Teisseirei barattinia Roselli 1939: the first sphinx moth trace fossil from palaeosols and its distinct type of wall

Abstract

The trace fossil Teisseirei barattinia, found in Cenozoic formations of Uruguay and Argentina, is an elongated chamber recognizable by its depressed cross-section, antechamber, and its multi-layered lining with an inner surface texture composed of densely packed sub-rectangular to sub-triangular pits. Our recent behavioural observations on larval and pupal stages of Sphingidae (Lepidoptera), particularly on Manduca rustica, suggest that Teisseirei barattinia is the pupation chamber of a sphinx moth. Last instar larvae of Manduca rustica, Eumorpha anchemolus and E. labruscae were placed in terraria to observe their burrowing behaviour and to recover pupation chambers. Chambers show depressed or plane convex cross-sections as T. barattinia. The internal surface texture of walls is also similar to that of T. barattinia. The same pattern could be obtained experimentally by pressing the true legs of Manduca rustica larva against plasticine. The multi-layered wall structure, shown by T. barattinia, is a new type of lining for insect trace fossils in palaeosols that result from soil packing combined with discharges of abundant liquid excretion by soft-bodied larvae, as in the case of Manduca rustica. T. barattinia is the first trace fossil documented in palaeosols attributed to sphinx moths and supported by macro and micromorphological comparisons with extant pupation chambers. The shallow emplacement of moth pupation chambers in soils suggests that T. barattinia would be a good indicator of palaeosol upper horizons.