Cretaceous Research 57 (2016) 199e207 Contents lists available at ScienceDirect Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes A ceratopsian dinosaur from the Late Cretaceous of eastern North America, and implications for dinosaur biogeography Nicholas R. Longrich Department of Biology and Biochemistry and Milner Centre for Evolution, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom article info abstract Article history: Tyrannosaurs and hadrosaurs from the Late Cretaceous of eastern North America (Appalachia) are Received 5 May 2015 distinct from those found in western North America (Laramidia), suggesting that eastern North America Received in revised form was isolated during the Late Cretaceous. However, the Late Cretaceous fauna of Appalachia remains 12 July 2015 poorly known. Here, a partial maxilla from the Campanian Tar Heel Formation (Black Creek Group) of Accepted in revised form 11 August 2015 North Carolina is shown to represent the first ceratopsian from the Late Cretaceous of eastern North Available online 12 September 2015 America. The specimen has short alveolar slots, a ventrally projected toothrow, a long dentigerous process overlapped by the ectopterygoid, and a toothrow that curves laterally, a combination of char- Keywords: Dinosauria acters unique to the Leptoceratopsidae. The maxilla has a uniquely long, slender and downcurved pos- Neoceratopsia terior dentigerous process, suggesting a specialized feeding strategy. The presence of a highly specialized Leptoceratopsia ceratopsian in eastern North America supports the hypothesis that Appalachia underwent an extended Appalachia period of isolation during the Late Cretaceous, leading the evolution of a distinct dinosaur fauna Black Creek group dominated by basal tyrannosauroids, basal hadrosaurs, ornithimimosaurs, nodosaurs, and leptocer- atopsids. Appalachian vertebrate communities are most similar to those of Laramidia. However some taxa-including leptoceratopsids-are also shared with western Europe, raising the possibility of a Late Cretaceous dispersal route connecting Appalachia and Europe. © 2015 Published by Elsevier Ltd. 1. Introduction duckbills, ceratopsids (Xu, Wang, Zhao, & Li, 2010b), leptocer- atopsids (Ryan, Evans, Currie, Brown, & Brinkman, 2012), pachy- During the Late Cretaceous, a shallow inland sea, the Western cephalosaurids (Longrich, Sankey, & Tanke, 2010) and Interior Seaway, extended from the Gulf of Mexico to the Arctic ankylosaurids (Sullivan, 1999) show the same. These patterns show Ocean, splitting North America in two. The resulting land masses- that a high-latitude land corridor joined North America and Asia in Laramidia in the west, and Appalachia in the east-each developed the Late Cretaceous (Russell, 1993), with extensive dispersal be- distinct dinosaurian faunas (Fig. 1). tween the two continents. In the Maastrichtian, the appearance of Late Cretaceous dinosaurs from Laramidia (Weishampel et al., titanosaurs (D'Emic, Wilson, & Thompson, 2010) and large alethi- 2004) show close affinities with the dinosaurs of Asia and to a nophidian snakes (Longrich, Bhullar, & Gauthier, 2012) in Laramidia lesser degree, South America. Among theropods, North America's and saurolophines (Prieto-Marquez, 2010) and multituberculate tyrannosaurids (Brusatte, Benson, & Norell, 2011), alvarezsaurs mammals (Kielan-Jaworowska, Cifelli, & Luo, 2004) in South (Longrich & Currie, 2009a), caenagnathids (Longrich, Barnes, Clark, America indicates dispersal between Laramidia and South America, & Millar, 2013), microraptorines (Longrich & Currie, 2009b) and either via a land bridge or across a narrow ocean channel or ornithomimids (Xu et al., 2011) all have relatives in Asia. Among archipelago. ornithischians, saurolophine (Godefroit, Bolotsky, & Lauters, 2012) The Late Cretaceous dinosaurs of Appalachia are highly distinct and hadrosaurine (Prieto-Marquez, Chiappe, & Joshi, 2012) from those seen in Laramidia, however. While Laramidia is domi- nated by Tyrannosauridae (Weishampel et al., 2004), Appalachia is dominated by basal tyrannosauroids such as Dryptosaurus and & Abbreviations: AMNH, American Museum of Natural History, New York; NMC, Appalachisaurus (Brusatte et al., 2011; Carr, Williamson, Britt, National Museum of Canada, Ottawa; YPM-PU, Yale Peabody Museum, Princeton Stadtman, 2011). Similarly, while Laramidia is dominated by lam- University Collections. beosaurine and saurolophine hadrosaurs (Weishampel et al., 2004), E-mail address: [email protected]. http://dx.doi.org/10.1016/j.cretres.2015.08.004 0195-6671/© 2015 Published by Elsevier Ltd. 200 N.R. Longrich / Cretaceous Research 57 (2016) 199e207 Fig. 1. Distribution of Leptoceratopsidae and possible dispersal routes: (1), Udanoceratops and Zhuchengceratops (Eastern Asia) (Kurzanov, 1992; Xu, Wang, Zhao, Sullivan, & Chen, 2010a), (2), Leptoceratops, Montanoceratops, Gryphoceratops, Unescoceratops and cf. Prenoceratops (Alberta) (Brown, 1914; Makovicky, 2010; Miyashita, Currie, & Chinnery-Allgeier, 2010; Ryan et al., 2012); (3) Montanoceratops, Prenoceratops, Cerasinops, and Leptoceratops (Brown, 1942; Chinnery & Horner, 2007; Ott, 2007)(Miyashita et al., 2010) (Montana); (4) Black Creek ceratopsian (this paper); (5) Kristianstaad ceratopsian (Sweden) (Lindgren et al., 2007); (6) Craspedodon lonzeensis (Belgium) (Godefroit & Lambert, 2007). in Appalachia hadrosaurine-grade hadrosaurs such as Hadrosaurus Ornithischia Seeley 1888. and Lophorhoton (Prieto-Marquez et al., 2012) dominate. These Ceratopsia Marsh 1890. patterns suggest that Appalachia saw an extended period of isola- Leptoceratopsidae Nopsca 1923 tion beginning in the Late Cretaceous, becoming an island conti- Leptoceratopsidae sp. nent with an endemic fauna, similar to Australia in the Cenozoic. Unfortunately, our knowledge of Appalachian dinosaurs re- 2.1. Material mains limited (Schwimmer, 1997; Weishampel et al., 2004), with only tyrannosauroids (Brusatte et al., 2011), hadrosaurids (Prieto- YPM-PU (Yale Peabody Museum, Princeton University collec- & Marquez, Weishampel, Horner, 2006), ornithomimosaurs tion) 24964, posterior end of a left maxilla (Fig. 2). (Russell, 1972) and nodosaurs (Langston, 1960) known from the eastern United States. The discovery of new dinosaurs from eastern North America is therefore of great interest to understanding the 2.2. Locality and horizon Appalachian fauna and its origins. Recently, an unusual dinosaur specimen from the Campanian Clifton Farm, Giddensville, Sampson County, North Carolina Black Creek Group of North Carolina (Fig. 1) was identified in Yale (Fig. 2). The same locality has produced a theropod tooth, probably University's Peabody Museum collections. The specimen consists of from a tyrannosauroid (YPM PU 23197), and teeth and scutes of the the posterior end of a left maxilla. Although originally identified giant crocodilian Deinosuchus rugosus (YPM-PU 23429). Although and catalogued as a hadrosaur, the specimen shows apomorphies of the collection is very limited, marine vertebrates such as mosa- the Ceratopsia and specifically the Leptoceratopsidae. This spec- saurs, bothremydid turtles and sharks, which are abundant in the imen is the first ceratopsian known from the Late Cretaceous period nearby Phoebus Landing locality (Miller, 1967) were not collected of eastern North America. from the locality, suggesting a freshwater or estuarine depositional environment. Provenance data for the specimen identify it as from the “Black 2. Systematic paleontology Creek Formation”. The Black Creek Formation has since been raised to the level of group, containing three formations (Fig. 3); from Dinosauria Owen 1842. bottom to top, these are the Tar Heel, Bladen, and Donoho Creek N.R. Longrich / Cretaceous Research 57 (2016) 199e207 201 Fig. 2. Map showing outcrops of Upper Cretaceous Black Creek Group and Peedee Formation strata, and the locality of the Black Creek ceratopsian. The specimen comes from the Clifton Farm locality, south of Giddensville, Sampson County, N 35.13, W 78.22. The lower Campanian Tar Heel Formation outcrops in this area. Map after Owens and Sohl (Owens & Sohl, 1989); stratigraphic column after Harris and Self-Trail (Harris & Self-Trail, 2006). Note that the position of the specimen in the Tar Heel is currently unconstrained. formations. Maps of outcrop (Owens & Sohl, 1989) put the Clifton depending on the model used (Harris & Self-Trail, 2006). Farm locality in the Tar Heel Formation. The Tar Heel was deposited A nearby assemblage from the Tar Heel, Phoebus Landing on the during the early Campanian (Harris & Self-Trail, 2006; Mitra & Cape Fear River, has produced hadrosaurids, a possible ornitho- Mickle, 2007); previous dates, based on strontium isotopes, suggest mimosaur, and a diverse fauna of freshwater and marine verte- an age of 82.3e73.4 Ma or 74.5e82.6 Ma for the formation, brates (Miller, 1967). Recent work on Phoebus Landing suggests Fig. 3. Black Creek ceratopsian, YPM-PU 24964, left maxilla. A, medial, B, ventral, C, lateral, D, dorsal view. Abbreviations: ag, alveolar groove; dp, dentigerous process. 202 N.R. Longrich / Cretaceous Research 57 (2016) 199e207 that the dinosaurs date to 77.1e78.5 Ma (Self-Trail, Christopher, this skull shape is characteristic of basal Neoceratopsia (You & Prowell, & Weems, 2004), the middle of the Campanian. Dodson, 2004). The process is rugose laterally, but there is a smooth dorsal facet 2.3. Description where the pterygoid would have dorsally overlapped the maxilla; pterygoid overlap of the