''Cyrtarachne nagasakiensis'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

in the orb-weaver spider family Araneidae, found in Pakistan, India, China, Korea and Japan. Spiders in the genus ''

Cyrtarachne ''Cyrtarachne'' is a genus of orb-weaver spiders 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 ...

'' 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 female has a body length of 5–7 mm. The

carapace A carapace is a Dorsum (biology), 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 tor ...

is wider than long, and is reddish brown with dark brown markings. The sternum is also reddish brown. The abdomen is broad, wider than long, and marked with a broad white band running from side to side, with a gold edge at the rear. The

epigyne The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. ...

has no scape. The male is smaller, with a body length of 1–5 mm. It is darker than the female and lacks the white band on the abdomen. 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 nagasakiensis'' was first described by Embrik Strand in 1918. Strand included drawings, but said that nothing was known other than that it was collected in

Nagasaki is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan. It became the sole port used for trade with the Portuguese and Dutch during the 16th through 19th centuries. The Hidden Christian Sites in the ...

. The genus ''

'' 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 Cyrtarachninae is a subfamily of spiders in the family Araneidae (orb-weaver spiders, araneids). The group has been circumscribed in several different ways. It originated as the group Cyrtarachneae, described by Eugène Simon in 1892. The group wa ...

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References

{{taxonbar, from1=Q2404699 Araneidae Spiders of Asia Spiders described in 1918