BIOSECURITY
NEW ZEALAND
POST-BORDER DETECTION
1982
9 AUGUST 2023
ACT
012.3145
DG-257382
INFORMATION
OFFICIAL
THE
UNDER
Morelia spilota mcdowelli
s9(2)(a)
Bioresearches Group Ltd.
c/o Babbage Consultants
Level 4, 68 Beach Road
RELEASED
Auckland
1010
s9(2)(a) @bioresearches.co.nz
s9(2)(a)
Daniel Green
Diagnostic & Surveillance Services
Biosecurity New Zealand
PO Box 40 742
1982
Upper Hutt 5140
ACT
Dear Daniel,
Re: Submission Reference: DG-257382
I have identified the specimen received on 7 August 2023 and my determination follows:
Accompanying information
Description:
Snake (python), ex. Australia INFORMATION
Interception:
Post-border
Life state on arrival:
Alive
Observation date:
5 August 2023
Location:
OceanaGold, Waihi, Coromandel
BNZ contact:
Daniel Green; Incursion Investigator (Biosecurity New Zealand)
OFFICIAL
Phone:
s9(2)(a)
Email:
[email address]
THE
Taxonomy
Species:
(Reptilia: Pythonidae)
Morelia spilota (Lacépède, 1804)
Subspecies/ morph:
Morelia spilota mcdowelli Wells & Wellington 1984
UNDER
Common names:
Coastal carpet python
Conservation status:
IUCN Redlist: Least Concern (ver. 3.1, 2017)
CITES listing: Appendix II
Status in New Zealand:
Morelia spilota is not presently found in New Zealand.
RELEASED
Specimen description
Medium-sized snake (total length 792 mm) found alive at a mine site in Waihi, Coromandel on 5
August 2023. Diagnostic morphometric details: snout–vent length 680 mm; vent-tail length 112
mm; head width 16.4 mm; head length 27.3 mm; weight 90.68 g; mid-body scale rows 50; ventral
1982
scales 282; subcaudal scales 82. Sex: male (juvenile). No ectoparasites associated with specimen.
Signs of minor trauma (i.e., a small puncture wound) were found on the ventral surface of the body.
ACT
The round tail, enlarged ventral scales covering less than half the width of the body, fragmented
head scales, and the >30 mid-body scale rows confine this specimen to the F. Pythonidae. Several
diagnostic characters identify it as a species of
Morelia—including the presence of teeth on the
premaxilla, the absence of apical pits on the dorsal scales, the uniform size of the gular scales
bordering the mental groove and heat-sensing pits on the rostral. It keys to
Morelia spilota sensu
lato in having fragmented head scales, <9 scales across the head between the eyes, numerous
loreals, 1st and 2nd supralabials with shallow pits, infralabials with six pits in a deep groove below
the eye, and smooth body scales.
INFORMATION
Morelia spilota is a species complex1 that has been the source of considerable confusion and
argument relating to its geographical distribution and taxonomic status2. Depending on the
authority, the complex comprises several morphs, subspecies, or in some cases full species
distinguished largely based on geographic distribution but also on differences in colour pattern.
Generally, there are six accepted subspecies, plus a Papuan subspecies of which the taxonomic
OFFICIAL
validity remains controversial. Some authors have chosen to raise particular subspecies to full
species (e.g.,
Morelia spilota imbricata to
M. imbricata) but for the purpose of this report I have
chosen to follow the subspecific determinations.
THE
The colour pattern of the current specimen is typical of the so-called coastal carpet python,
Morelia
spilota mcdowelli Wells & Wellington 1984. That is, it displays an olive brown to tan background
colour overlaid with paler blotches and stripes that are edged in black. However, as the colour
UNDER
pattern of
M. spilota can vary considerably and alone does not provide a diagnostic character for
subspecific identification, closer examination of the meristic (scale) characters is necessary. The
current specimen has 50 scale rows at mid-body, 282 ventral scales, and 82 subcaudal scales, and a
total length/ snout-vent length ratio of 1.165, which places it closer to the eastern subspecies/
populations of
M. spilota (i.e.,
M. s. mcdowelli) than to the western, central, southern, or northern
RELEASED
1 A group of closely related organisms that are so similar in appearance and other features that the boundaries between them
are often unclear.
2 O’Shea, M. (2007). Boas and pythons of the world. New Holland Publishers. London, UK. 160 pp.
populations according to Schwaner
et al., (1988)3. On the weight of morphological evidence, this
specimen has been identified as
M. s. mcdowelli.
Distribution and natural history
1982
Morelia spilota sensu lato has a wide distribution in Australia, including most of the continent except
for the arid regions of the centre and west, and the cool southern parts of New South Wales, Victoria
ACT
and South Australia. It is also present in southern and south-eastern New Guinea but is absent from
Tasmania.
Morelia spilota mcdowelli occurs along the eastern seaboard from Cape York to northern
New South Wales.
Morelia spilota sensu lato occupies a wide range of habitat types ranging from dense rainforests to
semi-arid woodland and shrubland. It has coped well with environmental modification and is
commonly present in agricultural and horticultural areas, and in well-vegetated urban
environments. It is a very elusive nocturnal species that hides during the day in dense vegetation or
in or under other secure cover, including entering buildings. Because of its secretive habits,
Morelia
INFORMATION
spilota sensu lato is generally a lot more abundant than observations of it suggest.
Morelia spilota sensu lato is arboreal or terrestrial, and feeds primarily on vertebrates, including
small mammals, birds and reptiles, with the juveniles typically feeding on lizards. Prey items are
killed by constriction (suffocation) and are swallowed whole.
Morelia spilota mcdowelli can reach a
considerable size, with adults easily growing to 2.5–3 m long and some specimens recorded up to
OFFICIAL
4.2 m long.
THE
Morelia spilota sensu lato is oviparous and as an adult, breeds in the wild only every two or three
years. Oviposition in the wild is in late spring to early summer. The average clutch sizes are 15–35
(range 7–54) but this varies a bit between the different ‘subspecies’ (e.g.,
M. s. mcdowelli may only
produce 10–13 eggs). After oviposition, the eggs are ‘incubated’ by the female until they hatch.
Incubation takes around two months depending on temperature (range 37–102 days). Size at
UNDER
hatching is variable with recorded total lengths ranging from 280–580 mm (typically 300–400 mm).
RELEASED
3 Schwaner, T.; Francis, M.; Harvey, C. (1988). Identification and conservation of Carpet pythons (
Morelia spilota imbricata) on
St. Francis Island, South Australia.
Herpetofauna, 18 (2): 13–20.
Circumstances surrounding detection
The live snake was found by employees of the OceanaGold Waihi Operation mine, approximately 6
km underground in an active mine shaft at approximately 16:00hrs on Saturday 5 August 2023. The
snake reportedly emerged from a “large pile of rock bolts”4 and was sighted by a mine worker(s),
1982
who promptly captured and secured the snake in a plastic container. The observation was reported
to the Ministry for Primary Industries via the 0800 pest and disease hotline at 17:30 hrs on 5 August
2023. The snake was contained overnight and was collected from the OceanaGold premises by a
ACT
certified MPI snake handler on Sunday morning, 6 August 2023. It was transported in a secure
container to the Auckland Zoo Vet Hospital where it was humanely euthanised the same day. The
dead snake specimen was delivered to s9(2)(a)
for formal determination on 7 August 2023.
Information provided by OceanaGold following an enquiry by MPI Investigators into the possible
importation pathway, revealed that the company uses high volumes of rock bolts in its mining
operation and there have been 30 shipments of rock bolts to the Waihi mine in the past 12 months.
Most recently, shipments of rock bolts were received from
DSI Underground, Brisbane on 27 March
INFORMATION
2023 and another arrived from
Split Set Mining Systems, Perth on 28 June 2023. It was from the
stack of Brisbane-origin bolts that the snake reportedly emerged.
The rock bolts are the split set or friction type, each of which consists of a ~30–40 mm diameter,
≈3.5 m long steel tube with a slot along its entire length. The rock bolts are transported to New
Zealand in bundles on flat rack containers (see
Additional photographs below) and the bundles are
OFFICIAL
stacked and stored in yards above ground at the Waihi mine until required for use. Once moved
underground, the bolts are stored loose in the ‘bolt store’, laying directly on the ground. The long
hollow steel tubes could offer potential sites for snakes to enter and seek refuge, which is a plausible
THE
scenario especially where these rock bolts are stored, or even temporarily held, in outdoor yards in
Australia prior to export. Furthermore, once the rock bolts are stacked in bundles the detection of
potential stowaway snakes among the steel tubes would be extremely difficult.
UNDER
To investigate the likelihood of the snake joining the consignment of rock bolts in Australia, a review
of the aerial imagery of the two Australian rock bolt suppliers was undertaken. This showed that
the premises of the Perth supplier (
Split Set Mining Systems) was located in a built-up industrial
estate in the suburb of Kewdale, not surrounded by parks nor bushland where pythons would
typically be expected to occur. In contrast, the Brisbane
DSI Underground premises is located on the
outskirts of the greater Brisbane metropolitan area and is surrounded to the east and south by
RELEASED
4 A rock bolt is a steel rod inserted into the roof or walls of a rock formation to support underground excavation or to stabilise
a jointed rock mass. They are widely used in the underground mining industry.
undeveloped bushland that forms the Freshwater National Park.
Morelia s. mcdowelli is regarded
as relatively common in southern Queensland and around the Brisbane area (including all suburbs
and the inner city) and indeed, this species
has been reported from Freshwater National Park5, as
well as from the wider landscape surrounding the
DSI Underground premises (
iNaturalist.nz;
1982
accessed 8 August 2023). Therefore, it is conceivable that the subject python could have entered
the
DSI Underground yard in Brisbane of its own accord and got into a bundle of hollow rock bolts,
which were subsequently exported to New Zealand.
ACT
If this was indeed the case, then there is a time difference of just over four months between the
arrival of the snake in New Zealand (27 March 2023) and its detection at Waihi (6 August 2023). The
length and weight of the snake indicates it is a juvenile and comparisons with captive growth rate
information places it in the age class of approximately 1-2 months6. Seemingly, this estimated age
does not align with the March arrival into New Zealand. However, growth rates of wild pythons are
expected to be slower than captive individuals and in the current case, stress associated with
inadvertent transport to a foreign country with a cooler environment and the likelihood of little or
no feeding on route will have certainly had a negative effect on the individual’s growth rate. Thus,
INFORMATION
it is very possible that the individual is older than two months and is simply small for its age. Pythons
(and many other species of snake) can remain sedentary for long periods of time without the need
for food, so it is quite plausible that the juvenile python could have remained with the imported
bundle of rock bolts over the entirety of the four-month period (spanning New Zealand winter)
while in New Zealand.
OFFICIAL
Considering the available information, the import pathway involving a juvenile python arriving in
New Zealand as a stowaway among rock bolts from Brisbane, rather than Perth, is relatively
THE
convincing. This is the thirteenth record of
Morelia spilota sensu lato in New Zealand. Previous
records include: two specimens (one of which was a shed skin) that were illegally imported, six
specimens (two of which were shed skins) that arrived as stowaways with shipping containers from
Australia and Papua New Guinea, two specimens that arrived as stowaways in the undercarriages
of aircraft from Australia, and one specimen that stowed away in a vehicle from Brisbane.
UNDER
RELEASED
5 https://wetlandinfo.des.qld.gov.au/wetlands/facts-maps/wildlife/?AreaID=national-parkfreshwater&Kingdom=animals&SpeciesFilter=Native
6 Fearn, S. (1996). Captive growth of a carpet python
Morelia spilota.
Litteratura Serpentium, 6 (4): 94–102.
Potential threat to New Zealand
Morelia spilota is non-venomous and not a danger to humans, although if provoked large individuals
can inflict painful bites that carry the additional risk of bacterial infection at the bite site.
1982
The ecology of
Morelia spilota sensu lato (i.e., its broad habitat use; tolerance to cold—even
including snowfall—; and high fecundity) and the southern limit of its distribution in Australia
ACT
(S37.65) indicates this species could potentially naturalise in the warmer parts of New Zealand if
suitable propagules reached this country (Figure 1). If this species naturalised in New Zealand, it
would present a potentially serious conservation threat to small vertebrates (e.g., birds, reptiles).
In addition, it is possible there would be a risk of introducing novel diseases or parasites that might
affect the indigenous reptile fauna.
Action:
No further biosecurity action is recommended with respect to this detection.
INFORMATION
OFFICIAL
THE
UNDER
Figure 1. Climate match assessment of New Zealand with the climate parameters of the native range of Morelia
spilota sensu lato (0 = climate not similar; 10 = very similar).
RELEASED
Additional photographs
1982
ACT
The method of shipment (flat racks) for rock bolts imported from the Perth. The Brisbane shipment was
transported using the same flat rack method. Images provided by OceanaGold.
INFORMATION
OFFICIAL
THE
UNDER
RELEASED
1982
ACT
Thanks to the MPI snake handler Zoran Sinovcic for collecting and delivering the specimen to me,
and thanks to MPI Investigators Daniel Green and Harry Taylor and OceanaGold staff for providing
background information that assisted with this determination. A copy of this report has been sent
to [email address], Specimen Reception Wallaceville, and Daniel Green, Lisa Maria,
and Clive Pigott of BNZ (MPI).
INFORMATION
Yours sincerely,
s9(2)(a)
OFFICIAL
s9(2)(a)
| Senior Ecologist | Herpetologist |
Bioresearches (Babbage Consultants)
Level 4 | 68 Beach Road | Auckland 1010
Mobile s9(2)(a)
DDI s9(2)(a)
THE
www.bioresearches.co.nz7.
UNDER
7 This report has been prepared and written by Bioresearches for the Biosecurity New Zealand (BNZ).
RELEASED
Bioresearches and BNZ, while not requesting copyright on this material, do ask for acknowledgement when the work is used in part and ask
that prior permission is requested from BNZ if sections are used substantially or wholly.
This report cannot be further distributed without the prior approval from BNZ.
