Jumping spider

Fact Box Species: Opisthoncus abnormis ID derived from photos in Whyte R. and Anderson G. in "A Field Guide to Spiders of Australia" (2017) but see notes below Family: Salticidae Body length: female:4.5 mm male: 5 mm Habitat: Usually found on the leaves and bark of trees Toxicity: Unknown; a bite may cause local inflammation and pain

Another view Female underside

Opisthoncus species are generally quite easy to recognize to genus because of a small 'lump' between the last pair of eyes. However, there are many known Australian Opisthoncus species and for most of them one of the two sexes has not been adequately (if at all) described but is likely to have a very different appearance when compared with the other sex. In addition, several of the more common species are sufficiently similar in appearance and surface markings that they can only be distinguished from each other by a careful examination of their genitalia.

Perhaps the most recent and comprehensive review of the Australian Opisthoncus species can be found in the following paper: Gardzinska J and Zabka M (2013) "Redescription of the genus Opisthoncus L. Koch, 1880 (Araneae: Salticidae)" Zootaxa 3717, 401-447. This paper contains many images of Opisthoncus species but unfortunately these are all of preserved specimens (many of which have clearly suffered some damage) which therefore have changed colour patterns. These authors have suggested that Opisthoncus abnormis and Opisthoncus tenuipes may actually be the same species and Whyte and Anderson in their 2017 book have accepted this suggestion as being correct.

Note that the male of Opisthoncus abnormis has an appearance significantly different from that of the female, which also has a variable appearance from specimen to specimen.

Spider(s) with a very similar appearance: Several other salticid species, and especially Opisthoncus species, with a similar body shape.