Myrmarachne aurea, Ceccarelli, F. Sara, 2010

Ceccarelli, F. Sara, 2010, New species of ant-mimicking jumping spiders of the genus Myrmarachne MacLeay, 1839 (Araneae: Salticidae) from north Queensland, Australia, Australian Journal of Entomology 49, pp. 245-255 : 248-249

Myrmarachne aurea sp. nov. Figures 10–18

Etymology. This name derives from the adjective aurea , chosen because of the golden appearance of the opisthosoma. Material examined. Holotype: AM KS93119 (male collected by FS Ceccarelli in Townsville , 19°19′40″S, 146°45′33″E, 16 November 2005) . Allotype: QM S66649 (female collected by FS Ceccarelli in Townsville , 19°19′39″S, 146°45′32″E, 4 June 2003) . Paratypes: QM S41386 (female collected by MF Downs in Townsville , 1 June 1981) ; QM S20339 (female collected by M Shaw near Canowindra , 14 March 1992) ; QM S73293 (male collected by BM Baehr at Mary Creek 25 km south of Musgrave , Northern Territory, 29 May 1993) ; AM KS56467 (two females collected by G Milledge in Kenilworth state forest , 7 May 1998) ; AM KS93120 (female collected by FS Ceccarelli in Townsville , 16 November 2005) .

Diagnosis. Males chelicerae are not protruding when viewed from above, and contain three promarginal and three retromarginal teeth. The tibia of the male palps has a poorly developed flange, and a sinuous apophysis; the diameter of the tegulum is approximately two-thirds the length of the cymbium. The cymbium contains two larger setae at the distal tip. Females have small, round spermathecae that are separated from each other; there are also two lateral pouches that are found in contact with each other. M. aurea can be distinguished from M. luctuosa by the fact that M. aurea male chelicerae do not protrude.

Description. Male: Carapace: black with few white hairs, wedge-shaped depression with more dense white hairs. Eyes: procurved, surrounded by white hairs. Clypeus: fringed with white hairs. Chelicerae: not protruding, black with a dark red fang, retromarginal dentition: three teeth, promarginal dentition: three teeth. Maxillae and labium: black maxillae with a yellow inner edge, labium black. Sternum: black. Opisthosoma: black and yellow with fairly densely packed golden yellow hairs, giving the opisthosoma a golden sheen, slightly constricted in the middle. Legs: slender. Legs I: tarsus black; metatarsus black; tibia yellow with black marks, typically a line running down the length of the leg segment; patella same as tibia; femur same as tibia and patella; trochanter black and yellow; coxa yellow/cream coloured. Legs II: tarsus yellow with black markings; metatarsus yellow with black markings; tibia yellow with black markings; patella yellow with black markings; femur yellow with black markings; trochanter yellow with black markings; coxa black. Legs III: tarsus yellow; metatarsus black; tibia black; patella yellow; femur black; trochanter black; coxa black. Legs IV: tarsus black; metatarsus black; tibia black; patella black and yellow; femur black; trochanter yellow and black; coxa yellow. Legs I spination: metatarsus 2-1, tibia 2-2-2, patella 0. Palp: tibial apophysis with a black sinuous hook, embolus coiled around bulbous tegulum, about 200 μm in diameter (about two-thirds the length of the cymbium), large, marginate seminal reservoir, cymbium and proximal depression fringed with setae with two larger ones at the distal end. Dimensions: total length: 4.5– 5.5 mm; carapace length: 1.8–2.5 mm; ratio of carapace-tochelicera length: 2–4; Ratios AME: ALE: PME: PLE: 4.12:1.61:1:2. Female: Carapace: same as ♂. Eyes: same as ♂. Clypeus: same as ♂. Chelicerae: same as ♂. Maxillae and labium: same as ♂. Sternum: same as ♂. Opisthosoma: same as ♂, but occasionally more bulbous. Legs: same as ♂. Legs I spination: metatarsus 2-2, tibia 2-2-2, patella 0. Epigyne: black and yellow pigmentation, lateral pouches separate, spermathecae simple and round, ducts relatively wide. Dimensions: total length: 3.8–4.5 mm; carapace length: 1.8–2.1 mm; Ratios AME: ALE: PME: PLE: same as ♂.

Distribution. Specimens recorded from Queensland, Australia: Canowindra (33°35′S, 148°38′E), Townsville (19°13′S, 146°48′E) and Kenilworth state forest (27°41′S, 147°46′E); and Northern Territory, Australia: Musgrave (26°05′S, 132°00′E); other areas unknown.

Remarks. Myrmarachne aurea belongs to the volatilis group, and is widely distributed in Townsville and surrounding areas, and can be found either walking on trees, in particular eucalypts ( E. platyphylla and Corymbia tessellaris ), or inside retreats under loose bits of bark. It is not uncommon to find more than one retreat under a piece of bark, with several M. aurea (typically between two and six, often at different instar stages), each living in a separate retreat. The model ant species for M. aurea is Polyrhachis nr. obtusa Smith, 1857 ( Formicidae : Formicinae ). M. aurea and its model ant species P. nr. obtusa are found living in sympatry, but not always on the same tree. M. aurea do not develop the golden-haired opisthosoma until they reach adulthood. Before that, the spiderlings are of a dark brown colour with white markings on both the pro- and opisthosoma.