A NEW
SUBSPECIES OF Strophurus
INTERMEDIUS (SQUAMATA:GEKKONIDAE) FROM SOUTH AUSTRALIA.
Raymond Hoser
488 Park Road
Park Orchards, Victoria, 3114, Australia.
E-mail:
adder@smuggled.com
First published in hard copy
in Boydii (Journal of the Herpetological Society of Queensland), Spring
2005.
ABSTRACT
A new subspecies
of Strophurus intermedius, namely S. intermedius burrelli subsp.
nov. is described from Ardrossan, South Australia Lat. 34°137'S Long. 7°22'E. It differs from the nominate form in terms
of colouration and habits. This
subspecies probably accounts for all S. intermedius from the
south-western part of the species range.
INTRODUCTION
Southern
Spiny-tailed Geckos (Strophurus intermedius), otherwise formerly known
as Diplodactylus intermedius have been familiar with herpetologists in
Australia for many years. They are also
commonly kept and bred by private reptile keepers.
According
to Hoser (1989) they are found throughout semi-arid parts of Southern
Australia, and the Macdonnell Ranges in the Northern Territory.
As
adults they attain 10-12 cm in total length (on average). Most specimens are
found during the day under tree bark, or in upright tree hollows. In areas without trees specimens may be
caught under rocks (Hoser 1989). This nocturnal lizard is able to exude a
sticky substance from the spines in its' tail when harassed. Adult females produce two eggs at a
time. Breeding in the wild appears to
be restricted to the warmer months, which is in contrast to at least some other
species found in the same areas (see below).
As
in most Australian geckos, sexing of adults is easy.
Males
have large hemipenal bulges above the vent.
In females the region around the vent is flat in profile.
Photos
of this species appear in many books and publications, including at the top of
page 69 of Hoser (1989) and a colour description is best derived from one of
these photos.
Notwithstanding
this, the species is generally greyish above with a pattern (usually) and is
light creamish-grey below.
In
two semidistinct rows, are small blunt orange-brown spines at more-or-less
regular intervals, becoming more prominent towards the rear body and tail (in
non-regenerated tails).
These
lizards will exude or squirt an orangeish brown fluid from these spines if
provoked.
To
get a lizard to do this, it's easiest to rub the upper tail, being careful not
to apply too much pressure or else the tail may be shed (via a process known as
autotomy).
If
and when the tail is shed, it invariably sheds from a single connection point
near the base, which is in contrast to most small skinks (in Australia), which
will shed at almost any point where pressure is applied.
However
shedding of the tail is a defence of last resort for this species.
Most
adults found in the wild still retain original tails.
The
eye is usually orangeish brown in colour and the inside of the mouth is a deep
dark blue colour.
When
agitated, these lizards will open their mouth wide and charge an aggressor.
At
the same time they will let out an audible barking sounS.
Strophurus INTERMEDIUS INTERMEDIUS OGILBY
1892
This is the
nominate form fitting the description above.
Also refer to the
papers by Kluge (1967) and Ogilby (1892).
The type locality
(via lectotype) is the interior of NSW.
Strophurus INTERMEDIUS BURRELLI
SUBSP. NOV.
HOLOTYPE
An adult male
from Tiddy Widdy Beach, 1 km north of Ardrossan, on the Yorke Peninsula, South
Australia, Lat. 34°137'S
Long. 7°22'E,
lodged in August 2003 at the National Museum of Victoria. Specimen number is
D71584.
PARATYPE
An adult male
from Tiddy Widdy Beach, 1 km north of Ardrossan, on the Yorke Peninsula, South
Australia, Lat. 34°137'S
Long. 7°22'E,
lodged in August 2003 at the National Museum of Victoria. Specimen number is
D71585.
DIAGNOSIS
Strophurus
intermedius burrelli subsp. nov. is differentiated from S.
intermedius intermedius as diagnosed in Cogger (2000), and to which it
would otherwise key out as, by several traits.
Strophurus
intermedius burrelli subsp. nov. is characterized by darker,
more brown than orange spines on the rear body and tail than is seen in S.
intermedius intermedius. The
easiest way to see this difference is by comparing typical specimens of each
subspecies.
The two forms can
also be separated by distribution.
Strophurus
intermedius burrelli subsp. nov. is currently only known from
the Yorke Peninsula in South Australia, but probably accounts for all S.
intermedius from the western part of the species range.
By contrast S.
intermedius intermedius is probably restricted to inland NSW and
immediately adjacent areas.
The status of
specimens from central Australia isn't known, but may be another as yet
undescribed subspecies.
Strophurus
intermedius burrelli subsp. nov. is also separated from S.
intermedius intermedius in terms of biology and habits.
Strophurus
intermedius burrelli subsp. nov. is more inclined to open it's
mouth and make a sound than is S. intermedius intermedius. It is also more likely to squirt fluids from
it's tail than is seen in most S. intermedius intermedius.
While S.
intermedius intermedius has a preference for resting by day under bark, in
upright hollow logs or occasionally under rocks, Strophurus intermedius
burrelli subsp. nov. instead prefers to hide in vegetation.
While it may
appear that this shift in biology is due to different habitats inhabited,
observations of Strophurus intermedius burrelli subsp. nov. in the wild
indicated that this shift is also a trait of the subspecies, because where tree
bark and upright hollow logs were present the subspecies Strophurus
intermedius burrelli subsp. nov. still chose to reside by day in
vegetation.
In terms of
potential predators for either subspecies, none are known.
On 12 August 2003
an adult male Strophurus intermedius burrelli subsp. nov. was found
sheltering under a small sheet of tin resting on top of an adult (65 cm) female
Death Adder (Acanthophis antarcticus cliffrosswellingtoni).
While it is
obvious that the distributions of both subspecies of Strophurus intermedius have
become fragmented as agriculture has taken over much of southern Australia, it
is uncertain as to how much gene flow occurred between the two subspecies
before European settlement of Australia.
Notwithstanding
this, it is evident that DNA properties between the two subspecies would differ
and that specimens of both subspecies could be separated from one another by
comparative DNA analysis.
In the wild state
on 15 August 2003, I was fortunate enough to be able to observe 8 adults
including both sexes in the wild state at Tiddy Widdy Beach.
None were
noticeably gravid. This was in sharp
contrast to the 20 adult Marbled Geckos (Christinus marmaratus) observed on the
same day in the same locality and sharing the same microhabitat. Most, if not all adult females were
noticeably gravid and by my (crude) estimate due to lay their eggs within about
four weeks.
ETYMOLOGY
Named in honour
of reptile keeper and breeder, Roland (Roly) Burrell, of Reynalla, South
Australia, who has over many years bred and supplied to the captive trade
hundreds of reptiles. He has been
particularly successful with Death Adders (Acanthophis spp.), including
the variant known from the type locality of this gecko subspecies.
CONSERVATION
The subspecies is
common where it occurs and is probably common in other areas of suitable
habitat within the Yorke Peninsula and nearby regions.
As a reptile,
it's collection and keeping is regulated by the wildlife laws of South
Australia and other Australian states.
As there is little demand for this species in the pet trade, much of the
regulation in terms of this taxa is probably not necessary.
There are no
known threats to this taxa, although perhaps the greatest risk to this and
other "non-threatened" Australian taxa is from exotic diseases that
may be brought into Australia via the legal or illegal trade in non-native
species.
REFERENCES
Cogger,
H. G. 2000. Reptiles and Amphibians of Australia (Sixth edition),
Reed/New Holland Publishers, Sydney, Australia:808 pp.
Hoser, R. T. 1989. Australian
Reptiles and Frogs. Pierson and Co., Mosman, NSW, 2088, Australia. 238 pp.
Kluge, A. 1967. Systematics,
phylogeny and zoogeography of the lizard genus Strophurus Gray
(Gekkonidae). Australian Journal of Zoology 15:1007-1108.
Ogilby,
J. S. 1892. Descriptions of three new Australian Lizards. Records of the
Australian Museum 2:6-11.
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