Annals of Botany 123: 451–460, 2019 doi: 10.1093/aob/mcy170, available online at www.academic.oup.com/aob Cretaceous asterid evolution: fruits of Eydeia jerseyensis sp. nov. (Cornales) from the upper Turonian of eastern North America Brian A. Atkinson1,2,*, Camila Martínez3 and William L. Crepet3 1Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66044, USA, 2Biodiversity Institute and Museum of Natural History, University of Kansas, Lawrence, KS 66044, USA and 3L. H. Bailey Hortorium, Plant Biology Downloaded from https://academic.oup.com/aob/article/123/3/451/5096126 by guest on 28 September 2021 Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA *For correspondence. E-mail [email protected] Received: 21 March 2018 Returned for revision: 5 May 2018 Editorial decision: 13 August 2018 Accepted: 10 September 2018 Published electronically 13 September 2018 • Background and aims The asterids (>80 000 extant species) appear in the fossil record with considerable diversity near the Turonian–Coniacian boundary (~90 Ma; Late Cretaceous) and are strongly represented in the earliest diverging lineage, Cornales. These early asterid representatives have so far been reported from western North America and eastern Asia. In this study, we characterize a new cornalean taxon based on charcoalified fruits from the upper Turonian of eastern North America, a separate landmass from western North America at the time, and identify early palaeobiogeographical patterns of Cornales during the Cretaceous. • Methods Fossils were studied and imaged using scanning electron microscopy and micro-computed tomogra- phy (micro-CT) scanning. To assess the systematic affinities of the fossils, phylogenetic analyses were conducted using maximum parsimony. • Key results The charcoalified fruits are represented by tri-locular woody endocarps with dorsal apically open- ing germination valves. Three septa intersect to form a robust central axis. Endocarp ground tissue consists of two zones: an outer endocarp composed of isodiametric sclereids and an inner endocarp containing circum-locular fibres. Central vasculature is absent; however, there are several small vascular bundles scattered within the septa. Phylogenetic analysis places the new taxon within the extinct genus Eydeia. • Discussion Thick-walled endocarps with apically opening germination valves, no central vascular bundle and one seed per locule are indicative of the order Cornales. Comparative analysis suggests that the fossils represent a new species, Eydeia jerseyensis sp. nov. This new taxon is the first evidence of Cornales in eastern North America during the Cretaceous and provides insights into the palaeobiogeography and initial diversification of the order. Key words: Asterids, Cornales, core eudicots, Cretaceous, fossils, fruits, New Jersey, palaeobiogeography. INTRODUCTION charcoalified flowers, an abundance of ericalean taxa have been characterized from the uppermost Turonian of eastern Exceptionally well-preserved fossils recently recovered from North America (Nixon and Crepet, 1993; Crepet et al., 2013; Upper Cretaceous deposits (~100–66 Ma) have provided mean- Martínez et al., 2016). For much of the Late Cretaceous, North ingful advancements in our understanding of the initial diversifi- America was divided by the Western Interior Seaway, sepa- cation of major core eudicot clades, the asterids and rosids (e.g. rating two distinct landmasses, Laramidia (western half) and Friis et al., 2011, 2016; Atkinson, 2016, 2018; Martínez et al., Appalachia (eastern half). Abundant palaeontological data sug- 2016; Atkinson et al., 2018). The earliest known core eudicots gest that northern Laramidia was connected with eastern Asia are rosid flowers and infructescences from the middle Cretaceous during the Late Cretaceous (discussed in Farke et al., 2014). (~100 Ma) of North America (Basinger and Dilcher, 1984; Friis However, despite their strong representation at the Turonian– et al., 2016; Manchester et al., 2018). Asterids appear relatively Coniacian boundary, Cornales have not yet been recovered late in the fossil record, near the Turonian–Coniacian boundary from Appalachia and Ericales have not yet been recovered from (~90–89 Ma) (Takahashi et al., 2002; Martínez-Millán, 2010; Laramidia or Asia (see Atkinson et al., 2018 for a discussion Friis et al., 2011; Manchester et al., 2015; Atkinson et al., 2018), on early asterids). It appears that each order initially diversified indicating that the initial phase of core eudicot evolution was in separate geographical regions, suggesting early endemism. dominated by rosid taxa; however, this pattern could be due to In this study, we characterize a new asterid taxon based on reporting and sampling biases. 106 charcoalified fruits from the upper Turonian Old Crossman Turonian–Coniacian asterids are represented by the two Clay Pit locality. The morphology and anatomy of these fruits successive earliest-diverging lineages, Cornales and Ericales, are indicative of the order Cornales. Phylogenetic analyses respectively. A diversity of cornalean fruits are known from and their unique combination of characters indicates that they the lowermost Coniacian of Asia and western North America represent a new species, Eydeia jerseyensis sp. nov. Atkinson, (Takahashi et al., 2002; Atkinson et al., 2018). Based on Martínez et Crepet. This report corresponds to the first record © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: [email protected]. 452 Atkinson et al. — Cretaceous Cornales evolution of Cornales in Appalachia during the Cretaceous, and expands Facility, Corvallis, OR, USA). Micro-computed tomography their known geographical distribution at the time of their earli- (micro-CT) scanning was also used to view internal structure of est appearance in the fossil record. The early diversity and dis- the holotype fruit (CUPC 1601) and was conducted at Cornell tribution of the cornalean fossil record supports the hypothesis University on the Zeiss Versa 520, at 60 kV/5 W, using the ×4 that the asterids were diversifying alongside the rosids prior to objective and an LE3 filter. The data were reconstructed from the Coniacian (Atkinson et al., 2018). 1601 fluoroscopy exposures of 1 s. The voxel size was 3.71 µm. The program used to visualize the CT scan results was OsiriX 64 bit DICOM Viewer. Images were processed using Photoshop MATERIALS AND METHODS CS 5.0 (Adobe, San Jose, CA, USA). Palaeobiogeographical maps (Fig. 5) were obtained from Scotese (2001) and Colorado One hundred and six charcoalified fruits were recovered from Plateau Geosystems (2014). the Old Crossman Clay Pit locality, south of the Raritan River Downloaded from https://academic.oup.com/aob/article/123/3/451/5096126 by guest on 28 September 2021 in Sayreville, Middlesex County, NJ, USA (40°28’ N, 74°19′ W; Fig. 1). Geologically, this locality belongs to the South Phylogenetic analyses Amboy Fire Clay Member of the Raritan Formation (Fig. 1). The Raritan Formation is composed of four members, of which the With the addition of the taxon described in this study, the mor- upper one corresponds to the South Amboy Fire Clay Member phological data matrix generated by Atkinson (2018) using 59 (Christopher, 1979; Sirkin, 1991). This member consists of mas- taxa (25 fossil and 34 extant) and 77 characters was utilized as sive unconsolidated to laminated, dark grey clay, and contains the basis of the phylogenetic analyses using maximum parsimony lignitized plant fragments, charcoalified flowers, stems, wood and is available through MorphoBank (O’Leary and Kaufman, fragments, fruits, and small pieces of amber that may have inclu- 2012; Project P3236). Seven characters were deactivated to sions of plant or insect material (Sugarman et al., 2005; Grimaldi improve phylogenetic resolution (Atkinson, 2018). The matrix and Nascimbene, 2010). The unconsolidated clay-silt beds gener- was analysed with and without a constraint topology. For the con- ally occur in channels, and are commonly adjacent to cross-bed- straint topology six nodes, grouping modern clades known from ded, fine to medium quartz sands with thin carbonaceous layers molecular phylogenies (Xiang et al., 2011), were constrained: (Sugarman et al., 2005). One of the more prevalent hypotheses (1) Cornaceae + Alangiaceae; (2) Nyssaceae–Mastixiaceae– to explain the three-dimensional preservation at the cellular level Davidiaceae; (4) Hydrangeaceae; (5) Loasaceae; and (6) the of these charcoalified fossils is that wildfires converted plant Ericales outgroup. None of the fossil taxa was constrained for the remains to carbonized replicas that were buried in the forest leaf analysis. The phylogeny was estimated based on maximum par- litter (Grimaldi and Nascimbene, 2010; Friis et al., 2011). simony criteria using TNT (Goloboff, 1998) through Winclada The paucity of marine invertebrates in rocks from the version 1.99 (Nixon, 2015). In the TNT analyses, ten sets of 500 Cretaceous Atlantic Coastal Plain has prevented precise cor- iterations and 10 % perturbation of characters were used for the relations of the lithological units with zonations based on ratchet analysis (Nixon, 1999), and default values were used for marine organisms; therefore, age determinations have been drift, sectorial search and tree fusion. A strict consensus and a based primarily on palynology (Christopher,