''Ommatoiulus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

millipede Millipedes (originating from the Latin , "thousand", and , "foot") are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derive ...

s in the family

Julidae Julidae is a family of millipedes in the order Julida, containing more than 600 species in around 20 genera. Its members are largely confined to the Western Palaearctic, with only a few species extending into the Oriental and Afrotropical realm ...

. The

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were described in 2012, and those just from

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

.Akkari, N. and H. Enghoff. (2012)
Review of the genus ''Ommatoiulus'' in Andalusia, Spain (Diplopoda: Julida) with description of ten new species and notes on a remarkable gonopod structure, the fovea.
''Zootaxa'' 3538 1-58. Six new species were described from Portugal in 2017. There are many millipedes known to belong to this genus that do not yet have official names.Bailey, P. T. and T. R. de Mendonça. (1990)
The distribution of the millipede ''Ommatoiulus moreleti'' (Diplopoda, Julida: Julidae) in relation to other ''Ommatoiulus'' species on the south-western Iberian Peninsula.
''Journal of Zoology'' 221(1) 99–111. Ommatoiulus sabulosus 2

This genus is distinguished by the position of the

ozopore An ozopore is the opening of a defensive gland present in some arthropods, notably in millipedes of the order Polydesmida ocelli A simple eye or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

and the gonopod legs, the presence of accessory claws on the juveniles, and the presence in males of a large fovea, a cavity where

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

are stored. Familiar species include the black Portuguese millipede (''Ommatoiulus moreletii''). It is an

invasive species in Australia Invasive species are a serious threat to endemic Australian species, and an ongoing cost to Australian agriculture. Numerous species arrived with European maritime exploration and colonisation of Australia and steadily since then. There is ...

known for its "plagues", when it emerges in swarms so massive that they stop trains, which crush them in huge numbers and make the rails slippery. Like some other millipedes, it produces a secretion with an obnoxious odor and tendency to stain floors when the swarms invade houses.Yuncken, L
Millipede madness.
ABC Science. April 5, 2007. Another well-known species is the striped millipede (''O. sabulosus''), which also swarms. In 2002 it flooded the streets of

Dąbrowa Górnicza Dąbrowa Górnicza () is a city in Zagłębie Dąbrowskie, southern Poland, near Katowice and Sosnowiec. It is located in eastern part of the Silesian Voivodeship, on the Czarna Przemsza and Biała Przemsza rivers (tributaries of the Vistula Rive ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

, "causing panic among the inhabitants". Swarms in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

have consisted of "thousands of millions" of individuals, far too many to count. This species has also been known to stop trains. VERHOEFF K. W. (1900)
Wandernde Doppelfüßler, Eisenbahnzüge hemmend
in Zool. Anz., 23, p. 465—473. Species include:
Systema Naturae 2000. *'' Ommatoiulus alacygni'' *'' Ommatoiulus andalusius'' *'' Ommatoiulus aurozonatus'' *'' Ommatoiulus avatar'' *'' Ommatoiulus baenai'' *''

Ommatoiulus baileyi ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus bipartitus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus camurus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus caspius ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus cingulatus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus denticulatus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus diplurus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

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Ommatoiulus dorsovittatus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 10 new species were d ...

'' *'' Ommatoiulus fuentei'' *'' Ommatoiulus fuscounilineatus'' *'' Ommatoiulus hoffmani'' *'' Ommatoiulus ibericus'' *'' Ommatoiulus ilicis'' *'' Ommatoiulus inconspicuus'' *'' Ommatoiulus jaenensis'' *'' Ommatoiulus kessleri'' *'' Ommatoiulus kimei'' *'' Ommatoiulus lapidarius'' *'' Ommatoiulus litoralis'' *''

Ommatoiulus lusitanus ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The Taxonomy (biology), taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 1 ...

'' *'' Ommatoiulus martensi'' *'' Ommatoiulus moreletii'' *'' Ommatoiulus navasi'' *'' Ommatoiulus niger'' *'' Ommatoiulus oliveirae'' *'' Ommatoiulus oxypygus'' *'' Ommatoiulus paralellus'' *'' Ommatoiulus porathi'' *'' Ommatoiulus pseudoflagellatus'' *'' Ommatoiulus punicus'' *'' Ommatoiulus recueroi'' *'' Ommatoiulus reipi'' *''

Ommatoiulus rutilans ''Ommatoiulus'' is a genus of millipedes in the family Julidae. The Taxonomy (biology), taxonomy of the genus has had a complicated history. As it stands now, there are approximately 60 described species, but this is likely to change. At least 1 ...

'' *'' Ommatoiulus sabinarensis'' *'' Ommatoiulus sabulosus'' *'' Ommatoiulus schubarti'' *'' Ommatoiulus staglae'' *'' Ommatoiulus stellaris'' *'' Ommatoiulus tetuanus'' *'' Ommatoiulus vilnensis''

References

{{Taxonbar, from=Q4298887 Julida