iHerp Australia Issue 14 | Page 60

Mad Science. The latest cool reptile research from around the globe. What came first – the lizard or the egg? W ell, in this case, it was the eggs, but the lizard wasn’t far behind. Recently, researchers observed a Three-toed Skink (Saiphos equalis) lay eggs; later the female gave birth to a live young from the same litter, the first time this has been witnessed in a vertebrate. At first glance, there is little remarkable about the Three- toed Skink, other than the fact that it is sufficiently distinct to warrant its own genus. It is a small, coppery- coloured lizard with shortened limbs that is common near the east coast of Australia, from central NSW to southern Queensland. It burrows under surface debris and feeds upon invertebrates at night. But S. equalis is one of only two Australian skinks that are capable of bimodal reproduction (perhaps that should be trimodal – more later); that is, they both lay eggs and bear live young, and this makes them of special interest to evolutionary biologists. Egg-laying is the ancestral strategy, and although the transition to live birth requires significant physiological, anatomical and behavioural change, this has occurred independently in many different lineages of reptiles. There are advantages to both forms of reproduction. Egg-laying is less arduous and entails less risk for the female, as she does not have to carry large young to term in a lengthy pregnancy. This means that she can take advantage of favourable conditions, with bigger clutches,