''Gasteracantha diardi'' is a species of

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 spiny orb-weaver genus ''

Gasteracantha ''Gasteracantha'' is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. Species of the genus are known as spiny-backed orb-weavers, spiny orb-weavers, or spiny spiders. The females of most species are brightly colored wi ...

''. It occurs in Southeast Asia.

Distribution

The range of ''Gasteracantha diardi'' includes southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

, and other

Sunda Islands The Sunda Islands (; Tetun: ''Illa Sunda'') are a group of islands in the Indonesian Archipelago. They consist of the Greater Sunda Islands and the Lesser Sunda Islands. Etymology "Sunda" denotes the continental shelves or landmasses: the Sun ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Description

Females of the species have very wide abdomens, much wider than long, giving them a horizontal appearance that is further accentuated by their spines. They have three pairs of spines on the abdomen. The first (anterior) pair is usually small and conical. The second (median) pair is long and strong, generally horizontal but often curving slightly backward and downward or even slightly forward. The hind pair of spines is always well-developed and intermediate in length between the first two pairs. Adult females are usually dark red or brown and can show pale yellowish or whitish stripes horizontally across the upper surface of the abdomen
example from Thailand
. The upper surface of the abdomen fluoresces blue under ultraviolet light.

Similar species

''G. diardi'' can be confused with '' G. mengei'', which lacks hind spines and has longer, straighter anterior spines and straight, tapering median spines. The two species overlap on the Greater Sundas, Peninsular Malaysia, and Singapore. ''G. diardi'' can also be confused with '' G. doriae'', which is brown with light stripes and has a slightly longer abdomen than ''G. diardi'' (creating a rounder silhouette), forward-pointing anterior spines, and median spines that are thin, relatively short, and curved somewhat back. Because ''G. diardi'' is widespread and variable, it has numerous synonyms, most of which were brought together by zoologist

Friedrich Dahl Karl Friedrich Theodor Dahl (24 June 1856 in Rosenhofer Brök north of Dahme, Schleswig-Holstein, Dahme, Holstein – 29 June 1929 in Greifswald) was a German zoologist, and in particular an arachnologist. The son of a farmer, Dahl studied at the ...

in 1914 based on his examination of specimens at the

Natural History Museum, Berlin The Natural History Museum () is a natural history museum located in Berlin, Germany. It exhibits a vast range of specimens from various segments of natural history and in such domain it is one of three major museums in Germany alongside Natur ...

References

{{Taxonbar, from=Q2248800 diardi Spiders of Asia Spiders described in 1835