Nectrideans are a Carboniferous and Permian group of tetrapods, typically regarded as 'amphibians' and classified alongside microsaurs and lysorophians within the group Lepospondyli. However, close relationships with the long-bodied aïstopods have been supported by some: indeed, nectrideans have been found to be paraphyletic to aïstopods in some studies (Ruta et al. 2003). Thomson & Bossy (1970) gave the name Holospondyli to a hypothesised nectridean + aïstopod clade. Diplocaulus - the most famous nectridean - is typically portrayed as here. However, fossils show that these 'horned' nectrideans actually had skin webs connecting the tips of their 'horns' to their bodies.
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Refs - -
Ruta, M., Coates, M. I. & Quicke, D. L. J. 2003. Early tetrapod relationships revisited. Biological Reviews 78, 251-345.
Thomson, K. S. & Bossy, K. H. 1970. Adaptive trends and relationships in early Amphibia. Forma et Functio 3, 7–31.
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ABOUT THE AUTHOR(S)
Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow Darren Naish on Twitter
