''Ordgarius monstrosus'' 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 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

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

, Australia. ''O. monstrosus'' is a

bolas spider A bolas spider is a member of the orb-weaver spider (family Araneidae) that, instead of spinning a typical orb web, hunts by using one or more sticky "capture blobs" on the end of a silk line, known as a "bolas". By swinging the bolas at flying ...

. Rather than using a web, adult females catch their prey by using a line with one or two sticky drops (a "

bolas Bolas or bolases (singular bola; from Spanish and Portuguese ''bola'', "ball", also known as a ''boleadora'' or ''boleadeira'') is a type of throwing weapon made of weights on the ends of interconnected cords, used to capture animals by entan ...

") which they swing.

Description

A female described in 1886 had a total length of 13.0 mm. The

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

was 5.0 mm long and almost as wide. Its upper surface was reddish brown, with white hairs and five projections, a long forward-pointing one at the front and four smaller ones behind. The two rows of eyes were slightly recurved. The

sternum The sternum 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 blood vessels from injury. Sh ...

was longer than wide, and was yellow with brown tints, as were the

chelicerae The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly ...

. The legs were yellow with brown rings, mostly not fully closed, and were covered with fine white hairs. The first leg was longest, with a total length of 15.5 mm. The abdomen was wider (10.2 mm) than long (9.6 mm). Its upper surface was yellow with brown spots and indistinct bands. The corners had distinct humps. The underside of the abdomen was solid yellow.

Taxonomy

''Ordgarius monstrosus'' was first described by

Eugen von Keyserling Eugen von Keyserling (22 March 1833 in Pockroy, Lithuania – 4 April 1889 in Dzierżoniów, Silesia) was a Baltic-German arachnologist. He studied in the University of Tartu. He was the author of ''Die Spinnen Amerikas'', and completed ''Die Ara ...

in 1886. It was the first species described in his new genus ''

Ordgarius ''Ordgarius'' is a genus of orb-weaver spiders first described by Eugen von Keyserling in 1886. Adult females of the genus are bolas spiders, capturing their prey with one or more sticky drops at the end of a single line of silk rather than in ...

''. The genus has been placed in the broadly defined 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 w ...

, and, as a bolas spider, would be expected to fall within the informal group of mastophorines, although not included in the

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 ...

study that defined this group.

Prey capture

Like the rest of the genus ''Ordgarius'', ''O. monstrosus'' is a

, catching its prey using one or more sticky drops on a line (a "

") rather than with a web. Adult females capture prey (usually a male moth) when it approaches by whorling the bolas using a second leg. There is evidence to suggest that, like related genera, ''Ordgarius'' can produce a mimic of the

sex pheromone Sex pheromones are pheromones released by an organism to attract an individual of the same species, encourage them to mate with them, or perform some other function closely related with sexual reproduction. Sex pheromones specifically focus on ind ...

used by a female moth to attract a male.

References

{{taxonbar, from1=Q2576327 Araneidae Spiders of Australia Endemic fauna of Australia Spiders described in 1886 Taxa named by Eugen von Keyserling