Iridomyrmex bicknelli luteus Forel, species inquirenda

Iridomyrmex bicknelli lutea Forel, 1915: 77.

Types. Holotype worker from Kimberley district, Western Australia (not located during this study, apparently lost).

Comments: Treatment of I. bicknelli luteus is complicated by the apparent loss of the holotype combined with an original description consisting of the single sentence (translated from German) “Completely bright red-yellow, otherwise completely like [bicknelli]; the head in the back somewhat less convex”. Unfortunately, we are unaware of any species that is similar to I. bicknelli but is bright red-yellow and occurs in northern Western Australia. Iridomyrmex bicknelli itself is brown to black in colour and even callow or faded workers would not be described as bright red-yellow, normally being pale yellow. The description is suggestive of the pale form of I. agilis, but this taxon does not occur near the reported type locality of I. luteus. A more likely candidate would be the bright-red, narrow headed form of I. minor, a very common species in northern Western Australia which has a less convex posterior margin of the head when compared to I. bicknelli. However, without the type and with little more than a vague one line description it is impossible to determine, with any confidence, the true identity of this taxon. We therefore treat this name as species inquirenda within Iridomyrmex until the lost holotype can be located.