| Diplurans | |
|---|---|
 | |
| Campodea staphylinus, Belgium | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Clade: | Pancrustacea |
| Subphylum: | Hexapoda |
| Order: | Diplura Börner, 1904 |
| Families [2] | |
TheorderDiplura ("two-pronged bristletails") is one of three orders of non-insect hexapods within the classEntognatha (alongside Collembola (springtails) andProtura).[3] The name "diplura", or "two tails", refers to the characteristic pair of caudal appendages or filaments at the terminal end of the body.
Around 800 species of diplurans have been described.
.jpg)
Diplurans are typically 2–50 millimetres (0.08–1.97 in) long, with most falling between 7 and 10 millimetres (0.28 and 0.39 in).[4] However, some species ofJapyx may reach 50 mm (2.0 in).[5] They have noeyes and, apart from the darkened cerci in some species, they are unpigmented.[5] Diplurans have longantennae with 10 or morebead-like segments projecting forward from the head.[6] The abdomens of diplurans bear eversible vesicles, which seem to absorb moisture from the environment and help with the animal'swater balance.[6] The body segments themselves may display several types ofsetae, or scales and setae.[7]
Diplurans possess a characteristic pair ofcerci projecting backwards from the last of the 11 abdominalsomites.[8] These cerci may be long and filamentous or short and pincer-like,[9] leading to occasional confusion withearwigs.[10] Some diplurans have the ability to shed their cerci if necessary (autotomy). Moulting occurs up to 30 times throughout the life of a dipluran, which is estimated to last up to one year.
Asentognaths, the mouthparts are concealed within a small pouch by the lateral margins of the head capsule. The mandibles usually have several apical teeth.[7] Diplurans do not possess any eyes or wings.[4]
In males, glandular setae or disculi may be visible along the first abdominal sternite. External genital organs are present on the eighth abdominal segment.[7]
Diplurans are common in moistsoil,leaf litter orhumus,[11] but are rarely seen because of their size and subterranean lifestyles.[6] They have bitingmouthparts and feed on a variety of live prey and dead organic matter.[3] Those species with long cerci are herbivorous.[10]
Diplurans are found on nearly all land masses, except Antarctica and several oceanic islands.[7] Their role as soil-dwelling organisms may play a key role in indicating soil quality, and as a measure ofanthropogenic impact (e.g. soil nutrient depletion as a result of farming).[12][13]
Like other non-insect hexapods, diplurans practiceexternal fertilisation. Males lay up to 200spermatophores a week, which are held off the ground by short stalks and probably only remain viable for about two days.[11] The female collects the spermatophore with her genital opening, and later layseggs in a cavity in the ground.[10][6][11] The hatchlings (ornymphs) do not undergometamorphosis, but resemble the adults, apart from their smaller size, lesser number ofsetae and their lack of reproductive organs.[3]
Several major lineages withinDiplura are readily recognizable by the structure of their cerci.
The relationships among the four groups of hexapods are not resolved, but most recent studies argue against amonophyleticEntognatha.[15] Thefossil record of the Diplura is sparse, but one apparent dipluran dates from theCarboniferous.[2] This early dipluran,Testajapyx, hadcompound eyes, andmouthparts that more closely resembled those of true insects.
Data related toDiplura at WikispeciesAuthority control databases: National |
|---|
