Atherton delma
Delma mitella
Distribution: originally described from two individuals from the Atherton Tablelands, Queensland (Herberton and near Koombooloomba) (Shea 1987). More recent surveys targeting pygopod lizards in the Atherton Tablelands by the North Queensland Herpetological Society have failed to locate further individuals (M. Anthony pers. comm.). More recently, collected individuals came from the vicinity of Paluma (Conroy 1999).
Habit and habitat: almost unknown. The Paluma specimens were collected in open forest and at the ecotone between open and closed forest (Conroy 1999).
Activity period: not known, but possibly peaking in spring if the breeding season is similar to that of other Delma species. The paratype specimen was found dead on a road in November at 7.05 pm. Active time of day is unknown.
Survey methods
Data on this infrequently-collected species is insufficient to assess the efficacy of potential collection methods given that most individuals have been found serendipitously. However, on the basis of collection methods for other Delma species, it is likely that the Atherton delma could be collected by a combination of active hand-searching under sheets of tin and other large items on the ground such as rocks and logs, and by pitfall trapping. If the survey involves a targeted search for this species, a series of pitfall trap lines are recommended, comprising six 10 litre buckets spread along a 15 metre fence, although it is probable that trap returns would be very low and the pits may need to be deeper than for other Delma. Conroy (1999) pitfall trapped only a single individual of this species in 6840 trap nights (or 0.01 per 100 trap nights, a figure lower than for two other rare Delma species; see striped legless lizard D. impar and collared delma D. torquata). This species is very large for a Delma, and it is possible that pitfall traps may need to be deeper than for other Delma to prevent trap escapes (the single individual trapped by Conroy [1999] was a juvenile [Queensland Museum specimen]).
Similar species in range: the species overlaps in distribution with two other Delma species, D. tincta and the striped-tailed delma D. labialis. It differs from the striped-tailed delma in lacking the dark dorsolateral stripe along the tail, and in having a broader, blunter snout. It differs from D. tincta in adult size, being much larger than that species. However, juvenile Atherton delmas are of similar size to adult D. tincta, and have a similar pattern, with a dark head interrupted by several narrow pale bands. The two species may be differentiated by the Atherton delma having the fourth supralabial below the eye (vs the third), 16 midbody scales (vs usually 14) and the dorsal margin of the rostral scale flat rather than peaked. Given the difficulty in distinguishing between juvenile Atherton delma and D. tincta within the range of the former species, it is recommended that tissue samples be taken for any small Delma (snout-vent length less than 9 centimetres) in north-east Queensland with a dark hood interrupted by pale bands on the head. Photo voucher specimens are recommended for any records beyond the known distribution.
Anthony, M. North Queensland Herpetological Society. Personal Communication.
Cogger, H.G. 2000. Reptiles and Amphibians of Australia. Reed New Holland, Sydney.
Conroy, S. 1999. Lizard assemblage response to a forest ecotone in northeastern Australia: a synecological approach. Journal of Herpetology 33(3): 409-419.
Shea, G.M. 1987. Two new species of Delma (Lacertilia: Pygopodidae) from northeastern Queensland and a note on the status of the genus Aclys. Proceedings of the Linnean Society of New South Wales 109(3): 203-212.
Baudin Island spiny-tailed skink
Egernia stokesii aethiops
Summary information
Distribution: known only from Baudin Island, Western Australia. The taxonomic status of this subspecies is uncertain. Aplin and Smith (2001) note unpublished studies by Aplin and colleagues that consider the Baudin Island spiny-tailed skink to be merely a variant of the Houtman Abrolhos spiny-tailed skink E. s. stokesii (recently collected on the adjacent mainland) or a population of hybrid origin.
Habit and habitat: closely tied to crevices in limestone outcrops, spending active periods basking close to sheltering sites, in which they seek refuge on any disturbance. Brief periods of diurnal foraging, usually within a few metres of the chosen crevice. Other subspecies live in small family groups in these crevices; the social structure in the Baudin Island spiny-tailed skink is not studied, but is presumed to be similar. Other subspecies may also inhabit crevices in timber, in cracks in branches, or hollows. Such shelters are probably rare on Baudin Island.
Activity period: not known specifically, but likely to bask and feed in mornings and afternoons, avoiding the heat of the day in crevices. Peak activity is likely to be spring and early summer under warm to hot conditions. Activity period should not affect the efficacy of survey methods. The type series was collected in August.
Survey methods
The Baudin Island spiny-tailed skink is readily detected by direct observation of individuals in crevices. Care should be taken to avoid damaging the friable limestone. The Baudin Island spiny-tailed skink is known to adopt communal defecation sites, and the resulting scat piles are an indication of the presence of this or related species.
Similar species in range: The Baudin Island spiny-tailed skink is a medium to large skink (maximum snout-vent length 16 centimetres), dark in colour, with a very short, flattened tail, and the body and tail dorsum covered with hard, sharp posteriorly directed spines. It cannot be confused with any other reptile species occurring on Baudin Island. If it were discovered on the mainland, it could be confused with other subspecies of E. stokesii, or with the pygmy spiny-tailed skink E. depressa. It differs from other subspecies of E. stokesii in its evenly dark black-brown coloration, and additionally from the pygmy spiny-tailed skink in its larger size, in having the nasal scales usually separated (not in contact) and the scales on the back with one or two small spines (not one large and two small spines).
Given the taxonomic uncertainty of the subspecific status of this taxon, any records that are from localities other than Baudin Island should be verified with preferably tissue samples for genetic studies.
Key references for Egernia stokesii aethiops
Aplin, K.P. & Smith, L.A. 2001. Checklist of the frogs and reptiles of Western Australia. Records of the Western Australian Museum Supplement (63): 51-74.
Cogger, H.G., Cameron, E.E., Sadlier, R.A. & Eggler, P. 1993. The action plan for Australian reptiles. Australian Nature Conservation Agency, Canberra. 254 pp.
Storr, G.M. 1978. The genus Egernia (Lacertilia, Scincidae) in Western Australia. Records of the Western Australian Museum 6(2): 147-187.
Storr, G.M, Smith, L.A. & Johnstone, R.E. 1990. Lizards of Western Australia. I. Skinks. Second Edition. Western Australian Museum, Perth.
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