Unixenus karajinensis Short & Huynh, 2011

Short, Megan & Huynh, Cuong, 2013, Four new species of Unixenus Jones, 1944 (Diplopoda, Penicillata, Polyxenida) from Australia, ZooKeys 278, pp. 75-90 : 86-87

Unixenus karajinensis Short & Huynh, 2011

Material examined.

A number of collections of various stadia, in poor quality: Wittenoom WA, May 1973, EN Wahl, WAM T116466, T116467, T116469; Wittenoom, WA, from out of drain pipe in bath at night, also on floors in house, 10 October 1983, Mrs. M. McKay, WAM T116468; Tom Price Caravan park, Tom Price, WA, 22 December 1982, K. Campbell, WAM T116450; Tom Price Caravan park, Tom Price, WA, 2 December 1982, A. Davies, WAM T116470; Hamersley Station, WA, under house, 20 April, 1989, JS Bogle, T117557; Mt Stuart Station, 0.7 km W Urandy Bore (1: 100,000 map ref: 2153-283201), huge numbers on surface of ground (gibber slope) at night, 6 August 1985, large collection in very poor condition, A Baynes and TA Smith, WAM T117558. Selected specimens mounted on slides for identification, remainder in ethanol, all deposited in WAM.

Revised diagnosis.

Differs from Unixenus mjoebergi in longer and thinner tergal trichomes, 6 pairs of coxal glands in males on leg pairs 6-11, telotarsus with anterior spinous projection shorter than the claw, 5-9 ornamental trichomes c each side. Antennal articles VI and VII with distinctive notched appearance at the distal edge, article VI with setiform sensillum anterior to 3 basiconic sensilla. Number of setae on coxae 3-13 varies more widely from 1-6 in contrast to 2-3 in Unixenus mjoebergi . The hooked caudal trichomes have double barbs proximal to the hooks. The last sternal plate has 2 setae.

Remarks.

Examination of further specimens of Unixenus karajinenis has confirmed that the original diagnosis for the species is in error in stating that the number of ornamental trichomes c is 8 each side ( Short and Huynh 2011). Although the number is 8 each side in the majority of specimens examined, the number can vary from 5-9.

A number of the collections examined were from the two previous collection sites: the type locality Wittenoom and the nearby township of Tom Price. However the species has now been identified from two further locations in the Pilbara region of Western Australia, with one site being 200 km from the type locality indicating that its distribution is not as tightly restricted to the Hamersley Ranges as originally recorded (Fig. 5).

Collections were sent to WAM for identification after reports from 1972 of the millipedes reaching nuisance proportions in parts of the Pilbara, particularly the Hamersley Ranges area and the townships of Tom Price and Wittenoom ( Koch 1985). Koch identified the species involved as Unixenus mjoebergi and a study was done for the Western Australian Department of Agriculture ( Burt 1984) to determine ways of reducing millipede numbers and swarming behaviour. However after recent examination of collections in WAM it appears that Unixenus karajinensis also occurred in huge numbers and has been found associated with housing. It appears very likely to have been involved in swarming behaviour.