(FIGURES 2A, 3 A–F, 4A–D, 5A–C, 6A–F, 7A–D, 8A–D, 9A–B)
Material examined. MALE HOLOTYPE (WAM–T147349) from Australia, Western Australia, Mount Romance, 34°51'06.0"S, 117°08'54.0"E, 88m, M. Duncan, 25 Sep. 2018. PARATYPES: 3 male, 2 female (WAM-T147350), same collection data as holotype.
Etymology. The specific name (aquilus, Latin, m., noun, English translation: eagle) refers to the markings on the dorsal opisthosomal plate which resemble an eagle’s face as seen from the front.
Diagnosis. This species belongs to the Maratus vespa group (Otto & Hill, 2017B), with respect to the presence of many long bristle-like setae on legs III of the male, and the courtship display of the male which rapidly turns from side to side with a raised opisthosoma and extended large, lobate lateral opisthosomal flaps, displaying to females at close proximity (within millimetres). M. aquilus can be distinguished from other males of the group by its unique dorsal opisthosomal pattern. Females of M. aquilus are similar to other females in the M. vespa clade and identification is not possible without association with a male. The structures of the external male and female genitalia of M. aquilus are of no use in distinguishing them from other Southwestern Australia endemic Maratus species.
Description. Male (WAM–T147349). Carapace mostly black and glabrous; median thoracic tract comprised of white scales extends from rear slope of carapace to between PLE (may be worn in some specimens, see Figure 8C); lateral tracts comprised of white scales situated behind each PLE (Figure 3 A–F); carapace rimmed with welldefined marginal band comprised of white scales; ocular quadrangle region with dense cover of dark red scales interrupted by 4 distinct diverging bands of grey scales extending from between the AME forming ‘V’ shape (Figure 3 A–F). PME closer to PLE than to ALE; AME bordered with tan scales below, grey scales laterally, and dark red scales dorsally; long white setae project downwards from below anterior median eyes forming triangular shape; clypeus dark brown and covered with short, white setae (Figure 4C); chelicerae dark brown to black and glabrous; coxae and labium dark brown and glabrous; endites dark brown with pale upper edges and glabrous; sternum dark brown (Figure 4B) with light covering of fine, white setae.
Dorsal opisthosomal plate distinctly marked with complex pattern of scales resembling an eagle’s head as seen from the front; anterior margin of dorsal opisthosomal plate dotted with white scales suffused with orange scales, becoming darker posteriorly and forming triangular shape that extends to approximately 1/3 the length of opisthosoma; below this on each side of dorsal opisthosoma, complex diamond-like structures of turquoise/blue scales bordered by black scales and interrupted by irregularly shaped orange patches of scales form false ‘eye spots’; below, distinctive ‘m’ shape comprised of tan scales interrupted by tracts of black scales and bordered by black scales forms ‘beak’-like structure of ‘eagle’; below, emerald green double-teardrop shaped structure extends to posterior margin of opisthosoma, bordered by black scales and inset with elliptical shape of tan scales medially (Figures 3B and 3C, 4A).
Large lateral opisthosomal flaps fold beneath opisthosoma and are extended during courtship; lateral opisthosomal flaps covered mostly with tan setae; posterior edges covered with light blue to white setae; fringed with long, white setae on upper perimeter and long black setae on lower perimeter (Figure 2A). Legs I and II subequal in length; legs III and IV longer; legs III by far longest. Legs I, II, and IV ringed with alternating bands of dark brown and white setae; legs III with infrequent and less distinctive rings; anterior surface of femora of legs III with heavy cover of white setae; femora, patellae, and tibiae of legs III ornamented with heavy fringing of long white setae; tarsi of legs III tipped with white setae (Figures 2A, 3 A–F, 4A–D).
Pedipalp covered dorsally with long off-white setae; relatively large palpal bulb with retrolateral sperm duct loop, large retrobasal tegular lobe, finger-like retrolateral tibial apophysis; embolus with pointed inner apex beneath thicker outer apex (Figure 5 A–C).
Female (WAM-T147350). Ocular quadrangle region with incomplete cover of red-brown and white setae; area posterior to ocular quadrangle black and mostly glabrous; incomplete bands of white setae extend from PME to rear margin of carapace; area below dark brown to black and mostly glabrous; rim of carapace glabrous and lacking marginal band (Figure 6 A–F, 7B and C).
Anterior eyes bordered with red-brown and white scales dorsally, and white scales laterally and below; PME closer to PLE than to ALE; long white setae project downwards from below AME forming triangular shape (Figures 6A and 7A); clypeus covered with short, white setae; chelicerae dark brown to black and glabrous; coxae, endites, and labium dark brown, translucent and mostly glabrous; sternum dark brown with light covering of fine, white setae (Figure 7A).
Dorsal opisthosoma dark brown to black with incomplete cover of off-white and dark brown setae; central spot of off-white setae on dorsal opisthosoma; patches of white setae cover each of the four dorsal opisthosomal apodemes; posterior edge of dorsal opisthosoma with broad band of off-white and light brown setae; colular tuft of off-white setae situated above dark-grey spinnerets (Figure 6B and F); opisthosoma flanked laterally with off-white and light brown setae; ventral opisthosoma light brown and covered with small dark spots and three dark stripes (Figure 7A).
Legs I and II subequal in length; legs III and IV longer; legs III longest; integument of each leg with alternating bands of light brown and dark brown; ventral femoral surface of each leg distinctively marked with dark bands (Figure 7A); each leg with light cover of short white setae; tarsi of each leg tipped with dark brown setae; pedipalps dark brown and translucent with incomplete cover of white setae (Figure 6A).
Epigynum with pair of large ovate fossae separated by septum; ovate posterior spermatheca behind each fossa; sclerotized ducts present anterior to each spermatheca (Figure 7D).
Variation. The black tracts of scales on the dorsal opisthosoma of males may be more or less distinct in some individuals. The false ‘eye spots’ described above on the dorsal opisthosoma of the males may vary slightly in shape, and in colour from turquoise to blue. The median thoracic tract of white scales may rub off in some individuals (Figure 8 A–D).
The paratype females differ little in colour and pattern from the description above (Figure 9A and B).
Dimensions. Male. Total length: 3.45–3.75 (3.59±0.07, n=4). Carapace length 1.67–2.09 (1.92±0.09, n=4). Opisthosoma length 1.56–1.78 (1.67±0.05, n=4). Leg I length: 2.79–2.85 (2.82±0.01, n=4). Leg II length: 2.82–2.85 (2.81±0.01, n=4). Leg III length: 4.12–4.20 (4.15±0.02, n=4). Leg IV length: 3.73–3.78 (3.74±0.01, n=4).
Dimensions. Female. Total length: 3.85–3.91 (3.88±0.03, n=2). Carapace length 1.98–2.01 (2.00 ±0.02, n=2). Opisthosoma length 1.87–1.90 (1.89± 0.02, n=2). Leg I length: 2.44–2.49 (2.47±0.03, n=2). Leg II length: 2.48–2.52 (2.50±0.02, n=2). Leg III length: 4.14–4.20 (4.17±0.03, n=2). Leg IV length: 3.73–3.76 (3.75±0.02, n=2).
Distribution. Known from near Mount Romance, Western Australia. Similar specimens which may belong to the same species were collected by Jürgen Otto at another location 8 km west of Mount Romance in November 2018 (Otto, 2018, pers. comm.). Photographs of these specimens can be viewed on Flickr (https://www.flickr.com/ photos/59431731@N05/albums/72157704355034594).
Courtship display. The male elevates legs III, flexing them slightly outwards and holding them in place for the duration of the courtship display. The pedipalps are held apart, exposing the chelicerae. The entire body trembles before slowly elevating and waving the opisthosoma. When the opisthosoma reaches complete elevation, the opisthosomal flaps are extended, and the opisthosoma is once again lowered and the flaps retracted. The female begins to near the male and the elevation and lowering of the opisthosoma and the extension and retraction of the opisthosomal flaps becomes more rapid. The male then begins to move from side to side, angling the opisthosoma towards one side of the body and extending the corresponding opisthosomal flap while the female closely follows. The alternations between the sides that the male angles the opisthosoma appears random and does not follow a predictable pattern. (Figure 2A). (Note: only partial courtship display observed, the males may exhibit a more complete courtship display with multiple modes of courtship).