Myrmarachne rubra, 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 : 246-248

Subfamily MYRMARACHNINAE Myrmarachne rubra sp. nov. Figures 1–9

Etymology. The specific name is an adjective chosen because of the red colour that most individuals have on their carapace. Material examined. Holotype: QM S66648 (male, collected by FS Ceccarelli in Townsville 19°19′39″S, 146°45′32″E, 11 March 2003) . Allotype: QM S88158 (female, collected by FS Ceccarelli in Townsville 19°19′39″S, 146°45′27″E, 18 July 2005) . Paratypes: QM S73296 (female, collected by BM Baehr 1 km south of Dimbulah , 5 June 1993) , AM KS93121 (male, collected by FS Ceccarelli in Townsville , 5 November 2005) , AM KS18335 (female, collected by M Zabka north of Kuranda , 10 June 1982) , AM KS81341 (female, collected by M Zabka in the Atherton area , 18 October 2002) , AM KS5770 (male, collected by NC Coleman in Wolfram , 15 June 1970) . Diagnosis. Male chelicerae usually two-thirds the length of the carapace, with four retromarginal teeth at the distal and one at the proximal end of each chelicera. The bulb of the male palp is three-quarters of the total length of the cymbium; the tibial segment has a poorly developed flange, and a small, sinuous apophysis, and the whole segment is longer than wide at its base. The female epigyne has d-shaped spermathecae, and a continuous median pouch. M. rubra can be distinguished from M. erythrocephala and M. striatipes (paratypes examined from QM) by the number of spines on the first pair of legs, where M. rubra has a pair of spines on the metatarsi, and a single spine and a pair on the tibia, whereas both M. erythrocephala and M. striatipes have two pairs of spines on the metatarsi of legs I. In addition, male M. rubra have protruding chelicerae with four retromarginal teeth at the distal- and one at the proximal end of each chelicera, whereas the chelicerae of M. striatipes males do not protrude.

Description. Male: Carapace: ranging from orange-brown to red-brown or black with sparse white hairs, wedge-shaped depressions behind the anterior lateral eyes. Eyes: surrounded by black pigmentation, procurved anteriors surrounded by hairs. Clypeus: fringed with white hairs. Chelicerae: rugulose and protruding, orange-brown to red-brown with black pigmentation at distal end, no fang apophysis, retromarginal dentition: one tooth on proximal end and four on distal end. Maxillae and labium: orange with black hairs and setae. Sternum: orange-brown with some black markings. Opisthosoma: distal end black, front part red-brown to orange-brown or in some cases black; sparsely covered with fine white hairs, central depression more densely fringed with white hairs. Legs: slender. Legs I: tarsus black; metatarsus black and orange; tibia light orange with black markings; patella light orange with black markings; femur orange brown and black; trochanter cream; coxa cream. Legs II: tarsus cream; metatarsus black and orange; tibia light orange with black markings; patella light orange with black markings; femur orange brown and black; trochanter cream; coxa cream. Legs III: tarsus cream; metatarsus cream; tibia orange; patella orange; dark brown and black; femur dark brown and black; trochanter cream; coxa black. Legs IV: tarsus cream; metatarsus cream; tibia orange; patella orange; dark brown and black; femur dark brown and black; trochanter cream; coxa yellow and black. Legs I spination: metatarsus 2, tibia 1–2, patella 0. Palp: tibial apophysis relatively small, sinuous and black; flange not very developed; cymbium and proximal depression fringed with setae; embolus coiled once around bulbous tegulum of approximately 210 μm in diameter; seminal reservoir large and marginate. Dimensions: total length: 3.7–4.5 mm; carapace length: 1.8–2.4 mm; ratio of carapace-to-chelicera length: 1.22–1.67; Ratios AME: ALE: PME: PLE: 5.78:1.41:1:2.7.

Female: Carapace: same as ♂. Eyes: same as ♂. Clypeus: fringed with white hairs. Chelicerae: rugulose, nonprotruding, mainly black with some dark red pigmentation. Maxillae and labium: same as ♂. Sternum: same as ♂. Opisthosoma: same as ♂, but often more bulbous. Legs: slender. Legs I: tarsus black; metatarsus light orange; tibia light orange and cream; patella light orange and cream; femur light orange; trochanter cream; coxa cream. Legs II: same as legs I. Legs III and IV: same as legs I and II, but slightly darker. Legs I spination: metatarsus 2, tibia 1–2, patella 0. Epigyne: orange and dark-red, continuous median pouch, spermathecae simple (d-shaped), ducts relatively wide. Dimensions: total length: 4.0– 4.7 mm; carapace length: 2.0– 2.5 mm; Ratios AME: ALE: PME: PLE: 5.78:1.41:1:2.7.

Distribution. Specimens recorded from north Queensland, Australia: Atherton (17°17′S, 145°30′E), Dimbulah (17°08′S, 145°04′E), Kuranda (16°48′S, 145°35′E), Townsville (19°13′S, 146°48′E) and Wolfram (17°05′S, 144°55′E); other areas unknown.

Remarks. Myrmarachne rubra belongs to the volatilis group. It is a visual mimic of the ant Opisthopsis haddoni Emery, 1893 ( Formicidae : Formicinae ). M. rubra can be found on tree trunks (mainly eucalyptus trees of the species Eucalyptus platyphylla ), usually closely associated with their model ant. Males and females usually build retreats under loose pieces of bark, but male retreats tend to be sheet-like, and males are more likely to be found walking up the tree trunks. Females build more wool-like retreats with thicker strands of silk ‘anchoring’ the retreat to the tree, and lay between 10 and 20 eggs in their retreat, which they stay with until the spiderlings hatch. During instars 3 and 4, M. rubra look like small black ants from the genus Crematogaster Lund, 1831 ( Formicidae : Myrmicinae).