Arctosa alpigena, Alpine bear-spider

Arctosa alpigena (Doleschall, 1852) (Alpine bear-spider)

≤ 1900

1901-1979

1980-2005

2006 ≤

Description: The overall colouration of the species is reddish brown. Posterior end of carapace with two blackish dots. The legs are brown with dark annulations. The pale, very clear whitish cardiac mark is relatively wide and outlined by thin black line. Sometimes the cardiac mark is truncated at rear. Behind the cardiac mark there are some light transverse lines. The male and female have similar coloration. Size: Female 7-10 mm; male 5-8 mm.

Genus: Arctosa C. L. Koch, 1847. (Bear-spiders). Characters of genus: Medium-sized to large spiders characterized by a rather flattened carapace without clear median band, and with the eyes directed somewhat upwards. Most species lack longitudinal bands, and are well-camouflaged against the substrate. Legs with clear annulations or distinct spots. Males rather similar to females in general appearance. Depending on habitat, the species make burrows in sand, moss, detritus or under stones, but specimens are also frequently seen running about.

Family: Lycosidae Sundevall, 1833 (Wolf Spiders). Characters of family: The lycosids belong to the group of araneomorph, ecribellate spider families having 8 eyes and 3 tarsal claws. The eyes are all dark in colour and arranged in three rows in a characteristic fashion. The anterior row has four small eyes set in a straight or slightly curved row, the second row has two large eyes further up on the on the vertical front, and the posterior row has two medium-sized eyes on the sides of the head which can be more or less steep sided. There are only few additional diagnostic characters of importance for the family, i.e. the lack of a retrolateral tibial apophysis on the male palp and that the female of many species carries her egg sack attached to the spinners. The carapace is longer than wide with the head region narrowed and high. It is usually densely covered with hairs and often with longitudinal median or lateral bands or both. In some genera there are characteristic bars in the median band or elongate U-, Y-shaped marks. The sternum is oval to shield shaped (scutiform). The chelicerae are relatively strong with toothed cheliceral furrow and prominent lateral condyle (boss). The labium is a wide as long, about half the length of endites. Legs are spinose and provided with 3 tarsal claws, usually with scopulae for adhesion. The second segments of the legs (trochanters) are notched. The abdomen is oval, always covered with dense hairs. There is no colulus in front of the spinners. The tracheal spiracle is situated just in front of the spinners. The epigyne is well sclerotized median septum which may be large and plate-like. The male palp is only rarely provided with a tibial apophysis. The tip of the male palp may have one or more claws.