Genus Castianeira Keyserling

Castianeira Keyserling, 1879. Verh. Zool. Bot. Ges. Wien.: 335.

Thargalia Karsch, 1880. Zeit. f.d. Ges. Natur. 53: 374.

Tylophora Simon, 1887. Ann. Soc. Ent. Fr.: 377.

Geotrochu Emerton, 1890. Trans. Conn. Acad. Arts Sci. 8: 4.

Castiuneira Comstock, 1940. The Spider Book. New York: 592.

Medium-sized (4-8 mm long) clubionids with elongated ant-like bodies and moderately long and thin legs. The members of the genus are easily recognized by the heavily sclerotized, sometimes shiny carapace and abdomen; carapace elongate ovoid, bulging and highest along fovea dark brown to reddish black, darker in eye area; small eyes uniform in size, in two transverse rows with AE recurved, AME closer to laterals than to each other, PE distinctly procurved and longer than AE; chelicerae moderately long, robust, and hirsute, with two promarginal and two (sometimes three) retromarginal teeth; outer laterals of maxillae convex and not constricted; legs long and slender, usually orange to dark brown or black, possessing short dense claw tufts and thin scopulae; trochanter IV with prominent apicoventral notch; femur I with two or three dorsal spines, one or two prolaterals, metatarsus I with four ventral spines in two pairs. Abdomen elongated, ovoid to slender, with transverse bands of white scale-like setae and large shiny dorsal epigastric and ventral scuta (reduced in females), lacks cluster of long erect setae at anterior end; femur and patella of male palpus without apophysis; tibia with strong retrolateroventral ridge bearing one or more small teeth; cymbium basally rounded, long and slender distally; tegulum like cymbium but enclosing two loops of seminal duct within base; embolus long and slender, straight, spirally twisted apically, emanating directly from elongated tip; epigynum with rounded convex hairy plate, copulatory openings small, round, elliptical and slit-like, well separated, distinct, and often linked by shallow grooves; spermathecae longer than wide, touching midline, rugose, and commonly with slender posterior part quite close to the anterior of genital groove.

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These spiders are common in leaf litter in shady environments, some associated with ants.