Chaco socos is a species of mygalomorph spiders of Chile, named after its type locality: Socos, Limarí, Region IV (Coquimbo region).[1] This species differs from C. tigre by its spermathecae having a longer duct and a less globose fundus, and by constructing a beveled door for its burrow; the general colouration is grayish, while C. tigre is more brownish coloured.
The male has a total length of 11.3mm; a cephalothorax length of 5mm and width of 4.27mm; a cephalic region length of 3.1mm and width of 2.67mm; an ocular quadrangle (OQ) length of 0.61mm and width of 1.07mm; a labium length of 0.52mm and width of 0.79mm; and a sternum length of 2.75mm and width of 2.11mm. The labium possesses five cuspules. Its posterior sternal sigilla is small and shallow. Its cephalothorax is ashgray, with a lycosid-like pattern, while the legs and palpi are gray with darker spots; its abdomen yellowish with darker dorsal spots.
The female has a total length of 14.89mm; a cephalothorax length of 5.25mm and width of 4.36mm; its labium length is 48% of the width; the sternum width is 72% of the length. The labium possesses three cuspules. The colour is the same as in the male.
This species has been collected in two localities, in high mountains near the sea, with moist soil. The animals construct a thick door for their burrow, which fits into the burrow opening. The outer face of the door is slightly concave, while the burrow walls are well-compacted and lined with silk.