Comment on “ Aysheaia prolata from the Utah Wheeler Formation (Drumian, Cambrian) is a frontal appendage of the radiodontan Stanleycaris ” by Stephen Pates, Allison C. Daley, and Javier Ortega-Hernández

Pates et al. (2017) and Pates and Daley (2017) reinterpreted a number of presumable xenusians (lobopodians) and described some new fossils from various Cambrian Lagerstätten as radiodontan (anomalocaridid) frontal appendages. The authors suggested that some features including overall length of a specimen, a number of tentative podomeres, a number of ventral blades (spines) and dorsal spines, their morphology, and an angle between the dorsal and ventral surfaces (θ) of a specimen provide enough information for a fairly good morphological description and a relevant systematic interpretation of stem group ecdysozoans. The case of xenusian Mureropodia apae from the lower Cambrian Valdemiedes Formation of Murero, northeastern Spain (Gámez Vintaned et al. 2011), which Pates and Daley (2017) identified as radiodontan Caryosyntrips cf. camurus, does not verify a plausibility of such a reductive approach.