ICHNOTAXONOMIC UPDATES FROM THE NEWARK SUPERGROUP

Rainforth, Emma C., Environmental Science, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, NJ 07430; erainfor@ramapo.edu


The Newark Supergroup (Late Triassic – Early Jurassic) of eastern North America is world-famous for it’s fossil footprint assemblages. Footprints are the most common tetrapod fossils from these strata. The field of ichnology owes it’s existence to the pioneering work of Edward Hitchcock who, beginning in the 1830s, named and described Newark Supergroup footprints from the Connecticut Valley (Hartford and Deerfield basins), primarily from the Early Jurassic strata. These footprints are dominantly dinosaurian in origin, including several ichnogenera attributable to theropods. Subsequent studies elsewhere in the Supergroup have resulted in a few additional ichnogenera and ichnospecies being discovered, including Apatopus and Brachychirotherium from Milford, NJ. Whilst the nomenclature of the Connecticut Valley prints has been addressed (Rainforth 2005), the ichnotaxonomy (relationships between footprints) has not been revised in detail. It is recommended here that not only the synonymy of Grallator and Anchisauripus with Eubrontes be upheld, but in addition, the remaining prints from the Connecticut Valley attributed to theropods should also be synonymized with Eubrontes because they are only behaviorally (rather than osteologically) distinct. Examination of two ichnogenera attributed to crurotarsans have also resulted in nomenclatural and ichnotaxonomic revisions. Some of Hitchcock’s ichnospecies of Batrachopus are synonymized; Shepardia and Comptichnus are synonymized with Batrachopus; and Lockley et al.’s (2004) synonymization of Selenichnus with Batrachopus is rejected. Apatopus is found to only occur at one location in the Newark Supergroup (Milford NJ); specimens from other localities and stratigraphic horizons were mis-identified and are brachychirotheres.


REFERENCES

Lockley, M.G., Kirkland, J., and Milner, A.R.C., 2004. Probable relationships between the Lower Jurassic crocodilomorph trackways Batrachopus and Selenichnus; evidence and implications based on new finds from the St. George area southwestern Utah. Ichnos 11: 143-149.
Rainforth, E.C. 2005. Ichnotaxonomy of the fossil footprints of the Connecticut Valley (Early Jurassic, Newark Supergroup, Connecticut and Massachusetts). Ph.D. thesis, Columbia University, 1302 pp.








Geological Association of New Jersey 24th Annual Meeting, October 12-13, 2007. In Rainforth, E.C. (ed.), 2007, Contributions to the Paleontology of New Jersey (II): Field Guide and Proceedings, Geological Association of New Jersey 24th Annual Conference and Field Trip, p. 5.