RECONSTRUCTING THE ROSTRUM OF THE SAWFISH, ISCHYRHIZA MIRA, FROM THE LOWER NAVESINK FORMATION (CAMPANIAN-MAASTRICHTIAN), MONMOUTH COUNTY, NEW JERSEY

Cartilage fragments from sclerorhynchid sawfish occur in a lag deposit exposed directly above a prominent disconformity defining the Campanian- Maastrichtian boundary in Monmouth County, New Jersey. Comparison of this material to sclerorhynchid remains preserved in Lebanon, Morocco, and Mexico indicates that these fragments derive from several different parts of the rostrum, including the mid-rostrum, ophthalmic and buccopharyngeal nerve grooves, outer rostral margins and medial canal. The mutual occurrence in the lag of these rostral fragments together with oral and rostral teeth of the sclerorhynchid species Ischyrhiza mira Leidy (1856), and the absence of remains from other sawfish, suggests that the rostral fragments derive from this sclerorhynchid species. The Monmouth County cartilage assemblage illustrates the utility of fragmentary, non-tooth fossil evidence in anatomical interpretation of Upper Cretaceous chondrichthyans and has the potential for evaluating sawfish fossils collected from Upper Cretaceous locations elsewhere in the world.