Taxonomy

Saratus has one Australian species, Saratus hesperus. It is part of a distinct group of Australian genera related to the Old World genus Saitis (Zhang and Maddison 2015) including Barraina, Hypoblemum, Jotus, Maratus and Prostheclina (Otto and Hill, 2012, Zhang and Maddison, 2015) (Maddison et al 2008). Further information on the genus and described species can be found in Otto and Hill (2017) and depicted on p. 271 of Whyte and Anderson (2017) as ‘White-dot’ ACT.

Description

Saratus is a small-sized spider, body length 3 to 4 mm. Males have a brightly-coloured ovate abdomen. Females have drably-coloured ovate abdomens. The head, viewed from above, is rectangular with rounded sides or slightly pear-shaped with the widest point behind the posterior lateral eyes. The carapace is high, the highest point at the posterior lateral eyes. Chelicerae have a single (unident) sharp retromarginal tooth and two promarginal teeth. The first legs are similar in shape to the other legs. The third and fourth legs are of a similar size in the male and there is no fringing along the third leg. The fourth leg is longest in the females.  

The male’s palpal tibia has a single, pointed, medium-sized retro-lateral tibial apophysis. The tegulum is long with a proximal lobe. The short embolus is distal to the tegulum. It has an anticlockwise twist and winds around a separate sclerite.

Females have two small, epigynal atria without sclerotised guides. The antero-medial copulatory openings lead into bulbous ducts which travel laterally in short curves before joining the anterior margins of the spermathecae. The spermathecae are rounded, well-separated and partly within and partly posterior to the margins of the atria, close to the epigastric fold.

Biology

The only known species has been found in grass and on grass tussocks in a wide variety of habitats. The males have brightly coloured abdomens featuring an intense blue with a central white spot. The abdomen and the third pair of legs are raised as part of complex courtship rituals.

Distribution

Saratus hesperus is widely distributed and has been found at many locations between eastern Victoria and southern Queensland.

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., Bodner, M.R. & Needham, K.M. 2008. Salticid spider phylogeny revisited, with the discovery of a large Australian clade (Araneae: Salticidae). Zootaxa 1893, 49-64.

Otto, J.C. & Hill, D.E. 2017. Five new peacock spider from eastern Australia (Araneae: Salticidae: Euophryini: Maratus Karsch 1878 and Saratus, new genus). Peckhamia 147.1, 1-86.

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

Zhang, Junxia & Maddison, W.P. 2015. Genera of euophryine jumping spiders (Araneae: Salticidae), with a combined molecular-morphological phylogeny. Zootaxa 3938: 1-147.

* The information sheet should be interpreted 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.