| Acariformes | |
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| Trombidium holosericeum (Trombidiformes:Trombidiidae) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Superorder: | Acariformes Zakhvatkin, 1952 |
| Clades andorders | |
TheAcariformes, also known as theActinotrichida, are the more diverse of the two superorders ofmites. Over 32,000 describedspecies are found in 351families, with an estimated total of 440,000 to 929,000 species, includingundescribed species.
The Acariformes can be divided into two mainclades –Sarcoptiformes andTrombidiformes. In addition, aparaphyletic group containing primitive forms, theEndeostigmata, was formerly also considered distinct. The latter is composed of only 10 families of little-studied, minute, soft-bodied mites that ingest solid food, such asfungi,algae, and soft-bodiedinvertebrates such asnematodes,rotifers, andtardigrades. These clades were formerly consideredsuborders, but this does not allow for a sufficiently precise classification of the mites and is abolished in more modern treatments; the Endeostigmata are variously considered to form a suborder on their own (the old view) or are included mainly in the Sarcoptiformes, thus making both groupsmonophyletic.[1] The superfamilyEriophyoidea, traditionally considered members of the Trombidiformes, have been found to be basal mites in genomic analyses, sister to the clade containing Sarcoptiformes and Trombidiformes.[2]
Another group often mentioned is theActinedida, but in treatments like the present one, this is split up between the Sarcoptiformes (and formerly the separate Endeostigmata) and Trombidiformes (which contains the bulk of the "Actinedida"), because it appears to be a massively paraphyletic "wastebin taxon", uniting all Acariformes that are not "typical"Oribatida andAstigmatina.[1][3] The Trombidiformes present their own problems. The small groupSphaerolichida appears to be the most ancient lineage among them. However, theProstigmata are variously subdivided into theAnystina andEleutherengona, andEupodina. The delimitation and interrelationships of these groups are entirely unclear; while most analyses find one of the latter two, but not the other to be a subgroup of the Anystina; neither of these mutually contradicting hypotheses is very robust; possibly this is a simple error becausephylogenetic software usually fails in handling nondichotomous phylogenies. Consequently, it may be best for the time being to consider each of the three main prostigmatan lineages to be equally distinct from the other two.[3]
The oldest fossils of acariform mites are from theRhynie Chert, Scotland, which dates to the earlyDevonian, around 410 million years ago[4][5] TheCretaceousImmensmaris chewbaccei had idiosoma of more than 8 mm (0.31 in) in length and was the largest fossil acariform mite and also the largesterythraeoid mite ever recorded.[6]
The Sarcoptiformes ingest solid food, being mainly microherbivores,fungivores anddetritivores. SomeAstigmatina – thePsoroptidia – have become associated withvertebrates and nest-buildinginsects. These include the well knownhouse dust mites, scab mites and mange mites, stored product mites, feather mites and some fur mites. The relationships between their main groups are not well-resolved and subject to revision. In particular it appears as if theOribatida need to be split up in two, as theAstigmatina are closer to some of them (e.g. certainDesmonomata) than the latter are to other "Oribatida".
The Trombidiformes are most noted for the economic damage caused by manyplantparasite species. All of the most important plantpests among theAcari are trombidiformans, such asspider mites (Tetranychidae) andEriophyidae. Many species are also predators,fungivores, and animal parasites. Some of the most conspicuous species of free-living mites are the relatively large and bright red velvet mites, that belong to the familyTrombidiidae.
Oribatid mites and to a much lesser extent others are a source of alkaloids in poison frogs (namely small species like thestrawberry poison-dart frogOophaga pumilio). Such frogs raised without these oribatids in their diets do not develop the strong poisons associated with them in the wild.[7]
Acariformes species appear to have evolved from a sexual ancestor and the primary manner of reproduction during the course of evolution has beensexual reproduction.[8] However, within the super order Acariformes,parthenogenetic species have arisen numerous times during the course of evolution.[8] In contrast to the commonly held view that parthenogenetic lineages are short lived, four species-rich parthenogenetic clusters of the orderOribatida are very ancient and likely arose 400-300 million years ago.[8] In some parthenogenetic species that undergoautomixis (a kind of self-fertilization that retainsmeiosis) sexual reproduction has re-emerged.
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Eriophyidae, plantparasites, e.g.Acalitus essigi (redberry mite)
| Acariformes |
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| Parasitiformes |
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Authority control databases: National |
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