A new Late Devonian genus with seed plant affinities

Area of Science:

• Paleobotany
• Evolutionary Biology
• Plant Anatomy

Background:

• Limited understanding of early spermatophyte vascular systems, especially from Euramerica.
• Controversy exists regarding the anatomical differentiation of Late Devonian and Carboniferous seed plant groups.
• Further research on protostele evolution in early spermatophytes is needed.

Purpose of the Study:

• To describe a new fossil taxon, Yiduxylon trilobum, from the Upper Devonian (Famennian) of China.
• To investigate the anatomical features of its stems, fronds, and vascular system.
• To clarify the evolutionary relationships of early seed plants.

Main Methods:

• Discovery and excavation of fossilized plant material.
• Detailed anatomical study of stem and petiole cross-sections.
• Analysis of vascular tissue, xylem, and cortex morphology.

Main Results:

• Yiduxylon trilobum exhibits a unique protostele with peripheral protoxylem strands.
• Secondary xylem shows multiseriate bordered pitting and high rays.
• Leaf trace arrangement and petiolar vascular bundles display distinct characteristics.

Conclusions:

• Yiduxylon justifies a new genus due to its unique protostele and leaf trace structure.
• Anatomical similarities link Yiduxylon to Calamopityales and Lyginopteridales.
• Transitional features suggest a link between early spermatophytes and progymnosperms.