Maratus aurantius, 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 : 4-17

Maratus aurantius , new species

Type specimens. The holotype male (♂ #1), three paratype males (♂ #2-4), two paratype females (♀ #1, 3), and one paratype female (♀ #4) collected when immature and reared to adulthood, were collected near Orange , New South Wales (S33.25344°, E148.93661°, 25 OCT 2015, coll. M. Doe, M. Duncan, A. Fletcher). All types will be deposited in the Australian Museum, Sydney .

Etymology. The species group name ( aurantius, Latin , m., adjective, English translation orange) refers to the bright orange colouration of the adult male.

Diagnosis. Male and female genitalia are similar to those of other members of the anomalus group ( Otto & Hill 2016b). Females are cryptic brown and similar in colouration to other grassland peacock spiders, but have a relatively well-defined light brown stripe on either side of the midline of the opisthosoma ( Figure 3 ). These are best identified by association with the distinctive males. The eye region of the male is covered with dull orange setae, and the dorsal opisthosoma is marked with a narrow, shiny or light blue stripe on either side of the midline leading back to a small black posterior spot, on a background of bright red-orange setae.

Description of male ( Figures 4 -8). Males are 3.8-4.2 mm in length (n=4). The chelicerae are light brown and translucent. Off-white setae extend diagonally from the brown, translucent clypeus toward the midline between the chelicerae. The eye region and the sides of the carapace just below the lateral eyes are covered with uniform dull orange to brown scales or setae. The sides of the carapace are light brown and translucent and may bear two narrow vertical stripes of off-white setae. There is no marginal band and the lateral rims of the carapace are clearly visible.

Dull orange scales may extend toward the rear of the carapace behind the eye region, and a wide band of off-white scales extends behind each PLE, converging toward the rear where the two bands are separated by a wide, dark, mostly glabrous median stripe. The PME are slightly closer to the PLE than to the ALE.

The dorsal plate of the opisthosoma bears five relatively distinct longitudinal bands of colourful setae. The median band is comprised of bright red-orange pigmented scales, flanked on either side by a band of light green to blue to purple iridescent scales, in turn flanked by a lateral band of bright red-orange pigmented scales. In certain lighting conditions the iridescent bands appear as a pair of dark stripes on a red-orange field ( Figure 5 : 1). At the rear of the dorsal plate the background scales are uniform light brown or tan, with a small black spot on either side. Laterally the dorsal plate is fringed with white to offwhite setae, and the sides of the opisthosoma have a dense cover of long, off-white setae. The spinnerets are black below ( Figure 6 ), but fringed with off-white setae and they may be extended during courtship display ( Figure 5 : 1-2). The ventral opisthosoma is brown and mostly glabrous with scattered white to off-white setae, flanked on either side by a distinct black stripe. The sternum, labium, coxae, and endites are almost colourless and translucent with scattered white to off-white setae.

All legs are quite uniform in colouration, very light orange and translucent and bearing many off-white to very light orange scales and setae. Longer cuff-like setae may extend from each metatarsus and tarsus, but these "cuffs" are not as prominent or distinct in this species as they are in M. cinereus and M. lentus . As in other Maratus , legs I and II are shorter and of the same length, while legs III and IV are longer and legs III are the longest.

Each pedipalp is light brown and translucent, covered with long light brown or off-white setae in the front ( Figures 4 : 3, 5: 1). The detailed structure (Figure 8) is similar to that of other members of the anomalus group, with a prominent outer ring of the embolus terminating in a blunt or bifurcated apex, beneath which is a shorter pointed apex of a short inner ring. SEM images that show these structures in more detail have been published for other members of the anomalus group ( Baehr & Whyte 2016). Although useful for association with the anomalus group, these structures are of little use for identification of species as they vary little within that group.

Description of female ( Figures 9-13 ). Females range from 4.6-4.8 mm in length (n=3). The chelicerae, clypeus, and lower parts of the carapace are light brown, translucent, and glabrous. Longer white setae extend anteromedially below the front eye row. The carapace lacks a marginal band and the lateral rims are clearly visible. The eye region is covered with dull orange-brown setae. Behind the posterior eyes the dorsal carapace is mostly glabrous, with a wide dark, glabrous median stripe. On either side of this the carapace is lighter brown and may be covered with off-white scales or setae ( Figure 9 : 7). The PME is about the same distance from the ALE as from the PLE. The dorsal opisthosoma is covered with an indistinctly striated or variegated pattern of mixed light to dark brown scales, with a light stripe on either side of the midline, flanked on the sides of the opisthosoma by a wide band of off-white scales and setae. The legs are uniform in colour, light brown and translucent with a covering of off-white setae above, primarily on legs III and IV. Legs I and II are shorter, legs III and IV longer, and legs III are the longest. The ventral opisthosoma is covered with shorter off-white setae and may be flanked on either side by a narrow black stripe ( Figure 11 : 1). The venter of the prosoma including the coxae is mostly light brown, glabrous, and translucent. The epigynum closely resembles that of other members of the anomalus group, with dark sclerotized ducts visible laterally and medially at the rear of each fossa ( Figure 13 ).

lines on either side of the ventral opisthosoma, corresponding to those of the male.

Courtship display ( Figures 14-17 ). The courtship display by male Maratus aurantius is relatively simple, with the flattened fan held in an erect position, usually with one or both legs III extended and elevated in a partly flexed position, as the male steps from side to side in front of a female. The spinnerets may also be extended and held apart, and the legs III may be slowly moved during this display.

Habitat. The open woodland where Maratus aurantius was found on grasses near Orange, NSW, is shown in Figure 18 .

Figures

Figure 3. Adult females of the four new grassland peacock spider species. Females within this group are very similar with respect to size and colouration and can be difficult to identify. 1-4, The female M. aurantius, like the male, has a narrow light brown stripe running along either side of the midline of the opisthosoma. These are less distinct than in the male and variable with respect to their colour and definition. These stripes can also be found, generally with less definition, in some female M. cinereus (7), or M. lentus (9). 5-12, Female M. cinereus (5-8) and M. lentus (9-12) have similar scale patterns on the dorsal opisthosoma. M. lentus females may have more distinct chevrons along the midline of the opisthosoma, but some M. cinereus females (8) also have these. 13-16, Like the male, the female M. neptunus has one median and two lateral dark stripes along the length of the dorsal opisthosoma, all well-defined.

Figure 4. Views of the living holotype (1-4) and two paratype male M. aurantius (5-6, 7-9).

Figure 5. Views of two living paratype male M. aurantius (1-3, 4-7).

Figure 6. Two ventral views of the living holotype male M. aurantius.

Figure 9. Views of a living female Maratus aurantius.

Figure 10. Three living female Maratus aurantius (1-3, 4, 5-8).

Figure 11. Ventral view of three living female Maratus aurantius. 1, This individual has dark, narrow

Figure 12. Views of three female M. aurantius fixed in alcohol.

Figure 13. Ventral or external view of the epigynum of three female Maratus aurantius. The anterior direction is toward the top of each photograph. As in other members of the anomalus group, heavily sclerotized ducts may be seen at the rear of each fossa, on either side. Note variations in the relative size of the large posterior spermathecae and the width of the septum that separates the fossae.

Figure 14. Display positions of the holotype male M. aurantius, showing elevation and flexion of a leg III.

Figure 15. Display positions of three paratype male M. aurantius (1, 2-8, 9). 1-3, A male may display by simply raising the fan in front of a female, but as the action proceeds usually one or both legs III is extended and partially flexed. Movement of legs III is relatively slow and the fan itself is not waved as the male steps from side to side. 4-5, The extended spinnerets may be separated (4) or pulled together (3) during the display. 6-8, Often the posterior medial spinnerets are retracted to the rear during display.

Figure 16. Sequence of frames (5fps, from 25fps video) showing the relatively slow movement of a male M. aurantius as he stepped around a branch while facing a female. Leg LIII was held in an extended position as leg RIII was slowly extended during this display. Note the extended spinnerets. The fan was not waved.

Figure 17. Sequential but not consecutive frames (from 25fps video) showing positions of a male M. aurantius moving slowly from side to side in front of a female. Leg RIII was held in an extended position as leg LIII was extended (7-10) and then flexed (11-12) in ~2s.

Figure 18. Grassland habitat of Maratus aurantius near Orange, NSW. Photograph by Adam Fletcher.