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Simaetha Thorell, 1881

Taxonomy

Simaetha is a widespread genus found in Oriental and Pacific Regions as well as Australia which has ten species: Simaetha almadenensis, S. atypica, S. broomi, S. colemani, S. knowlesi, S. paetula, S. robustior, S. tenuidens, S. tenuior  and S. thoracica. It is closely related to the Australian genus Simaethula.

Description

Simaetha spp. are medium-sized spiders, ranging in body length from 4 to 7 mm. The head, viewed from above, is rounded, widest at the posterior lateral eyes. The carapace is high, with a steep thoracic slope. There are distinct prominences towards the midline next to the posterior lateral eyes. Chelicerae have one or two retromarginal teeth, a large, variably-shaped retromarginal projection and one or two promarginal teeth. The sternum has a large central bulge or prominence found only in this genus. The abdomen is rounded or ovate. The first pair of legs is a little longer but much heavier than the others. The spines on the tibia and metatarsus of the first pair of legs are well developed.

The male’s palp has a small to medium-length embolus arising from behind the distal edge of the tegulum. The tegulum is rectangular to oval in shape, without a proximal lobe. There may be a groove in the distal mid-line of the tegulum. The palpal tibia has a small retro-lateral tibial apophysis varying in shape between species.

The female has no epigynal atrium. The copulatory openings are small and near the epigastric fold. Short insemination ducts lead to laterally-located, rounded spermathecal chambers. These are well separated by a large median pouch between them on the epigastric fold.

Biology

Simaetha is found in grassland, woodland and open forest, on foliage, under bark and on the ground, often in gardens.

Distribution

The genus occurs widely across the wetter areas of Australia in all States and Territories, including Tasmania.

References

Davies, V.T. & Żabka, M. 1989, Illustrated keys to the genera of jumping spiders (Araneae: Salticidae) in Australia. Memoirs of the Queensland Museum 27, 189-266.

Maddison, W.P. 2015. A phylogenetic classification of jumping spiders (Araneae: Salticidae). Journal of Arachnology 43, 231-292.

Richardson, B.J. & Żabka, M. 2017. Salticidae. Arachnida: Araneomorphae. Canberra, Australian Faunal Directory. Australian Biological Resources Study, at https://biodiversity.org.au/afd/taxa/SALTICIDAE.

Whyte, R. & Anderson, G. 2017. A field guide to the spiders of Australia. Clayton: CSIRO Publishing 451pp.

Żabka, M. 1994. Salticidae (Arachnida: Araneae) of Oriental, Australian and Pacific Regions, X. Genus Simaetha Thorell. Records of the Western Australian Museum 16, 499-534.

* The information sheet should be read in the context of the associated diagrams and photographs. Diagrams explaining anatomical terms can be found in the ‘Salticidae’ pictures at the beginning of the list of genera.