Scolicia, ichnotaxonomic practices, and the limits of behavioural convergence

Abstract

Many studies convincingly documented the diagnostic morphology of Scolicia, establishing a functional link with the burrowing activities of heart urchins, common components of the marine mobile faunas that emerged during the Mesozoic Marine Revolution. However, this ichnotaxon has been repeatedly mentioned in both continental successions and Paleozoic marine strata, even though its diagnostic characteristics were absent. This approach may reflect the implicit belief that behavioural convergence is rampant in the ichnologic record and can be uncritically adopted in almost all cases. We underscore the importance of a definition of Scolicia that is based on diagnostic morphologic features and supported by a solid analysis from the perspective of function and mode of construction. This view of Scolicia highlights its value in paleoenvironmental reconstructions and its significance to unravel macroevolutionary trends. Attribution to an ichnotaxon should involve understanding of morphologic features in terms of its mode of production rather than the mere observation of superficial similarities.

Keywords:

• Trace fossils
• echinoid burrowing behaviour
• functional morphology

Acknowledgements

We thank Andrei Ichaso who guided Mángano and Buatois to the outcrops of Zumaya in the Basque Country of Spain. Two anonymous reviewers, AE Renata Netto, and Co-editor Murray Gingras are thanked for their valuable feedback.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

We thank funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grants 311727-20 and 422931-20 awarded to Mángano and Buatois, respectively. Mángano recognizes additional funding from the George J. McLeod Enhancement Chair in Geology.