Histological examinations of facial glands in <Emphasis Type="Italic">Saccopteryx</Emphasis><Emphasis Type="Italic">bilineata</Emphasis> (Chiroptera,Emballonuridae), and their potential use in territorial marking

Scent marking is widespread among individuals of Mammalia species, especially in resource defence social systems. Apart from urine and faeces that are used for claiming resource ownership, specialised scent glands are the main source of secretions in scent marking individuals. Most previous studies have described secretory epithelia macroscopically, since many glands are conspicuous. But macroscopically inconspicuous scent glands or morphological structures might then be overlooked. In Saccopteryx bilineata (greater sac-winged bat), behavioural observations suggest that both sexes have, apart from the conspicuous gular glands of males, specialised facial glands to display territorial marking. We investigated the facial glands of two males and one female S. bilineata histologically and found, first, that both sexes possess a bilateral symmetrically intermandibular gland, which is composed of a bed of modified apocrine sudoriferous cells. Second, we found lip glands consisting of modified apocrine sudoriferous cell units with pigmented ducts around the upper and the lower lip. Both gland types are probably involved during territorial marking.