Corinnidae
Guides
Castianeira
Ant-mimic Sac Spiders, Ant-mimic Spiders
Castianeira is a genus of ant-mimicking sac spiders in the family Corinnidae, first described by Eugen von Keyserling in 1879. The genus contains approximately 127 species distributed across Eurasia, Africa, and the Americas, with notable diversity in North America (26 species) and Mexico/Central America. These spiders are recognized for their remarkable ant-mimicry, achieved through body shape, coloration, and behavioral adaptations.
Castianeira alteranda
Prairie Ant-mimic Sac Spider
Castianeira alteranda is a species of ant-mimic spider in the family Corinnidae. It occurs in the northern United States and southern Canada, with records from Alberta, Manitoba, and Saskatchewan. The species was described by Gertsch in 1942. Like other members of the genus Castianeira, it exhibits ant-mimicry as a defensive strategy.
Castianeira athena
Castianeira athena is a species of ant-mimic spider in the family Corinnidae, first described by Reiskind in 1969. Like other members of its genus, it exhibits Batesian mimicry of ants as a defensive strategy against predators. The species occurs in the United States and Mexico. As a corinnid spider, it is an active hunter rather than a web-builder.
Castianeira cingulata
twobanded antmimic, two-banded ant-mimic sac spider
Castianeira cingulata is a small ant-mimicking spider in the family Corinnidae, commonly known as the twobanded antmimic. Females measure 7–8 mm in body length, males 6–7 mm. The species exhibits Batesian mimicry of carpenter ants through coloration, body shape, and behavioral displays including bobbing movements and foreleg waving that simulates antennae. It inhabits woodland leaf litter across eastern North America, where it hunts insect prey.
ant-mimicryBatesian-mimicryleaf-litter-predatorCorinnidaeeastern-North-Americaforest-floor-spiderharmless-to-humansoverwintering-in-silk-sacksdiurnal-and-nocturnalslow-deliberate-movementforeleg-waving-displaysmall-size-6-8mmtwo-pale-abdominal-bandscarpenter-ant-mimicwoodland-habitatactive-hunternon-web-building-spidersilken-retreat-constructionpotential-multi-year-lifespan-in-southwandering-behavior-brings-indoorsCastianeira crocata
Red-spotted Ant-mimic Sac Spider, Red Stripe Spider
Castianeira crocata is a small ant-mimic spider in the family Corinnidae, first described by Nicholas Marcellus Hentz in 1847. It is found in the United States. The species has a black body with distinctive red dorsal markings, a color pattern that can lead to misidentification as a black widow spider despite its very different body shape. Like other Castianeira species, it exhibits ant-mimicry behaviors and morphology.
Castianeira crucigera
Castianeira crucigera is a species of ant-mimic spider in the family Corinnidae, found in the United States. Like other members of its genus, it exhibits ant-mimicry morphology and behavior. The species is poorly documented in the scientific literature compared to congeners such as C. cingulata.
Castianeira descripta
Red-spotted Ant-mimic Sac Spider, Redspotted Antmimic
Castianeira descripta is a small ant-mimicking spider in the family Corinnidae. It exhibits Batesian mimicry of ants, particularly carpenter ants, through body shape, coloration, and behavioral adaptations. The species is distributed across the United States and Canada.
Castianeira dorsata
Castianeira dorsata is a species of true spider in the family Corinnidae, first described by Banks in 1898. It is distributed across the United States and Mexico. Like other members of its genus, it is an ant-mimicking spider, though specific behavioral and ecological details for this species remain poorly documented.
Castianeira floridana
Castianeira floridana is a species of ant-mimicking spider in the family Corinnidae, native to the southeastern United States and Cuba. Like other members of its genus, it exhibits myrmecomorphy—mimicking ants in appearance and behavior as a defensive adaptation. The species was described by Banks in 1904. Information specific to this species beyond its geographic range is limited in published sources.
Castianeira longipalpa
Long-palped Ant-mimic Spider
Castianeira longipalpa is an ant-mimic spider in the family Corinnidae, recognized as the most widespread member of its genus in the United States and Canada. This species exhibits Batesian mimicry of ants, gaining protection from predators that avoid aggressive ant species. It is a fast, ground-dwelling hunter active during daylight hours.
Castianeira thalia
Castianeira thalia is a species of ant-mimic spider in the family Corinnidae, first described by Reiskind in 1969. It belongs to a genus known for ant-mimicry, where spiders resemble ants in appearance and behavior to avoid predation. The species has been documented in the western United States, particularly along the West Coast.
Castianeira variata
Variegated Ant-mimic Sac Spider
Castianeira variata is an ant-mimicking spider in the family Corinnidae, found in North and Central America. Females typically measure 7–9 mm in body length and are larger than males. The species exhibits Batesian mimicry of ants, particularly carpenter ants, as a defense strategy against predators. It is similar in general appearance to C. longipalpus and can be distinguished by specific coloration and pattern details.
Castianeira walsinghami
Castianeira walsinghami is a species of true spider in the family Corinnidae. It occurs in the United States and Canada. Beyond basic taxonomic placement and geographic distribution, detailed natural history information for this specific species is limited in available sources.
Creugas bajulus
Creugas bajulus is a species of true spider in the family Corinnidae, first described by Gertsch in 1942. It is known from Mexico and has been reported in California, USA. The genus Creugas belongs to a group of ground-dwelling spiders commonly known as ant-mimics or ant-like spiders, though species-specific behavioral details for C. bajulus remain poorly documented.
Creugas gulosus
Creugas gulosus is a species of true spider in the family Corinnidae, first described by Thorell in 1878. Native to South America, it has established introduced populations across Africa, Myanmar, Australia, and Pacific islands. The species belongs to a genus of ground-dwelling spiders that are part of the diverse corinnid fauna.
Falconina gracilis
Falconina gracilis is a species of true spider in the family Corinnidae, a group commonly known as ground spiders or ant-mimicking spiders. It is native to South America, with established populations in Brazil, Paraguay, and Argentina. The species has been introduced to the United States and Cuba, where it occurs as a non-native species. Records from GBIF also indicate presence in Peru, Bolivia, and Uruguay.
Myrmecotypus lineatus
Myrmecotypus lineatus is a species of true spider in the family Corinnidae, subfamily Castianeirinae. It is the only species in the genus Myrmecotypus with a documented occurrence in the United States, making its distribution atypical compared to congeners which are otherwise restricted to the Neotropical region (Mexico to Panamá). The species was described by Emerton in 1909. Very few observations of this spider exist in public databases.
Septentrinna bicalcarata
Septentrinna bicalcarata is a species of true spider in the family Corinnidae, first described by Eugène Simon in 1896. The species is recorded from the United States and Mexico. It belongs to a small genus of ground-dwelling spiders within the ant-mimic spider family Corinnidae. Published information on its biology and ecology remains limited.
Trachelas
Trachelas is a genus of hunting spiders in the family Trachelidae, established by Ludwig Carl Christian Koch in 1872. The genus contains approximately 99 species with worldwide distribution across tropical, subtropical, and temperate regions. Trachelas sensu stricto is restricted to the Old World, while New World species represent a distinct lineage only distantly related to the core group. The genus has undergone significant taxonomic revision, with species previously assigned to Corinnidae now placed in Trachelidae.
Xeropigo
Xeropigo is a genus of sac spiders in the family Corinnidae, first described by O. Pickard-Cambridge in 1882. The genus comprises 17 described species distributed across South America and the Caribbean, with the majority of species occurring in Brazil. Recent taxonomic revisions have significantly expanded the known diversity, with seven new species described from Brazil in 2016. The genus shows notable species richness in northeastern Brazilian states, particularly Piauí, Ceará, and Maranhão.
Xeropigo tridentiger
Xeropigo tridentiger is a corinnid spider species first described from Colombia in 1870. It is one of the most widespread species in the genus, with records spanning northern South America including Colombia, Venezuela, and Brazil. The species name refers to the three-toothed (trident) structure of the male pedipalp, a diagnostic feature. Recent taxonomic work has updated its known distribution, confirming its presence across multiple Brazilian states.