''Castianeira'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of ant-like corinnid sac spiders first described by

Eugen von Keyserling Eugen von Keyserling (22 March 1833 in Pockroy, Lithuania – 4 April 1889 in Dzierżoniów, Silesia) was a Baltic-German arachnologist. He studied in the University of Tartu. He was the author of ''Die Spinnen Amerikas'', and completed ''Die Ara ...

in 1879. They are found in

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

, but are absent from

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. Twenty-six species are native to North America, and at least twice as many are native to Mexico and Central America.

Description

Spiders of this genus have eight eyes in two procurved rows, the upper row slightly wider than the lower row. This distinguishes them from species of '' Micaria'' that almost always have straight rows of eyes. The

opisthosoma The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma (cephalothorax). It is a distinctive feature of the subphylum Chelicerata (arachnids, horseshoe crabs and others). Although it is similar in most respects to a ...

is not constricted, and has an elongate to oval shape to mimic that of ants. In addition to the ant-like coloration, the abdomen has white scale-like

setae In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

. The rear pair of legs are the longest, and the front pair are second longest.

Mimicry

Some species mimic specific groups of ants, while others only have generic body modifications to look more ant-like, such as an elongated body or a carapace pattern that creates the illusion of a third body segment. Some mimic ant behavior as well, waving their front two legs as if they were antennae or bobbing their abdomen to look more ant-like. Certain species found in Texas mimic fire ants to prey on them, while some species use

Batesian mimicry Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on bu ...

, appearing like velvet ants to take advantage of their

aposematism Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

in order to deter predators.

Ant mimicry

Known ant-spider mimicry: *''C. cingulata'' – short carpenter ants *''C. longipalpus'' –

myrmicine Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and ...

ponerine Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including ''Dinoponera gigantea'' - one of the world's largest species of ant. Mated workers have replaced the queen as the fu ...

ants *''C. memnonia'' – ''

Pachycondyla ''Pachycondyla'' is a ponerine genus of ants found in the Neotropics. Distribution ''Pachycondyla'' is currently distributed from southern United States to northern Argentina, but some fossil species (e.g. '' P. eocenica'' and '' P. lutzi'') a ...

obscuricornis'' Emery *''C. rica'' – ''

Atta Atta or ATTA may refer to: * Atta Halilintar, Indonesian YouTuber, singer and entrepreneur * ''Atta'' (ant), a genus of ants in the family Formicidae * ''Atta'' (novel), a 1953 novel by Francis Rufus Bellamy * Atta flour, whole wheat flour made f ...

'' sp, '' Odontomachus'' sp, and others *''C. trilineata'' – reddish carpenter ants ( Latreille)

Species

it contains 127 species:

Description

Mimicry

Ant mimicry

Species

References

Further reading