Hironoia Fusiformis Gen. Et Sp. Nov.; a Cornalean Fruit from the Kamikitaba Locality (Upper Cretaceous, Lower Coniacian) in Northeastern Japan
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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/10907742 Hironoia fusiformis gen. et sp. nov.; a cornalean fruit from the Kamikitaba locality (Upper Cretaceous, Lower Coniacian) in northeastern Japan Article in Journal of Plant Research · January 2003 DOI: 10.1007/s10265-002-0062-6 · Source: PubMed CITATIONS READS 56 258 3 authors: Masamichi Takahashi Peter R. Crane Niigata University Oak Spring Garden Foundation 85 PUBLICATIONS 1,696 CITATIONS 282 PUBLICATIONS 18,235 CITATIONS SEE PROFILE SEE PROFILE Steven R Manchester Florida Museum of Natural History 300 PUBLICATIONS 10,149 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Investigation of fossil flora from the Deccan Intertrappean Beds of India View project Cretaceous Angiosperms Hunting View project All content following this page was uploaded by Steven R Manchester on 06 June 2014. The user has requested enhancement of the downloaded file. Journal of Plant Research DOI 10.1007/s10265-002-0062-6 Original Article Hironoia fusiformis gen. et sp. nov.; a cornalean fruit from the Kamikitaba locality (Upper Cretaceous; Lower Coniacian) in northeastern Japan Masamichi Takahashi( ) · Peter R. Crane · Steven R. Manchester M. Takahashi Department of Environmental Sciences, Faculty of Science, Niigata University, Ikarashi, Niigata City, 950-2181 Japan P.R. Crane Royal Botanic Gardens, Kew, Richmond, Surrey, UK S.R. Manchester Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA E-mail: [email protected] Phone: +81-25-2626991 Fax: +81-25-2626991 Received: 17 June 2002 / Accepted: 30 August 2002 / Published online: Abstract. The application of sieving techniques to bulk samples from the Ashizawa Formation, Futaba Group (Lower Coniacian) of northeastern Honshu, Japan, has yielded well-preserved mesofossil assemblages comparable with those recently described from eastern North America, Europe, and central Asia. Among the most abundant and distinctive components of these assemblages are fusiform fruits that are assigned here to a new genus and species, Hironoia fusiformis gen. et sp. nov. The fruits developed from an epigynous ovary with three to four locules. Each locule bears one seed and has a distinctive dorsal germination valve. These features of the fruit, along with the adnate calyx, indicate an affinity to extant Cornales and specifically the Cornaceae sensu lato. The recognition of an unequivocal cornalean fruit in the Early Coniacian-Early Santonian of Japan provides the earliest record of this group in the fossil record. It also establishes a minimum age for the early divergence of the asterid clade, a major group of living angiosperms comprising more than a third of all species of extant flowering plants. - 1 - Keywords. Angiosperms - Ashizawa Formation - Cornales - Futaba Group - Hironoia fusiformis gen. et sp. nov. - Japan Introduction Over the last 15 years studies of the early fossil history of flowering plants have been revolutionized by the discovery of abundant small, well-preserved and systematically informative fossil flowers, fruits and seeds from Cretaceous sediments. These specimens have yielded spectacular, new information relating to the early diversification of many lineages of extant angiosperms, and have provided new insights into the evolution of angiosperm pollination and dispersal biology (Crane et al. 1995). Most of these new data have been based on mesofossil assemblages discovered in eastern North America and Europe (e.g., Friis 1983, 1984; Knobloch and Mai 1984, 1986; Crane et al. 1994, 1995). Recently, however, similar mesofossil assemblages have been recognized in Kazakhstan, central Asia (Frumin and Friis 1996, 1999), and also from the Futaba Group (Early Coniacian-Early Santonian) of northeastern Japan (Takahashi et al. 1999a, b, 2001). In parallel with these paleobotanical advances, our understanding of phylogenetic relationships among extant angiosperms has steadily improved through combined analyses of morphological and molecular data (often several genes) for many taxa (Soltis et al. 1999). The increased resolution of natural monophyletic groups among extant angiosperms provides an improved framework for the use of fossils to establish the age and former geographic distribution patterns of angiosperm clades. The Cornales, now identified as the earliest diverging lineage of a major clade of angiosperms - the asterids - are one of many groups of angiosperms in which patterns of evolution are becoming much better understood as a result of integrated neobotanical and paleobotanical investigations. In this paper we describe a new fossil representative of the Cornaceae sensu lato, which is the earliest published record of this family. This material contributes a new species to the very small number of fossil angiosperm reproductive structures so far described from the Late Cretaceous of Japan (Stopes and Fujii 1910; Nishida 1985, 1991, 1994; Takahashi et al. 1999a, b, 2001), and provides important new information on the time of diversification of the asterid clade. Materials and methods Plant mesofossils were isolated from two sets of bulk samples collected 1998-2001 in the Futaba Group exposed in northeastern Honshu, Japan. The samples that yielded the fossils described here (collection F16) comprised a poorly sorted carbonaceous black sandy siltstone collected at the Kamikitaba locality along a tributary at the Kitaba River, Hirono-machi, Fukushima Prefecture, northeastern Japan (study Route B of Ando et al. 1995; 37°12 N, 140°57 E). These samples were from the Asamigawa Member of the Ashizawa Formation, which comprises the lowermost sediments in the Futaba Group. About 90 specimens of fusiform fruits were examined. Other levels in the Futaba Group were also sampled and have yielded mesofossil assemblages that lack the characteristic fruits described in this paper. The Futaba Group is a fluvial to shallow marine sedimentary succession that occurs in the southern Abukuma Belt in northeast Japan close to the Pacific Coast of Honshu (Ando et al. 1995). In the north it unconformably overlies the Early Cretaceous Abukuma granite, while in the south it rests unconformably on the shales of the Permian Takakurayama Group. It is overlain by Tertiary sediments (Ando 1997). Based on the occurrence of Lower Coniacian ammonites and inoceramids, the age of the Futaba Group is thought to range from Early Coniacian to Early Santonian. The age of the plant-bearing sediments in the Asamigawa Member is probably Early Coniacian (ca. 89 million years B.P., Gradstein et al. 1995). - 2 - The dispersed palynoflora from the Futaba Group has been described by Miki (1977) and Takahashi (1988). Three samples from the Ashizawa Formation were studied by Miki (1977). Conifer pollen dominated all of the samples with taxodiaceous and podocarpaceous-pinaceous (saccate) grains predominating. Putative araucariaceous pollen also occurred in some samples; and Classopollis (extinct Cheirolepidiaceae) was also consistently present at low levels. Pollen of angiosperms, pteridophytes and presumed cycads, Bennettitales, Ginkgo, and Gnetales were also significant in these palynofloras. Knowledge of the flora of the Futaba Group has recently been expanded significantly by the discovery of mesofossil assemblages have been recovered from the Futaba Group (Takahashi et al. 1999a, 1999b, 2001), which have yielded a rich assemblage of angiosperms, gymnosperms, and pteridophytes, including both reproductive structures and vegetative remains. Bulk samples were dried, disaggregated in water, and sieved through a 125-µm mesh. The residual carbonaceous debris was then cleaned in hydrofluoric and hydrochloric acids, rinsed in water, and dried in air. Individual specimens were then separated under the dissecting microscope. Some of the specimens were frozen in absolute ethanol with liquid nitrogen and fractured on a TF-1 chamber. Specimens selected for scanning electron microscopy were mounted on polished aluminum scanning electron microscope stubs, sputter coated with platinum-palladium, and examined in a Hitachi S-800 field emission scanning electron microscope (FE-SEM). All specimens illustrated in this article are deposited in the paleobotanical collections of the Department of Geology and Paleontology, National Science Museum (NSM-PP), Tokyo, 169-0073 Japan. Systematic description Class Magnoliopsida Order Cornales Family Cornaceae sensu Eyde (1988) Genus Hironoia gen. nov. See Figs. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38.. Diagnosis. Fruit fusiform, developed from an epigynous flower. Perianth attached just above the broadest part of the fruit with free, short, triangular to ovate tepals. Ovary extending beyond the perianth and tapering to a single narrow style. Ovary also narrowing at the base into a slender stalk. Fruit thick-walled, composed mainly of fibers, with three or four locules each containing one pendulous seed. Each locule opening by a single dorsal valve that often becomes detached first at the apex of the ovary. Type species. Hironoia fusiformis sp. nov. Etymology. The genus name Hironoia refers to the town of Hirono, which is located close to the site where the fossils were collected. - 3 - - 4 - Figs. 1-9. Hironoia fusiformis gen. et sp. nov., Kamikitaba assemblage, Asamigawa Member,