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Dopyeria elongata, gen. et sp. nov.: A New Genus and Species of Anatomically Preserved Ribbed Axes with Secondary Xylem from the Early Devonian (Emsian) of New Brunswick, Canada.

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Title: Dopyeria elongata, gen. et sp. nov.: A New Genus and Species of Anatomically Preserved Ribbed Axes with Secondary Xylem from the Early Devonian (Emsian) of New Brunswick, Canada.
Authors: Gensel, Patricia G.1 (AUTHOR) pgensel@bio.unc.edu
Source: International Journal of Plant Sciences. 2026, Vol. 187 Issue 4, p379-391. 13p.
Subjects: Plant anatomy, Devonian Period, Paleobotany, Vascular plants, Plant growth
Geographic Terms: New Brunswick
Abstract: Premise of research. Compressions of unornamented, ribbed, and branched axes with regions of preserved anatomy were obtained from the Emsian of New Brunswick, Canada, and provided one of the first examples of secondary growth in Early Devonian plants. The plant consists of branched axes exhibiting a similar distinctive cortex pattern, xylem shape, and mode of lateral trace departure with some axes showing only primary xylem and some secondary xylem (wood). These features and details about lateral trace departure support establishing a new basal euphyllophte taxon, Doperyia elongata gen. et sp. nov., adding to the known diversity of small Early Devonian plants with secondary growth. Methodology. Adpressions of axes were prepared by dégaging. Localized regions of permineralization on axes and nodules in the adjacent matrix were removed, embedded, and sectioned. Sections were polished, etched and mounted on slides, and then examined with LM, SEM, and micro–computed tomography scanning. Pivotal results. Ribbed axis fragments of D. elongata exhibit anisotomously dividing main axes with or without secondary xylem and isotomously divided lateral axes. Larger axes have a variably thick sclerenchymatous outer cortex, and smaller axes have less so. Lateral traces depart singly from either end of the elongate haplostele and then divide, producing two elongate-ovoid xylem strands. In axes with secondary xylem, only early stages of lateral trace departure are known. All tracheids exhibit scalariform-bordered pitting with multiperforate apertures (P-type). Conclusions. These remains represent a single Early Devonian euphyllophyte taxon, named D. elongata , presenting information on the presence or absence of secondary xylem in an Early Devonian plant and details of lateral trace departure. These fossils demonstrate that similar-appearing, anisotomously branched, ribbed axes are a feature of several euphyllophyte genera that possess different internal anatomy. Anatomical changes from the main to the lateral axis indicate a more pseudomonopodial architecture than inferred from external morphology. Secondary xylem features support a mosaic expression of regulatory modules, as suggested for other Early Devonian woody plants. [ABSTRACT FROM AUTHOR]
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Abstract:Premise of research. Compressions of unornamented, ribbed, and branched axes with regions of preserved anatomy were obtained from the Emsian of New Brunswick, Canada, and provided one of the first examples of secondary growth in Early Devonian plants. The plant consists of branched axes exhibiting a similar distinctive cortex pattern, xylem shape, and mode of lateral trace departure with some axes showing only primary xylem and some secondary xylem (wood). These features and details about lateral trace departure support establishing a new basal euphyllophte taxon, Doperyia elongata gen. et sp. nov., adding to the known diversity of small Early Devonian plants with secondary growth. Methodology. Adpressions of axes were prepared by dégaging. Localized regions of permineralization on axes and nodules in the adjacent matrix were removed, embedded, and sectioned. Sections were polished, etched and mounted on slides, and then examined with LM, SEM, and micro–computed tomography scanning. Pivotal results. Ribbed axis fragments of D. elongata exhibit anisotomously dividing main axes with or without secondary xylem and isotomously divided lateral axes. Larger axes have a variably thick sclerenchymatous outer cortex, and smaller axes have less so. Lateral traces depart singly from either end of the elongate haplostele and then divide, producing two elongate-ovoid xylem strands. In axes with secondary xylem, only early stages of lateral trace departure are known. All tracheids exhibit scalariform-bordered pitting with multiperforate apertures (P-type). Conclusions. These remains represent a single Early Devonian euphyllophyte taxon, named D. elongata , presenting information on the presence or absence of secondary xylem in an Early Devonian plant and details of lateral trace departure. These fossils demonstrate that similar-appearing, anisotomously branched, ribbed axes are a feature of several euphyllophyte genera that possess different internal anatomy. Anatomical changes from the main to the lateral axis indicate a more pseudomonopodial architecture than inferred from external morphology. Secondary xylem features support a mosaic expression of regulatory modules, as suggested for other Early Devonian woody plants. [ABSTRACT FROM AUTHOR]
ISSN:10585893
DOI:10.1086/740773