A new family of ensiferous Orthoptera from the coastal sands of southeast Queensland

Abstract

A new family, COOLOOLIDAE, of Orthoptera is proposed, based on a single new genus and species COOLOOLA propator, from southeast Queensland, Australia. The cricket-like insect, referred to as the Cooloola monster, is an aberrant member of the suborder Ensifera. It is unusual in possessing very short antennae which, in turn, have a reduced number of articles, 10 in number. Nearly all species in all families of Ensifera have antennae with 30 or more articles. The structure of the mouthparts is unique in the Orthoptera in that the lacinia of the maxilla is larger and more developed than the mandibles. The lacinia is knife-shaped and not hooked. This suggests a piercing rather than the usual sorting and cleaning function for that structure. The mandible is elongate, indicative of a predaceous habit as opposed to short, stout mandibles which are possessed by plant feeders. C. propator has no close relatives but superficially resembles several species of the stenopelmatid Oryctopus. This genus is known from south India and Ceylon. Both genera share modification for a burrowing habit as illustrated by shortened antennae and legs, excavate, trowel-like modified spines, pale coloration, reduced eyes, and brachypterous males and apterous or micropterous females. The tarsal claw of both genera is sexually dimorphic. In females it is greatly reduced but normal in males. This may indicate a more sedentary role for females. Detailed examination of mouthparts, alimentary tract and wing venation reveal that Oryctopus possesses all of the characteristic structures of the Stenopelmatidae, whereas Cooloola does not. The convergence of characters is interpreted as adaptation to a fossorial existence. C. propator lives in sandy, moist soils and is not particularly associated with a single vegetation type. In rainforest and open forest, the soil is densely laced with roots. There is little accumulated litter on the surface and the soil is devoid of humus.