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A reappraisal of Neocalamites and Schizoneura (fossil Equisetales) based on material from the Triassic of East Antarctica

2013; Taylor & Francis; Volume: 37; Issue: 3 Linguagem: Inglês

10.1080/03115518.2013.764693

1752-0754

Benjamin Bomfleur, Ignacio H. Escapa, Rudolph Serbet, Edith L. Taylor, Thomas N. Taylor,

Plant and animal studies

Abstract Sphenophytes are a common floral element in the Triassic of Gondwana. Most sphenophyte compression fossils have been conventionally assigned to a few, presumably very widespread species of Neocalamites based on vegetative features of the stems (or pith casts) and the foliage. During recent decades, however, new reports on morphological and anatomical details of some of these fossils have cast doubt on the systematic affinities of many Gondwanan Triassic sphenophytes. Here we describe Neocalamites suberosus (Artabe & Zamuner) nov. comb. et emend. and Schizoneura africana Feistmantel emend. from several Triassic deposits in the central Transantarctic Mountains and Victoria Land, East Antarctica. The material enables a critical reevaluation of morphological and anatomical features that have been historically used to define the two genera, including leaf-base morphology, degree of leaf fusion, stem vasculature and vallecular canals, and features of the nodal diaphragm. The diagnoses of Neocalamites and Schizoneura are emended so that they more accurately reflect recent advances in our understanding of the anatomy and ontogeny of these plants. [Benjamin Bomfleur [bbomfleur@ku]edu], Rudolph Serbet [serbet@ku.edu], Edith L. Taylor [etaylor@ku.edu] and Thomas N. Taylor [tntaylor@ku.edu], Department of Ecology and Evolutionary Biology, and Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA; Ignacio H. Escapa [iescapa@mef.org.ar], CONICET—Museo Paleontológico Egidio Feruglio, Trelew, Chubut 9100, Argentina. Received 4.7.2012; revised 22.12.2012; accepted 7.1.2013. Bomfleur, B., Escapa, I.H., Serbet, R., Taylor, E.L. & Taylor, T.N., 2013. A reappraisal of Neocalamites and Schizoneura (fossil Equisetales) based on material from the Triassic of East Antarctica. Alcheringa 37, 1–17. ISSN 0311-5518. 根据东南极洲三叠纪材料,对Neocalamites和Schizoneura(化石Equisetales)的新看法 契叶植物是冈瓦纳三叠系中的一个常见分子。大多数契叶印痕化石传统上根据茎(或髓部铸型)和叶的特征而被鉴定为Neocalamites的一些分布广泛的种。然而,在最近几十年中,关于这些化石的形态和解剖学的新发现导致人们对很多冈瓦纳三叠纪契叶植物的系统关系产生疑问。在此,我们描述了采自东南极洲横南极山中部和维多利亚地区的若干三叠纪沉积物中的Neocalamites suberosus (Artabe & Zamuner)nov. comb. et emend. 和Schizoneura africana Feistmantel emend. 。这些材料使得我们能够对形态和解剖学特征进行重新审视;这些特征历史上用来定义这两个属,包括:叶基形态、叶愈合程度、茎脉管和沟管以及节点膈的特征。Neocalamites 和Schizoneura 的鉴定标准在此得以修正,这样它们会更准确的反映我们对这些植物的解剖学和个体发生学的新理解。 Key words: Sphenophyta Paraschizoneura Nododendron Transantarctic MountainsVictoria Land Acknowledgements We cordially thank Josefina Bodnar, Analia E. Artabe, Eduardo M. Morel and Adolfo Zúñiga for the friendly welcome, generous support and valuable discussion during BB's visit to the collection of the Museo de La Plata, Argentina. We gratefully acknowledge detailed and constructive reviews by Heidi Schwyzer-Holmes, Evelyn Kustatscher, Keith Holmes and Stephen McLoughlin. Financial support by the Alexander von Humboldt-Foundation (Feodor Lynen fellowship to BB) and the National Science Foundation (ANT-0943934 to ELT and TNT) is gratefully acknowledged.