Mexcala elegans Peckham & Peckham, 1903

Wesolowska, Wanda & Haddad, Charles R., 2009, Jumping spiders (Araneae: Salticidae) of the Ndumo Game Reserve, Maputaland, South Africa, African Invertebrates 50 (1), pp. 13-103 : 56-58

Mexcala elegans Peckham & Peckham, 1903

Figs 101–104, 247

Mexcala elegans: Peckham & Peckham 1903: 248 , pl. 29, fig. 2; Wesolowska 2009: 158, figs 30–46. Cosmophasis natalensis: Lawrence 1942: 184 , fig. 30. Mexcala natalensis: Wesolowska & Cumming 2008: 197 , figs 92–97.

Redescription:

Measurements (male/female): Carapace length 3.2/3.2, width 2.2/2.3, height 1.4/1.5. Abdomen length 3.6/4.8, width 1.9/2.9. Eye field length 1.3/1.3, anterior width 1.7/2.0, posterior width 1.7/2.0.

Male.

Medium-sized, slender spider with long legs and contrasting colouration. Carapace high with short eye field and gently sloping posterior part; brown bristles near eyes; clypeus low. Chelicerae long, brown, with short sharp spike-like setae on dorsal surfaces; labium, endites and sternum dark brown.Abdomen slightly elongate, in living specimens bright silver-grey with three velvet black transverse bands, second of them forming triangle at about half of abdomen length ( Fig. 101); sparse brown bristles cover abdomen; venter dark; spinnerets dark. Legs brown, long and thin, last pair longest. Pedipalp with single narrow apophysis; embolus short, tegulum with triangular posterior lobe ( Fig. 102).

Female.

General appearance in Fig. 247; slightly larger than male. Abdominal pattern similar to male but with additional thin transverse white band and two pairs of large yellow patches ( Fig. 103); venter with broad median brown stripe. Epigyne with two large rounded shallow depressions ( Fig. 104).

Material examined: 2ơ Between Crocodile farm and Main camp, 26 ° 54.431'S: 32 ° 19.045'E, broadleaf woodland, under rocks, 7.vii.2000 ( NMSA 21859 ) ; 1ơ 1^Crocodile Farm , 26 ° 54.426'S: 32 ° 19.185'E, broadleaf woodland, under log, 3.iv.2003 ( NMSA 21860 ) ; 2ơ Eastern shore of Shokwe Pan , 26 ° 52.516'S: 32 ° 12.407'E, grass at tree bases, 24.i.2006 ( NCA 2006 /838); 1^2 imm. same locality, A. xanthophloea bark, 24.i.2006 ( NCA 2008 /1864); 2^Main Camp, 26 ° 54.581'S: 32 ° 18.798'E, broadleaf woodland, leaf litter, 6.vii.2000 ( NMBA 11600 ) ; 1ơ 1 imm. same locality but 20.vi.2005 ( NCA 2005 /984); 3^Near Environmental Centre, 26 ° 55.275'S: 32 ° 17.947'E, broadleaf woodland, leaf litter, 6.ii.2005 ( NCA 2005 / 35); 1ơ Southern boundary fence, 26 ° 55.578'S: 32 ° 19.081'E, deep sand forest, sifting leaf litter, 11.i.2007 ( NCA 2007 /3039); 1ơ 9 imm. Southern shore of Hotwe Pan, 26 ° 52.730'S: 32 ° 18.452'E, A. xanthophloea bark, 10.vii.2004 ( NCA 2008 /635); 1ơ 1 imm. same locality but 22.vi.2005 ( NCA 2008 /649); 1ơ 1^South-western shore of Banzi Pan, 26 ° 53.118'S: 32 ° 16.927'E, under tree bark, 28.vi.2003 ( NMSA 21861 ) ; 1^same locality, A. xanthophloea bark, 5.ii.2005 ( NCA 2008 /660); 1ơ 1 imm. same data but 23.i.2006 ( NCA 2008 /1848); 1ơ 2 imm. Western shore of Nyamiti Pan , 26 ° 53.767'S: 32 ° 16.557'E, A. xanthophloea bark, 10.vii.2004 ( NCA 2008 /593); 1^3 imm. same data but 19.vi.2005 ( NCA 2008 /604); 1^5 imm. same data but 23.i.2006 ( NCA 2008 /608); 1ơ Western shore of Shokwe Pan, Ficus sycomorus forest, 26 ° 52.013'S: 32 ° 12.982'E, leaf litter, 9.i.2002 ( NMSA 21862 ) ; 1ơ same locality, on Ficus bark, 9.i.2002 ( NMSA 21863 ) .

Distribution: Species known only from South Africa and Zimbabwe.

Habitat and biology: This species was collected from all of the habitats in the reserve, predominantly wandering on the ground, low-growing plants, on bark and on the walls of houses. This species demonstrates polymorphic colouration: early instar immatures have a metallic silver-blue carapace and metallic green or purple abdomen, with a median triangular marking; late instar immatures have a metallic blue carapace and abdomen, with a median triangular marking; adults have a metallic silver-blue carapace and abdomen, with a triangular marking medially on the abdomen, or an abdomen with white or yellow markings (anterior band and two pairs of spots medially and posteriorly).

These variations suggest mimicry of two different groups of Hymenoptera , namely ants ( Formicidae ) and velvet ants ( Mutillidae ). None of these colour variations point to a specific species of model, and these spiders can rather be regarded as generalised mimics. Their behaviour and movements resemble ant movements, with the forelegs moving up and down to resemble antennal movements, the abdomen moving up and down, and rapid darting runs. M. elegans was observed preying on a wide variety of ant species, and no other prey was observed being captured. Early instar immatures captured Oecophylla and Crematogaster ants, while subadults and adults captured Streblognatha sp., Camponotus spp. , Myrmicaria natalensis (Smith, 1858) , Anoplolepis custodiens (Smith, 1858) , Polyrachis gagates Smith, 1858 and Pachycondyla tarsata (Fabricius, 1798) . The predation behaviour of this species will be dealt with in more detail in a separate paper (Haddad unpubl.).