Letter: On the discovery of a new species of marine reptile

From Nicholas Longrich, University of Bath, UK, and colleagues

You covered a study that suggests Xenodens calminechari, a new species of mosasaurid named by us, could be based on a forged jaw fossil. We can confirm the authenticity of the fossil (25 January, p 21).

Our team includes world experts in Moroccan mosasaurs. Having published 20 papers, described 10 new mosasaurids, examined thousands of specimens over two decades, carried out fieldwork and worked under two international official academic agreements between Morocco, France and the UK, we are familiar with recognising fossil alteration.

We can confirm the fossil’s authenticity because the first author prepared the specimen from the original matrix using a pin vice and paintbrush. Any alteration would have been obvious. Furthermore, during preparation, a tooth detached, exposing the interior of the crown and root, showing both are original. The “gummy” texture identified in the study you covered as possible reconstructed material is standard Paraloid B-72 resin used to prepare the fossil for study. Last, two new Xenodens, identical to the holotype, are now under study. We plan further research, including CT scans, and are confident this will vindicate X. calminechari and lay all doubts to rest.