Koolan Island Zoological notes 
263 
macrodon, Pupoides pacificus Stenopylis coarctata, 
Nesopupa mooreana and Discocharopa aperta. These 
species are all likely to occur on Koolan because 
they disperse readily (see Solem and McKenzie 
1991) and were found in environments that are well 
represented on the island (Table 5). For the same 
reasons, two of the other non-camaenid species 
that are known from the adjacent mainland might 
occur on Koolan: Pumilicopta kessneri Solem 1989 
and Gastrocopta simplex Solem 1989 (Pupillidae). In 
our opinion, a further field survey is needed if a 
complete listing of the island's non-camaenid land 
snails is to be obtained. 
Six camaenid species (five genera) are known 
from the Buccaneer Archipelago. Four of these are 
known to occur on Koolan. Unlike the other land 
snail families represented in the Kimberley, most 
camaenid genera show strongly localised patterns 
of endemism at the species level (Solem 1991). 
Thus, species such as Amplirhagada astuta and the 
Setobaudinia sp. may be endemic to just a few 
adjacent islands. Others such as Kimboraga 
yampensis are also known from the adjacent 
mainland (Solem 1991). Data in Table 5 and Solem 
(1991) suggest that Torresitrachia bathurstensis, a 
representative of the genus Rhagada and even a 
seventh species could also occur on Koolan 
( NGEN5 NSP50 fide A. Solem was collected by V. 
Kessner from an old termite nest on nearby 
Margaret Island, 16°09'30"S, 123°34'20"E, 26 July 
1988). 
We found only one introduced land-dwelling 
mollusc on Koolan ( Laevicanlis alte). Although this 
slug occurs elsewhere in tropical Australia, and 
ranges as far south as Dampier in Western 
Australia, it is confined to watered gardens and 
may not persist on the Island once the town is 
dismantled. 
The list of 34 Koolan butterflies is a sub-set of the 
Kimberley fauna, although the single specimen of 
Vanessa itea is the first record from the north 
Kimberley. The collection is dominated by large 
species. Except in the families Lycaenidae and 
Hesperiidae, the island's butterfly fauna is almost 
identical to that recorded by Bailey and Richards 
(1975) from the Prince Regent Nature Reserve, 
approximately 125km to the north-east. The Prince 
Regent collections suggest that further collecting 
would double the list of Koolan Lycaenids and 
Hesperids. A preliminary examination of the W.A. 
Museum's moth collection from Koolan suggests a 
similar sampling bias towards large species. 
Although ants are a significant and visible 
component of the island's fauna, only two species 
have been identified. One of these, the introduced 
Singapore Ant, was a significant pest in the 
townsite (see 'Results'). We know of only one other 
introduced insect. A "large black cockroach up to 
1.5 inches long" was introduced to an adjacent 
island (Cockatoo) about 1962, and later to Koolan 
Island (R. Lind, pers. comm.). 
Between 1961 and 1993, 35 reptile and one 
amphibian species were recorded on Koolan 
Island. Reptile surveys on Koolan Island have been 
opportunistic or brief, and sampling bias is 
apparent from the high proportion of snakes in 
relation to other reptile species in the list (13 of 34). 
The list indicates the Torresian affinities of the 
island's fauna, and provides a good indication of 
the richness that might be expected on other 
islands of similar size in the Kimberley. In fact, 
Koolan is less diverse in terms of its substrates and 
vegetations than many equivalent or larger islands 
in the archipelagos and other island groups further 
north along this coast. It comprises two sandstone 
formations, but only small areas of mangrove and 
beach strand vegetation; its few rainforest patches 
(semi-deciduous vine thickets) are minute (< 0.2 
ha), narrow, open canopied even in the wet season, 
and floristically poor. 
A review of the reptiles known from similar 
habitats on other islands in the Archipelago, and/ 
or the adjacent mainland, suggests that a variety of 
additional species could occur on Koolan despite 
its relatively narrow range of habitats (Table 6). 
The absence of permanent creeks or pools 
provides a reasonable explanation for the lack of 
riparian reptiles such as Crocodylus johnstoni, Elseya 
dentata, Emydura victoriae, Liasis fuscus, 
Tropidonoplius tnairii, Gemmatophora gilberti, Varanus 
mertensi and V. panoptes. Similarly, only a single 
species of amphibian has been collected on Koolan, 
even though 10 additional species (2 families) are 
known to occur on the adjacent Yampi Peninsula 
(Leptodactylidae: Ranidella bilingua and Uperoleia 
sp.; Hylidae: Cyclorana australis, Litoria bicolor, L. 
caerulea, L, coplandi, L. nasuta, L. rothii, L. splendida 
and L. wotjulumcnsis). Two other frog species have 
been seen on Koolan; both were smaller than Litoria 
rubella, but they have not been identified and no 
voucher specimens have been taken (L.F., pers. 
obs.). The lack of red sand surfaces provides a 
basis for arguing that species such as Varanus 
gouldii and Ctenotus pantherinus do not occur on the 
island. 
The other Yampi Formation (Pky) islands in the 
Buccaneer Archipelago extend in a chain westward 
from Koolan. Their reptile faunas were sampled 
during a field survey of the Archipelago in 1982. 
The relevant collections are lodged in the W.A. 
Museum. These islands are smaller in area and 
their known reptiles faunas are subsets of the 
Koolan fauna. Pscudechis australis (Cockatoo, 
Irvine), Deltna borea (Cockatoo), Gehyra occidental^ 
(Irvine, Bathurst), Heteronotia planiceps (Irvine, 
Bathurst), Oedura gracilis (Irvine, Bathurst), O. 
obscura (Irvine, Bathurst), Carlia triacantha 
(Cockatoo, Irvine, Bathurst), Ctenotus inornatus 
