Maratus flavus, Otto & Hill, 2018

Otto, Jürgen C. & Hill, David E., 2018, Two new peacock spiders from Western Australia (Araneae: Salticidae: Euophryini: Maratus Karsch 1878), Peckhamia 160 (1), pp. 1-42 : 23-42

Maratus flavus , new species

Type specimens. The holotype male (♂ #1) five paratype males (♂ #2-6), and four paratype females (♀ #1-4) were collected in Banksia woodland at Tims Thicket near Dawesville, Western Australia (32.639883°S, 115.6274°E, 20 OCT 2017, coll. J. Otto). Five paratype males (♂ #7-11) and three paratype females (♀ #5-7) were also collected in the same habitat (32.639423°S, 115.627531°E, 7-8 OCT 2017, coll. C. Anderson). All types will be deposited in the Western Australian Museum , Perth .

Etymology. The species group name ( flavus, Latin , m., adj.), translated as yellow in English, refers to the mustard-yellow colouration of scales that cover the dorsal opisthosomal plate of the male.

Diagnosis. Most closely related to Maratus boranup as noted in the description of that species, but males can be readily separated by the pattern of scales on their fan ( Figure 2 ). We place this species in the flavus group with M. boranup . Unlike that species, the male M. flavus does raise his opisthosoma during courtship display, but both species rely greatly on a bilaterally symmetric display of their extended legs III. Females of the two species are very similar and difficult to distinguish.

Description of male ( Figures 19 -22). The male types are 3.7-4.2 mm in length (n=11). The chelicerae are black and glabrous. The carapace is black, and the clypeus is mostly glabrous except for several off-white setae at the midline. Except at the top the anterior eyes are surrounded by grey scales. The eye region is covered with grey scales that extend below the lateral eyes on either side, interrupted by four prominent red-orange or red-brown stripes, one running to the rear behind each of the anterior eyes. To the rear and sides the carapace is mostly black and glabrous. A variable cover of scattered off-white setae is present on the sides of the carapace and a bright white median band extends to the rear behind the eye region. A band of bright white scales is also present along each lateral margin of the carapace. The PME are closer to the PLE than to the ALE.

The dorsal plate of the opisthosoma is subovate, more rectangular at the front and rounded at the rear margin. There are no lateral flaps or fringes except for some longer setae projecting forward at the front. The pattern of scale cover is distinctive, with orange or mustard-yellow scales radiating from a series of black lines or figures, on a background of iridescent scales that are green to yellow, orange, or grey depending on direction. A narrow black transverse line demarcates the rounded rear section of the fan, and on either side this line is surrounded by a small group of dull to bright red-orange scales. Behind the dorsal plate the opisthosoma is black except for a group of off-white setae in front of a small triangular patch of white colular scales. Below this patch the spinnerets are brown to black. The sides of the opisthosoma are black, covered with off-white setae below, and the venter is brown and mostly glabrous with a variable cover of scattered setae and with a darker line extending along its length on either side from the book lungs to the posterior margin. From below, the coxae and proximal femora are light brown to grey with a sparse cover of off-white setae. The sternum, labium, and endites are dark grey and mostly glabrous.

Legs I and II are shorter, legs III and IV longer, and legs III by far the longest. From the distal femur to the tarsus legs I, II and IV are brown with scattered white to off-white setae with generally indistinct banding. The anteroventral margin of the femur of each leg III is black. A red-brown dorsal stripe extends from the femur to the tibia of each leg III. The patella III and tibia III bear a fringe of longer white setae. The metatarsus III is fringed on all sides with long black setae, and the tarsus III is covered with bright white setae.

Dorsally the pedipalps have a cover of white setae and ventrally they are dark brown. Detailed structures of the pedipalp (Figure 22) are similar to those of other Maratus . A single serration or projection is present on the ventral edge of the outer apex of the embolus (Figure 22:19).

Description of female ( Figures 23-26 ). The female types are 4.7-5.3 mm in length (n=7). The chelicerae are light brown, glabrous, and translucent. The carapace is light brown and translucent, except for the eye region and a stripe of dark pigment extending to the rear behind the eye region on either side ( Figure 25 :1,4,8). Long white to off-white setae extend over the clypeus, anteromedially below the anterior eyes. The eye region is mostly covered with light brown setae, except for a distinct, darker red-brown stripe running behind each AME. Behind the eye region, a median stripe of off-white setae extends to the rear, surrounded on either side by a wide, dark brown band that is mostly glabrous. On either side below the lateral eyes and on either side of these dark brown bands is a band of off-white setae. Otherwise the sides of the carapace are almost entirely glabrous and translucent, with no lateral marginal bands. The PME are closer to the PLE than to the ALE.

The dorsum of the opisthosoma is brown to dark brown, at the front with a cover of scattered off-white setae arranged in three irregular longitudinal bands. The lateral margins of this brown area are marked by a wavy line that separates it from a broad marginal band of off-white setae on either side. Below each marginal band is a dark brown stripe, separating this from the venter which is mottled with small brown spots and covered with shorter off-white setae. A small tuft of white to off-white colular setae is present.

From below the coxae, trochanters, proximal femora, sternum, and endites are mostly light brown to brown, translucent, and glabrous. Legs I and II are shorter and of similar length, and legs III and IV are longer, also of similar length. The legs are generally brown and irregularily spotted with dark pigment. The pedipalps are light brown and translucent with a cover of off-white setae.

The epigynum ( Figure 26 ) has a pair of relatively large ovate to circular fossae, separated by a septum of variable width. Behind each fossa is a larger, ovate to circular posterior spermatheca. Sclerotized ducts are present anterior to each spermatheca, visible through the ipsilateral fossa.

Courtship display ( Figures 27-29 ). The male M. flavus waves his extended and elevated legs III in a mostly bilaterally symmetric manner. High speed video recording (180 fps) has allowed us to time the very fast movement or vibration of these legs, alternately raised and lowered to the side at a rate of ~29-36 cycles/s ( Figures 28-29 ). Legs III are held in a relatively vertical position as they are waved. Like M. boranup , M. flavus males also bob or wave their elevated opisthosoma as they wave legs III, but at a much lower and more irregular rate of ~5-10/s. As with M. boranup pedipalp movement is not part of this display, but in M. flavus each pedipalp is held to the side, exposing the black, glabrous chelicerae to the front in the direction of the courted female.

Display by females. As has been reported for other Maratus species ( Otto & Hill 2016), female M. flavus display to males by rising on their legs and waving their elevated opisthosoma ( Figure 30 ). They may also extend their legs III during this display. We consider this to represent a display of rejection targeted at a courting male.

Habitat. The habitat of M. flavus in the Swan Coastal Plain Banksia woodland of Tims Thicket near Dawesville, just south of Perth, Western Australia is shown in Figure 31 . Most of the individuals collected by one of us (J. Otto) were found on small shrubs belonging to the genus Hibbertia , identifiable in Figure 31 by their yellow flowers.

Figures

Figure 2. Comparison of the fan of the male Maratus boranup (1-2) with that of M. flavus (3). In both species relatively large pigmented scales (orange in M. boranup, mustard-yellow in M. flavus) radiate from a series of black lines. M. boranup has a small orange anterior lateral flap and a tuft of long, white setae on either side of the fan, but the fan is only known to be elevated as shown here (1) when the spider mates. In contrast M. flavus will raise the fan as part of courtship display (3), but there are no flaps or long setae on the sides of this fan.

Figure 19 (continued on next page). Living male types for Maratus flavus. 2, 6, 12, Detail of fan.

Figure 23 (continued on next page). Living female types for Maratus flavus.

Figure 24. Ventral view of living female types for Maratus flavus.

Figure 25. Female type specimens for Maratus flavus in ethanol.

Figure 26. Ventral view of the epigynum of the seven female type specimens for Maratus flavus in ethanol. 4, Detail of inset rectangle in (3).

Figure 27 (continued on next page). Courtship display by male M. flavus. Note how the pedipalps were held to the side to expose the black chelicerae during this display.

Figure 28. Consecutive frames from a high speed video (180 fps) of courtship display by a male Maratus flavus. Arrows indicate direction of movement of legs III or the fan relative to the previous frame. The extended and elevated legs III were waved in a nearly bilaterally symmetric manner very quickly (~36 cycles/s), while the fan was waved more slowly (~5-10/s) through a relatively low amplitude of rotation.

Figure 29. Sequential but not consecutive frames from a high speed video (180 fps) recording of courtship display by a male Maratus flavus. The extended and elevated legs III were waved in a bilaterally symmetric manner at a rate of ~29 cycles/s, as the fan was waved through a low amplitude of rotation at a slower rate of ~5-6 cycles/s.

Figure 30. Sequence of positions assumed during the rejection display of a female Maratus flavus. 2, 9, Note extension of one (2) or both (9) legs III during this display.

Figure 31. Maratus flavus were found on or near the ground in this Banksia woodland near Dawesville, Western Australia.