Maratus icarus, Otto & Hill, 2019

Otto, Jürgen C. & Hill, David E., 2019, Three new peacock spiders from the southeast and southwest of Australia (Araneae: Salticidae: Euophryini: Maratus), Peckhamia 189 (1), pp. 1-77 : 29-53

Maratus icarus , new species

Type specimens. The holotype male (♂ #1), 9 paratype males (♂ #2-10), and 11 paratype females (♀ #1- 11) were collected at Mount Frankland National Park, approximately 16 km NW of Walpole in Western Australia (S34.912295°, E116.567454°, 9 NOV 2018, coll. Jürgen C. Otto). One additional male (♂ #11) was previously photographed but not collected at Mount Frankland National Park, approximately 6 km from the type locality and 12 km NW of Walpole in Western Australia (S34.95950°, E116.60026°, 11 OCT 2017, Jürgen C. Otto). All types will be deposited in the Western Australian Museum , Perth .

Etymology. The species group name ( icarus, Greek , m., noun in apposition) is a reference to the presence of a figure on the dorsal opisthosoma of the adult male that resembles the winged Icarus of Greek mythology.

Diagnosis. Based on the colour and distribution of scales and other setae of the male, Maratus icarus is most closely related to M. cristatus Otto & Hill 2017b , but also fairly close to M. unicup Otto & Hill 2018b ( Figure 16 ). We place all three species in the vespa group. The opisthosomal flaps are more rounded in M. cristatus and more elongated in M. icarus . The middorsal tract of red scales on the fan of M. icarus extends almost all the way to the front margin, but in M. cristatus this is divided into two diverging lateral tracts well behind the front margin.

Description of male ( Figures 16 :2, 17-20). Adult males are 3.6-4.3 mm in length (n=10). The chelicerae and carapace are black. Long white to off-white setae extend over the proximal end of each paturon. White to off-white setae surround the anterior eyes and also cover the eye region, interrupted there by 7 (5 in front, 2 to the rear) small patches of red scales. The PME are closer to the PLE than to the ALE. To the rear and on the sides the carapace is black and glabrous, except for a middorsal patch of white scales that may be found in the thoracic region, and a well-defined marginal band comprised of white scales.

The dorsal opisthosomal plate (fan) has a prominent, lobate flap on either side that can be extended during courtship display. The pattern of scales on the fan closely resembles that of Maratus cristatus , but in M. icarus the dull to bright red anteromedian stripe extends almost completely to the front and is not divided as in M. cristatus . There is a diverging red stripe on either side of this median stripe, against a background of iridescent light blue to blue-green scales. Toward the rear a transverse line of light blue scales, usually interrupted to appear as four spots near the midline, extends from the lateral margin of one flap to the other. At the rear of the fan the cover of red scales is interrupted by three tufts of bright white setae on either side, and there is an additional tuft of white setae at the lateral margin of each flap.

Legs I and II are shorter, legs IV longer, and legs III by far the longest. The legs have a cover of brown or off-white or white setae, much longer on the patella and tibia of each leg III. Dorsally the pedipalps are covered with long off-white or white or brown setae. The RTA, tegulum and embolus ( Figure 20 ) are unremarkable and compare closely with those of other species in the linnaei , vespa and other Maratus groups in southwestern Australia. Both outer and inner apices of the embolus are heavy and black, and as in related species there is a distinct projection near the distal end of the outer apex of the embolus.

Description of female ( Figures 21-24 ). Adult females are 4.3-5.2 mm in length (n=11). The chelicerae are brown and glabrous with scattered off-white setae. The clypeus is covered with longer off-white setae that extend over the proximal part of each paturon. The eye region is covered with off-white to brown or red-brown scales. The PME are closer to the PLE than to the AME. Behind this the carapace is mostly black and glabrous except for a prominent medial stripe of white scales on the elevated thoracic region. The sides of the carapace are mostly glabrous, translucent and dark brown, except for a wide tract of offwhite to white scales behind and below the posterior eyes on either side, and scattered off-white scales below this. These lateral tracts of white scales, in combination with the white mediothoracic stripe, are useful but not definitive for the identification of this species. Scattered off-white scales may be present near each lateral margin of the carapace, but there is no definitive marginal band of the carapace as in the male.

The dorsal opisthosoma is dark brown with scattered off-white to brown scales. On either side a broad marginal band of off-white to bright white scales runs to the rear, converging with the band of the opposite side at the rear. These bands have some dark brown mottling and in some individuals the medial margin of each band is well-defined and contrasting. There is a small triangular patch of white setae above the spinnerets. Below, the opisthosoma is covered with off-white setae. The coxae, sternum, labium and endites are brown and translucent, mostly glabrous with few scattered setae.

The pedipalps are uniform light brown, covered with longer off-white setae. Legs I and II are shorter, legs III and IV longer. The legs are brown to dark brown with indistinct banding comprised of off-white setae. The epigynum resembles that of related species in the vespa and linnaei groups, with a large posterior spermatheca behind each fossa. The fossae are separated by a septum of variable width. Darker, sclerotized ducts of variable appearance can be seen behind the posterior part of each fossa.

the extended spinnerets.

Courtship ( Figures 25-28 ). We have observed two primary modes of courtship display by male Maratus icarus . In one ( Figures 25-27 ) the elevated and extended fan is rotated (waved) on one side and then the other through an amplitude of about 20°, with both legs III in an elevated and extended but not a bracketing position. At a greater distance from the female ( Figure 26 ) this display can include fan-waving at ~3.2 cycles/s, bilaterally symmetrical up-and-down flicker of both pedipalps at ~5 cycles/s, and less frequent (~2 cycles/s, ~0.12s/cycle), low amplitude "calipers" movement (together and then apart, or apart and then together) of both extended legs III. Closer to a female ( Figure 27 ) the male may wave the fan in a similar manner (~4.8 cycles/s) without movement of the legs or pedipalps, but with intermittent depression and rotation of the fan to either the right or left to display one of the flaps outside of the figure defined by the extended legs III ( Figures 25 :15, 27:39,50). In a second display mode ( Figure 28 ) the fan was only slightly extended and partly elevated as it was waved from side to side at a low amplitude of several degrees and at a slower speed (~2.5/s). The appears to represent an advertisement at a greater distance, and the advertising male may also step from side to side and wave the extended legs III. The two primary modes of display closely resemble those of M. cristatus ( Otto & Hill 2017a) , but in that species the flaps are not displayed at the side during the first mode, and the flaps are fully extended when the fan is depressed during the second mode of display.

Mating ( Figure 29 ). As in other Maratus , the flexibility of the female opisthosoma is evident when these spiders mate.

speed of this vibration was not measured.

Habitat and distribution. Maratus icarus was found at two localities ( Figures 1 , 30 ).

Figures

Figure 1. Localities associated with three new species of Maratus in Australia.

Figure 16. Comparison of the male Maratus icarus (center) with the closely related M. cristatus (left) and M. unicup (right), all members of the vespa group, endemic to southwestern Australia. Based on leg colour, there are brown and white forms of both M. cristatus and M. icarus.

Figure 20 (continued from previous page). Medial to lateral views of the left pedipalp of the adult male type specimens for Maratus icarus in ethanol.

Figure 21 (continued on next page). Living adult female types for Maratus icarus.

Figure 22. Ventral views of living adult female types for Maratus icarus. 6, Inset shows detailed ventral view of

Figure 23 (continued from previous page). Adult female type specimens for Maratus icarus in ethanol.

Figure 24. Epigynum of adult female type specimens for Maratus icarus in ethanol.

Figure 25 (continued on next page). Display by adult male types for Maratus icarus.

Figure 26. Consecutive frames from a 25 FPS video showing continuous courtship display by an adult male Maratus icarus. White arrows indicate movement of the fan, legs III and the pedipalps relative to the preceding frame. The fan was waved through an amplitude of ~20° at ~3.2 cycles/s and the pedipalps were moved up and down at ~5 cycles/s.

Figure 27 (continued on next page). Selected frames from a 25 FPS video showing courtship display by an adult male Maratus icarus. The fan waved was through an amplitude of ~20° at a rate of ~4.8 cycles/s.

Figure 28. Selected frames from a 25 FPS video showing courtship display by an adult male Maratus icarus. This shows low amplitude (several degrees, ~2.5 cycles/s) waving of the depressed and folded fan behind extended legs III.

Figure 29. Mating positions of Maratus icarus. 4-11, Sequential frames from a 25 FPS video showing intermittent (~12.5/s), rapid vibration of the opisthosoma as indicated by blurred images (arrows). The

Figure 30. Habitat of Maratus icarus. 1-2, Type locality at Mount Frankland National Park, about 16 km NW of Walpole in Western Australia. 3, Second locality where this species was originally found, about 6 km from the type locality.