Revised paleoecology of placodonts – with a comment on ‘The shallow marine placodont Cyamodus of the central European Germanic Basin: its evolution, paleobiogeography and paleoecology’ by C.G. Diedrich (Historical Biology, iFirst article, 2011, 1–19, doi: 10.1080/08912963.2011.575938)

Abstract

A recent article published by Diedrich (2011a, Hist Biol. iFirst online, 1–19, doi: 10.1080/08912963.2011.575938) aspired to provide a complete revision of the known material of the placodont genus Cyamodus Meyer, 1863 from the Germanic Basin of central Europe. It is the latest in a series of similar articles by the same author (see Diedrich 2010, Palaeogeogr Palaeoclimatol Palaeoecol. 285(3–4):287–306; 2011b, Nat Sci. 3(1):9–27 for overview) focussing on the European members of the Placodontia (Reptilia: Sauropterygia), a diverse group of enigmatic marine reptiles known from Triassic shallow marine deposits. In a similar fashion to some previous works by Diedrich (see Tintori 2011, Palaeogeogr Palaeoclimatol Palaeoecol. 300(1–4):205–207 for similar points of criticism), this newest article demonstrates a narrow scope of presenting and discussing data, including omitted articles relevant to the topic, and over-interpretation of results, all with the aim of embedding the idea of placodonts being herbivorous Triassic ‘sea cows’ feeding on macroalgae (Diedrich 2010, 2011b). The present contribution is intended to clarify mistakes and misinterpretations made by Diedrich (2011a), to incorporate vital citations previously omitted which allow alternative interpretations, and to put the paper into perspective by including a more general evolutionary and paleoecological overview of the remaining placodonts.

Keywords:

• Triassic
• Placodontia
• Cyamodontoidea
• sea cows
• durophagous
• Cyamodus hildegardis

Acknowledgements

The colleagues at the PIMUZ are thanked for discussions and technical help. The manuscript further greatly benefited from the constructive comments of an anonymous reviewer. The study was funded by the Swiss National Science Foundation (No. 31003A 127053/1 to TMS).