''Anatea formicaria'' is an ant-mimicking spider. It is only known from the rain forest of

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

. Before 1967, it was considered to belong to the family

Clubionidae The sac spiders of the family Clubionidae have a very confusing taxonomic history. Once, this family was a large catch-all taxon for a disparate collection of spiders, similar only in that they had eight eyes arranged in two rows and conical anter ...

. It was placed there based on the ant-like outward modifications and male genitalia, which superficially resemble those of the genus '' Micaria''. In fact it is closely related to the genera '' Euryopis'' and possibly '' Achaearanea''. Males and females look very similar; the male is 2.5 mm long. Although the ant shape is unlikely to deceive an ant, the spider does hunt ants. The ant form is therefore probably to evade predators that would eat spiders, but not ants. Unlike all other ant mimics from the family Theridiidae, ''A. formicaria'' mimics the ant's petiole by an elongation of the

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

. In addition the dorsum of the "petiole" is rugose and has a distinct "node", like most ants do. The

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

is rounded and highly shiny, mimicking an ant's gaster. The spider mimics the 2.6 mm long

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 ...

ant ''

Monomorium croceiventre ''Monomorium'' is a genus of ants in the subfamily Myrmicinae. As of 2013 it contains about 396 species. It is distributed around the world, with many species native to the Old World tropics. It is considered to be "one of the more important grou ...

'', which lives in the same habitat. The color pattern (dark brown anterior, light, yellow brown posterior) of both is quite rare in ants, although two other myrmicine ants from the same area of rain forest ('' Xiphomyrma tenuicrius'' and ''

Lordomyrma ''Lordomyrma'' is a genus of ants in the subfamily Myrmicinae. Distribution and habitat The genus is known principally from Melanesia and Australia, with the one exception to this otherwise circumscribed distribution being the single species '' ...

sp.'') also show it. Myrmicine ants have large stings, this avoiding predation. The occurrence of the pattern in these three ant species could be Müllerian mimicry, while the spider uses

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 ...

(as it is palatable).

References

* {{Taxonbar, from=Q1645158 Theridiidae Spiders of New Caledonia Spiders described in 1927