Maratus jactatus, Otto & Hill, 2015

Otto, Jürgen C. & Hill, David E., 2015, Two new peacock spiders of the calcitrans group from southern Queensland (Araneae: Salticidae: Euophryinae: Maratus), Peckhamia 121 (1), pp. 1-34 : 1-15

Maratus jactatus , new species

Type specimens. The holotype male (♂ #1) and one paratype female (♀ #1) were collected at Wondul Range National Park in southern Queensland (S 28.04862°, E 151.04878°, 13 SEP 2013, M. Girard & E. A. King coll.). The paratype female produced eggs and three of her offspring were reared to maturity (paratype ♂ #2-4). One additional paratype female (♀ #2) was reared from an immature collected with M . sceletus in the same area (S 28.04841°, E 151.04669°, 438 m, 27 JUL 2014, J. Otto coll.). All types will be deposited in the Queensland Museum in Brisbane .

Etymology. The species group name ( jactatus , noun, Latin) means rocking or jolting, a reference to the very rapid lateral rocking that punctuates the courtship display of males of this species.

Diagnosis. Male M. jactatus can be readily identified by their unique colour pattern. They are most similar to M. calcitrans and M. digitatus in general appearance, but can be separated from these by the presence of narrow lateral opisthosomal flaps that can be extended to expand the background cover of irridescent blue scales of the opisthosomal plate. M. calcitrans has no flaps at all, and M. digitatus has a larger pair of semicircular, iridescent, dull-green flaps. Males of all three species inflate their black posterior opisthosoma and two pairs of spinnerets (median and posterior) when they display to females.

Description of male ( Figures 1 -5). The holotype and two paratype males (♂ #1, 2, 4; N=3) range from 4.5 to 4.6 mm in body length, not including the spinnerets.

of the embolus can be observed in lateral views (3, 5, 7). In all respects these resemble the pedipalps of most other male Maratus .

The carapace and chelicerae are black, faded to brown or dark brown in preserved specimens. Red scales are present on the front of the chelicerae. The anterior eyes are bordered with red-brown scales above, white to grey scales below. Scattered white setae are present on the clypeus. A band of red-brown scales extends into the eye region behind each of the four anterior eyes, merging into a uniform field of redbrown scales in front of the posterior eye row. Three bands of grey scales separate these bands in the anterior half of the eye region. The field of red-brown scales extends around the lateral eyes on either side, and extends medially to form an indistinct dorsomedian thoracic tract extending half-way from the posterior eye row to the posterior margin of the carapace. Laterally and to the rear the carapace is mostly black and glabrous, except for a prominent marginal band of white setae on either side. The PME are nearly equidistant from the ALE and PLE.

The sides of the opisthosoma are nearly parallel when the narrow lateral flaps of the fan (dorsal opisthosomal plate) are retracted, but the fan is oval in shape when these flaps are extended. The fan is covered with uniform blue-green to blue iridescent scales, interrupted by three bold transverse bands of red-orange to orange pigmented scales. Behind these bands lies a single median spot of red-orange scales behind a small darker area. Toward the anterior and posterior margins of the fan are additional figures comprised of the same red-orange scales, and there is an anterior marginal band of orange scales. The posterior opisthosoma and spinnerets are generally black and considerably inflated during courtship display. The median and posterior spinnerets are fringed with white and black setae, and several tufts of these setae can also be observed on the black inflated (expanded) part of the opisthosoma that carries the spinnerets, when they are extended. The ventral opisthosoma is tan in living spiders, yellow to white in specimens preserved in ethanol. Coxae, sternum, labium, and endites are dark, fading to white in ethanol.

Legs I and II are about the same length, much shorter than legs III and IV. Legs III are by far the longest. All legs, and legs I-II in particular, bear a dense cover of long white to grey setae. The pedipalps also have this dense cover of long white to grey setae. Legs III have bright white tarsi, offset by a black distal half of each metatarsus. Dark banding at the distal end of each leg segment is most evident on legs IV. When viewed from below, each pedipalp is typical for this genus, with apices of the inner and outer rings of the embolus in close contact to form a single heavy apex ( Figure 4 ).

Description of female ( Figures 6-8 ). The paratype females (N=2) range from 5.0 to 5.3 mm in body length, not including the spinnerets.

instar offspring (3).

posterior spermathecae are similar in size to the fossae, whereas in (2) the spermathecae are much larger. Conspecificity of female #2 was confirmed through mating.

The carapace and chelicerae are dark brown. The chelicerae are glabrous. Anterior eyes are bordered above and below with white to grey scales. Longer white to grey setae project forward over the chelicerae at the median. The entire body (prosoma and opisthosoma) is generally brown, darker above, and covered with white to grey or light brown setae without distinctive markings. The carapace is glabrous and translucent at the sides and toward the rear, lacking lateral marginal bands. The PME are mid-way between the ALE and the PLE. The coxae, sternum, labium, and endites are relatively glabrous and translucent brown.

Legs I and II are about the same length, much shorter than legs III and IV, and legs III are the longest. The legs are mostly translucent, light brown and only weakly banded.

Dark, sclerotized ductwork of the epigynum occupies less than the posterior half of each fossa, and the prominent posterior spermathecae vary in size from close to the diameter of the fossae to about 1.5 times their diameter ( Figure 8 ).

Immatures. Immature stages of males that were reared are shown in Figure 9 . These had relatively bold markings when compared to those of females. In penultimate males ( Figure 9 : 10-12) three dark transverse bands, apparently corresponding to the bright red-orange bands of the adult, can be seen on the dorsal opisthosoma.

Male courtship display ( Figures 10-16 ). Male Maratus jactatus display by tilting the expanded fan (with inflated spinnerets) to one side or the other, and then moving the extended ipsilateral leg III, mostly behind the fan. At cycles of ~1-3Hz, the extended leg that is positioned behind the fan is first lowered over ~0.2-0.4s, then rapidly raised (or returned to its position behind the fan) to trigger a very rapid jolting or rocking movement of the whole body that lasts for only 20-30msec ( Figure 16 ). This rocking involves rapid ipsilateral (in the direction of the extended leg and tilted fan) rotation, followed by a return to the original position.

Mating ( Figure 17 ). As in other Maratus , the flexible pedicel of the female M. jactatus permits rotation of the opisthosoma by 180° during mating.

Figures

Figure 1. Holotype (1-4, ♂ #1) and paratype (5-9, ♂ #2) male Maratus jactatus. 2, Although normally retracted, the fringed median and posterior spinnerets are greatly extended when the posterior opisthosoma is inflated during courtship. 4, White tarsi are offset by black distal metatarsi on legs III. The legs are densely covered with long white setae, giving these spiders a soft appearance.

Figure 4. Views of the left pedipalp of three male Maratus jactatus. Separation of the inner and outer apices

Figure 6. Views of a paratype female Maratus jactatus, with one of her recently emerged second

Figure 8. Ventral view of epigynum of the two paratype female Maratus jactatus. In (1), the

Figure 9. Reared immature Maratus jactatus. As a convention, we consider the first free-living forms to emerge from the eggsac to be instar 2.

Figure 10. Positions assumed during the fan dance of a male Maratus jactatus facing a female. As with other members of the calcitrans group, this display is assymetric, involving rotation of the expanded fan and spinnerets toward one side, and movement of the extended ipsilateral leg III, usually behind the fan. The inflated spinnerets are moved little during the display, but the pedipalps may be moved up and down in unison from time to time.

Figure 11. Positions assumed by male Maratus jactatus during their courtship display, facing a female. 1, Signalling with one leg III extended, without an expanded fan. 4-5, Expanded (4) and retracted (5) fan.

Figure 12. Consecutive video frames (1-24, 25fps, exposure/frame 20msec, ~1s total duration) depicting the fan dance of a male Maratus jactatus facing a female. Vertical arrows identify movement of the extended ipsilateral (right, same direction as tilt of the fan) leg III, behind the fan. Double arrows in frames 3, 11, and 20 indicate rapid (blurred images) lateral rocking movement of the body and fan that took place at a rate of 3/s (3Hz) in this sequence. During each cycle, the extended leg III was moved laterally (down in this example) in ~0.2-0.3s, then moved medially more rapidly in less than 0.1s just before the onset of rocking movement.

Figure 13. Consecutive video frames (1-24, 25fps, exposure/frame 20msec, ~0.8s total duration) depicting the fan dance of a male Maratus jactatus facing a female. Vertical arrows identify movement of the extended ipsilateral (left) leg III, behind the fan. Double arrows in frames 6 and 18-19 indicate rapid rocking movement of the entire body, occurring at ~2Hz in this sequence.

Figure 14. Consecutive video frames (1-24, 25fps, exposure/frame 20msec, ~1s total duration) depicting the fan dance of a male Maratus jactatus facing a female. Vertical arrows identify movement of the extended ipsilateral (right) leg III, behind the fan. Double arrows in frames 3 and 23 indicate rapid rocking movement of the entire body, occurring at ~1Hz in this sequence.

Figure 15. Consecutive video frames (1-24, 25fps, exposure/frame 20msec, ~1s total duration) depicting the fan dance of a male Maratus jactatus facing a female. Vertical arrows identify movement of the extended ipsilateral (left) leg III, behind the fan. Double arrows in frames 4 and 18 indicate rapid rocking movement of the entire body, occurring at ~1.4 Hz in this sequence.

Figure 16. Three sets (1-4, 5-8, 9-12) of sequential video frames (not consecutive, from 1000fps clips) depicting rapid sideways rocking movement during the fan dance of a male Maratus jactatus facing a female. White diagonal lines indicate the approximate position of the prosomal sagittal plane at the beginning of each cycle of rocking movement, which is similar to its position at the end of that cycle. Yellow arrows identify the direction of movement of the body relative to its position in the previous frame. Each cycle, comprised of rapid ipsiplateral movement followed by a return to the original position, was completed in ~20-30msec. At slower frame rates (Figures 12-15; 25fps and exposure/frame 20msec), this movement is blurred and cannot be resolved.

Figure 17. Mating pair of Maratus jactatus.