Articles | Volume 19, issue 1
Foss. Rec., 19, 1–9, 2016
Foss. Rec., 19, 1–9, 2016

Research article 16 Nov 2015

Research article | 16 Nov 2015

Two new species of megasporangiate Sigillariostrobus Schimper (Sigillariostrobaceae) fructifications from the British Coal Measures

B. A. Thomas1 and L. J. Seyfullah2 B. A. Thomas and L. J. Seyfullah
  • 1Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, UK
  • 2Department of Geobiology, Georg-August-Universität Göttingen, 37077 Göttingen, Germany

Abstract. The arborescent lycophyte group known as the sigillarians bore pedunculate fructifications, including Sigillariostrobus Schimper, which has a known propensity to disaggregate, making comparisons of cones and in situ spores often difficult if not impossible. Sigillariostrobus is monosporangiate, containing either megaspores or microspores. Two new species of Sigillariostrobus with megaspores are described from the British Coal Measures. Two cones of Sigillariostrobus saltwellensis sp. nov. are described from Langsettian–Duckmantian strata of Great Britain, containing in situ Laevigatisporites glabratus (Zerndt) Potonié and Kremp spores, making this the first British Sigillariostrobus species described containing such spores. Sigillariostrobus barkeri sp. nov. is given here to the previously described cone with in situ Tuberculatisporites brevispiculus (Schopf) Potonié and Kremp spores. This is the first Sigillariostrobus cone with this megaspore species in situ, and thus shows that T. brevispiculus and T. mamillarius (Bartlett) Potonié and Kremp are not conspecific as others have previously suggested.

Short summary
We discovered two new species of Sigillariostrobus cones belonging to the extinct arborescent lycophytes (club mosses). These cones usually fall apart, so finding new intact cones is rare and very important for understanding the diversity of Carboniferous lycophytes. The two species are the first from Britain, although the other cones are known from Europe. One of the cone species has Laevigatisporites glabratus-type spores inside; the other has Tuberculatisporites brevispiculus-type spores.