Salticus mutabilis

Salticus mutabilis is a species of jumping spider in the family Salticidae. It has a wide distribution across Macaronesia, Europe, North Africa, Turkey, and the Caucasus, and has been introduced to Argentina.^[1]

S. mutabilis is widely distributed across the Mediterranean region and Europe, extending from the Macaronesian islands in the west to the Caucasus in the east.^[1] The species is found throughout much of Europe, including France, Germany, Italy, and Sicily, where historical records show it replacing the closely related Salticus scenicus.^[2] It also occurs in North Africa and Turkey. The species has been introduced to Argentina, where it was first recorded in the 19th century.^[1]

Salticus mutabilis shows considerable sexual dimorphism and variation in coloration patterns.^[2]

Males measure 4-4.75 mm in body length. The cephalothorax (front body section) is black with white borders and three white spots. The abdomen is white with a dark median band bordered by black on each side. The legs are yellow with dark rings, and the chelicerae (mouthparts) are two-toothed.^[2]

The male's cephalothorax is shorter and narrower than in the related Salticus scenicus, with a squarely cut front edge. The anterior eyes form a more pronounced projection when viewed from above. The cephalothorax is black, bordered posteriorly with a bright white line and decorated with three white spots - one on the front border and two in the middle of the thorax, which are elongated and parallel.^[2]

Females are larger than males, measuring up to 6 mm in body length. The female's cephalothorax is often covered with tawny down that conceals the border and two central spots.^[2]

The female's abdomen shows considerable variation and can appear in several forms. In one variety, the median band is interrupted at the second constriction and is completely bordered by a black line forming a figure-8 pattern with a greyish center. In another form, the median band is narrow and bright yellow, terminating in a point at the front and bordered by a black line resembling an accent mark or spear point. A third variety shows the abdomen entirely white with a very pale tawny median band effaced at the constricted areas, appearing to be replaced by three spots - the first being an arc and the other two being somewhat darkened triangles at their angles.^[2]

The species is commonly found in various European habitats and has been observed to live in a similar manner to Salticus scenicus in areas where both species occur.^[2]

Salticus mutabilis was first described by Lucas in 1846. The species has a complex taxonomic history with several synonyms, including Callietherus zebraneus and Callitherus tenerus, both described by Simon in 1868, and Marpissa civilis described by Holmberg in 1876.^[1]