It was most likely that Darwin identified the Black Tigersnake. He assumed it was harmless as in the Northern hemisphere harmless snakes are long and thin and the dangerous species short and fat. However this is not true for the Southern hemisphere species so he would have had no idea how close he came to death when he killed the Tigersnake with a stick. In so doing he observed that live young emerged from the burst abdomen, the first scientific observation of the ovoviviparous (live bearing) rather than egg laying nature of this type of snake,  possibly an adaptation to cold as about 100 viviparous  lizards and snakes have evolved independently, usually in cold areas like Tasmania.

“The abdomen being burst in catching the animal: a small snake appeared from the disrupted egg [membranous egg sacs]: Hence ovoviparous [modern term is ovoviviparous]: Is not this curious in Coluber?” Coluber refers to the family Colubridae which at that time encompassed most of the European snakes with which Darwin would have been familiar.

Lizards

Examples of five of the six lizards Darwin collected and described

1. Tiliqua nigrolutea - Blotched Blue-tongue skink.
Darwin notes  its behaviour as follows “ Animal so torpid and sluggish a man may almost tread on it, before it will move. I lay down close to one and touching its eye with a stick it would move its nictitating membrane and each time turn its head a little further: at last it turned its whole body, when upon a blow on its tail ran away at a slow awkward pace, like a thick snake. Endeavouring to hide itself in a hole in the rocks – appears quite inoffensive and has no idea of biting.” Interestingly contrary to Darwin’s experience, Blotched Blue-tongues can be a lot more agitated when first encountered and have been known to bite.

Darwin also dissected a blue-tongue and recorded “stomach capacious full of pieces of a white mushroom and a few large beetles … hence partly herbivorous!” This was most probably the first time herbivory had been recorded in a skink.

3. Tiliqua casuarinae - She-oak skink
Darwin C. 1840:  Zoology of the Voyage of H.M.S. Beagle under the command of Captain FitzRoy, R.N. during the years 1832 to 1836 Part V ‘Reptiles’ by Thomas Bell. Plate 15 fig. 3 Cyclodus Casuarina. The modern scientific name is Tiliqua casuarinae.

Darwin described it as follows “scales on the centre of the back light greenish brown, edged on their sides with black; scales on the sides of the body above greyer and with less black, below reddish; belly yellow, with numerous narrow, irregular, waving, transverse lines of black, which are formed by the lower margin of some of the scales being black; head above grey, beneath whitish …It is common in the open woods near Hobart Town in Van Diemen’s Land.”

Plate 15 fig. 3 Cyclodus Casuarina.

Specimen: Tiliqua casuarinae - She-oak skink

5. Amphibolurus diemensis - Mountain Dragon

Specimen:Amphibolurus diemensis - Mountain Dragon