Maratus ammophilus Otto &amp; Hill 2022, new species
Creators: name: Otto, Ju. rgen C.
name: Hill, David E.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Salticidae
Maratus
Maratus ammophilus

description: <i>Maratus ammophilus</i>, new species <i>Type specimens</i>. The holotype male (&amp;male; #1), five paratype males (&amp;male; #2-6), and two paratype females (&amp;female; #1-2) were collected at Pumpkin Hollow on the coast north of Perth, Western Australia (30.233116°S, 115.014010°E, 7-18 FEB 2021, coll. Caleb Bartell). &amp;male; #1-4 and &amp;female; #2 were caught as juveniles and raised to adulthood, &amp;male; #5 and &amp;female; #1 were caught as adults, and &amp;male; #6 was raised from an egg deposited by &amp;female; #1. Three paratype males (&amp;male; #7-9) and four paratype females (&amp;female; #3-6) were collected at nearby South Bay, Green Head (30.073353°S, 114.978204°E, 7-18 FEB 2021, coll. Caleb Bartell). &amp;male; #9 was caught as an adult, &amp;male; #7-8 and &amp;female; #3-6 were collected as juveniles and raised to adulthood. All types will be deposited in the Western Australian Museum, Perth. <i>M.</i> <i>ammophilus</i> has also been observed at Lake Thetis in Cervantes (30.505942°S, 115.078376°E, JUL 2018; Su Rammohan, pers. comm.), and at the beach in Kalbarri (27.703654°S, 114.167276°E, JUN 2022; Michael Lun, pers. comm.). <i>Etymology</i>. The species group name, <i>ammophilus</i> (Latin, adjective, m.), means <i>sand-loving</i>, a reference to the sandy beach habitat of these spiders. <i>Diagnosis</i>. The distinctive wheel-rim shape of the embolus and the use of legs I in courtship clearly place the male <i>Maratus ammophilus</i> in the <i>fimbriatus</i> group of the genus <i>Maratus</i>. The male resembles <i>M. speculifer</i> with respect to the unusual shape and yellow-green colour of femora I, with a wider proximal <i>subsegment</i> separated from a narrower distal subsegment by a shelf on the anterior side. However, the overall colouration of the male <i>M. ammophilus</i> (Figure 1) is quite different, like the female almost entirely off-white. The setae of the dorsal opisthosoma of <i>M. ammophilus</i> are off-white and moderately iridescent, whereas the fan of the male <i>M. speculifer</i> bears a singular dark and glabrous, shiny scute, the basis for its species name. In addition the anterior femora I and II of <i>M. ammophilus</i> have a transverse black bar at the distal end of each subsegment, or at least at the end of each proximal subsegment, easily visible from the front during courtship display. <i>Description of male</i> (Figures 4-7). Males (n=9) ranged from 3.2-3.8 mm in length. Almost the entire body, including the ventral opisthosoma, is covered with white to off-white or light-brown setae. The face is bright white, the chelicerae mostly glabrous and dark brown. An indistinct, middorsal thoracic tract of lighter setae may be present. The sides of the carapace have a distinct marginal band of white to offwhite setae. The PME are closer to the PLE than to the ALE. The dorsal opisthosoma tends to be light brown rather than white, often with a moderate iridescence. Legs I and II of similar length, shorter than legs III and IV, all with indistinct dark bands at the joints. Legs III are the longest. Sternum, labium and endites are dark brown to grey, almost glabrous except for longer white to off-white setae radiating from the posterior and lateral margins of the sternum. Cuticle of the prosoma and opisthosoma dark, that of the appendages almost lacking pigment. Ventral surface of each femur I and II translucent and almost glabrous, yellow-green. Each femur I and II is divided into a proximal <i>subsegment</i> of greater diameter, and a distal subsegment of lesser diameter, each subsegment (or at least the proximal subsegment) marked distally by a dark transverse band on the ventral surface; these subsegments are separated by a distinct, ventral shelf associated with the transverse band of the proximal subsegment (Figure 4:8,52). Pedipalps are light in colour, covered with long white setae. The retrolateral tibial apophysis (RTA) is unremarkable, similar to that of other <i>Maratus</i>. As is the case for other members of the <i>fimbriatus</i> group, the embolus resembles a wheel-rim, darker along the upper and lower margins of that rim, with a distally projecting terminus that bears the apical pore. <i>Description of female</i> (figures 8-10). Females (n=5) ranged from 4.0- 4.9 mm in length. Colour very much like the male, although the yellow-green colouration beneath femora I and II may be subdued and obscured by long white setae. Most of the type females have a fairly uniform but variable cover of off-white to light brown setae on the dorsum, but one (&amp;female; #2, Figure 8:4-12) is much more patterned or contrasty on the dorsum, with many areas bearing darker brown setae. Variable pigmentation of the cuticle is more evident in alcohol (Figure 10:1-20). All females have long, bright white setae on the face, projecting anteromedially over the top of the dark brown, glabrous chelicerae. Setae covering the lower sides of the carapace are also bright white. PME closer to the PLE than to the ALE. Legs I and II are shorter and of similar length, legs III and IV longer and also of similar length. The epigynum (Figure 10: 25-28) is unremarkable and similar to that of other <i>Maratus</i>, with large fossae and posterior spermathecae of similar size. <i>Immatures</i> (Figure 11). Immature <i>Maratus ammophilus</i>, even in the first emergent (free-living) instar (II), have a colouration similar to that of adults. <i>Courtship</i> (Figures 12-16). Courtship display in <i>Maratus ammophilus</i>, as observed under natural conditions in the laboratory, is relatively simple, with the male moving intermittently (discontinuously) from side to side in front of the female, holding each new position with legs I extended and elevated to display the prominent markings on the underside of the femora, as legs III are extended to the sides. In this position, the ornamentation under legs II is also visible to the front. During this display the white pedipalps are held in place in front of the dark and glabrous chelicerae. As shown in Figure 12, the male tends to keep legs II in place when moving the elevated and extended legs I and III to one side or the other, and may even keep legs II and IV in place during this movement without any stepping at all. This fixed placement or stance of legs II keeps them in a position where the ventral femora II, like the ventral femora I, are readily visible from the front. When legs III are widely extended this side-to-side rocking movement also has a <i>see-saw</i> effect. The extent to which the opisthosoma is raised (never to a vertical position), or legs III are extended, varies. In addition, detailed placement of legs II and IV during each stance varies according to the surface on which the male is displaying. All aspects of this display are similar to those seen in other members of the <i>fimbriatus</i> group, although one species, <i>Maratus fimbriatus</i>, does not extend legs III, but also rotates the fan with each side-to-side movement. <i>Mating</i>. The erection of spines during mating by spiders corresponds to the transient increase in internal fluid pressure that occurs as seminal fluid is pumped from each pedipalp into the corresponding (same side) sperm duct of the female. This is documented for <i>Maratus ammophilus</i> in Figure 17. <i>Habitat</i>. <i>Maratus ammophilus</i> has been found on sandy ground, in coastal dunes along the Indian Ocean in Western Australia (Figures 2, 3:1-2, 18-19).
description: Published as part of <i>Otto, Ju. rgen C. &amp; Hill, David E., 2022, Maratus ammophilus, a new peacock spider in the Fimbriatus group from Western Australia (Araneae: Salticidae: Euophryini), pp. 1-65 in Peckhamia 273 (1)</i> on pages 4-31, DOI: 10.5281/zenodo.7171540