Xysticus is a genus of around 300 ground crab spider species described by C. L. Koch in 1835, belonging to the order Araneae, family Thomisidae.
The genus name is derived from the Ancient Greek root xyst, meaning "scraped, scraper".
Behaviour The spiders of the genus Xysticus do not build webs; like most Thomisidae they are ambush hunters and prefer to hunt near the ground (hence the common name "ground crab spiders"). They move slowly, and commonly hunt by stationing themselves in a high-traffic area and grabbing whatever arthropod passes close enough. Also like most other Thomisidae, they seize prey with their enlarged anterior two pairs of legs and kill it by a venomous bite.
Description Xysticus and Coriarachne are dark brown or reddish-brown crab spiders often encountered on weeds or trees. While similar to the 'flower spiders', they tend to have shorter, sturdier legs. Many, but not all, species have abdomens more patterned than most Thomisus species, rather like some of the Synema species. Some however, that are more terrestrial, resemble earth in colour and texture.
Most species of the genus Xysticus are small to medium sized spiders. They show a sexual dimorphism in size. Females of typical species reach a maximum of of body length, while their males are about long, about half the size of the females.
The basic colour of these species is usually brown, beige or gray. The prosoma is sometimes slightly smaller than the opisthosoma. In many species the front body shows in the middle a broad, pale longitudinal band. The opisthosoma is clearly flattened in most species and shows a median broad and dark leaf marking.
The species are often very similar to each other, and in most cases can be distinguished only by a microscopic examination of the reproductive organs.
Diagnostic characters
Members of this genus have a smooth or granulated integument and their colour is cryptic fawn to reddish brown to blend in with the soil surface. The body and legs are covered with simple setae, rarely blunt. The tibiae and metatarsi I and II each have more than three pairs of setae ventrally. They are all cryptic and difficult to identify, with genitalia playing an important role in distinguishing between species.
Species
, this genus includes 275 species and ten subspecies.
These species have articles on Wikipedia:
Xysticus alboniger Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus ampullatus Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus auctificus Keyserling, 1880 – Canada, United States Xysticus audax (Schrank, 1803) – Europe, Turkey, Caucasus, Russia (Europe to Far East), Kazakhstan, Iran, China, Korea, Japan (type species) Xysticus britcheri Gertsch, 1934 – Russia (Europe to Far East), Alaska, Canada, United States Xysticus californicus Keyserling, 1880 – Canada, United States, Mexico Xysticus canadensis Gertsch, 1934 – Russia (Europe to Far East), Canada, United States Xysticus concursus Gertsch, 1934 – United States Xysticus cristatus (Clerck, 1757) – Europe, Turkey, Caucasus, Russia (Europe to South Siberia), Kazakhstan, Iran, Central Asia, Nepal, China, Korea, Japan. Introduced to Canada, United States Xysticus croceus Fox, 1937 – India, Nepal, Bhutan, China, Taiwan, Korea, Japan, Vietnam Xysticus discursans Keyserling, 1880 – North America Xysticus elegans Keyserling, 1880 – Canada, United States Xysticus ellipticus Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus emertoni Keyserling, 1880 – Russia (Urals to Far East), Kazakhstan, Central Asia, China, Alaska, Canada, United States Xysticus fagei Lessert, 1919 – Tanzania, Zimbabwe, South Africa Xysticus ferox (Hentz, 1847) – Alaska, Canada, United States Xysticus fervidus Gertsch, 1953 – Canada, United States Xysticus fraternus Banks, 1895 – Canada, United States Xysticus funestus Keyserling, 1880 – North America Xysticus gosiutus Gertsch, 1933 – Canada, United States Xysticus gulosus Keyserling, 1880 – North America Xysticus havilandi Lawrence, 1942 – South Africa Xysticus locuples Keyserling, 1880 – North America Xysticus lucifugus Lawrence, 1937 – South Africa Xysticus luctans (C. L. Koch, 1845) – Canada, United States Xysticus luctuosus (Blackwall, 1836) – North America, Europe, Turkey, Caucasus, Russia (Europe to Far East), Kazakhstan, Iran, Central Asia Xysticus montanensis Keyserling, 1887 – Alaska, Canada, United States Xysticus mulleri Lawrence, 1952 – South Africa, Lesotho, Eswatini Xysticus namaquensis Simon, 1910 – South Africa Xysticus natalensis Lawrence, 1938 – Zimbabwe, Mozambique, South Africa, Lesotho, Eswatini Xysticus obscurus Collett, 1877 – North America, Europe, Russia (Europe to Far East) Xysticus pellax O. Pickard-Cambridge, 1894 – North America Xysticus pretiosus Gertsch, 1934 – Alaska, Canada, United States Xysticus punctatus Keyserling, 1880 – Canada, United States Xysticus sagittifer Lawrence, 1927 – Namibia, South Africa Xysticus simonstownensis Strand, 1909 – South Africa Xysticus texanus Banks, 1904 – United States, Mexico Xysticus triguttatus Keyserling, 1880 – Canada, United States Xysticus tugelanus Lawrence, 1942 – South Africa, Lesotho Xysticus ulmi (Hahn, 1831) – Europe, Turkey, Caucasus, Russia (Europe to Middle and South Siberia), Central Asia, China Xysticus urbensis Lawrence, 1952 – South Africa, Lesotho
Xysticus abditus Logunov, 2006 – Bulgaria, Greece, Turkey Xysticus acerbus Thorell, 1872 – Europe, Central Asia, Russia (Europe to Far East) X. a. obscurior Kulczyński, 1895 – Moldova Xysticus acquiescens Emerton, 1919 – Canada, United States Xysticus advectus O. Pickard-Cambridge, 1890 – Guatemala, Costa Rica Xysticus aethiopicus L. Koch, 1875 – Ethiopia Xysticus albertensis Dondale, 2008 – Canada Xysticus albolimbatus Hu, 2001 – China Xysticus alboniger Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus aletaiensis Hu & Wu, 1989 – Kazakhstan, China Xysticus alpicola Kulczyński, 1882 – Poland, Slovakia, Ukraine Xysticus alpinus Kulczyński, 1887 – Alps (Switzerland, Italy, Germany, Austria) Xysticus alsus Song & Wang, 1994 – China Xysticus altaicus Simon, 1895 – Kazakhstan Xysticus altitudinis Levy, 1976 – Israel Xysticus ampullatus Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus apachecus Gertsch, 1933 – United States Xysticus apalacheus Gertsch, 1953 – United States Xysticus apertus Banks, 1898 – Mexico Xysticus apricus L. Koch, 1876 – Italy Xysticus aprilinus Bryant, 1930 – United States Xysticus arenarius Thorell, 1875 – Ukraine Xysticus arenicola Simon, 1875 – France Xysticus argenteus Jézéquel, 1966 – Ivory Coast Xysticus asper (Lucas, 1838) – Canary Islands Xysticus atrimaculatus Bösenberg & Strand, 1906 – China, Korea, Japan Xysticus auctificus Keyserling, 1880 – Canada, United States Xysticus audax (Schrank, 1803) – Europe, Turkey, Caucasus, Russia (Europe to Far East), Kazakhstan, Iran, China, Korea, Japan (type species) X. a. massanicus Simon, 1932 – France Xysticus audaxoides B. S. Zhang, Y. Zhang & Song, 2004 – China Xysticus austrosibiricus Logunov & Marusik, 1998 – Russia (Urals to north-eastern Siberia), Kazakhstan, Mongolia, China Xysticus autumnalis L. Koch, 1875 – Australia (New South Wales) Xysticus aztecus Gertsch, 1953 – Mexico Xysticus bacurianensis Mcheidze, 1971 – Turkey, Caucasus (Russia, Georgia, Azerbaijan) Xysticus bakanas Marusik & Logunov, 1990 – Kazakhstan Xysticus banksi Bryant, 1933 – Canada, United States Xysticus barbatus Caporiacco, 1936 – Libya Xysticus benefactor Keyserling, 1880 – Canada, United States Xysticus bengalensis Tikader & Biswas, 1974 – India Xysticus bengdakus Saha & Raychaudhuri, 2007 – India Xysticus beni Strand, 1913 – DR Congo Xysticus berlandi Schenkel, 1963 – China Xysticus bermani Marusik, 1994 – Russia (middle to north-eastern Siberia), China Xysticus bharatae Gajbe & Gajbe, 1999 – India Xysticus bicolor L. Koch, 1867 – Greece Xysticus bicuspis Keyserling, 1887 – Canada, United States Xysticus bifasciatus C. L. Koch, 1837 – Europe, Turkey, Caucasus, Russia (Europe to South Siberia), Kazakhstan, Central Asia, China Xysticus bimaculatus L. Koch, 1867 – Australia (Queensland) Xysticus bohdanowiczi Zhang, Zhu & Song, 2004 – China Xysticus bolivari Gertsch, 1953 – Mexico Xysticus bradti Gertsch, 1953 – Mexico Xysticus breviceps O. Pickard-Cambridge, 1885 – India Xysticus brevidentatus Wunderlich, 1995 – Italy, Croatia, Bosnia and Herzegovina, Montenegro, Albania Xysticus britcheri Gertsch, 1934 – Russia (Europe to Far East), Alaska, Canada, United States Xysticus brunneitibiis Caporiacco, 1939 – Ethiopia Xysticus californicus Keyserling, 1880 – Canada, United States, Mexico Xysticus canadensis Gertsch, 1934 – Russia (Europe to Far East), Canada, United States Xysticus caspicus Utochkin, 1968 – Russia (Europe to Central Asia), Azerbaijan, Kazakhstan, Turkmenistan Xysticus caucasius L. Koch, 1878 – Georgia Xysticus chaparralis Schick, 1965 – United States Xysticus charitonowi Mcheidze, 1971 – Georgia Xysticus chippewa Gertsch, 1953 – North America, Northern Europe Xysticus chui Ono, 1992 – China, Taiwan Xysticus cochise Gertsch, 1953 – United States Xysticus coloradensis Bryant, 1930 – United States Xysticus concinnus Kroneberg, 1875 – Central Asia Xysticus concretus Utochkin, 1968 – Russia (Far East), China, Korea, Japan Xysticus concursus Gertsch, 1934 – United States Xysticus conflatus Song, Tang & Zhu, 1995 – China, Korea Xysticus connectens Kulczyński, 1901 – China Xysticus cor Canestrini, 1873 – Azores, Southern Europe, Turkey, Iran Xysticus corsicus Simon, 1875 – France (Corsica) Xysticus crispabilis Song & Gao, 1996 – China Xysticus cristatus (Clerck, 1757) – Europe, Turkey, Caucasus, Russia (Europe to South Siberia), Kazakhstan, Iran, Central Asia, Nepal, China, Korea, Japan. Introduced to Canada, United States Xysticus croceus Fox, 1937 – India, Nepal, Bhutan, China, Taiwan, Korea, Japan, Vietnam Xysticus cunctator Thorell, 1877 – Canada, United States Xysticus curtus Banks, 1898 – Mexico Xysticus dali Li & Yang, 2008 – China Xysticus davidi Schenkel, 1963 – Russia (Far East), China Xysticus denisi Schenkel, 1963 – China Xysticus desidiosus Simon, 1875 – Europe Xysticus discursans Keyserling, 1880 – North America Xysticus diversus (Blackwall, 1870) – Italy (Sicily) Xysticus doriai (Dalmas, 1922) – Italy Xysticus dzhungaricus Tystshenko, 1965 – Kazakhstan, Russia (Central Asia to Far East), Central Asia, China Xysticus edax (O. Pickard-Cambridge, 1872) – Turkey, Azerbaijan, Israel, Iraq, Iran Xysticus elegans Keyserling, 1880 – Canada, United States Xysticus elephantus Ono, 1978 – Nepal, China Xysticus ellipticus Turnbull, Dondale & Redner, 1965 – Canada, United States Xysticus emertoni Keyserling, 1880 – Russia (Urals to Far East), Kazakhstan, Central Asia, China, Alaska, Canada, United States Xysticus ephippiatus Simon, 1880 – Kazakhstan, Russia (Central Asia to Far East), Central Asia, Mongolia, China, Korea, Japan Xysticus erraticus (Blackwall, 1834) – Europe, Turkey, Caucasus (Russia) Xysticus facetus O. Pickard-Cambridge, 1896 – Mexico, El Salvador Xysticus fagei Lessert, 1919 – Tanzania, Zimbabwe, South Africa Xysticus federalis Gertsch, 1953 – Mexico Xysticus ferox (Hentz, 1847) – Alaska, Canada, United States Xysticus ferrugineus Menge, 1876 – Europe, Turkey, China Xysticus ferruginoides Schenkel, 1963 – Russia (South Siberia, Far East), Mongolia Xysticus fervidus Gertsch, 1953 – Canada, United States Xysticus flavitarsis Simon, 1878 – DR Congo Xysticus flavovittatus Keyserling, 1880 – United States Xysticus floridanus Banks, 1896 – United States Xysticus fraternus Banks, 1895 – Canada, United States Xysticus funestus Keyserling, 1880 – North America Xysticus furtivus Gertsch, 1936 – United States Xysticus gallicus Simon, 1875 – Europe, Turkey, Caucasus, Iran