The Botanical Review

, 70:121 | Cite as

Two new petrified cycad stems,Brunoa gen. nov. andWorsdellia gen. nov., from the Cretaceous of Patagonia (Bajo de Santa Rosa, Río Negro Province), Argentina

  • Analía E. Artabe
  • Alba B. Zamuner
  • Dennis Wm. Stevenson

Abstract

Polyxylic columnar stems covered by persistent leaf bases and found in sediments assignable to the Upper Cretaceous of Bajo de Santa Rosa, Río Negro Province, Argentina, are described as two new generic entities in the Cycadales. Anatomical characters are the basis for their being assigned to the Encephalartoideae of the Zamiaceae.Brunoa santarrosensis gen. et sp. nov. is characterized by the presence of polyxyly, cone domes, mucilage cavities, and uniseriate to triseriate araucaroid, scalariform, or bordered intervascular pitting.Worsdellia bonettiae gen. et sp. nov. has polyxyly, anastomosing medullary vascular bundles, centripetal xylem, mucilage canals, and concentric extraxylary bundles. Some characters (polyxyly, medullary vascular bundles, and cone domes) were used to determine the systematic position, while other characters (mucilage reservoirs and centripetal xylem) were used to establish the relationship between polyxylic and monoxylic forms.

Literature Cited

  1. Andreis, R. 1996. The Cretaceous-Tertiary boundary around the Somuncurá Massif (northern Patagonia, Argentina): Considerations about the Los Alamitos and Allen Formations. News of the First Annual Conference of IGCP Project 381 (SAMCI), Salvador, Bahia, Brazil 5: 12–14.Google Scholar
  2. E. Ancibor, S. Archangelsky, A. E. Artabe, J. Bonaparte &J. Genise. 1991. Asociación de vegetales y animales del Cretácico tardio del norte de la Patagonia. Ameghiniana 28(1–2): 201–202.Google Scholar
  3. Archangelsky, S. &D. Brett. 1963. Studies on Triassic fossil plants from Argentina, II.Michelilloa waltonii nov. gen. et sp. from the Ischigualasto Formation. Ann. Bot. 27: 147–154.Google Scholar
  4. Artabe, A. E. 2001. The fossil Cycadales of Argentina. Savitriana 1: 1–26.Google Scholar
  5. D. W. Stevenson. 1999. Fossil Cycadales of Argentina. Bot. Rev. 65: 219–238.Google Scholar
  6. -& A. B. Zamuner. 1999. A new cycad stem from the Upper Cretaceous of Patagonia, Argentina. Boletim do 5° Simposio o Cretáceo do Brasil, UNESP, Campus de Rio Claro/SP: 309–313.Google Scholar
  7. Ash, S. 1985. A short thick cycad stem from the Upper Triassic of Petrified Forest National Park, Arizona and vicinity. Museum of Northern Arizona Bulletin 54: 17–32.Google Scholar
  8. Cantrill D. J. 2000. A petrified cycad trunk from the Late Cretaceous of the Larsen Basin, Antarctica. Alcheringa 24: 307–318.CrossRefGoogle Scholar
  9. Chamberlain, C. J. 1909.Dioon spinulosum. Bot. Gaz. 48: 401–413.CrossRefGoogle Scholar
  10. —. 1911. The adult cycad trunk. Bot. Gaz. 52: 81–104.CrossRefGoogle Scholar
  11. Crane, P. R. 1988. Major clades and relationships in “higher” gymnosperms. Pp. 218–272in C. B. Beck (ed.), Origin and evolution of gymnosperms. Columbia Univ. Press, New York.Google Scholar
  12. Dorety, H. 1909. The extrafascicular cambium ofCeratozamia. Bot. Gaz. 47: 150–152.CrossRefGoogle Scholar
  13. Gould, R. E. 1971.Lyssoxylon grigsbyi, a cycad trunk from the Upper Triassic of Arizona and New Mexico. Amer. J. Bot. 58: 239–248.CrossRefGoogle Scholar
  14. Greguss, P. 1968. Xylotomy of the living cycads, with a description of their leaves and epidermis. Akademiai Kiadó, Budapest.Google Scholar
  15. Hill, K. D., D. W. Stevenson &R. Osborne. 2004. The world list of cycads. Bot. Rev. 70(2): 274–298.CrossRefGoogle Scholar
  16. Jain, K. P. 1962.Fascivarioxylon mehtae gen. et sp. nov., a new petrified cycadean wood from the Rajmahal Hills, Bihar, India. The Palaeobotanist 11: 138–143.Google Scholar
  17. Johnson, L. A. S. 1959. The families of cycads and the Zamiaceae of Australia. Proc. Linn. Soc. N. S. W. 84: 64–117.Google Scholar
  18. Lutz, A. & A. Crisafulli. 1998. Lenos de Cycadales de la Formación La Temera (Triásico Superior), Chile. Resümenes 7° Congreso Argentino de Paleontologia y Bioestratigrafía, Bahía Bianca: 9.Google Scholar
  19. Mamay, S. H. 1969. Cycads—Fossil evidence of Late Paleozoic origin. Science 164 (3877): 295–296.PubMedCrossRefGoogle Scholar
  20. — 1976. Paleozoic origin of the cycads. U.S. Geological Survey Professional Paper 934: 1–48.Google Scholar
  21. Nishida, H., M. Nishida &K. Tanaka. 1991. Petrified plants from the Cretaceous of the Kwanto Mountains, central Japan, [II. A polyxylic cycadean trunk,Sanchucycas gigantea gen et sp. nov. Bot. Mag. (Tokyo) 104: 191–205.CrossRefGoogle Scholar
  22. Norstog, K. &T. Nicholls. 1997. The biology of the cycads. Cornell Univ. Press, Ithaca, NY.Google Scholar
  23. Petriella, B. 1969.Menucoa cazaui nov. gen. et sp., tronco petrificado de Cycadales, Provincia de Rio Negro, Argentina. Ameghiniana 6(4): 291–302.Google Scholar
  24. — 1972. Estudio de las maderas petrificadas del Terciario inferior del área central de Chubut (Cerro Bororó). Revista del Museo de La Plata (n.s.), sección Paleontología 6: 159–254.Google Scholar
  25. — &J. V. Crisci. 1975. Estudios numéricos en Cycadales, I. Cycadales actuales: Sistemática. Boletfn Sociedad Argentina de Botánica 16(3): 231–247.Google Scholar
  26. —. 1979. Estudios numéricos en Cycadales, II. Cycadales actuales: Simulación de érboles filogenéticos. Obra del Centenario del Museo de La Plata 3: 151–159.Google Scholar
  27. Smoot, E. L., T. N. Taylor &T. Delevoryas. 1985. Structurally preserved fossil plants from Antarctica, I.Antarcticycas, gen. nov., a Triassic cycad stem from the Beardmore Glacier area. Amer. J. Bot. 72: 1410–1423.CrossRefGoogle Scholar
  28. Stevenson, D. W.. 1988. Strobilar ontogeny in the Cycadales. Pp. 205–244in P. Leins, S. Tucker & P. Endress (eds.), Aspects of floral development. J. Cramer, Berlin.Google Scholar
  29. — 1990. Morphology and systematics of the Cycadales. Mem. New York Bot. Gard. 57: 8–55.Google Scholar
  30. — 1992. A formal classification of the extant cycads. Brittonia 44: 220–223.CrossRefGoogle Scholar
  31. Taylor, T. N. 1969. Cycads: Fossil evidence of the Upper Pennsylvanian. Science 164: 294–295.PubMedCrossRefGoogle Scholar
  32. Worsdell, W. C. 1896. The anatomy of the stem ofMacrozamia compared with that of other genera of Cycadaceae. Ann. Bot. 10(40): 601–620.Google Scholar
  33. — 1901. Contributions to the comparative anatomy of the Cycadaceae. Trans. Linn. Soc. London, ser. 2(6): 109–121.Google Scholar
  34. — 1906. The structure and origin of the Cycadaceae. Ann. Bot. 20: 129–155.Google Scholar
  35. Zamuner, A. B. 1992. Estudio de una tafoflora de la localidad tipo de la Formación Ischigualasto (Netotrias), Provincia de San Juan. Tesis inédita N 483. Facultad de Ciencias Naturales y Museo de La Plata, U.N.L.P.Google Scholar
  36. Zhu, J.-N. &Du, X.-M. 1981. A new cycadPrimocycas chilensis gen. et sp. nov. from the Lower Permian in Shanxi, China and its significance. Acta Botanica Sinica 23: 401–404.Google Scholar

Copyright information

© The New York Botanical Garden 2004

Authors and Affiliations

  • Analía E. Artabe
    • 1
  • Alba B. Zamuner
    • 1
  • Dennis Wm. Stevenson
    • 2
  1. 1.Facultad de Ciencias Naturales y Museo de La PlataDivisión PaleobotánicaLa PlataArgentina
  2. 2.New York Botanical GardenBronxUSA

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