Sj. Rehorek et al., The structure of the nasal chemosensory system in squamate reptiles. 1. The olfactory organ, with special reference to olfaction in geckos, J BIOSCI, 25(2), 2000, pp. 173-179
The luminal surface of the chemosensory epithelia of the main olfactory org
an of terrestrial vertebrates is covered by a layer of fluid. The source of
this fluid layer varies among vertebrates. Little is known regarding the r
elative. development of the sources of fluid (sustentacular cells and Bowma
n's glands) in reptiles, especially in gekkotan lizards (despite recent ass
ertions of olfactory speciality). This study examined the extent and morpho
logy of the main olfactory organ in several Australian squamate reptiles, i
ncluding three species of gekkotans, two species of skinks and one snake sp
ecies. The olfactory mucosa of two gekkotan species (Christinus marmoratus
and Strophurus intermedius) is spread over a large area of the nasal cavity
. Additionally, the sustentacular cells of all three gekkotan species conta
ined a comparatively reduced number of secretory granules, in relation to t
he skinks or snake examined. These observations imply that the gekkotan olf
actory system may function differently from that of either skinks or snakes
. Similar variation in secretory granule abundance was previously noted bet
ween mammalian and non-mammalian olfactory sustentacular cells. The observa
tions in gekkotans suggests that the secretory capacity of the non-mammalia
n olfactory sustentacular cells show far more variation than initially thou
ght.