1116


Journal of Paleontology


is the Ellisdale site of New Jersey, discovered in 1980 by Robert C. O’Neill and Robert K. Denton Jr. (e.g., Weishampel and Young, 1996). Since then, tens of thousands of fossil specimens have been recovered from Ellisdale pertaining to a menagerie of vertebrate and invertebrate clades (e.g., Weishampel and Young, 1996; Denton et al., 2004, 2011). The site has yielded an extremely important record of microvertebrates, with finds including some of the best specimens of mammals from the Late Cretaceous of eastern North America (Grandstaff et al., 1992; Gallagher, 1993; Denton et al., 2011), a species of batracho- sauroidid salamander (Parrisia neocaesariensis Denton and O’Neill, 1998), and a species of teiid lizard (Prototeius stageri Denton and O’Neill, 1995). Indeed, the site has been noted for its importance in understanding the biodiversity of coastal Appalachian ecosystems (e.g., Grandstaff et al., 1992; Denton and O’Neill, 1995, 1998; Denton et al., 2004, 2011; Weisham- pel, 2006). Dinosaur remains from Ellisdale, particularly those of ornithopods, have been recovered in the hundreds (Denton et al., 2011; personal observation, 2017). These fossils preserve both skull and appendicular elements from several species, with the taxa Dryptosaurus, Hadrosaurus, and Hypsibema reported from the site along with the remains of indeterminate theropods and hadrosaurids (e.g., Grandstaff et al., 1992; Gallagher, 1993). However, the sheer number of dinosaur specimens collected from Ellisdale warrants further study of specimens identifiable past such general ranks as “Theropoda indet.” in order to better characterize dinosaur diversity at this site and on Appalachia generally. Here, theropod specimens from Ellisdale referable to more


inclusive clades within that group are described. Several recent studies have noted that theropod teeth may not be diagnostic to the species level (e.g., Longrich, 2008a; Sankey, 2008; Wil- liamson and Brusatte, 2014). Nevertheless, some studies have quantified differences in apparently distinct theropod tooth morphotypes (e.g., Larson and Currie, 2013; Williamson and Brusatte, 2014). Caution was taken with assigning any of the specimens to particular genera. The Ellisdale site theropod specimens, which represent a diverse assemblage of theropod dinosaur clades, are important for further illuminating the diversity of theropod dinosaurs in the Atlantic Coastal Plain and on Appalachia generally, for their biogeographic implications for dinosaur provincialism on Appalachia, and for under- standing the differences between Appalachian and Laramidian faunas.


Geological setting Materials and methods


The Englishtown Formation, made up of slightly glauconitic lignitic cross-bedded sands (e.g.,Owens and Sohl, 1969; Owens et al., 1998), crops out at the base of the exposed deposit at Ellisdale and is uncomfortably overlain by a series of highly lignitic bedded clays, flaser sands, and thin layers of cross- bedded sands (e.g., Grandstaff et al., 1992). These latter three sand layers are overlain by marine sands and glauconitic sedi- ments, and all have been identified as the Marshalltown For- mation (e.g., Grandstaff et al., 1992; Denton and O’Neill, 1995; Denton et al., 1998, 2004, 2011). The Marshalltown Formation was dated at ca. 75.7–71.2 Ma by Miller et al. (2004). More recently, palynological study of the bedded clays that straddle


Referral of teeth to specific dinosaur clades.—In order to sup- port referral of the teeth described to particular clades, they were carefully inspected for phylogenetically informative characters included in the matrices of Carr et al. (2017) (for the tyr- annosauroid teeth) and Turner et al. (2012) (for the dromaeo- saurid teeth). Principle component and discriminant function analyses (PCA and DFA) were not undertaken on the Ellisdale theropod teeth due to the fragmentary or eroded nature of many of the specimens. Nevertheless, the teeth are informative enough to be assigned to specific clades, and possibly genera, of ther- opod dinosaurs.


the main fossiliferous layer of siderite clay pebble-filled sand (Grandstaff et al., 1992) has revealed their age as between 76.4–79.6 Ma (e.g., Denton and Tashjian, 2012), placing the Marshalltown Formation in the middle to late Campanian and thus making the unit closely comparable tem- porally with well-documented western deposits such as the Kaiparowits, Dinosaur Park, Judith River, and Two Medicine formations (e.g., Gates et al., 2010), as well as the upper Tar Heel and Coachman formations of the Carolinas (e.g., Harris and Self-Trail, 2006; Schwimmer et al., 2015). At least four different paleoenvironments are represented at Ellisdale based on the fauna and geology of the site: lagoonal/backbay, estuar- ine, marine, and terrestrial (e.g., Grandstaff et al., 1992; Denton and O’Neill, 1995; Denton et al., 2004, 2011; Denton and Tashjian, 2012), and several models have been proposed to account for the apparent pre-burial transport and disarticulation of species from these several environments at the Ellisdale site. For example, the site has been interpreted as a storm deposit (e.g., Gallagher et al., 1986; Tajishan, 1990; Grandstaff et al., 1992). Denton et al. (2004) proposed that the fossiliferous deposits at Ellisdale were formed when coastal storms flooded a barrier island and washed, churned, and disarticulated the bod- ies of dead marine and island-inhabiting organisms trapped in the storm surge and washed them into an inlet, where they mixed with the eroded, river-deposited remains of species from environments further upland. More recently, Denton and Tash- jian (2012) suggested that formation of the layers at the Ellisdale


site occurred in several steps in a backbay/estuarine setting. The first step, deposition and regression of sediments from the Englishtown Formation, was followed by transgressions that rapidly changed environments surrounding the backbay and thus changed the type of flora and fauna being deposited (Denton and Tashjian, 2012). The deposition of species from different terrestrial and coastal environments, in this model, would have been interspersed by storm events that mixed together already deposited fossil beds and dead biological mat- ter from greater distances (Denton and Tashjian, 2012). The hypotheses of Denton et al. (2004) and Denton and Tashjian (2012) are supported by the presence of heavy erosion on some of the theropod remains and only very slight signs of abrasion on others. The Marshalltown Formation at Ellisdale is overlain by the early Maastrichtian Mount Laurel Formation and Pleis- tocene gravel deposits (e.g., Grandstaff et al., 1992; Miller et al., 2004).


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