A
long the east coast of
Australia live a group of geckos
that showcase the brilliance of
natural selection. Although similar
to other geckos in many respects,
one feature makes them stand
out as some of the most recog-
nisable of their kind....or, perhaps
it would be more appropriate to
say, some of the least recognis-
able of their kind! For, although
the leaf-tailed geckos may be
distinguished by having a most
unusual caudal appendage, they
are also superbly camouflaged in
their natural environment.
Australia is home to 17 species of
leaf-tailed geckos. All are closely
related and belong to the family
Carphodactylidae. Three genera
are recognised: Phyllurus, with
nine species; Saltuarius, with six
species; and the monotypic
genus Orraya. Scientific names
often have some descriptive
significance, and these are no
exception. Phyllurus, the first
genus to be formally described,
was aptly named, since this
translates from the Latin as ‘leaf
tail’. Saltuarius reflects these
species’ affinity for rainforest
habitat, and means ‘keeper of the
forest’. The etymology for Orraya
occultus is also revealing, since
the generic name is derived from
the local indigenous word for
‘older brother’, and is indicative of
how this genus was found to be
genetically divergent and basal to
the other two genera. The spe-
cies epithet is from the Latin for
‘hidden’; denoting how this gecko
is both rare and difficult to find.
Species in the three genera differ
both in terms of internal and
external morphological character-
istics; there are differences in
mitochondrial and nuclear DNA,
as well as in the number of
chromosomes. They are
relatively large in size, ranging
from around 7cm snout-to-vent
length to 14cm or more. Phyllurus
species are generally smaller,
with simply-flared tails, whereas
Saltuarius species are signifi-
cantly larger, with elaborate and
expansive tails. In fact,
S. cornutus is the longest of
Australia’s approximately 175
species of native geckos. Orraya
occultus has spidery legs and an
elongated neck. This unique spe-
cies has the distinction of occupy-
ing the most northerly distribution
of any leaf-tail, in the McIlwraith
Range on Cape York Peninsula,
and is of high conservation value.
Described only in 1993, it was
initially placed in the genus
Saltuarius, however subsequent
morphological and genetic data
revealed it was highly distinct,
resulting in the creation of a new
genus. Despite targeted surveys
since its discovery, it is known
from just a few specimens found
at night on granite boulders within
the rainforest.
Leaf-tailed geckos have broad,
flat tails that are shaped very
much like leaves. However,
despite the superficial resem-
blance, this appears to be related
to achieving a more flattened
appearance so that the animals
can blend into the substrate. The
rest of their body is likewise
dorso-ventrally compressed, and
the effect is augmented by the
animals’ habit of resting flat
against a surface. The entire
body is covered with a mottled
pattern of greys, greens, blacks,
creams and browns. This
enhances crypsis in two ways.
Firstly, the mottled colouring
Left and below: Some ‘old leaves’ were
clustered together on the roll of white fabric!
Images by Kit Prendergast and Mark Donald,
unless otherwise noted.