Maratus neptunus, Otto & Hill, 2017

Otto, Jürgen C. & Hill, David E., 2017, Five new peacock spiders from eastern Australia (Araneae: Salticidae: Euophryini: Maratus Karsch 1878 and Saratus, new genus), Peckhamia 147 (1), pp. 1-86 : 51-69

Maratus neptunus , new species

Type specimens. The holotype male (♂ #1), two paratype males (♂ #2-3) and one paratype female (♀ #1) were collected at Butterwick , New South Wales (S32.65402°, E151.65008°, 6 OCT 2014, coll. J. Otto). Four paratype males (♂ #4-7), and two paratype females (♀ #3-4) were collected near Tamworth, New South Wales (S31.20371°, E151.08811°, 27 MAY 2015, coll. M. Doe, M. Duncan, A. Fletcher). Three paratype males (♂ #8-10) and two paratype females (♀ #2, 5) were reared from eggs deposited by the Butterwick female . All types will be deposited in the Australian Museum, Sydney.

Etymology. The species group name ( neptunus, Latin , m., noun in apposition, English translation Neptune, the Roman sea god) was selected to suggest the bright marine blue colour of the adult male. The three bold black stripes of the dorsal opisthosoma can also be associated with Neptune's trident.

Diagnosis. The detailed structure of male and female genitalia is similar to that of other members of the anomalus group. Colouration and display of legs III of the male, black with white setae on the metatarsus and tarsus, is similar to M. julianneae except for a patch of white scales or setae on each patella III. Otherwise the colour and scale patterns of M. neptunus , including three prominent dark stripes on a uniform field of bright iridescent scales of the dorsal opisthosoma, are quite different ( Figure 2 ). Females may be distinguished from other grassland peacock spiders by the presence of three prominent dark brown stripes along the length of the dorsal opisthosoma.

Description of male ( Figures 55-62 ). Male M. neptunus are 4.2-4.6 mm in length (n=8). The chelicerae, clypeus and sides of the carapace are dark brown or black and glabrous. A cover of dull, red-orange scales surrounds the eyes and the front and sides of the eye region. Behind this, the carapace is black and a wide median, glabrous, black band extends to the rear of the carapace. There is no marginal band but two short bands of white scales extend upwards from the exposed rim of the margin. A wide band of bright white scales runs medially behind each PLE, then turns and runs toward the rear of the carapace on either side of the black median band.

The dorsal opisthosomal plate (fan) is densely covered with iridescent grey or blue or purple scales, interrupted by a three black stripes, one at the median line and one on either side of the median. This three-striped pattern is a useful field mark for M. neptunus males and females. In one male from Tamworth ( Figure 56 : 11-12) the three black stripes were bordered with red scales. Each of the lateral black lines terminates in a small more-or-less distinct spot at the rear, a characteristic of males within the anomalus group. The fan is fringed laterally with long white setae. The sides of the opisthosoma are covered with long white setae, and the venter, light brown with few setae at the median, is flanked with a black line near the margin on either side (Figure 60). The coxae, sternum, labium, and endites are light brown and glabrous except for scattered white setae. Legs I and II are about the same length. Legs III and IV are longer and legs III are the longest. Legs I, II and IV are similar in colour, covered with white setae interrupted by a black or brown ring at each joint. Legs III are black from the base of each femur to the proximal metatarsus, with some white scales on the dorsal patella. The distal metatarsus and tarsus of leg III are covered with white setae.

The pedipalps are covered with long, bright white scales above and on their anterior surfaces. The detailed structure of the male pedipalp is similar to that of other members of the anomalus group, with a long circular outer ring of the embolus terminating anterolaterally with a blunt or bifurcated apex, and a short inner process beneath this terminating with a smaller, pointed apex ( Figures 61-62 ).

Description of female ( Figures 63 -68). Female M. neptunus are 4.7-5.7 mm in length (n=5).

Female 68. Ventral view of epigynum of five female Maratus neptunus . The anterior direction is toward the top of each photograph. Note variation in the relative size of the large posterior spermathecae and the position of the heavily sclerotized ducts at the rear of each fossa.

The clypeus and chelicerae are light-brown, translucent and glabrous. Beneath the anterior eye row long white setae extend anteromedially. The eye region and the sides of the carapace just below the lateral eyes are covered with off-white to brown setae. Behind the eye region a dark median band extends to the rear of the carapace, and behind each PLE a wide, irregular band of off-white setae extends to the rear on either side of the dark median band. The sides of the carapace are light brown, glabrous and translucent and there is no marginal band. The PME is almost equidistant between the ALE and the PLE. The opisthosoma is light coloured with a dorsal pattern of one dark brown median stripe flanked on either side by a wide stripe comprised of off-white setae, in turn flanked by a more-or-less well-defined dark brown stripe. Lateral to this stripe the dark brown markings of the dorsal opisthosoma vary in definition but may appear as four parallel, irregular lines if well-defined ( Figure 64 :6). The sides and ventral opisthosoma are light-brown with a covering of short, off-white setae. From below, the legs, sternum, labium, and endites are light-brown, translucent, and mostly glabrous. The legs and pedipalps are uniform in colouration, light-brown and translucent with a moderate dorsal cover of off-white scales and setae. Legs I and II are about the same length and quite glabrous. Legs III and IV are longer, legs III the longest. The epigynum (Figure 68), with sclerotized ducts visible at the medial and lateral sides of the each posterior fossa, is typical for females of the anomalus group.

Immatures. Emergent (second instar) juveniles resemble those of other grassland peacock spiders ( Figure 69 ). Penultimate females ( Figure 70 ) and penultimate males ( Figure 71 ) resemble adult females in their colouration and scale patterns, with three prominent dark brown stripes on the dorsal opisthosoma.

Courtship display ( Figures 72-75 ). The courtship display of the male Maratus neptunus is relatively simple. The male elevates the fan, extends the spinnerets above it, raises and (usually) slightly flexes legs III at the femuropatellar joint, and holds the extended pedipalps, turned medially and often touching, to the front. In this fixed position the male continuously rotates the entire body from side to side, either by stepping around a stem ( Figure 74 ), or by pivoting the legs in place ( Figure 75 ).

Mating. Final approach and mating positions of Maratus neptunus are shown in Figure 76 . When mating pumping of the pedipalp bulb occurs in synchrony with erection of the spines of all legs ( Figure 77 : 1-2), suggesting that cyclic pressure changes in the ventral prosoma (below the endosternite) affect fluid pressure in connected appendages simultaneously. Extension and retraction of the pretarsus including the paired claws and footpads of leg LIV of a mating female is also shown here ( Figure 77 : 3-12). Although part of the normal leg movement of salticids this has seldom been documented ( Hill 2010).

pumping cycle of a pedipalp is associated with extension of the spines (macrosetae) of legs I-IV of the male (1, arrows), followed by retraction of those spines (2). 3-12, Magnified view of the tarsus and pretarsus of leg LIV of the mating female, corresponding to the inset rectangle in (1-2), from selected, sequential but not consecutive frames. Arrows indicate retraction (4, 9, 11) and extension

(5, 10, 12) of the two claws and two footpads of the pretarsus.

Habitat. The habitat of Maratus neptunus near Butterwick and Tamworth, NSW is shown in Figure 78 .

Figures

Figure 2. Courtship display by males of the five known grassland peacock spiders. 1, M. julianneae was recently described from Carnarvon Station. 2-7, Four new species described here are M. aurantius (2), M. neptunus (3-4), M. cinereus (5-6) and M. lentus (7).

Figure 55. Three paratype (1-3, 4-7, 8-12) male M. neptunus from Butterwick, New South Wales. 12, Rear view during display. Note extreme extension of the pedicel.

Figure 56. Four paratype (1-3, 4-5, 6-10, 11-12) male Maratus neptunus from Tamworth, NSW.

Figure 57. Two living paratype male M. neptunus (1-6, 7-12), reared from Butterwick, NSW parents.

Figure 58. Holotype (1-5) and two paratype (6-9 & 13, 10-12 & 14) male M. neptunus fixed in alcohol.

Figure 61. Medial to lateral views of the left pedipalp of two paratype male M. neptunus (1-2, 3-5).

Figure 62. Medial to lateral views of the left pedipalp of the holotype (1-4) and four paratype (5-8, 9-11, 12-15, 16-20) male Maratus neptunus.

Figure 63. Two living female Maratus neptunus (1-6, 7-12). 4, The three dark brown stripes on the opisthosoma of the female correspond to the three black or dark red stripes on the opisthosoma of the male.

Figure 64. Two living female Maratus neptunus (1-4, 5-10). 10, In some individuals a series of bold chevrons can be seen beind the median stripe of the dorsal opisthosoma.

Figure 69. Emergent (second instar) Maratus neptunus, reared from adults captured at Butterwick, NSW. 1, Second instar with mother at left to show relative size.

Figure 70. Two penultimate female Maratus neptunus (1-3, 4-5) reared from adults captured at Butterwick, NSW. These look very much like adult females.

Figure 71. Five penultimate male Maratus neptunus (1-2, 3-5, 6-7, 8-10, 11-12) reared from adults captured at Butterwick, NSW. Scattered white setae may be present on the sides of the carapace of the penultimate male.

Figure 72. Display positions of five male Maratus neptunus (1, 2-3, 4-5, 6-7, 8-9) in front of a female.

Figure 73. Display positions of four male Maratus neptunus (1, 2-6, 7-10, 11-12) in front of a female. 3, Posterolateral view showing the flattened opisthosoma. Note the fringes of the extended spinnerets.

Figure 74. Sequential positions (5/s frames selected from a 25fps video) during the display of a male Maratus neptunus. In this sequence the male first rotated to his left (1-8), then to his right (9-18), then back to his left (19-28). Movement of the entire body was continuous as the spider stepped and pivoted around a narrow stem in front of a female.

Figure 75. Sequential positions (5/s frames selected from a 25fps video) during the display of a male Maratus neptunus. This male first pivoted to his right (1-10), then to his left (11-20), then back to his right (22-30) with almost continuous motion.

Figure 76. Mating positions of male and female Maratus neptunus. 1-2, In the final approach this male touched the carapace of the female with his legs I.

Figure 77. Movement during mating by Maratus neptunus (frames from a 25fps video). 1-2, Each

Figure 78. Grassy habitat of M. neptunus near Butterwick (1) and Tamworth (2), New South Wales. Photographs by Jürgen Otto (1) and Michael Doe (2).