PUBLISHED VERSION Macphail, Michael Keith; Carpenter, Raymond John; Iglesias, Ari; Wilf, Peter First evidence for Wollemi Pine-type pollen (Dilwynites: Araucariaceae) in South America, PLoS One, 2013; 8(7):e69281. © 2013 Macphail et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. PERMISSIONS http://www.plosone.org/static/license Open-Access License No Permission Required PLOS applies the Creative Commons Attribution License (CCAL) to all works we publish (read the human-readable summary or the full license legal code). Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, and/or copy articles in PLOS journals, so long as the original authors and source are cited. 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For queries about the license, please contact us. 1st October 2013 http://hdl.handle.net/2440/80041 First Evidence for Wollemi Pine-type Pollen (Dilwynites: Araucariaceae) in South America Mike Macphail1*, Raymond J. Carpenter2, Ari Iglesias3,4, Peter Wilf5 1 Department of Archaeology and Natural History, College of Asia and the Pacific, Australian National University, Canberra, Australian Capital Territory, Australia, 2 School of Earth and Environmental Sciences, University of Adelaide, South Australia, Australia, 3 Divisio´n Palaeobota´nica, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, La Plata, Argentina, 4 Consejo Nacional de Investigaciones Cientı´ficas y Te´cnicas, Argentina, 5 Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, United States of America Abstract We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Ma´rquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America. Citation: Macphail M, Carpenter RJ, Iglesias A, Wilf P (2013) First Evidence for Wollemi Pine-type Pollen (Dilwynites: Araucariaceae) in South America. PLoS ONE 8(7): e69281. doi:10.1371/journal.pone.0069281 Editor: Lee A. Newsom, The Pennsylvania State University, United States of America Received March 13, 2013; Accepted June 7, 2013; Published July 19, 2013 Copyright: ß 2013 Macphail et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: Funding provided by NSF DEB-0919071 to PW and AI. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: [email protected] Introduction the morphospecies that most closely resembles modern Wollemia pollen, can be traced back as far as the Turonian Age (89.8 to The Southern Hemisphere monkey-puzzle tree family, Arau- 93.9 Ma) of the Late Cretaceous [11–13]. So far, Dilwynites has cariaceae, was long believed to comprise two living genera: been identified in Paleogene to Neogene deposits of western, Araucaria Juss., with about 19 species endemic to the southwest central, and northern Australia (references in [14]), in Cretaceous Pacific and South America, and Agathis Salisb., with about 20 to Neogene deposits of New Zealand [15], and in late Eocene species distributed from Sumatra to New Zealand but absent in deposits of East Antarctica [16]. However, apart from a possible South America. Remarkably, a third araucarian genus was record from the Paleogene of Seymour Island [17], no Dilwynites discovered in 1994 in New South Wales, Australia, whose sole pollen has previously been recognized from West Gondwana. species is Wollemia nobilis W.G. Jones, K.D. Hill & J.M. Allen, Since 2000, the first author has also recognized that at least one common name Wollemi Pine [1]. species of Agathis produces pollen that is morphologically consistent With fewer than 40 adult specimens known to survive in the with Dilwynites, and thus the nearest extant relatives of the plants wild, W. nobilis is one of the world’s rarest trees. Adding to the that produced Dilwynites pollen are best regarded as both Wollemia spectacular nature of the discovery was the location of the stands, and Agathis (e.g., [14]). This observation is consistent with the in a remote gorge within 150 km of Sydney, Australia’s largest results of many recent molecular studies indicating that Wollemia city; the large stature of the trees (up to 40 m tall); and the and Agathis are sister taxa [18–23], along with several character- apparent similarity of the foliage to that of the Jurassic species istics of the seed cones of the two genera that may be ‘‘Agathis’’ jurassica M.E. White [2] and the Cretaceous to early Cenozoic genus Araucarioides [3–6]. So far, none of the similar synapomorphic, especially the condition of the seeds being winged macrofossils has been convincingly demonstrated to belong to and nearly free from the fused bract and scale [24]. By contrast, in Wollemia [6,7], and indeed ‘‘A.’’ jurassica differs from foliage of Araucaria, the seeds are embedded in the bract/scale complex. Wollemia in details of venation, leaf arrangement and leaf shape We here present microfossil evidence that araucarians produc- [8]. However, the presumed close relationship quickly led to W. ing Dilwynites pollen were growing in southern Patagonia during nobilis being given the status of a ‘‘living fossil from the age of the late Paleocene to early middle Eocene. This discovery greatly dinosaurs’’ in the popular press (e.g. [9]). augments evidence for the past range of Wollemia and/or Agathis In contrast, once pollen was made available, it was quickly conifers that produce this pollen type and adds to the growing recognized that the Wollemia clade had a well-established fossil paleobotanical evidence for extensive trans-Antarctic interchange history provided by the morphogenus Dilwynites W.K. Harris [10], between Patagonia and Australia during the globally warm early comprising D. granulatus W.K. Harris and D. tuberculatus W.K. Paleogene. Harris [6,11,12]. For example, in southern Australia, D. granulatus, PLOS ONE | www.plosone.org 1 July 2013 | Volume 8 | Issue 7 | e69281 South American Dilwynites Figure 1. Map of study area. The new fossil plant locality occurs along the Rı´o Zeballos (arrow, star) in Santa Cruz Province, Argentina. Also shown is the previously reported type locality of the Ligorio Ma´rquez Formation [26], the Ligorio Ma´rquez coal mine in XI Regio´n, Chile. doi:10.1371/journal.pone.0069281.g001 Geological Setting and Age Control Ligorio Ma´rquez Basin) that subsequently was uplifted by compressional Andean tectonic activity during and since the early Ethics Statement Miocene [28,29]. The material studied here was derived from a All necessary permits were obtained for the described study, ,0.5 m thick carbonaceous shale bed containing abundant fossil which complied with all relevant regulations. Permits were issued leaves (under separate study), from a probable coastal swamp. by the Secretarı´a de Estado de Cultura de la Provincia de Santa The local exposure of the Ligorio Ma´rquez Formation lies Cruz, Argentina. unconformably above the Cretaceous Rı´o Tarde Formation and is The Dilwynites specimens reported here came from an isolated, itself overlain unconformably by marine rocks of the Centinela newly recognized, streamcut outcrop of the Ligorio Ma´rquez Formation [30–32]. Stratigraphic correlation of the fossil locality is Formation in Santa Cruz Province, Patagonia, Argentina, located extremely difficult due to limited outcrop area and local cover. All along the Rı´o Zeballos and 36 km south-southwest of the town of radioisotopic ages listed below are as originally reported and Los Antiguos (Fig. 1). Precise locality data are available on request would need recalibration with new constants and reanalyses with from AI, PW, or Museo Padre Jesu´s Molina, Rı´o Gallegos, Santa updated methods for any detailed analysis. Cruz, Argentina (MPM), where material is stored. The Ligorio 40K/39Ar dates derived from ash beds at the top of the Rı´o Ma´rquez Formation, previously studied only on the Chilean side Tarde Formation at Lago Posadas (100 km south of our study of the nearby border [25–27], comprises a sequence of coastal area) were 97.163.8 and 99.165.6 Ma [33].