| Abstract Detail
Mesozoic and Cenozoic plant evolution and biotic change: A symposium in honor of Ruth Stockey Doyle, James [1], Kvaček, Jiří [2], Daviero-Gomez, Véronique [3], Gomez, Bernard [3], Endress, Peter K. [4]. Pseudoasterophyllites from the mid-Cretaceous of Europe: a link between Ceratophyllum and Chloranthaceae? Above the basal ANITA grade of angiosperms, relationships among magnoliids, monocots, eudicots, Chloranthaceae, and Ceratophyllum remain unresolved, but morphological data and a growing number of molecular analyses indicate that the enigmatic rootless aquatic Ceratophyllum may be sister to Chloranthaceae. Morphological phylogenetic analyses with living angiosperms constrained to a primarily molecular backbone tree in which Ceratophyllum and Chloranthaceae form a clade have indicated that Appomattoxia, based on carpels from the Albian of Virginia with adhering Tucanopollis pollen, may be a stem relative of Ceratophyllum. However, Appomattoxia has not been associated with vegetative parts. Recently, KvaĂ„Ťek et al. (2012, Acta Palaeontol. Pol. 57: 437-443) associated Pseudoasterophyllites cretaceus Feistmantel ex Velenovský, a putative halophyte with several orders of slender stems and linear, opposite leaves from the Cenomanian of Bohemia and France, with stamens containing Tucanopollis-like pollen. New material reported here indicates that the stamens were borne in spikes, whereas the carpels were solitary in leaf axils and contained one orthotropous ovule of the Spermatites type. TEM confirms that the pollen resembles Tucanopollis from the Barremian and Aptian of Congo and Gabon in having a continuous tectum, supratectal spinules, granular-columellar infratectum, thick foot layer, and endexine below the round sculptured aperture. In a phylogenetic analysis with a backbone tree where Ceratophyllum and Chloranthaceae form a clade, Pseudoasterophyllites is sister to Ceratophyllum, based on opposite leaves, unisexual flowers, male spikes of naked, unistaminate flowers, and solitary female flowers consisting of a single carpel containing one orthotropous ovule. With a backbone tree where Ceratophyllum is linked with eudicots and Chloranthaceae with magnoliids, Pseudoasterophyllites is sister to Chloranthaceae, but a relationship to Ceratophyllum is only one step less parsimonious. In both cases, inclusion of Pseudoasterophyllites increases the morphological parsimony of a relationship of Ceratophyllum to Chloranthaceae rather than eudicots. If the plants that produced abundant Tucanopollis pollen in the Barremian-Aptian of Africa-South America are related to Pseudoasterophyllites, these results suggest that Chloranthaceae and Ceratophyllum are relicts of one of the most important clades in the early radiation of angiosperms, which included not only colonizers of disturbed terrestrial habitats but also halophytes and/or aquatics. Association of other vegetative remains with Tucanopollis (and with Pennipollis, which phylogenetic analyses have also linked with Ceratophyllum) could test these hypotheses.
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1 - University Of California Davis, Dept Of Evol & Ecology, One Shields Avenue, Davis, CA, 95616-8537, USA
2 - National Museum, Palaeontology, Václavské Nam. 68, Prague, 115 79, Czech Republic
3 - Université Lyon 1, CNRS-UMR 5276 Terre, Plančtes, Environnement, Villeurbanne, 69622, France
4 - University of Zurich, Institute of Systematic Botany, Zurich, 8008, Switzerland
Keywords:
angiosperms
Cretaceous
Pseudoasterophyllites
Ceratophyllum
Chloranthaceae
paleobotany.
Presentation Type: Colloquium Presentations
Session: C6
Location: Salon 5/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 2:45 PM
Number: C6006
Abstract ID:242
Candidate for Awards:None |
