Insect Trace Fossils in Substrates Other than Paleosols II. Bones, Caddisfly Cases, Trackways, Imprints and Aerial Nests

Abstract

The universe of insect trace fossils also include those produced in bones, caddisfly cases, trackways, imprints and aerial nests. Larvae of Dermestidae, Tenebrionidae, other beetles, Diptera, termites, ants are usually mentioned as producers of traces in bones. The most common morphologies hollow or comminuted bone-filled cylindrical borings; shallow, hemispherical and star-shaped pits; rosettes or pits in construction; U-shaped borings and notches; ellipsoid chambers; grooves, trails, furrows and networks. Recognized ichnogenera are: Cubiculum, Osteocallis, and Asthenopodichnium, but the unnamed trace fossils, also reviewed in this chapter, are many. The first fossil caddisfly cases were described and named as Indusia in 1805. It is the first insect ichnotaxon named and nowadays there are more than 200 ichnospecies described belonging to different ichnogenera. These are based on the different materials that caddisfly larvae utilize to construct the cases. Folindusia, for cases constructed with leaf bites; Terrindusia for those constructed with clasts and sand grains; Indusia with mollusk shells; Pelindusia with fragments of bivalvian shells; Ostracindusia with ostracod shells, and Conchindusia with conchostrocan shells, among others. Insect trackways, imprints, trails and shallow burrows can be produced on unconsolidated substrates and become preserved. Ichnogenera of trackways attributed to insects are many, Stiaria, Lithographus, Permichnium, Stiallia, Tonganoxichnus among others. Trackway components and ichnotaxonomical treatment related to preservational variants are reviewed. Trails attributed to insects are grouped in Helminthoidichnites, Gordia, Helminthopsis, Cochlichnus, Treptichnus and Spongeliomorpha. Insect imprints, beside behavioral data, may yield detailed evidence of insect ventral morphology. Rotterodichnium, Avolatichnium and Orbiculichnus are some of the known ichnogenera. Insect aerial nests may be preserved as fossils when fallen to soil or by resin or carbonate engulfing. One of the most outstanding examples is Brownichnus favosites, a Cretaceous paper wasp nest. Blueprints illustrate traces in bones, caddisfly cases and trackway descriptive methodology, whereas color plates illustrate producers, traces and morphological details.