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Article on Gerrothorax

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  • Neal Robbins
        An illustration of Gerrothorax is on this link. http://en.wikipedia.org/wiki/File:Gerrothorax_BW.jpg      Gerrothorax was a temnospondyl amphibian
    Message 1 of 1 , May 23, 2013
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          An illustration of Gerrothorax is on this link.
       
          Gerrothorax was a temnospondyl amphibian of the Triassic. The systematic paleontology of it is:
       
      Amphibia Linnaeus 1758
      Temnospondyli von Zittel 1888
      Stereospondylomorpha Yates and Warren 2000
      Stereospondyli von Zittel 1888
      Trematosauria Yates and Warren 2000
      Plagiosauridae Abel 1919
      Gerrothorax Nilsson 1934
      Gerrothorax pulcherrimus Jenkins et al. 2008=Plagiosternum pulcherrimus Fraas 1913
       
          Gerrothorax had a length of about 1 m. (3.28 feet). Its body was amazingly flattened. S. Sanchex and R.R. Schoch wrote an article titled Bone Histology Reveals a High Environmental Metabolic Plasticity as a Successful Evolutionary Strategy in a Long-Lived Homeostatic Triassic Temnospondyl. It was published in 2013 in Evol Biol. This quote from the abstract says:
       
      Evolutionary stasis (long term stability of morphology in an evolving lineage) is a pattern for which explantions are usually elusive. The Triassic tetrapod Gerrothorax pulcherrimus, a gill-bearing temnospondyl, survived for 35 million years in the Germanic Basin of Central Europe presisting throughout the dinosaur-dominated late Triassic period. This evolutionary stasis coincides with the occurrence of this species in a wide range of habitats and environmental conditions by the combination of palaeoecological and palaeohistological analyses, we found great ecological flexibility in G. pulcherrimus and present substantial evidence of developmental and metabolic plasticity despite the morphological stasis. We conclude that G. pulcherrimus could show the capacity to settle in water bodies too harsh or unpredictable for most other tetrapods. This would have been made possible by a unique life history strategy that involved a wider reaction norm, permitting adjustment to fluctuating conditions, such as salinity and level of nutrients. Growth rate, duration of juvenile period, age at maturity, and life span were all subject to broad variation within specimens of G. pulcherrimus in one single lake and in between different lakes. In addition to providing a better understanding of fossil ecosystems, this study shows the potential of such a methodology to encourage palaeobiologists and evolutionary biologists to consider the mechanisms of variation in extant and fossil organisms by using a similar time-scope reference. 
          The complete text is on this link.
       
          Neal Robbins
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