RE-EVALUATING THE ICHNOGENUS TEREDOLITES: A PROXY FOR COMPETITION, SALINITY, AND ENVIRONMENT

The ichnogenus Teredolites––a teardrop to vermiform borings in woody media––is produced by pholadoidean bivalves in marine-influenced, oligo- to hyperhaline depositional environments. Such borings record ephemeral linkages between the continental and marine realms via exploitation of allochthonous media (i.e., isolated floatsam), when concentrated in transgressive lags, and delineate marine flooding surfaces when found within in situ composite woodgrounds. The abundance and distribution of Teredolites in Jurassic and younger sedimentary successions is inherently related to local and regional changes in sea level, providing an excellent proxy for shoreline trajectory in sequence stratigraphic analyses and for petroleum exploration. Studies of this ichnotaxon and its extant tracemakers with respect to community ecology and metacommunity analyses suggest exploitation of ephemeral media and high interspecific competitive stress resulted in the evolution of various life history strategies––reproductive adaptations, media preferences, and salinity tolerances––to maximize syntopy. Our study synthesizes ichnological and community ecology frameworks to utilize Teredolites in a large-scale spatiotemporal analysis to semiquantitatively reconstruct paleosalinity in strata interpreted to have been deposited in paralic to shallow marine depositional environments through application of modern tracemaker niche dynamics in oligo- to euhaline conditions onto trends identified in boring metrics, distribution, abundance, and densities of fossil examples. This study aims to produce: (1) a quantitative framework to utilize Teredolites as a high-resolution index trace in outcrop to basin-scale investigations; (2) a statistical proxy for prediction of paleosalinity and paleoenvironment via differences between within-sample densities and salinity-size relations at the ichnospecies level; and (3) inferences to distinguish a spectrum of competitive strategies in the rock record via statistical determination of fossil community succession along disturbed surfaces and within inferred climax communities as to parallel community succession theory to environmental signal propagation.