The specific nameaudax is derived from the Latin word meaning "bold" or "daring" (German: verwegen), referring to the spider's behavior as observed by the original describer.[3]
Xysticus audax exhibits considerable variation in coloration and pattern, making identification challenging, particularly for females.[1][2]
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.[2]
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.[2]
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.[2]
The legs show a distinctive pattern with distal segments mostly pale yellowish-brown and proximal segments dark brown with yellow-white dots and patches. The opisthosoma is dark brown with a whitish, distinctly dentated median band and dull yellowish-white margins.[2]
Males can be distinguished from the closely related Xysticus cristatus by specific characteristics of the pedipalp. The median apophysis has a pickaxe shape with short shaft ends that are nearly equal in length, and the longest tooth of the basal tegular apophysis is distinctive.[1]
Distribution
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.[1] The species has been recorded from numerous countries including Russia, Kazakhstan, Iran, China, Korea, and most European countries.[4]
Some records from Crete, Turkey, and Iran may require confirmation and could potentially represent misidentifications of related species.[1]
Habitat
The species inhabits a variety of open and semi-open habitats including meadows, groves, heathlands with Calluna, and dry pine forests.[2] It has been collected from various vegetation types including steppe slopes, mixed forests, and tundra environments.[1]
Biology
Adult males are active from the beginning of May to mid-July, while adult females can be found throughout the year.[2]
Taxonomy
Xysticus audax belongs to the cristatus species group and is most closely related to Xysticus cristatus and Xysticus pseudocristatus. The females of X. audax and X. cristatus are nearly indistinguishable, making male specimens essential for reliable species identification.[1]
The species has a complex taxonomic history with numerous synonyms, reflecting the difficulty in distinguishing it from related species. The name Xysticus pini was commonly used for this species in older literature before the current nomenclature was established.[5]
References
1 2 3 4 5 6 7 Azarkina, G. N.; Logunov, D. V. (2001). "Separation and distribution of Xysticus cristatus (Clerck, 1758) and X. audax (Schrank, 1803) in eastern Eurasia, with description of a new species from the mountains of central Asia (Aranei: Thomisidae)". Arthropoda Selecta. 9: 133–150.
1 2 3 4 5 6 7 8 Almquist, S. (2007). "Swedish Araneae, part 2 – families Dictynidae to Salticidae". Insect Systematics & Evolution, Supplement. 63 (2006): 285–601.
↑ Schrank, F. von P. (1803). Fauna Boica. Durchgedachte Geschichte der in Baiern einheimischen und zahmen Thiere. Dritter und lezter Band, erste Abtheilung. Landshut: Philipp Krüll. pp.229–244.
↑ Simon, E. (1918). "Notes sur la synonymie de plusieurs espèces de la famille des thomisides". Bulletin de la Société Entomologique de France. 23 (1): 51–52.
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