Notes on the occurrence and
habits of the Downs Bearded Dragon Pogona henrylawsoni (Wells
& Wellington, 1985). WW
Grant Turner and Rob Valentic.
is a medium sized Pogona
confined to the black-soil plains region of central and western
Queensland, from Gregory Downs to Longreach and Aramac (Witten 1994a,
Shea 1995). The species has had a somewhat unstable taxonomic
history. It was originally described by Wells &
Wellington (1985) as Pogona
their taxonomic revision of the Australian herpetofauna.
Following (unsuccessful) moves to have this work suppressed (ASK 1987,
ICZN 1991), the species and species name, failed to gain acceptance by
most authors. The species was present in live captive
since the early 1970’s in both the USA and Germany where it was known
It was only briefly referred to in books by Wilson & Knowles
and Ehmann (1992), and treated as an undescribed species in
was not referred to in Cogger (1986, 1992). Witten (1994a)
described the species as P.
brevis on account of a failure to locate the holotype and
the claimed inadequacy of the Wells & Wellington (1985)
diagnosis of P.
henrylawsoni. Shea (1995) subsequently claimed
these actions were invalid and proposed the retention of the original
name (P. henrylawsoni)
on the grounds of stability.
There is currently little information available on the natural history
of the downs bearded dragon, Pogona
In Wilson & Knowles (1988) the photographed specimen came from
Winton, Qld with the comment “moderately small very robust Pogona
with poorly developed ‘beard’. Apparently restricted to
cracking clay soils (black-soil plains) in interior of Qld”
(p.220). Ehmann (1992, p.138) referred to it as the
bearded dragon (Pogona
sp.) and provided a brief description and comment on its escape
behaviour. Greer (1989, p.13) referred to the species as ‘P. henrylawsoni’
but no information was presented on the species’ biology. The
species has been successfully maintained in some USA and German
collections for more than 20 years where it has been repeatedly bred
(Michl 1986-7, de Vosjoli & Mailloux 1993, p.47, 1996); it has
been bred at Melbourne Zoo (see Witten 1994b).
Our observations of P.
relate to a brief excursion through the black-soil plains region of
central-west Queensland in October 1996. During the afternoon
October 10 and the morning of October 11 we were able to make a series
of observations on P.
we travelled along the Landsborough Hwy between Longreach (144°15’E,
23°26’S) and McKinley (141°17’E, 21°17’S), passing through the towns of
Morella (143°52’E, 28°58’S), Winton (143°03’E, 22°23’S) and Kynuna
(141°55’E, 21°35’S) along the way.
total of 14 P.
were sighted and of these nine were captured. Locality data
the circumstances, conditions, etc. surrounding the sightings of each
lizard are presented in Table 1. Measurements and
seven of these lizards were taken and data are presented in Table
2. Measurements were performed with a rigid 500mm ruler
to 1mm), vernier calliper (accurate to 0.02mm) and spring balance
(accurate to 2g).
1 Locality data and observations relating to each of the
henrylawsoni sightings. Quoted
temperatures refer to air
temperatures in the shade, RH denotes the relative humidity and time is
EST. Locality data are given relative to the Winton township
10/10/96 - 4:56pm
Full sun 37.4°C;
of Winton, Qld
Prostrate on bitumen surface. Adult.
sun 37.0°C; RH
SE of Winton, Qld
Basking on rock 15m from road. Adult.
sun 37.0°C; RH
of Winton, Qld
Basking on rock 10m from road. Adult
sun 37.2°C; RH
SE of Winton, Qld
Basking on a rock 20m from road. Adult.
5:20pm Full sun
SE of Winton, Qld
Basking on a rock 15m from road. Adult.
Full sun 37.0°C; RH
13.0km SE of Winton,
Basking on a rock 15m
from road. Adult.
approx. 1 week old.
47km NW of Winton, Qld.
8 11/10/96 -
NW of Winton, Qld
on rock 15m from road.
Ground temp 42.3°C. Adult
10:01am Partial sun 30.1°C; RH
NW of Winton, Qld
Perched on rock; retreated down natural
10:27am Full sun
31.8°C; RH 37%
62.3km NW of Winton, Qld
Basking on rock; retreated down natural
crevice next to rock. Adult.
10:36am Full sun 35.0°C; RH
66.1km NW of Winton, Qld
Basking on rock; retreated down natural
crevice next to rock. Adult.
10:39am Full sun 35.0°C; RH
68.0km NW of
Basking on rock;
attempted to retreat down Landsborough
natural crevice 0.5m from rock.
Rock surface temp 37.4°C. Adult.
11:34am Full sun 36.8°C; RH
111.9km NW of
Propped against small
shrub on road edge
12.28pm Full sun
38.9°C; RH 31%
170.6km NW of Winton, Qld
Perched on a vertical branch of dead shrub;
Attempted to retreat down burrow. Adult.
The black-soil plains of the region are sparsely vegetated.
tree-layer is entirely lacking and shrubs where they occur are
sparse. While the region is known to support various grasses
(notably Mitchell Grass, Astrebla
sp.) at the time of our visit the
area was in drought and these were almost entirely lacking, leaving the
soil exposed. The soil is dark brown in colour, crumbling and
friable (to the extent that one leaves distinct indentations walking on
it). They form numerous deep cracks and labyrinthine
cavities. The roadside strip (10-30m wide strip between the
edge and fence) was almost entirely devoid of vegetation (see Figure
1). Small rounded rocks (<0.5m diameter) were common
strip but are generally uncommon beyond the fence line suggesting that
they were excavated during road construction. Wooden fence
were typically quite narrow (<10cm) and of uniform size and
Length measurements of seven P.
henrylawsoni are given in Table
2. Witten (1994a) records mature adult P. henrylawsoni as
having the following average SVL's: Males- SVL=128mm (range
91-148mm, n=5) and Females- SVL=130.8mm (range 122-138mm,
Most of the females in Table 2 fall outside this range; the
significance of this is not clear. The species may be smaller
the Winton area or drought conditions may have prevented full adult
size being attained. By comparison measurements of ‘breeding’
adults in de Vosjoli & Maillouz (1993, p.47, n=?) exhibited the
following ranges: Males-SVL=124-146mm, Total L= 254-305mm and
Females- SVL=127-152mm, Total L= 230-286mm. All but one of the
measurements given in Table 2 lie outside the combined SVL range
124-152mm, however all except one specimen (#13, with a truncated tail)
had total lengths (SVL+TL) within their stated range. Ehmann
(1992) gives head & body length ‘to 13cm’ and a total length of
25cm consistent with above. In Shea (1995) holotype
of P. henrylawsoni
SVL=126mm, TL=116mm and measurements of several Australian Museum
specimens are given as SVL=120, 117mm. In Table 2 all
in which the tail was complete, TL exceeded SVL and this was also noted
by Witten (1994a). None of the other specimens observed were
substantially larger or smaller than those in Table 2. No
specimens which could be classed as ‘sub adult’ or ‘juvenile' were
seen. We were unable to locate any published data on the mass
henrylawsoni for comparison with our data.
general colour and pattern description is based on the nine captured
lizards. Specimens were all grey-brown dorsally with five or six pale grey paravertebral blotches,
some individuals coalesce on the midline. The tail has
13-19 dark brown bands, which may be either distinct or
indistinct. Some had a dark pinkish-brown flush on the gular
region. Ventral surface was white with a grey-brown
pattern. The buccal cavity was lemon yellow to orange, with
tongue usually bright orange (see Wells & Wellington
Iris colour was typically gold sometimes with a red-brown
infusion. As with other Pogona
species, P. henrylawsoni
is capable of marked, rapid colour changes. This was
evident in specimen #13 whose ventral surface changed from clean white
to having a conspicuous superposed grey-brown variegated pattern within
5 minutes of capture; the gular region was also initially
and turned grey in this time. Specimens #1, 2 and 3 were
yellow-brown on capture; by the next morning they were a drab
grey-brown. Preanal pores numbered two (1L:1R) in all
while femoral pores numbered either four (2L:2R, n=5) or six (3L:3R,
n=4). These fall within the stated range of 6-12 (mean 8.18)
difficult and the sexes assigned to individuals in Table 2 are
tentative. None of the lizards examined had palpable eggs or
enlarged ova. Wells & Wellington (1985) report
females in January while northern hemisphere captives oviposit from
March to June (de Vosjoli & Mailloux 1993). There
obvious post-anal pouches indicating the presence of swollen hemipenes
in males. None of the specimens had the appearance of having
recently deposited eggs (e.g., ‘hollow’ abdominal region) and the mass
of individuals was fairly consistent (Table 2).
is known to occur sympatrically with P. henrylawsoni in
the Aramac region (Witten, pers.comm.) though we did not observe any
lizards fitting the description of the former. P. henrylawsoni
is distinguished from P.
vitticeps and other Pogona
by its relatively short tail and limbs, fewer lamellae under the fourth
toe and fewer preanal and
femoral glands (Witten 1994a); the specimens we observed were entirely
consistent with these criteria. In captivity the two species
known to hybridise (Rybak 1996). The size details of a small
number of adult hybrid specimens (n=5) are given in Rybak (1996)
however meristic characters were not provided. All SVL
measurements lie outside the range of Witten (1995a) being larger (ave
SVL=147mm combining male and female measurements); the TL measurements
also lie outside the range obtained by pooling all data for intact
tails (116-141mm vs. 146-216mm) and are also relatively larger (113 vs.
128% of SVL). The same is also true of mass measurements with
159g (130-205g) for hybrids. All specimens we examined were
excellent condition and none underweight for their size. It
therefore seems unlikely that the observed two-fold difference in
average mass could be attributed to captive conditioning alone, but
also to their larger size.
& Behaviour: Most P. henrylawsoni were
observed conspicuously perched either on rocks (n=10) or branches (n=1,
perched 0.4m from ground). The remainder were basking on the
bitumen road (n=2, including the road kill specimen) and one was
propped almost vertically against a small (0.15m tall) heavily grazed
shrub on the edge of the bitumen. No specimens were observed
use fence posts as perches. All exhibited postures consistent
with them basking before being disturbed by us, typically with the
dorsal surface expanded and either oriented towards the sun or
adpressed against rocks. Specimens #13 and 14 had their
vertical, no expanded dorsum with their white chest oriented towards
the sun. Air temperatures when specimens were observed ranged
from 29.0°C to 37.4°C while the relative humidity ranged from 31% to
42% but tended towards the lower end (mode 31%).
In the course of being captured we observed P. henrylawsoni
employ several kinds of behaviours in order to avoid detection and to
avoid capture once detected:
crypsis- on being approached some individuals would crouch down,
lowering the head and body so that it lay flat against the substrate
(rock, ground surface, soil or bitumen) while remaining completely
still, carefully watching our approach. Three individuals
easily captured by hand after employing this cryptic posture.
Another individual, when flushed out onto exposed soil, adopted the
cryptic posture and allowed us to approach to within 0.5m.
are able to blend very effectively in with the soil substrate; this
along with the cryptic posture are indicated in Figure 2.
retreat- on being approached some individuals would dismount their
perches (rocks or branches) and attempt to conceal
Four individuals basking on rocks simply dismounted and hid behind the
basking rock, where they crouched up against the base, still clearly
visible since there was no surrounding vegetation. Two
individuals were observed to retreat down burrows or deep soil
crevices. One of these initially attempted to conceal itself
amongst a dead shrub and on being flushed out ran some 12m across open
ground into a burrow. Three lizards attempted to retreat down
natural crevices located within 1m of their basking site, two lizards
down a burrow one <1m away and the other 12m away. The
of natural crevices utilised was no smaller than 20mm. One
individual could be seen poised vertically 0.3m below the soil surface
down a crevice which was at least 0.6m deep. We noticed that
lizards were capable of detecting our approach (by retreating) up to
30m away. Ehmann (1992) states that “When alarmed, it
into a wide soil crack or an associated burrow, usually under a rock or
fallen timber.” (p.138).
(iii) threat display- when approached
by us all lizards adopted behaviour (I) and (ii). However on
being restrained or cornered it was not uncommon for individuals to
expand their dorsal surface, gape their mouth and erect their rather
small ‘beard’ in a similar manner to P. barbata.
Several individuals were observed when threatened to jump small
vertical distances (<10cm) in attempts to bite objects overhead.
Parasites: On one individual (#12, Table 1) small patches of
orange mite were visible on the gular region and a skin fold on the
head. No other external parasites were visible.
fact that we saw no P.
on fence posts agrees with Witten (1994a) who states “The two specimens
I collected were on a dirt road in black soil country.
spending several months in the Aramac area I never saw Pogona of this [ P. henrylawsoni ]
size perching on fence posts”. Witten (1994a) continues: “It
is possible that P.
henrylawsoni defends territory without the
normal perching behaviour of other Pogona.
Almost half the other specimens in museum collections were road kills,
also suggesting the species is not obvious to passing
herpetologists.” Our observations run counter to the latter
statement as we found the species to be conspicuous when perched on
roadside rocks while travelling through the Winton region by motor
vehicle at 70-80km/h. The ease with which lizards are
roadside rocks would depend much on the surrounding vegetation cover;
at other times of the year these areas are known to support stands of
tussock grass which would make passing observations of P. henrylawsoni
difficult. It is notable that only adult P. henrylawsoni
were seen, indicating perhaps that juveniles constitute a relatively
small proportion of the population or else do not utilise perching
sites as adults do. While it may be argued that this was due
observer bias, in that juveniles would be more difficult to detect due
to their small size, this explanation cannot account for the fact that
we were readily able to spot adult Tympanoryptis
Wilson & Knowles 1988) in the same areas. The absence
juveniles might also indicate rapid growth with adult size being
attained in less than 12 months of age. Predators, in
feral cats, are known to prey on this species (G. Witten, pers.comm.)
and might also account for the lack of juveniles.
It would be of
interest to know how frequently the species occurs beyond the roadside
strip where rocks tend to be less numerous. That the
created roadside habitat (i.e., the displaced rocks) is utilised by P. henrylawsoni
is interesting in itself for it might predispose them to higher
mortality by road vehicles and also may indicate a preference for
similar areas away from roads.
It is evident from this work that there exist many gaps in the basic
ecology of P.
its natural range. There currently appears to be no
on the species natural diet, predators, growth (although see Witten
(1994b) for information on relative growth in captive specimens),
population structure and little information on the timing of
reproductive events. It is hoped that this work will
enquires into these various aspects.
with to thank Dr. Geoff Witten for his helpful discussions,
improvements to the manuscript and for providing us with several
references. We also thank the referees for alerting us to the
earlier usage of the name A.
rankini and making available private
correspondence on the subject.
2 Data on seven of the Pogona henrylawsoni
SVL mm TL
* ESTIMATED 20-30mm missing
** ESTIMATED 30-40mm missing
Note that the TL measurements of #13,14 are excluded from the
calculation of the average TL value.
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