MSGID: 1:317/3 627201ab   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Researchers discover overlooked Jurassic Park of lizards    
      
     Date:   
         May 3, 2022   
     Source:   
         University of Bristol   
     Summary:   
         New research moves back the moment of the radiation of squamates   
         -- the group of reptiles that includes lizards, snakes and worm   
         lizards -- to the Jurassic, a long time before current estimates.   
      
      
      
   FULL STORY   
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   New research published today in eLife by researchers from the Institut   
   Catala` de Paleontologia Miquel Crusafont (ICP) and the University of   
   Bristol (UB) moves back the moment of the radiation of squamates --   
   the group of reptiles that includes lizards, snakes and worm lizards --   
   to the Jurassic, a long time before current estimates.   
      
      
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   The Squamata is the largest order of reptiles, including lizards, snakes   
   and worm lizards. Squamates are all cold-blooded, and their skins are   
   covered by horny scales. They are key parts of modern terrestrial faunas,   
   especially in warmer climates, with an astonishing diversity of more   
   than 10,000 species.   
      
   However, understanding the evolutionary paths that forged their success   
   are still poorly understood.   
      
   There is consensus that all the main squamate groups had arisen before   
   the event that wiped out dinosaurs and other groups of reptiles at   
   the end of the Mesozoic era. Before that global catastrophic event,   
   through the Cretaceous, many terrestrial tetrapod groups like mammals,   
   lizards and birds, apparently underwent a great diversification during   
   the so-called Cretaceous Terrestrial Revolution, triggered by the rise   
   of flowering plants. The scarcity of fossil remains of squamates through   
   the Jurassic suggested that the main burst of squamate evolution happened   
   in the Cretaceous (between 145 and 66 Myr.), when their fossil record   
   dramatically improves.   
      
   Now, a new paper published in eLife, led by Arnau Bolet, paleontologist   
   at the Institut Catala` de Paleontologia Miquel Crusafont and the   
   University of Bristol, however, challenges this view by suggesting   
   a much earlier radiation of squamates. Along with colleagues from the   
   University of Bristol Michael Benton, Tom Stubbs and Jorge Herrera-Flores,   
   their research concludes that this group of reptiles probably achieved a   
   diverse array of adaptations in the Jurassic (between 201 and 145 Myr.),   
   long before previously thought. "Even though Jurassic squamates are rare,   
   reconstructed evolutionary trees show that all the main specializations   
   of squamates evolved then, and it's possible to distinguish adaptations   
   of geckoes, iguanas, skinks, worm lizards, and snakes some 50 million   
   years earlier than had been thought," explains Michael Benton, co-author   
   of the research.   
      
   But how could the scarce Jurassic fossils suggest an early burst in   
   evolution?  The key is in their anatomy. The few Jurassic squamates do not   
   show primitive morphologies as would be expected, but they relate directly   
   to the diverse modern groups. "Instead of finding a suite of generalized   
   lizards on the stem of the squamate tree, what we found in the Jurassic   
   were the first representatives of many modern groups, showing advanced   
   morphological features," says Arnau Bolet, lead author of the article.   
      
   The observed times of divergence, morphospace plots and evolutionary   
   rates, all suggest that the Jurassic was a time of innovation in squamate   
   evolution, during which the bases of the success of the group were   
   established. According to these results, the apparent sudden increase   
   in diversity observed in the Cretaceous could be related to an improved   
   fossil record, capable of recording a larger number of species, or to   
   a burst of origins of new species related to the new kinds of forests   
   and insects.   
      
   Establishing the timing and mode of radiation of squamates is key for not   
   only understanding the dynamics of terrestrial ecosystems in the Mesozoic,   
   but also for deciphering how the group achieved an astonishing diversity   
   of more than 10,000 species, only rivalled by birds among tetrapods.   
      
      
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   Story Source: Materials provided by University_of_Bristol. Note: Content   
   may be edited for style and length.   
      
      
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   Related Multimedia:   
       * The_fossil_of_Jurassic_lizard_Eichstaettisaurus   
   ==========================================================================   
   Journal Reference:   
      1. Arnau Bolet, Thomas L Stubbs, Jorge A Herrera-Flores, Michael   
      J Benton.   
      
         The Jurassic rise of squamates as supported by lepidosaur disparity   
         and evolutionary rates. eLife, 2022; 11 DOI: 10.7554/eLife.66511   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220503091754.htm   
      
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