Maratus

Genus of spiders
Automatic taxobox
| taxon = Maratus
| image = MalePeacockSpider. jpg
| image caption = Male Maratus volans
| image upright = 1.15
| authority = Karsch, 1878 thus emphasizing the appearance of the dorsal pattern. Not all species have colors that appear bright to human vision; Maratus vespertilio is relatively cryptically colored, with most iridescence on the lateral flaps. In almost all species, males have relatively long third legs, often brightly patterned, that are also used in courtship displays. Some Maratus including Maratus calcitrans, Maratus digitatus and Maratus jactatus display with greatly enlarged and decorated spinnerets when their abdomen is elevated. One species from Cape Riche, Western Australia, in a region which is something of a hot spot for Maratus species, does not use its abdomen in its display at all, instead using a combination of decorated third legs and its bright blue face and fluffy white pedipalps. Male palpal bulbs are relatively simple in appearance, with a circular embolus, and are rather similar in different species. The palp usually has a simple retrolateral tibial apophysis with a blunt tip. One mechanism uses pigments to produce reds, whites, and creams in barbed scales that help scatter light. To produce blues the spiders use arrays of nanostructures reflecting light of particular wavelengths, in the case of Maratus splendens a shiny, sometimes violet blue. The nanostructures are embedded in flat, convex, sac like scales, amplifying reflected light, according to University of Groningen's Doekele Stavenga. This is the only animal where this kind of reflection has been shown. Stavenga compared Maratus colours with patterns on butterfly wings, the colors of flowers, and the feathers of the parotia bird. The blues produced by nanostructures in Maratus do not fade over time, unlike the normal pigmenting method. Other blue animals, like beetles, are rare but also use nanostructures. Nathan Morehouse of the University of Pittsburgh found Maratus volans have four different photoreceptors (tetrachromats) allowing them to see red, blue, green, and ultraviolet and also resolve the intricacies of the male's display designs.

The genus Maratus was first described by Ferdinand Karsch in 1878. and honoured Jürgen Otto with Maratus ottoi, Michael Duncan and Michael Doe with Maratus michaelorum, and Julianne Waldock with Maratus julianneae. Maratus splendens and Maratus rainbowi refer to the same, single species, both listed here. Otto & Hill, when describing the female for the first time chose to continue to use Rainbow's Maratus splendens rather than Roewer's replacement name Maratus rainbowi. While Maratus rainbowi still appears in a number of on line catalogs, all published descriptions and studies of this spider to date have used the original name Maratus splendens, the replacement name never having gained currency, and no longer preoccupied. In 2017 Jurgen Otto and David Hill published a Catalogue of the Australian peacock spiders (Araneae: Salticidae: Euophryini: Maratus, Saratus) in Peckhamia, having also recently erected a new genus for peacock spiders with significantly different genitalia to Maratus, being Saratus Otto & Hill, 2017. In the catalogue a single species of Saratus is listed, adult males are shown in photographs, range maps shows areas that have been identified in prior publications, or by unpublished observations and posted photographs that the authors consider reliable.