Limb Loss in Scincid Lizards

I’m currently working on a long winded post about the new Homo erectus pelvis – which I hope to have up tomorrow – in the meantime it occurred to me that I had been meaning to mention a new paper in BMC Evolutionary Biology called Rapid and repeated limb loss in a clade of scincid lizards


The study focused on Lerista , a clade composed of some 75 species. They range from pentadactylic to entirely limbless, thus making them good candidates for a limbloss study. In order to do the study, however, they had to come up with a good phylogeny because the phylogeny of Lerista had not been worked out. Seventy two species and three outgroup taxa were used to construct the phylogeny based on genetic analysis (consult the paper for further details). Having come up with a phylogeny the researchers of the paper then turned to investigating the pattern and rate of limb reduction. They conclude that:

Many authors have noted the recurring evolution of an elongate, limb-reduced body form in squamates, however, even within this clade, the frequency and rate of limb reduction inferred here for Lerista are exceptional. Ancestral state reconstructions imply 27 instances of limb reduction … almost as many as reported by Greer [3] for all remaining scincids, and nearly half the number of reductions inferred for all other squamates. An interval of no more than 3.6 million years for the complete loss of limbs in one lineage of Lerista is less than one fourth of Brandley et al.’s [5] minimum estimate of the time required for this substantial phenotypic transition. These results emphasise the potential for extensive alteration of body form in squamates over (geologically) brief periods.

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6 Responses

  1. Careless lizards. Pah. If you find yourself legless that often, you need to book into Alcoholics Anonymous.

  2. Bob – Perhaps you should have held some warm coffee before you read that. Then you would have had more positive thoughts about the lizards…

  3. Bob was just pulling your leg….

  4. Yes, I know…

  5. …do squamids have a propensity for rapid and diversified evolution. Thanks for the paper, those of us out of the loop drink them like water. Here is a link to 30 year evolution off of Croatia.
    http://news.nationalgeographic.com/news/2008/04/080421-lizard-evolution.html
    Dior

  6. Still trying to be as anonymous as possible so I deleted my name. PZ wrote about the story you linked too and I have the article if you would like a copy. Lizards do seem to diversify rapidly

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