Maratus lobatus , Jürgen C. Otto & David E. Hill, 2016
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Maratus lobatus , new species
Type specimens. Five paratype females (♀ # 1 -3, 5- 6) were collected at Helms Arboretum, 15 km NNW of Esperance (33.72556 °S, 121.84250 °E, 15-17 NOV 2014, coll. A. Fletcher and M. Doe). The holotype male (♂ # 1), two paratype males (♂ # 2-3), and one paratype female (♀ # 4) were raised from eggs produced by one of these females. These will be deposited in the Western Australian Museum, Perth.
Etymology. The species group name ( lobatus, Latin , m., adjective, English translation lobed or having lobes) refers to the lobate shape of the lateral flaps of the dorsal opisthosomal plate of the male.
Diagnosis. This species closely resembles the eastern Maratus harrisi Otto & Hill 2011 , and we place both in a harrisi group within the genus Maratus . The fan of the male M. harrisi has a single pair of white spots associated with the central figure, whereas M. lobatus has one pair of straight lines and one pair of curved white lines, also comprised of white scales, in this position ( Figure 47 View Figure ). The male M. harrisi that we have
examined have two contiguous apices of the embolus of each pedipalp, and these are separate in M. lobatus . The female M. lobatus resembles many other species of Maratus , and cannot be compared here with the female M. harrisi which has not been described. The epigynum of female M. lobatus that we have examined varies greatly between individuals.
Males (N= 2) ranged from 4.92 to 5.07 mm in length.
The clypeus is black, almost devoid of setae. The carapace is almost entirely black, with dark red and grey setae around the eyes or the anterior and lateral margins of the eye region. The sides of the carapace are black and glabrous, but there is a prominent marginal band comprised of bright white setae. Behind the posterior eye row a narrow median and two wider lateral tracts of off-white setae extend less than half-
way to the posterior margin of the carapace, merging anteriorly. These may be more distinct in recently molted individuals ( Figure 48 View Figure : 10). The PME are clearly closer to the PLE than to the ALE.
The fan bears a distinctive pattern of black to red-brown and white scales on a light blue (toward the rear) or grey (toward the front) background comprised of densely packed scales. On this background lies a large 'V' figure pointed toward the front, flanked by a smaller pair of 'U' figures, open toward the front. These figures are dark red-brown and surrounded by white setae toward the front. There is a transverse
line of bright white scales extending laterally from each side of the large 'V' figure, and two curved lines of bright white scales surround the posterior ends of this figure ( Figures 47 View Figure : 4 -5, 49). The anterior margin of the opisthosoma is black or dark grey, with many long black setae projecting anteriorly. The rear margin of the fan is defined by a broad black band interrupted by a tract of white setae on either side. Black areas of the fan may be outlined with dark red-orange scales. The lateral margins of the dorsal plate are lobate
flaps that are normally wrapped around the opisthosoma, but extended during courtship display. The dorsal surface of these flaps is dark anteriorly and dull blue-green posteriorly, fringed with bright white setae. To the rear of and beneath the dorsal plate the opisthosoma is black with a cover of black setae ( Figure 49 View Figure :2, 5). A small white triangle of colular setae is present above the black spinnerets. From
below, the opisthosoma, coxae, sternum, labium, and endites are mostly grey and glabrous, except for a cover of short setae toward the front of the opisthosoma, and a group of setae originating with the posterior sternum.
Legs I and II are shorter and of similar length. Legs III and IV are longer, and legs III are by far the longest. Legs I, II, and IV are dark with irregular rings comprised of white or off-white setae. Legs III are dark brown with scattered setae, but the metatarsi are completely black and the tarsi are bright white. From the front ( Figure 50 View Figure : 1) the pedipalps are covered with long white setae. The embolus of the pedipalp is
Description of female ( Figures 53-56View Figure 53). Females (N= 3) ranged from 6.16 to 6.46 mm in length. The chelicerae and lower part of the clypeus are dark, almost black, and glabrous, but long white setae project forward from the upper clypeus beneath the anterior eye row. The carapace is also dark, with regular brown setae in the eye region and fewer setae to the sides and rear. The margin of the carapace is black
and glabrous and a regular marginal band is not present. The PME are midway between the ALE and PLE. The dorsal opisthosoma is covered with dark brown setae and an indistinct pattern of several paired spots, but is flanked at the posterolateral margins by a wide and distinctive marginal band of light brown ot off-white setae. There is a small white, triangular colular patch of setae, and the spinnerets are grey or light brown. The underside of the opisthosoma is almost uniform light brown. The coxae, sternum, labium, and endites are light grey with scattered setae.
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Legs I and II are shorter and similar in length and legs III and IV are longer. The legs and pedipalps are dark brown. The legs and pedipalps bear scattered patches of light brown setae and are dark at the joints. The pedipalps are fringed along their length with longer, light brown setae, with distal grey setae ( Figure 56 View Figure : 2). The epigynum ( Figure 55 View Figure : 9-13) is variable with respect to the width of the septum
separating the fenestrae, and the extent of sclerotization of the ducts visible as dark objects beneath the posterior fenestrae.
Immatures. Penultimate male and female Maratus lobatus are shown in Figure 57 View Figure . These are similar in general appearance and closely resemble the adult female, except for the narrow marginal band and the inflated and light-coloured developing pedipalps of the male. At this stage the two-tone pattern of the dorsal opisthosoma of both sexes includes elements that appear in colour on the fan of the adult male.
Courtship display ( Figures 58-59View Figure 58View Figure 59). Courtship was observed indoors in a naturalistic setting. Although rapid waving of legs III is an important part of the courtship display of Maratus harrisi (unpublished observation), this appears to play no part in the display of M. lobatus . M. lobatus simply raise and extend the fan, and then intermittently (at irregular intervals from about 0.15 to 2.5 s) vibrate the fan by moving
it from side to side. This vibration is so rapid that it occurs within a single frame of a 25 fps video ( Figure 59 View Figure ). The pedipalps are also vibrated at a similar, irregular frequency, but this is not always synchronous with fan vibration.
( Figure 1 View Figure ).
Localities where Maratus lobatus has been found are shown in Table 2 and in the map
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