New Zealand: tuataras extinct by global warming?


Brother Islands tuatara

From National Geographic:

Warming May Drive Gender-Bending Reptiles Extinct, Scientists Say

Dave Hansford in Wellington, New Zealand

November 10, 2006

Less than one degree Celsius (1.8 degrees Fahrenheit) is all that stands between the tuatara—New Zealand’s “living fossilreptile—and extinction, scientists say.

The sex of tuatara—the sole surviving species of an ancient family of reptiles dating back 200 million years—is determined by the incubation temperature of its eggs.

As the mercury climbs, so does the proportion of male hatchlings.

The mechanism is so delicate that a flagging population on remote North Brother Island in Cook Strait is already running short of breeding females.

Nicky Nelson, a senior lecturer at Victoria University in Wellington, New Zealand, says experiments show that 21.7 degrees Celsius (71 degrees Fahrenheit) could be the pivotal temperature.

See also here.

And here. And here.

More tuataras: here.

And here.

And here. And here.

Henry the Tuatara and his mate Mildred, aged between 70 and 80, produced 12 eggs in mid-July after mating earlier this year at the Southland Museum on New Zealand’s South Island, Tuatara curator Lindsay Hazley said: here.

Birds extinct by global warming? See here.

Global warming and red-winged blackbirds in Canada: here.

4 thoughts on “New Zealand: tuataras extinct by global warming?

  1. http://www.eurekalert.org/pub_releases/2008-03/cp-ttf032008.php

    Tuatara, the fastest evolving animal
    New DNA research has questioned previous notions about the evolution of the tuatara

    In a study of New Zealand’s “living dinosaur” the tuatara, evolutionary biologist, and ancient DNA expert, Professor David Lambert and his team from the Allan Wilson Centre for Molecular Ecology and Evolution recovered DNA sequences from the bones of ancient tuatara, which are up to 8000 years old. They found that, although tuatara have remained largely physically unchanged over very long periods of evolution, they are evolving – at a DNA level – faster than any other animal yet examined. The research will be published in the March issue of Trends in Genetics.

    “What we found is that the tuatara has the highest molecular evolutionary rate that anyone has measured,” Professor Lambert says.

    The rate of evolution for Adélie penguins, which Professor Lambert and his team have studied in the Antarctic for many years, is slightly slower than that of the tuatara. The tuatara rate is significantly faster than for animals including the cave bear, lion, ox and horse.

    “Of course we would have expected that the tuatara, which does everything slowly – they grow slowly, reproduce slowly and have a very slow metabolism – would have evolved slowly. In fact, at the DNA level, they evolve extremely quickly, which supports a hypothesis proposed by the evolutionary biologist Allan Wilson, who suggested that the rate of molecular evolution was uncoupled from the rate of morphological evolution.”

    Allan Wilson was a pioneer of molecular evolution. His ideas were controversial when introduced 40 years ago, but this new research supports them.

    Professor Lambert says the finding will be helpful in terms of future study and conservation of the tuatara, and the team now hopes to extend the work to look at the evolution of other animal species.

    “We want to go on and measure the rate of molecular evolution for humans, as well as doing more work with moa and Antarctic fish to see if rates of DNA change are uncoupled in these species. There are human mummies in the Andes and some very good samples in Siberia where we have some collaborators, so we are hopeful we will be able to measure the rate of human evolution in these animals too.”

    The tuatara, Sphendon punctatus, is found only in New Zealand and is the only surviving member of a distinct reptilian order Sphehodontia that lived alongside early dinosaurs and separated from other reptiles 200 million years ago in the Upper Triassic period.

    ###

    Lambert et al.:”Rapid molecular evolution in a living fossil.” Researchers include Jennifer M. Hay, Sankar Subramanian, Craig D. Millar, Elmira Mohandesan and David M. Lambert. http://dx.doi.org/10.1016/j.tig.2007.12.002

  2. Pingback: Tuatara conservation in New Zeraland | Dear Kitty. Some blog

  3. Pingback: First fossil mammal found in New Zealand | Dear Kitty. Some blog

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