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A size record and further distributional data for Dwyer's Snake Parasuta dwyeri (Elapidae) in the Sydney Basin.


By Rob Valentic.

Dwyer's Snake Parasuta dwyeri
An adult male Dwyer's Snake Parasuta dwyeri from brigalow habitat near Yelarbon, south-eastern Queensland, Australia.
INTRODUCTION

Ehmann (1992) gives a maximum total length of 540mm for Parasuta dwyeri and states that specimens from more eastern rocky areas are usually slender to strong bodied in comparison to specimens associated with the inland drainages west of the dividing range.  The largest specimen recorded to date in the literature is a male from Queensland (Qld) with a snout-to-vent length (SVL) of 456mm (Shine, 1988; 1994).  Shine (1988) presents a table showing a sexual size dimorphism in favour of males in the species with a SVL range of 233-456mm for males and 235-345mm for females of P. dwyeri (NSW and Qld specimens combined).  Coventry and Robertson (1991) give a total length of 600mm presumably for Victorian specimens of S. dwyeri and S. nigriceps, although it was not established whether these are formal measurements or only estimates.  Both Cogger (1992) and Wilson and Knowles (1988) give total lengths of 400mm for P. dwyeri.  The following note provides details of an adult male P. dwyeri from the Putty Road within the Sydney Basin exceeding the maximum SVL recorded by Shine (1988) and possessing an extremely robust build.


OBSERVATIONS

Date: 1st March 1997.

Time: 21.22hrs (Eastern Standard Time/Daylight Savings Time).

Weather Conditions:  Fine with no moon and a gentle breeze.  Air temperature: 25C.  Relative humidity: 76% (Measurements taken with a Smart Digital Thermo- hygrometer).

Location:  Colo Heights, New South Wales (Lat: 3323’S, Long: 15045’E.).

Habitat:  A Sandstone ridge-top vegetated predominately with eucalypts and with a Kangaroo grass Themeda sp. understory.

Notes:  A snake was spotted loosely coiled on the middle of the Putty Road roughly 100 metres south of the Service Station and was identified as a male P. dwyeri.  Head measurements were taken using a set of Mitutoyo Digimatic Callipers and weight obtained using a set of Ohaus Cent-o-Gram scales (0-311 grams, d = 0.01 gram).  The snake probed to a depth of seven subcaudals and weighed at 53.97 grams.  The following measurements were taken: SVL: 486mm.  Tail length: 72mm.  Total length: 558mm.  Head length: 21.4mm (taken from the anterior edge of the rostral scale to the posterior edge of the parietals).  Head width: 11.8mm.  There were 15 mid-body scales, 33 single subcaudals, single anal scale and 154 ventrals (all single).  The specimen was considerably darker dorsally and was more robust in build with a bulbous head in comparison to inland specimens from Nyngan, NSW (Lat: 3134’S,  Long: 14712’E.) and Bendigo, Victoria (Lat: 3646’S,  Long 14417E.) that I have examined.  The snake was photographed on a nearby rock slab and then released.


DISCUSSION

P. dwyeri is usually associated with granite outcrops on the drier western slopes of the ranges and is typically discovered within  rock exfoliations in both NSW and Victoria (pers. obs.).  Swan (1990) and Wilson and Knowles (1988) noted that the species extends into the Hunter Valley and Swan lists two locations on the upper Hawksbury drainages where the species has been found.  Shea (1994) highlighted some of the predominately arid or western slopes species that enter the northern Sydney Basin through the Hunter Valley corridor, and P. dwyeri is yet another example.  This species was not included in Griffiths (1987), but is in Griffiths (1997).  Anthony Stimson, a long-term resident of Colo Heights has never seen the species in the area although Richard Wells has confirmed the presence of P. dwyeri in the region (R. Wells, pers. comm.).

ACKNOWLEDGEMENTS


Thanks to Anthony Stimson for his hospitality during my visit to Sydney and to Grant Turner for his help in locating the Shine references and critically reading a draft manuscript.


REFERENCES

Cogger, H.G. 1992.  Reptiles and Amphibians of Australia.  5th Edition.  Reed, Sydney, 775pp.

Coventry, J. and Robertson, P. 1991. 
The Snakes of Victoria - A guide to their identification.  Department of Conservation and Environment, Melbourne, 76pp.

Ehmann, H. 1992. 
Encyclopedia of Australian Animals. Reptiles. Angus and Robertson, Sydney, 495pp.

Griffiths, K. 1987. 
Reptiles of the Sydney Region.  Three Sisters Productions, Winmalee, 120pp.

Griffiths, K. 1997. 
Frogs and Reptiles of the Sydney Region.  University of NSW Press, Sydney, 128pp.

Shea, G.M. 1994. 
Three Species of Goanna Occur in the Sydney Basin. Herpetofauna, 24(2):14-18.

Shine, R. 1988. 
Food Habits and Reproductive Biology of Small Australian Snakes of the Genera Unechis and Suta (Elapidae). J. Herpet., 22, 3:307-315.

Shine, R. 1994. 
Allometric Patterns in Ecology of Australian Snakes. Copeia 1994 (4):851-867.

Swan, G. 1990. 
A field guide to the snakes and lizards of New South Wales.  Three Sisters Publications, Winmalee, 224pp.

Wilson, S.K. and Knowles, D.G. 1988. 
Australia’s Reptiles. A Photographic Reference to the Terrestrial Reptiles of Australia. Collins, Sydney, 447pp.