Walk 'n Jump: Associated Insect Walking and Landing Trace Fossils from the Early Permian of the Southern Alps

ABSTRACT

We describe a compound trace fossil Stiaria cf. intermedia C Avolatichnium isp. from the lower Permian of Southern Alps (North Italy) and confidently attribute it to a wingless (apterygote) jumping insect producer belonging to the order Monura (Insecta: Archaeognatha). We discuss the common features linking the ichnogenera Avolatichnium, Rotterodichnium and Tonganoxichnus, and suggest a close affinity for their producers. Grounded on previous studies and on some exceptional features preserved in the described material, we provide a biomechanical model for jumping in Archaeognatha and hypothesize that Paleozoic Archaeognatha performed jumps with high vertical and very low horizontal component and only later acquired the ability to heighten the horizontal component of their jumps, therefore, becoming more efficient in propelling themselves far ahead as extant species do.

KEYWORDS:

• Insect behavior
• Archaeognatha
• Stiaria
• Avolatichnium
• Compound trace fossils

Acknowledgments

For making the specimens available and for precious advice, we thank F. Berra, F. Felletti, A. Paganoni, A. Ronchi, G. Santi and A. Tessarollo. We wish also to thank a number of colleagues, who helped us performing this study: D. Dalpiaz for German translations, M. Piovesana for drawing Figure 4. Two anonymous reviewers, S. Lucas and D. Knaust, together with the Co-Editor H. Klein, provided insightful comments, which improved the quality of this paper.