesmidae Leach, 1816 is almost strictly Holarctic, consisting of more than 60 nominal genera or subgenera and nearly ...
  4. [4]
    Research | Millipedes of the order Polydesmida
    Cyanide-producing millipedes of the order Polydesmida are widespread and ecologically significant, occurring in forests across Earth.
  5. [5]
    Natural history, taxonomy, and phylogenetics of Appalachian flat ...
    The most species-rich order is the Polydesmida, the flat-backed millipedes, which encompasses about 3,500 species. Appalachia has an abundance of Polydesmida, ...
  6. [6]
    MilliBase
    Between brackets is the number of accepted extant species explain all fields ... Superorder Juliformia (4 396); Superorder Merocheta (5 643); Order Polydesmida (5 ...
  7. [7]
    Biogeography and species diversity of millipede orders
    Among these, the order Polydesmida is the most speciesrich with more than 5,000 described species in 31 families (Brewer et al. 2012). ...Missing: count | Show results with:count
  8. [8]
    Phylogenetic review of the millipede genus Cherokia Chamberlin ...
    Jun 20, 2022 · The family Xystodesmidae (Polydesmida) includes 539 species with a center of diversity concentrated in the Appalachian Mountains (Means et al.
  9. [9]
    Ordinal-Level Phylogenomics of the Arthropod Class Diplopoda ...
    Nov 13, 2013 · ... Polydesmida. The polydesmidan exemplar, Pseudopolydesmus sp., was recovered as basal to the remaining eugnathan millipedes in the ML analysis.
  10. [10]
    Phylogeny of the millipede genus Sphaeriodesmus Peters, 1864 ...
    Aug 6, 2025 · Phylogeny of the millipede genus Sphaeriodesmus Peters, 1864 (Polydesmida: Sphaeriodesmidae) based on morphological characters. May 2008 ...
  11. [11]
    [PDF] Morphological evolution and phylogeny of millipedes (Diplopoda)
    The colobognathan Platydesmida show an intermediate state between those fluid-feeding millipedes and the eugnathan biting-chewing mouthpart configuration ( ...
  12. [12]
  13. [13]
    ITIS - Report: Polydesmida - Integrated Taxonomic Information System
    Polydesmidea Leach, 1815. References. Expert(s): ... Hoffman, Richard L. Publication Date: 1999 ... Acutangulus Attems, 1898-valid. Aenigmopus Loomis ...
  14. [14]
    ARTS: Systematics of cyanogenic millipedes in the order Polydesmida
    These millipedes are ancient remnants of a native guild of decomposers that have steadily declined due to forest habitat loss and competition with non-native ...
  15. [15]
    Review of the millipede genus Xystodesmus (Diplopoda ... - ZooKeys
    Mar 12, 2025 · In this paper we provide descriptions of seven new Xystodesmus species, two from Kyushu (Kagoshima, Kumamoto, and Oita prefectures) and five from the Central ...Missing: 2020-2025 Chonodesmus Nagaxytes
  16. [16]
    [PDF] Polydesmida) from Colombia: two new species of Inodesmus Cook, 18
    Jan 6, 2025 · The family Haplodesmidae Cook, 1895 currently comprises seven genera and over 70 species (Golovatch. 2018; Srisonchai et al. 2020). Its ...Missing: count | Show results with:count
  17. [17]
    A new millipede (Diplopoda, Helminthomorpha) from the Middle ...
    Millipede fossils of late Permian to Early Triassic age are exceptionally rare worldwide. Two specimens of Triassic millipedes, both associated with ...
  18. [18]
    [PDF] Ordinal Distributions in the Diplopoda - UNL Digital Commons
    Mar 18, 2011 · Chordeumatida, Merocheta/Polydesmida, and Siphoniulida are either extant or fossilized ... An early Triassic millipede from Siberia and its ...
  19. [19]
    POLYDESMIDA MILLIPEDES
    Polydesmida is by far the largest order of millipedes, with over 5000 species described worldwide. Polydesmida occur almost everywhere except Antarctica and ...
  20. [20]
    Diversity, distribution patterns, and fauno-genesis of the millipedes ...
    Apr 28, 2020 · Diplopods mainly occur in various woodlands, in caves, and high in the mountains. Most species (> 90 %, usually highly localised, including 160 ...
  21. [21]
    Phylogenetic Systematics of the Millipede Family Xystodesmidae
    Mar 1, 2021 · There are 830 species of Pauropoda and 12,000 species of Diplopoda—200 species ... These groups include a substantial number of undescribed ...
  22. [22]
    A bibliographic review of the Chelodesmidae of the Antilles and ...
    Nov 15, 2024 · This is a bibliographic review of Chelodesmidae in the Antilles and Bahamas, a type of flat-backed millipede (Myriapoda) in the Neotropical ...Missing: Madagascar | Show results with:Madagascar
  23. [23]
    A worldwide catalog of the family Paradoxosomatidae Daday, 1889 ...
    Aug 6, 2025 · A catalog of the family Paradoxosomatidae (order Polydesmida) is presented here listing a total of 198 genera with 975 valid species.
  24. [24]
    Three new genera and eighteen new species of miniature ...
    May 24, 2021 · Three new genera and eighteen new species of miniature polydesmid millipedes from the northwestern United States (Diplopoda, Polydesmida, ...
  25. [25]
    A revision of dragon millipedes I: genus Desmoxytes Chamberlin ...
    May 29, 2018 · Intensive field surveys focusing on this genus were made by our team ( ASRU ), mainly in Southeast Asia (Malaysia, Myanmar, Laos, Thailand).Missing: hotspot | Show results with:hotspot
  26. [26]
    Two new species of the flat-backed millipede genus Chonodesmus ...
    Jul 3, 2025 · Two new species of the flat-backed millipede genus Chonodesmus Cook, 1896 (Polydesmida, Cryptodesmidae, Cryptodesmini) from Colombia with a ...Missing: Andes hotspot
  27. [27]
    Conservation of terrestrial invertebrates: a review of IUCN and ...
    Apr 28, 2020 · Of them, three categories concern species with higher extinction risk: Critically Endangered ( CR ), Endangered ( EN ), and Vulnerable ( VU ).
  28. [28]
    Why be red listed? Threatened Myriapoda species in Brazil with ...
    Mar 7, 2018 · The red lists of threatened species are recognized as the most objective approach for evaluating the conservation status of species (IUCN 2013), ...
  29. [29]
    External Anatomy of Polydesmida: Body plans
    At the tail end of the millipede is the telson, which is made up of the preanal ring (PA) and the paraprocts and hypoproct, which close off the anus at the end ...
  30. [30]
    Pachydesmus - Lander University
    The body consists of a head and a trunk of many segments, most of which bear paired appendages. Most of the trunk segments occur in fused pairs, called ...
  31. [31]
    Head - External Anatomy of Polydesmida - myriapodology.org
    Even if they walked with their heads up they could not see where they were going, because Polydesmida have no eyes and are blind. They sense what is in front of ...
  32. [32]
    [PDF] Millipedes as Host for Microbes - A Review - idosi
    Polydesmida and Glomerida do not [43]. assimilate high calcium content and transform into calcium oxalate to form calciferous tergites [33] this is the reason.
  33. [33]
    A revision of the minor species group in the millipede genus ...
    Apr 13, 2021 · Millipedes in the family Xystodesmidae (Polydesmida) are often referred to as “colorful, flat-backed millipedes” for their bright aposematic ...
  34. [34]
    External Anatomy of Polydesmida: Size
    Adult Polydesmida range from 3 mm to over 130 mm, with most temperate species being 5-50 mm. Size can vary within a species.Missing: exoskeleton | Show results with:exoskeleton
  35. [35]
    Methanogenesis in the Digestive Tracts of the Tropical Millipedes ...
    As detritivores, millipedes depend on their intestinal microbiotas in the digestion of cellulose or recalcitrant humus (21). In general, methanogenesis may be ...Missing: detritivory | Show results with:detritivory
  36. [36]
    Structure of the midgut epithelium in four diplopod species
    Jul 15, 2021 · 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.
  37. [37]
    The polydesmidan milliped Leonardesmus injucundus Shelley ...
    In many species of the order Polydesmida, a unique, two-part gland consists of a reservoir, which stores a cyanohydrin (mandelonitrile or benzoyl cyanide) and a ...
  38. [38]
    Step-wise evolution of complex chemical defenses in millipedes
    Feb 16, 2018 · All but five millipede orders have repugnatorial glands that secrete chemical defenses when disturbed by predators. ... benzoquinones, phenols, ...Missing: HCN | Show results with:HCN
  39. [39]
    Tasmanian Millipedes: Polydesmida: Introduction and key
    Depending on species, adult Polydesmida have either 14 segments with two pairs of legs (H+20; segments 5-18), or 13 segments with two pairs of legs (H+19; ...
  40. [40]
    Polydesmid Millipedes - The Australian Museum
    Polydesmid millipedes live in forests. Distribution. Polydesmid millipedes are found throughout Australia.
  41. [41]
    Review of the millipede family Opisotretidae (Diplopoda ...
    Number of body segments. Like in most other families in Polydesmida, the number varies from 19 to 20, mostly being sex-characteristic. Thus, in Carlotretus ...
  42. [42]
    Gonopods - External Anatomy of Polydesmida - myriapodology.org
    Their sizes, shapes, branching patterns and other details are extremely diverse, even within a single polydesmidan family. It would be silly for me to try to ...
  43. [43]
    Is Millipede Taxonomy Based on Gonopod Morphology Too ...
    Aug 14, 2013 · The structure of the male gonopods of millipedes has been considered to be species-specific. As such, gonopods—which aid in copulation and ...
  44. [44]
    Sexual size and shape dimorphism in Brachydesmus troglobius ...
    Apr 28, 2020 · The present study is the first attempt to explore sexual shape and size dimorphism (SShD and SSD) of morphological structures in Polydesmida.Missing: paranota Desmoxytes<|separator|>
  45. [45]
    Convergent Evolution of Unique Morphological Adaptations to a ...
    Feb 8, 2017 · In this study, morphological characters were analyzed in species belonging to four different orders (Glomerida, Polydesmida, Chordeumatida, and ...
  46. [46]
    Three new cavernicolous species of dragon millipedes, genus ...
    Apr 23, 2012 · The large Southeast Asian genus Desmoxytes is slightly rediagnosed. A number of troglomorphic, most likely troglobitic, species occur in ...Missing: paranota elaborate crests sexual
  47. [47]
    On colour morphs of the millipede, Chondromorpha kelaarti ...
    Aug 6, 2025 · Furthermore, color does not likely have a strong influence ... Genetic and ecological differentiation between sympatric colour morphs of the ...Missing: keel shapes
  48. [48]
    Phylogenetic review of the millipede genus Cherokia Chamberlin ...
    Jun 20, 2022 · The family Xystodesmidae (Polydesmida) includes 539 species with a center of diversity concentrated in the Appalachian Mountains ( Means et al.
  49. [49]
    Anamorphosis in millipedes (Diplopoda)—the present state of ...
    A review of the postembryonic development of millipedes (Diplopoda) is given, based mainly on published information. Original observations are, however, ...
  50. [50]
    [PDF] Deviation of Dyar's rule in the post-embryonic development ... - bioRxiv
    Aug 24, 2020 · In polydesmida, the number of stadium is only eight with higher Dyar's value (mean 1.61) while in non-polydesmida, where number of stadium is ...
  51. [51]
    External Anatomy of Polydesmida: Growth
    A stadium 1 polydesmidan has only six legs. As the polydesmidan grows and moults, it adds more segments and legs at the rear end as shown in the drawings.
  52. [52]
    None
    Nothing is retrieved...<|separator|>
  53. [53]
    Backed Millipede (Polydesmida - Oxford Academic
    Jul 5, 2022 · (Polydesmida: Polydesmidae) millipedes incorporating two types of morphological elements: skeletal elements and muscles. In addition to ...
  54. [54]
    [PDF] 7 Millipedes (Diplopoda) and - CABI Digital Library
    Millipedes often take several years to reach sexual maturity and the longevity in some species can exceed a decade. Their longevity has been related to the ...
  55. [55]
    (PDF) Female reproductive patterns in the millipede Polydesmus ...
    Jun 20, 2025 · It was confirmed that females born from May to August have a 1-year life cycle and those born from late August onwards a 2-year life cycle ( ...Missing: wild | Show results with:wild
  56. [56]
    Polydesmida - 3D Atlas of Arthropods
    The body of flat-backed millipedes consists of a head and an elongated trunk composed of numerous metameric segments with walking legs.
  57. [57]
    Copulation, mating system and sexual dimorphism in an Australian ...
    Jun 28, 2010 · However, mating systems remain poorly described in many millipede groups, including species in the order Polydesmida (see Mukhopadhyaya and Saha ...
  58. [58]
    Male density influences mate searching speed and copulation ...
    Here we investigate the Australian Polydesmidan millipede Gigantowales chisholmi and describe their mating behaviour. We manipulated male density, exposing ...
  59. [59]
    [PDF] Polydesmida - bioRxiv
    Aug 24, 2020 · The millipedes are abundant in the months of June to. September when the males and females are pairing. An attempt has therefore been made in ...
  60. [60]
    Copulatory Sequences and Sexual Struggles in Millipedes
    Factors affecting egg-laying and clutch size of Archispirostreptus ... Observations on the natural population and sexual behaviour of Orthomorpha coarctata ( ...
  61. [61]
    (PDF) Mate-Guarding, Mating Success and Body Size in the Tropical ...
    Aug 7, 2025 · Males of the neotropical millipede Nyssodesmus python guard females for up to several days following copulation. The majority of the adult ...
  62. [62]
    Natural history of the social millipede Brachycybe lecontii Wood, 1864
    Apr 3, 2020 · They also observed a single adult male with a clutch of 24 eggs that hatched after 21 days (Youngsteadt and McAllister 2014). Like many species ...
  63. [63]
    Fertility Tables of Two Populations of the Parthenogenetic Species ...
    Fertility Tables of Two Populations of the Parthenogenetic Species Poratia Salvator (Diplopoda, Polydesmida, Pyrgodesmidae). Braz J Biol. 2011 May;71(2):501 ...
  64. [64]
    [PDF] Life cycle of Poratia salvator (Diplopoda: Polydesmida - SciELO
    The reproductive adult phase of females was the longest phase in the development, followed by the juvenile and pre-reproductive adult phases. The mean time of ...Missing: teloanamorphic scientific
  65. [65]
    Sexual size and shape dimorphism in Brachydesmus troglobius ...
    Apr 28, 2020 · The present study is the first attempt to explore sexual shape and size dimorphism ( SShD and SSD ) of morphological structures in Polydesmida.Missing: paranota Desmoxytes
  66. [66]
    Mate-Guarding, Mating Success and Body Size in the Tropical ... - jstor
    The sex ratio of solitary individuals was 6:7 (females: males). Body sizes of paired and solitary individuals did not differ for either sex, suggesting that ...
  67. [67]
    None
    Summary of each segment:
  68. [68]
    [PDF] Habitats and seasonality of riparian-associated millipedes in ...
    Millipedes are a diverse and ancient group of poorly known terrestrial organisms. While recent advances in their taxonomy and distribution have occurred in ...
  69. [69]
    Foraging behaviour as a mechanism for trophic niche separation in ...
    Recent experiments and observations confirm predominately nocturnal activity of millipedes in general, but also revealed species with a weakly pronounced ...
  70. [70]
    The chemical defenses of millipedes (diplopoda) - ScienceDirect.com
    The secretions of these glands may consist of topical irritants, repellents, antifeedants, or, in the case of the large and widespread Order Polydesmida, ...
  71. [71]
    Defensive Secretions in Three Species of Polydesmids (Diplopoda ...
    Repugnatorial glands are present in millipedes, except those in the orders Siphoniulida, Sphaerotheriida and Chordeumatida. The production of cyanogenic ...Missing: gut | Show results with:gut<|control11|><|separator|>
  72. [72]
    External Anatomy of Polydesmida: Coiling
    Some Polydesmida are built so that they can coil into a 'ball' or 'pill' (see image below), like pill millipedes in the orders Glomerida and Sphaerotheriida.
  73. [73]
    Millipede Envenomation - StatPearls - NCBI Bookshelf - NIH
    Their primary defense mechanisms consist of coiling up and secreting toxins from the sides of their body. Within these secretions, a variety of irritating ...
  74. [74]
    A review of thanatosis (death feigning) as an anti-predator behaviour
    Jan 15, 2018 · Even though TI has become co-opted into larger defence strategies in some species, such as aposematic warning or camouflage colouration ...
  75. [75]
    Xystodesmid Millipedes | Missouri Department of Conservation
    Millipedes in family Xystodesmidae often have bright colors that serve as a warning to potential predators that they may secrete foul or toxic substances.
  76. [76]
    Aposematic coloration in millipedes. An unidentified chelodesmid ...
    Aposematic coloration in millipedes. An unidentified chelodesmid from Brazil (Polydesmida, Chelodesmidae). Photo couresty Joseph Warfel. Source publication.
  77. [77]
    Millipedes - University of Kentucky
    Jan 27, 2012 · Most common millipedes are cylindrical, but millipedes in the order Polydesmida are flattened. Common species are black with yellow or orange ...
  78. [78]
    Millipedes Glow Away Predators - UMD Entomology Department
    Apr 5, 2016 · Marek hypothesized that glow of these millipedes warns potential nocturnal predators that they will be an unpleasant meal, just as the bright ...
  79. [79]
    Circumvention of a millipede's chemical defense by a predaceous ...
    The phengodid subdues the millipede by piercing the millipede's integument with its hollow sickle-shaped mandibles and apparently injecting gastric fluid. The ...
  80. [80]
    Some Notes on the Impact of Millipedes (Myriapoda
    Fungi ultimately benefit from dispersal activities of the animals although they may initially experience reduction in the form of feces. The process of litter ...
  81. [81]
    (PDF) Do the giant pill-millipedes (Arthrosphaera - ResearchGate
    Aug 9, 2025 · The faecal pellets of the two millipedes contained 16 species (14 species in common) of AM fungi whereas there were 19 species in soil. Up to ...
  82. [82]
    Taxonomic and Functional Response of Millipedes (Diplopoda) to ...
    Dec 29, 2019 · Millipedes are a key group of soil macrodetritivores and significantly influence soil quality, mainly through their essential role in nutrient ...
  83. [83]
    Symbiosis of the millipede parasitic nematodes Rhigonematoidea ...
    Jun 12, 2021 · We have previously described two nematode species, Rhigonema naylae and Travassosinema claudiae, which are parasites of the xystodesmid ...
  84. [84]
    Rhigonema naylae n. sp. (Rhigonematomorpha: Rhigonematidae) a ...
    May 22, 2017 · Rhigonema naylae n. sp. (Rhigonematomorpha: Rhigonematidae) a new parasitic nematode from a Japanese polydesmid millipede (Polydesmida: ...
  85. [85]
    Millipedes and centipedes (Myriapoda: Diplopoda, Chilopoda) in ...
    Apr 21, 2022 · The millipede and centipede fauna of greenhouses is barely known in Switzerland. We conducted a survey in greenhouses of nine botanical gardens ...
  86. [86]
    Occurrence and assemblage composition of millipedes (Myriapoda ...
    Mar 20, 2012 · It has been introduced by human activities into European greenhouses ( Blower 1985 ) and seldom survives outdoors in Europe ( Pedroli-Christen ...<|separator|>