''Callobius claustrarius'' is a species of spider in the family

Amaurobiidae Amaurobiidae is a family of three-clawed cribellate or ecribellate spiders found in crevices and hollows or under stones where they build retreats, and are often collected in pitfall traps. Unlidded burrows are sometimes quite obvious in crusty, ...

. Males of the species reach 8 mm, females about 11 mm. Head and legs are reddish brown, the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

is dark grey with an extended brown surface, dotted with lighter brown specks. Adults can be found from autumn to spring. This is a

palearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

species. In

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, it is found in mountainous regions, especially in old, moist forests under rocks. ''C. claustrarius'' is a rather rare species. The subspecies ''C. claustrarius balcanicus'' (Drensky, 1940) is only found in

Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...

.Platnick 2008

Footnotes

References

* (2008)
The world spider catalog
version 8.5. ''American Museum of Natural History''. {{Taxonbar, from=Q2578448 Amaurobiidae Endemic fauna of Bulgaria Spiders of Europe Spiders described in 1833 Taxa named by Carl Wilhelm Hahn