Jewel spider

Description

Austracantha is a genus of spider with a single species, Austracantha minax, commonly known as the jewel spider or the Christmas spider. It is a member of the family Araneidae (the orb-weavers) and is endemic to Australia. They are relatively small spiders, reaching a maximum total body length of only around 12 mm (0.47 in) for females, and 5 mm (0.20 in) for males. Their abdomen has six distinctive projections ("spines") that makes them easy to identify. They are predominantly a shiny black, with variable white, yellow, and orange patterns. Melanistic forms also occur during autumn. They are facultatively gregarious, and can be found in large aggregations of overlapping orb webs. They feed on small flying insects that get entangled in their webs. They are harmless to humans, though the webs can be a nuisance for bushwalkers. They are most abundant during the summer months. Austracantha minax is most commonly known as "jewel spiders" due to their body colouration. This may sometimes be specified further as "Australian jewel spiders" due to the common name being shared with the unrelated North American jewel spider Araneus gemmoides, as well as the widespread jewel box spider Gasteracantha cancriformis. In some parts of Australia they are also widely known as "Christmas spiders" because they are most numerous during the summer months (December and January). Other common names for the species include "six-spined spiders" and "spiny spiders" in reference to the spine-like projections on their abdomens. Austracantha minax is classified under the monotypic genus Austracantha of the orb-weaver family Araneidae. The generic name is derived from Latin auster ("south") and Greek ἄκανθα (ákantha, "thorn"). The specific name is from Latin mināx ("jutting out" or "projecting"). It was first described in 1859 by the Swedish arachnologist Tamerlan Thorell from a female specimen recovered from Sydney. He classified it under the genus Gasteracantha. In 1914, the German arachnologist Friedrich Dahl moved it to its own subgenus, Austracantha, within Gasteracantha. Austracantha was elevated to genus in 1974 by the French arachnologist Michel Emerit. Austracantha minax has five recognised subspecies.