Koll et al.—Gigantopteridium and Cathaysiopteris taxonomy
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thorough evaluation of Cathaysian G. huapingense and C. whitei is necessary to fully understand the global distribution and biogeographical relationships of these genera.
Acknowledgments
Figure 5. Gigantopteridium high order venation diagrams: (1) Gigantopteridium americanum, showing multiple branched tertiary veins and prominent intersecondary suture vein; (2) Gigantopteridium yochelsonii, showing typically unbranched tertiary veins and false suture; (3) Gigantopteridium utebaturianum n. sp., showing dichotomously branched tertiary veins and weak intersecondary suture vein.
venation in G. yochelsonii may have contributed to its earlier classification as a different genus, but overlapping in some traits with species of Gigantopteridium. This combination of lumping and splitting went so far as to lead to the suggestion of inter- generic hybrids, when, in fact, it appears that there was a set of three distinct, morphologically “adjacent” species. The primary distinguishing characters of each of the three species are subtle, most importantly in the: (1) angle of insertion of secondary and tertiary venation; (2) degree of tertiary branching; and (3) strength, or lack thereof, of a suture vein (Fig. 5 and Table 1). The more robust and obvious characters of leaf shape and the herringbone pattern have, understandably, caused the finer fea- tures to be rather overlooked until such time as it was possible to amassmany specimens from each species and examine them side by side. It is important to note that the variability in the highest order of venation was acknowledged in the original diagnosis of Cathaysiopteris yochelsonii by Mamay (1986), who stated that there appeared to be some overlap of characters between theNorth American Gigantopteridiumand Cathaysiopteris species possibly indicating the presence of an intermediate form. The evidence compiled in this study does not support the interpretation of Gigantopteridium utebaturianum n. sp. as an intermediate form between two genera, but suggests, rather, a separate, although related entity within a single genus. Fossil evidence supports a generic-level biogeographical
connection between Cathaysia and equatorial Pangea for Zeilleropteris, Gigantopteridium, Gigantonoclea,and Eupar- yphoselis. The case for Gigantopteridium, as discussed above, remains in some doubt. Similarly, although Gigantonoclea has been described from both regions, the known U.S. specimens are tiny scraps showing only ultimate venation. No attributes of leaf architecture are known for American specimens, and thus the possibility remains that these may not actually be congeneric with Chinese material. The transfer of G. yochelsonii from Cathaysiopteris to Gigantopteridium following the results of this study of North American Gigantopteridium taxonomy indicates endemism of Cathaysiopteris in Cathaysia and disjunction in global distributions of these genera. The comparison of previously diagnosed Pangean and Cathaysian species leads us to question the previously inferred connection between the two regions for both Cathaysiopteris and Gigantopteridium,however more
We are grateful to D. Chaney (Smithsonian Institute) for his support, patience, and expertise conducting fieldwork, mana- ging collection specimens, and for sharing his knowledge of the study region. We also wish to thank S. Simon (Dalhousie University) for her assistance during field collection and for her insight into the sedimentology of the study region. We are deeply indebted to the property owners involved with this study for allowing permission to access exposures. We also wish to acknowledge the scientists and private individuals who have contributed to amassing of theUSNMcollection, without whom this study would not have been possible, including but not limited to: C.B. Read, S. Mamay, A. Watt, N. Hotton III, E.C. Olson, R. Hook, D. Gregg, K. Craddock, and J. Nelson. We thank Dr. S. Mcloughlin (NRM) for providing images of Cathaysiopteris whitei from Halle (1927) specimens, which permitted a clearer understanding of currently diagnosed morphologic features. We thank H. Wang (FLMNH) for his help with accessing the Chinese literature. This work was supported by the American Philosophical Society through the Lewis and Clark Fund for Exploration and Field Research.
References
Booi, M., Van Waveren, I.V., and Van Konijnenburg-Van Citert, J.H.A., 2009, The Jambi gigantopterids and their place in gigantopterid classification: Botanical Journal of the Linnean Society, v. 161, p. 302–328.
Burago, V., 1986, The problem of the Angarian and Cathaysian Kingdom boundary, in Zakharov, W.D., and Onoprienko, Y.I., ed., Permian–Triassic events during the evolution of north-east Asia biota: Vladivostok, Russia, Far Eastern Scientific Centre, USSR Academy of Science, 128 p.
DiMichele, W.A., Looy, C.V., and Chaney, D.S., 2011, A new species of gigantopterid from the Middle Permian of the United States and China and its relevance to the gigantopterid concept: International Journal of Plant Sciences, v. 172, p. 107–119.
Glasspool, I.J., Hilton, J., Collinson, M.E., Wang, S. J., and Cheng-Sen, L., 2004, Foliar physiognomy in Cathaysian gigantopterids and the potential to track Palaeozoic climates using an extinct plant group: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 205, p. 69–110.
Gu, and Zhi, eds. (= Institute of Geology and Palaeontology and the Institute of Botany, Academia Sinica), 1974, Palaeozoic plants from China: Fossil Plants of China, 1: Beijing, Science Press, p. 1–226. [in Chinese]
Halle, T.G., 1927, Paleozoic plants from Central Shansi: Palaeontologica Sinica, v. 2, p. 1–316.
Hentz, T.F., and Brown, L.F., Jr., 1987, Wichita Falls-Lawton Sheet in Bureau of Economic Geology Geologic Atlas of Texas The University of Texas at Austin, scale 1:250,000.
Koidzumi, G., 1936, The Gigantopteris flora: Acta Phytotaxonomica et Geobotanica, v. 5, p. 130–139.
Koidzumi, G., 1934, Notes on Gigantopteris flora: Acta Phytotaxonomica et Geobotanica, v. 3, p. 112–114.
Kawasaki, S., 1934, The flora of the Heian System: Bulletin of the Geological Survey of Chosen (Korea), v. 6, p. 47–311.
Kon’no, E., and Asama, K., 1970, On the Gigantopteris flora: Acta Phytotax- onomica et Geobotanica, v. 5, p. 130–144.
Li, X., and Yao, Z-Q., 1983, Current studies of gigantopterids: Palaeontologia Cathayana, v. 1, p. 309–326.
Liu, L-J., and Yao, Z-Q., 1992, On venation of Emplectopteridium alatum Kawasaki: Acta Palaeontologica Sinica, v. 31, p. 646–656.
Liu, L-J., and Yao, Z-Q., 2002, Comparison in leaf architecture between Chinese and American species of Gigantopteridium: Acta Palaeontologica Sinica, v. 41, p. 322–333.
Mamay, S.H., 1960, Gigantopteridaceae in Permian floras of the southwestern United States: USGeological Survey Professional Paper, v. 400-B, p. B380.
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