Xysticus audax

Xysticus audax exhibits considerable variation in coloration and pattern, making identification challenging, particularly for females.

Female. As with crab spiders in general, females are larger than males, with a total length of 4.3–6.4 mm and cephalothorax length of 1.88–2.93 mm. Two main color varieties have been documented: a dark variety and a light variety. The dark variety has sides of the cephalothorax that are dark brown with yellowish dots and spots, while the light variety shows pale brown coloration with darker patches. The epigyne is highly variable and features an atrium divided by a broad septum that is usually broader than in X. cristatus. The anterior borders each bear a low but distinct tooth, and the copulatory ducts vary considerably in length.

Male. Males have a total length of 3.8–5.0 mm, with the cephalothorax measuring 1.97–2.91 mm in length and 1.88–2.59 mm in width. The cephalothorax is brown to dark brown with a median band that is brownish anteriorly and becomes yellowish-white posteriorly. The chelicerae are dark greyish-brown with a yellowish-white diagonal band, while the sternum is yellowish-white with black dots. The legs show a distinctive pattern with distal segments mostly pale yellowish-brown and proximal segments dark brown with yellow-white dots and patches. …

X. audax is a trans-Eurasian temperate species with a broad distribution across the Palearctic region. It ranges from Iceland in the west through the temperate belt of Eurasia to Sakhalin and Japan (Hokkaido and Honshu) in the east. The species has been recorded from numerous countries including Russia, Kazakhstan, Iran, China, Korea, and most European countries. Some records from Crete, Turkey, and Iran may require confirmation and could potentially represent misidentifications of related species.

The specific name audax is derived from the Latin word meaning "bold" or "daring" (German: verwegen), referring to the spider's behavior as observed by the original describer.