QUANTITATIVE ANALYSIS FOR THE TYPE MATERIAL OF PRICONODON CRASSUS: A DISTINCT TAXON FROM THE ARUNEL FORMATION IN SOUTHERN MARYLAND

Priconodon crassus, "thick saw-cone tooth," was first named and described by Marsh (1888) from a single worn tooth, holotype USNM 2135 discovered in the Arundel Formation in Prince George's County Maryland. Priconodon is predominantly known from teeth that are distinguished from all other Nodosaurid teeth by their very large size. The morphologic comparisons with Western Interior Nodosaurid and Ankylosaurid specimens in this discussion are among the first to quantitatively indicate Priconodon as a distinct taxon. Digital images of four Priconodon specimens, USNM numbers 437985, 497710, 497711, and holotype 2135 where compared with images of 24 dental specimens from Ankylosaurs magniventris, Edmontonia longiceps, Edmontonia rugosidens, Euoplocephalus tutus, and the holotype of Palaeoscincus costatus from pre-existing literature with the Image J digital image processing software. Comparisons were based on maximum length and height measurements of both the labial and lingual sides of all 28 specimens. All specimens exhibited species-specific grouping by size with the greatest dimensions expressed by Priconodon; the maximum height exhibited by USNM 497711 at 14.753mm and the maximum length exhibited by USNM 497710 at 14.178mm. Edmontonia rugosidens AMNH 5381, exhibited two teeth with height and length dimensions nearest to Priconodon with a maximum height of 9.925mm and a maximum length of 11.934mm.