A new species of the fossil fern Millerocaulis (Osmundales: Osmundaceae) from the Snow Hill Island Formation (Upper Cretaceous) of James Ross Island, Antarctic Peninsula
Eva Koppelhus , Ezequiel I. Vera , Rodolfo A. Coria , Philip J. Currie , Marcelo A. Reguero
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引用次数: 0
Abstract
A small permineralized stem containing an ectophloic-dictyoxylic siphonostele and petiole bases with an homogeneous sclerotic ring, referable to the fossil genus Millerocaulis Erasmus ex Tidwell emend. Vera, was recovered from the siltstones of the Gamma Member of the Snow Hill Island Formation (Marambio Group, Upper Cretaceous) of Santa Marta Cove, James Ross Island. The presence of high numbers of xylem strands, leaf traces per cross section, wide cauline xylem strands and lack of sclerenchyma in the petiole bases (apart from the sclerotic ring) at least until the fourth petiolar cycle allow its separation from other known species of the genus Millerocaulis, defining a new taxon Millerocaulis santamartaensis sp. nov.. This new taxon represents the fourth species of the genus identified from Antarctica. The fossil bearing strata are interpreted as upper Campanian to lower Maastrichtian. As a result, M. santamartaensis sp. nov. represents the youngest evidence of the presence of this genus of stem-Osmundaceae almost until the end of the Cretaceous.
期刊介绍:
The Review of Palaeobotany and Palynology is an international journal for articles in all fields of palaeobotany and palynology dealing with all groups, ranging from marine palynomorphs to higher land plants. Original contributions and comprehensive review papers should appeal to an international audience. Typical topics include but are not restricted to systematics, evolution, palaeobiology, palaeoecology, biostratigraphy, biochronology, palaeoclimatology, paleogeography, taphonomy, palaeoenvironmental reconstructions, vegetation history, and practical applications of palaeobotany and palynology, e.g. in coal and petroleum geology and archaeology. The journal especially encourages the publication of articles in which palaeobotany and palynology are applied for solving fundamental geological and biological problems as well as innovative and interdisciplinary approaches.