1126


Journal of Paleontology


rather than an indicator of the position of such tyrannosauroids outside Tyrannosauridae (e.g., Carr, 1999; Currie, 2003; Sam- man et al., 2005; Williamson and Brusatte, 2014). However, the CHs of the Ellisdale tyrannosauroid teeth are comparable to or exceed those of subadult or adult western tyrannosaurid teeth (e.g., Carr et al., 2005, supplemental information). Thus, the presence of the ziphodont condition in likely all the tyranno- sauroid teeth from Ellisdale is considered indicative that all these teeth are from large non-tyrannosaurid tyrannosauroids (e.g., Holtz, 2004; Carr et al., 2005; Brusatte et al., 2010, 2011, 2014; Loewen et al., 2013; Williamson and Brusatte, 2014; Brusatte and Carr, 2016; Carr et al., 2017). This referral is supported by the assignability of several of the Ellisdale teeth to Dryptosaurus or a closely related taxon and the similarity of the tyrannosauroid morphotype B teeth described to A. montgomer- iensis (e.g., Carr et al., 2005; Brusatte et al., 2011; Schwimmer et al., 2015). Appalachia was at least partially isolated from Laramidia


since the Albian–Cenomanian (e.g., Roberts and Kirschbaum, 1995; Russell, 1995; Schwimmer, 2002). However, it is notable that the theropod assemblage from Ellisdale does not resemble that of the Cenomanian Wayan Formation of the northern Rockies, the latter including incrassate-toothed small- and medium-sized tyrannosauroids, small dromaeosaurids, Richar- doestesia isosceles-like theropods represented by teeth, neovena- torids, and oviraptorosaurs (Krumenacker et al., 2017). The Ellisdale theropod assemblage also differs from that of the Albian–Cenomanian Mussentuchit Member of the Cedar Moun- tain Formation, which includes a large neovenatorid, small tyrannosauroids, theropods with teeth similar to Richardoestesia and Paronychodon, troodontids, and dromaeosaurids (e.g., Kirk- land et al., 1999; Zanno and Makovicky, 2011, 2013). The theropod assemblage of the Albian Cloverly Formation is somewhat more similar to that of Ellisdale, containing tyranno- sauroids of similar phylogenetic grade to Xionguanlong,the dromaeosaurid Deinonychus, and ornithomimosaurs (e.g., Ostrom, 1969, 1970; Zanno and Makovicky, 2011). Unlike the Cloverly, the Ellisdale theropod fauna lacks oviraptorosaurs (Makovicky and Sues, 1998) and large carcharodontosaurid dinosaurs (e.g., Kirkland et al., 1999; Weishampel et al., 2004; D’Emic et al., 2012). Because carcharodontosaurids seemto have gone extinct in the northern hemisphere sometime during the middle of the Late Cretaceous (e.g., D’Emic et al., 2012; Zanno and Makovicky, 2013) and none are known in the Campanian of the Atlantic or Gulf coastal plains (e.g., Gallagher, 1993, 1997; Ebersole andKing, 2011; Schwimmer et al., 2015), the absence of that group in the Ellisdale fauna is unsurprising. Regardless, the Ellisdale assemblage and other Appalachian theropod faunas from the Campanian lack troodontids or oviraptorosaurs (e.g., Galla- gher, 1993; Schwimmer et al., 2015; Schwimmer, 2016), which are fairly widespread among Campanian Laramidian formations (e.g., Weishampel et al., 2004; Gates et al., 2010, supplemental information; Larson and Currie, 2013; Longrich et al., 2013; Sampson et al., 2013a; Williamson and Brusatte, 2014; Funston and Currie, 2016; van der Reest and Currie, 2017). This absence may be due to preservation bias, because fossils of both of these groups in Laramidia are comparatively uncommon (e.g., Weishampel et al., 2004; Gates et al., 2010, supplemental information; Larson and Currie, 2013; Longrich et al., 2013;


Sampson et al., 2013b; Williamson and Brusatte, 2014; Funston and Currie, 2016; van der Reest and Currie, 2017). Nevertheless, differences between taxa of groups present in western North America and at Ellisdale indicate that Appalachia harbored a distinct theropod fauna from Laramidia, a biogeographic phenomenon previously recognized in the literature (especially for tyrannosauroids; e.g., Carr et al., 2005; Weishampel, 2006; Brusatte et al., 2011; Schwimmer et al., 2015; Schwimmer, 2016).


Comparison of the Ellisdale and southeastern North American theropod tooth morphotypes.—Faunal provincialism, though discussed extensively for Laramidian assemblages (e.g., Lehman, 1997, 2001; Gates et al., 2010, 2012; Sampson et al., 2010; Vavrek and Larsson, 2010; Loewen et al., 2013; Sampson et al., 2013a, 2013b; Thomson et al., 2013; Lucas et al., 2016), has only recently been investigated in the eastern North Amer- ican fossil record of the Cretaceous (e.g., Schwimmer, 2016). As noted in the case of Laramidian assemblages, microfossil sites have the potential to inform studies of such biogeographic patterns among vertebrates (e.g., Sankey, 2008; Gates et al., 2010; Williamson and Brusatte, 2014), and the Ellisdale site is certainly of importance in testing for the presence of this phe- nomenon on Appalachia in revealing a northern Appalachian theropod fauna. In the southeastern United States, the remains of at least


three theropod dinosaur genera representing three different clades have been recovered from deposits of similar age as the Marshalltown Formation (75.7–71.2 Ma; Miller et al., 2004) at Ellisdale (Campanian, palynological data indicates an age range of 76.4–79.6 Ma; Denton and Tashjian, 2012): Appalachio- saurus montgomeriensis from the Demopolis Chalk (Middle Campanian; e.g., Ebersole and King, 2011) and, along with cf. Saurornitholestes langstoni, an additional indeterminate dromaeosaurid, and ornithomimosaurs, from the Coachman Formation of northern South Carolina and Dryptosaurus, ornithomimosaurs, and other small theropods from the tempo- rally equivalent and geographically nearby Tar Heel Formation of southern North Carolina (78.7–74.5 Ma; e.g., Self-Trail et al., 2004; Harris and Self-Trail, 2006; Schwimmer et al., 2015). The close proximity and equivalent age of the Tar Heel and Coachman show that the dinosaur fauna of the Carolinas during the Campanian represented a mixing of northern (e.g., Dryptosaurus) and southern (e.g., cf. Sauronitholestes lang- stoni, Appalachiosaurus montogomeriensis) forms in the formations (e.g., Schwimmer, 2016). The Tar Heel and Coachman formations’ theropod


assemblage share the presence of two tyrannosauroids, one Dryptosaurus-like and one Appalachiosaurus-like, and ornitho- mimosaurswith Ellisdale.However, the teeth fromthe Coachman Formation assigned to cf. Saurornitholestes langstoni are significantly smaller than the Ellisdale dromaeosaurid teeth included inmorphotype Aand, unlike the Ellisdale teeth included in morphotype B, have peg-like distal denticles with interdenti- cular sulci that project onto the crown surface (Schwimmer et al., 2015). Furthermore, teeth of possible dromaeosaurine origin (based on their curvature and large mesial denticles) reported from the Coachman Formation by Schwimmer et al. (2015) further distinguish that theropod fauna from that of Ellisdale.Overall, the differences between the theropod faunas of southeastern North


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190