''Cyrtarachne inaequalis'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

in the

orb-weaver spider Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name ...

family Araneidae, found in India,

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

, China and Korea. Spiders in the genus '' Cyrtarachne'' construct "spanning-thread webs" rather than the more typical orb webs of the family Araneidae. These webs have a small number of radii and instead of a tight spiral of sticky threads, the sticky spanning threads are widely spaced and do not form a spiral. When prey is caught on one of the spanning threads, one end comes loose, and the prey, often a moth, dangles from the other end until hauled in by the spider.

Description

The body of the female is 8–13 mm long. The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is brownish with a darker head region. The

sternum The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...

is pale yellow. The abdomen narrows towards the posterior, and is wider than long. The upper surface of the abdomen is yellowish with two raised "shoulders" which have brownish or grayish rings. The lower surface is yellow with a dark brown median spot. The legs are yellow. The scape is triangular with thickened edges and a scoop-shaped tip. The male spider is much smaller with a body length of about 2–2.5 mm. The upper surface of the body is generally darker than that of the female except for the back part of the abdomen which is yellowish brown. The sternum is lighter brown and the underside of the abdomen is yellow with dark brown stripes. The median apophysis of the

palpal bulb The two palpal bulbs – also known as palpal organs and genital bulbs – are the copulatory organs of a male spider. They are borne on the last segment of the pedipalps (the front "limbs" of a spider), giving the spider an appearance often descr ...

is thick and has a pointed tip.

Taxonomy

''Cyrtarachne inaequalis'' was first described by

Tamerlan Thorell Tord Tamerlan Teodor Thorell (3 May 1830 – 22 December 1901) was a Sweden, Swedish arachnologist. Thorell studied spiders with Giacomo Doria at the Museo Civico di Storia Naturale de Genoa. He corresponded with other arachnologists, such as Oc ...

in 1895. The genus '' Cyrtarachne'' was included in

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies in 2014 and 2020 which placed it in the "cyrtarachnines" in the subfamily Cyrtarachninae '' s.l.'' Spiders found in Japan that had previously been identified as ''C. inaequalis'' were found to belong to two new species, '' C. akirai'' and '' C. jucunda''.

References

{{taxonbar, from1=Q2060021 Araneidae Spiders of Asia Spiders described in 1895 Taxa named by Tamerlan Thorell