SMALL POGONA VITTICEPS (REPTILIA: AGAMIDAE) FROM THE 
BIG DESERT, VICTORIA, WITH NOTES ON OTHER POGONA POPULATIONS 
Geoffrey J. Witten 1 and A. John Coventry 2 
'Department of Anatomy and Physiology, Phillip Institute of Technology, Plenty Road, Bundoora, 
Victoria 3083 
division of Natural History, Museum of Victoria, 285 Russell Street, Melbourne, Victoria 3000 
Witten, G. J. & Coventry, A. J.. 1990:11:30. Small Pogona vitticeps (Reptilia: Agamidae) 
from the Big Desert, Victoria, with notes on other Pogona populations. Proceedings of 
the Royal Society of Victoria 102(2): 117-120. ISSN 0035-921 1. 
Adults of Pogona vitticeps arc smaller towards the southern limit of the distribution of 
the species, the smallest animals occurring in the Big Desert in western Victoria. Females are 
not markedly smaller at sexual maturity than males, but males mature at a much smaller 
size. Data from P. barbata suggest that early male maturity in southern areas may occur also 
in that species. Relative growth and external morphology indicate that the Big Desert 
population is not taxonomically distinct from 
animals in the population are unknown. 
A POPULATION of Pogona lizards from the 
Big Desert rnallee heath in western Victoria has 
been extensively studied as part of an ongoing 
project. These lizards closely resemble P. vitti¬ 
ceps (Ahl) but are much smaller. P. vitticeps typi¬ 
cally grows to 250 mm snout-vent length (SVL) 
(Badham 1976), but the largest specimen col¬ 
lected from the Big Desert is a male of 175 mm 
SVL(NMVD54760). Morphological features of 
this population of clearly smaller animals were 
examined to establish its taxonomic status. 
METHODS 
Measurements and meristic characters were 
recorded from museum specimens (see Appen¬ 
dix). Limb, snout-vent and tail lengths were 
measured to the nearest 0.5 mm using a perspex- 
mounted ruler. Smaller measurements were 
taken using dial calipers accurate to 0.05 mm. 
Where possible, measurements were made bila¬ 
terally and the mean used in analysis. Head 
depth was measured through the centre of the 
orbit and the maximum head width was also 
recorded. Other measurements are self-explana¬ 
tory. 
Morphometric data were analysed by calculat¬ 
ing the least squares regression for measure¬ 
ments first converted to natural logarithms, 
allowing the calculation of Huxley’s formula for 
relative growth: 
Y = bX a 
where Y is the measurement under considera¬ 
tion, A the SVL, b a constant and a the allometric 
coefficient. These regressions were used to cal¬ 
culate theoretical measurements in hatchlings 
\ vitticeps. Factors causing the reduced size of 
(45 mm SVL) and in adults near the maximum 
size of specimens in the Big Desert population 
(150 mm SVL). 
Gonad size and condition were also recorded. 
Females were considered to be mature if they 
had oviducal eggs, convoluted opaque oviducts 
or ovarian follicles more than 5 mm in diameter. 
Males were assumed to be mature if their testes 
were enlarged and circular in cross-section. If 
testicular regression occurs in this species it does 
not alter the gross appearance of the testes; all 
males of adult size had apparently mature 
testes. 
Comparisons were made between four groups 
of specimens: P. vitticeps from the Big Desert; P. 
vitticeps from the “Sunset Country'” (north¬ 
western Victoria north of the Big Desert); P. vit¬ 
ticeps from elsewhere (including South Aus¬ 
tralia, New South Wales, Queensland and the 
Northern Territory); and P. barbata. 
RESULTS 
Sexual maturity and size 
Animals from the Big Desert are clearly smaller 
than those from the Sunset Country (T-test P < 
0.005), which are in turn smaller than those from 
elsewhere (P < 0.001) (Table 1). 
The smallest Big Desert female with oviducal 
eggs was 121 mm SVL (NMV D54754). and the 
smallest female with opaque, convoluted ovi¬ 
ducts (indicating previous egg production) was 
132 mm SVL (NMV D54051). The largest 
clearly immature female examined (NMV 
117 
