Structure of specialized osmetrichia in the brown antechinus Antechinus stuartii (Marsupialia : Dasyuridae)

The ultrastructure of specialized sternal gland hairs from the brown antech inus Antechinus stuartii was studied using a scanning electron microscope. The centre of the sternal gland of male A. stuartii possesses short and sti ff hairs that are capable of holding a large mass of lipids. The morphology of these hairs differs from those of the dorsal region of the same individ ual and sexual dimorphism is observed. The osmetrichia of the sternal gland region of male A. stuartii have flared and thickly packed cuticular scales . These scales differ morphologically from the large flattened conical scal es of hair from the female sternal region and male dorsum. The surface of t he osmetrichia is soaked with the red, oily secretion of the sternal gland, and the angled scales of the cortex have been modified into special ridged chambers which store the glandular secretions. We suggest that in A. stuar tii the unique cuticular structural modifications may serve in the retentio n and delayed oxidation of olfactory cues at the time of breeding.