Genus Coleosoma

koh-lee-oh-SO-muh

O. P.-Cambridge, 1882.

3 species in BugGuide's range (North America north of Mexico)

small

C. acutiventer: carapace and abdomen all dark brownish-black; legs entirely pale yellowish, except for a black streak on the anterior side of the coxa, trochanter, and base of femur I. Males are ant-mimics (constricted abdomen); females have a globular abdomen with a conical projection on the back that extends past the spinnerets (Chamberlin & Ivie, 1944)

C. floridanum: female's cephalothorax & legs orange-yellowish; female's abdomen w/o conical extension and yellowish-brown with 2 dorsal longitudinal black stripes (which may be broken into 4 black patches, and which enclose some white pigment). Male darker than female; abdomen moderately constricted and with more black pigment. (Saaristo, 2006, p. 60 & Levi, 1967c, p. 181)

C. normale: female's abdomen nearly cylindrical (no conical extension); male's abdomen without constriction; cephalothorax and legs of both genders are pale without dark markings; abdomen of both genders pale orange-yellow with two dorsal parallel dark stripes from front to spinnerets (stripes quite narrow about middle and heavier at ends) (Bryant, 1944, p. 56 & Levi, 1959a, p. 3)

C. acutiventer: southeastern United States (Levi, 1959a, p. 4)

C. floridanum: a pantropical species; Florida and other tropical regions in North America (Levi, 1967c, p. 181)

C. normale: records for Arizona, North Carolina, & Florida (Levi, 1959a, p. 3 & Bryant, 1944, p. 56)

Males of this genus may be confused with other spiders that have a constricted abdomen; Microlinyphia males have a long wiry embolus that turns a full circle larger than the pedipalp itself; both Neriene & Microlinyphia males have a much longer carapace than Coleosoma.

    Coleosoma                   Microlinyphia                 Neriene

see hyperlinks to PDFs in above sections