1042-0940/01 S12.00-i-.00 f^. The Insect Trace Fossil Tonganoxichnus irom the Middle

The ichnogenus Tonganoxichnus, produced by one or more monuran insect taxa, is now recorded from the Middle Pennsyl-vanian Mansfíeld Formation of Indiana. Tonganoxichnus is a rest-ing trace that has three important implications. First, it represents a recurrent behavioral pattern in Upper Carboniferous to Lower Permian marginal marine environments of North America. Sec-ond, it provides finely resolved anatomical information for axial and appendicular body structures and behaviors that are difficult to determine from body-fossil material alone. Third, integrated sedimentologic and ichnologic observations indicate that the Tonganoxichnus assemblage, inclusive of other ichnotaxa, is com-mon in tidal rhythmites that were developed under freshwater conditions, probably in the innermost part of estuarine systems, close to or at the fluvioestuarine transition