Reconstruction of the Pennsylvanian-age walchian conifer Emporia cryptica sp. nov. (Emporiaceae: Voltziales) Genaro R. Hernandez-Castillo a, ⁎, Ruth A. Stockey b , Gar W. Rothwell c , Gene Mapes c a Instituto de Recursos, Universidad del Mar, Puerto Escondido, Oaxaca, 71980, Mexico b Department of Biological Sciences, University of Alberta, Edmonton, Canada AB T6G 2E9 c Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA abstract article info Article history: Received 22 February 2009 Received in revised form 3 May 2009 Accepted 5 May 2009 Available online 12 May 2009 Keywords: conifer Emporia Emporiaceae fossil Paleozoic Voltziales This paper provides a whole plant concept for a new species, Emporia cryptica sp. nov. Hernandez-Castillo, Stockey, Rothwell & Mapes (Emporiaceae: Voltziales), the fourth conifer to be reconstructed from the rich fossil biota at the Late Pennsylvanian, Hamilton Quarry, Kansas. E. cryptica has an orthotropic stem, lateral plagiotropic branches with simple leaves, simple pollen cones, and compound ovulate cones. Branches have an endarch eustele with dense wood surrounding a parenchymatous pith with sclerotic nests/plates, and secondary xylem tracheids with multiseriate hexagonal bordered pits. Leaves on both penultimate and ultimate branches are simple and amphistomatic with two adaxial stomatal bands, monocyclic and dicyclic stomata, and two narrow abaxial rows of stomata with numerous trichome bases. Pollen cones are simple with helically arranged microsporophylls and adaxial pollen sacs. Prepollen is monolete, eusaccate, and monosaccate (Potonieisporites Bharadwaj). Ovulate cones are compound with bilaterally symmetrical dwarf shoots in the axils of helically arranged forked bracts. Axillary dwarf shoots bear numerous sterile scales interspersed with two megasporophylls, each bearing a single inverted terminal ovule. This plant displays morphological and cuticular characters similar to several morphogenera of Paleozoic walchian conifers but is most comparable to the fossil plant species Emporia lockardii and Hanskerpia hamiltonensis. E. cryptica is the only walchian conifer where ovules and seeds with megagametophytes, immature embryos and mature embryos have been documented, demonstrating that the most ancient conifers possessed seed dormancy and polycotyledonary embryos. This reproductive biology is similar to that of many Mesozoic and extant conifers with saccate pollen except for the presence of prepollen grains that are common among Paleozoic walchian conifers. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The most ancient conifers, or walchian conifers (Mapes and Rothwell, 1984), are known from Euramerican sediments (Upper Carboniferous and Lower Permian) and traditionally have been classified in several families within the Voltziales (Florin, 1938–45; Visscher et al., 1986; Kerp et al., 1990; Mapes and Rothwell, 1991; Galtier et al., 1992; Rothwell et al., 1997; Hernandez-Castillo et al., 2001b). Walchian plants are typically represented by isolated and/or fragmentary branches, pollen cones, and ovulate cones, usually at localities where more than one species of conifers has been identified (Florin, 1938–45; Rothwell, 1982; Clement-Westerhof, 1984; Mapes and Rothwell, 1984; Clement-Westerhof, 1987; Mapes and Rothwell, 1991; Meyen, 1997; Mapes and Rothwell, 1998). The first critical systematic work on walchian conifers was compiled by Florin (1927, 1938–45, 1950, 1951). Florin's interpretations remain as some of the most influential for living and fossil conifers. Nevertheless, modern studies have called to question Florin's systematics and his interpretations of the most primitive conifers (Schweitzer, 1963; Rothwell, 1982; Clement-Westerhof, 1984; Mapes and Rothwell, 1984; Meyen, 1984; Winston, 1984; Visscher et al., 1986; Clement-Westerhof, 1987; Clement-Westerhof, 1988; Kerp et al., 1990; Mapes and Rothwell, 1991; Meyen, 1997; Mapes and Rothwell,1998; Hernandez-Castillo et al., 2001a,b; Lausberg, 2002; Rothwell and Mapes, 2003; Hernandez- Castillo et al., 2009). The most recent interpretations result from a complete reexamination and a reevaluation of walchian conifer material, and employ new methodology and reliable criteria for circumscribing walchian conifers as species of extinct plants (Hernan- dez-Castillo et al., 2001b; Rothwell et al., 2005; Hernandez-Castillo, 2005; Hernandez-Castillo et al., 2009). This new methodology is based on interconnections among some organs, and a combination of morphological, cuticular, and anatomical characters that are used to Review of Palaeobotany and Palynology 157 (2009) 218–237 ⁎ Corresponding author. Tel.: +52 1 954 107 0528; fax: +52 954 582 4992. E-mail address: genarohc@zicatela.umar.mx (G.R. Hernandez-Castillo). 0034-6667/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.revpalbo.2009.05.003 Contents lists available at ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo