Belongs within: Thomisidae.
Xysticus, ground crab spiders, is a genus of crab spiders with a generally flattened abdomen, carapace with the front distinctly higher than the back, and the two pairs of lateral eyes on incompletely joined tubercles.
<==Xysticus Koch 1835S06 |--X. altaicus Simon 1895S95 |--X. audaxR14 |--X. augur Strand 1900S06 |--X. austerus Koch 1880S06 |--X. bifasciatus Koch 1837S06 |--X. bliteus (Simon 1875)PO08 |--X. borealis Keys. 1882S06 |--X. calenzanae Kraus 1955K55 |--X. canadensis Gertsch 1934PS08 |--X. caperatus Simon 1875PO08 |--X. connectens Kulczyński 1901K01 |--X. cristatus (Clerck 1757)PO08 |--X. cunctatorMC02 |--X. deichmanni Sörens. 1898S06 |--X. edax (Pickard-Cambridge 1872)PO08 |--X. elegansJVHN90 |--X. elongatus (Stoliczka 1869) [=Thomisus (Xysticus) elongatus]S69 |--X. emertoni Keyserling 1880M01 |--X. erraticus (Blackwall 1834)BBM02 |--X. excellens Kulcz. 1885S06 |--X. fienaeJD-S07 |--X. fucatus [incl. X. albimanus]K01 |--X. grallator Simon 1932K55 |--X. inaequalis Kulczyński 1901K01 |--X. kempeleni Thorell 1872PO08 |--X. kochii Thorell 1872K55 |--X. labradoriensis Keys. 1887S06 |--X. lanio Koch 1835MF11 |--X. lateralisK01 |--X. lineatus (Westring 1851)PO08 |--X. luctatorK01 |--X. luctuosus (Blackw. 1836)S06 |--X. nervosusE66 |--X. ninniBV00 |--X. norvegicus Strand 1900S06 |--X. nubilus Simon 1875K55 |--X. obscurus Collett 1887PS08 |--X. pini (Hahn 1831)S06 |--X. promiscuus Pickard-Cambridge 1876PO08 |--X. pugilis (Stoliczka 1869) [=Thomisus (Xysticus) pugilis]S69 |--X. punctatusJDW90 |--X. rainbowi Strand 1901 [=X. obscurus Rainbow 1898 non Collett 1887]M72 |--X. sabulosus (Hahn 1832)BBM02 |--X. secedensBV00 |--X. sexangulatus Strand 1900S06 |--X. stomachosusS06 |--X. striatipesK01 |--X. triguttatusS06 |--X. ulmi (Hahn 1831)K55 |--X. viaticus (L. 1758)S06 `--X. xerodermus Strand 1913PO08 Nomen nudum: Xysticus polarisS06
*Type species of generic name indicated
References
[BV00] Bayram, A., & M. İ. Varol. 2000. Spiders active on snow in eastern Turkey. Zoology in the Middle East 21: 133–137.
[BBM02] Bonte, D., L. Baert & J.-P. Maelfait. 2002. Spider assemblage structure and stability in a heterogeneous coastal dune system (Belgium). Journal of Arachnology 30 (2): 331–343.
[E66] Evans, H. E. 1966. The Comparative Ethology and Evolution of the Sand Wasps. Harvard University Press: Cambridge (Massachusetts).
[JDW90] Jennings, D. T., J. B. Dimond & B. A. Watt. 1990. Population densities of spiders (Araneae) and spruce budworms (Lepidoptera, Tortricidae) on foliage of balsam fir and red spruce in east-central Maine. Journal of Arachnology 18: 181–194.
[JVHN90] Jennings, D. T., W. M. Vander Haegen & A. M. Narahara. 1990. A sampling of forest-floor spiders (Araneae) by expellant, Moosehorn National Wildlife Refuge, Maine. Journal of Arachnology 18: 173–180.
[JD-S07] Jocqué, R., & A. S. Dippenaar-Schoeman. 2007. Spider Families of the World. Royal Museum for Central Africa: Tervuren (Belgium).
[K55] Kraus, O. 1955. Spinnen von Korsika, Sardinien und Elba (Arach., Araneae). Senckenbergiana Biologica 36: 371–394.
[K01] Kulczyński, V. 1901. Arachnoideák [Arachnoidea]. In: Horváth, G. (ed.) Zichy Jenő Gróf Harmadik Ázsiai Utazása [Dritte Asiatische Forschungsreise des Grafen Eugen Zichy] vol. 2. Zichy Jenő Gróf Harmadik Ázsiai Utazásának Állattani Eredményei [Zoologische Ergebnisse der Dritten Asiatischen Forschungsreise des Grafen Eugen Zichy] pp. 311–369. Victor Hornyánszky: Budapest, and Karl W. Hierseman: Leipzig.
[MF11] Mąkol, J., & M. Felska. 2011. New records of spiders (Araneae) as hosts of terrestrial Parasitengona mites (Acari: Actinotrichida: Prostigmata). Journal of Arachnology 39 (2): 352–354.
[MC02] Miliczky, E. R., & C. O. Calkins. 2002. Spiders (Araneae) as potential predators of leafroller larvae and egg masses (Lepidoptera: Tortricidae) in central Washington apple and pear orchards. Pan-Pacific Entomologist 78 (2): 140–150.
[M72] Monroe, R. 1972. Chelicerate type-specimens in the Queensland Museum. Memoirs of the Queensland Museum 16 (2): 291–307.
[M01] Morse, D. H. 2001. Harvestmen as commensals of crab spiders. Journal of Arachnology 29: 273–275.
[PS08] Pinzón, J., & J. Spence. 2008. Performance of two arboreal pitfall trap designs in sampling cursorial spiders from tree trunks. Journal of Arachnology 36 (2): 280–286.
[PO08] Pluess, T., I. Opatovsky, E. Gavish-Regev, Y. Lubin & M. H. Schmidt. 2008. Spiders in wheat fields and semi-desert in the Negev (Israel). Journal of Arachnology 36 (2): 368–373.
[R14] Ramírez, M. J. 2014. The morphology and phylogeny of dionychan spiders (Araneae: Araneomorphae). Bulletin of the American Museum of Natural History 390: 1–374.
[S95] Simon, E. 1895. Arachnides recueillis par Mr G. Potanine en Chine et en Mongolie (1876–1879). Izviestĭia Imperatorskoi Akademĭi Nauk” [Bulletin de l’Academie Imperiale des Sciences de St. Pétersbourg], Ser. 5, 4: 331–345.
[S69] Stoliczka, F. 1869. Contribution to the knowledge of Indian Arachnoidea. Journal of the Asiatic Society of Bengal 38 pt 2 (4): 201–251, pls 18–20.
[S06] Strand, E. 1906. Die arktischen Araneae, Opiliones und Chernetes. In: Römer, F., & F. Schaudinn (eds) Fauna Arctica. Eine Zusammenstellun der arktischen Tierformen, mit besonder Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898 vol. 4 pp. 431–478. Gustav Fischer: Jena.