About Micrathena crassa (Keyserling, 1864)
Micrathena crassa is a medium-sized spiny orb-weaver spider. Females of this species have a total body length between 5.0 and 7.7 mm, with a carapace that measures 2.3 mm long and 1.9 mm wide. Female carapaces and legs are orange-brown. Females have a notably spiny, mostly white abdomen, with dark brown sclerotized areas on the abdominal sides and posterior. White areas on the abdominal dorsum bear spines, and this species typically has four pairs of dorsal spines arranged across the abdomen. A distinct groove sits between the head and thorax regions, and the abdomen may have small anterior lobes positioned above the carapace. Males are smaller than females: recorded male specimens from Peru have a total length of 4.4 mm and a carapace length of 1.8 mm. Male coloration differs slightly from females; males have a dark olive-brown carapace that is darker along the sides, with whitish coxae and legs. Micrathena crassa can be told apart from closely related Micrathena species by its unique abdominal spination pattern and the deep groove across its carapace. This species has been recorded across a range from Costa Rica, south through South America to Argentina, including the countries of Venezuela, Colombia, Ecuador, and Peru, along with other South American nations. It typically inhabits cloud forests and montane environments. Known collected specimens include individuals from Monteverde, Costa Rica, found at an elevation of approximately 1,600 meters.
