中国科学院南京地质古生物研究所机构知识库

A new anachoropterid fern Ilansopteris uncinatus gen. et sp. nov. collected from the well-known Chinese "vegetational Pompeii" is recognized on the basis of both vegetative and fertile parts which are excellently preserved as adpressions, a few of which contain carbonized three-dimensional anatomy. Antepenultimate rachises average 3 mm in diameter and are covered by dense scales. Rachis anatomy conforms to the Anachoropteris clavata-type that is characterized by a horseshoe-shaped xylem trace with the lateral arms of its metaxylem being made up of larger tracheids than those in the medial part. Sterile fronds are tripinnately compound. Penultimate and ultimate pinnae are alternately arranged. Pinnules are sphenopterid with dentate margins. Hooked tendrils and aphlebiae are situated laterally and proximal to each penultimate rachis. On juvenile frond specimens, these structures are precocious, growing out before the laminate pinnae. The fertile frond is tripinnate with pinnules that arc identical to their sterile equivalents. Round reproductive organs are about 1 mm in diameter and singly attached to each fertile pinnule. in situ spores are sub-triangular, trilete with labra and assignable to the dispersed miospore genus Leiotriletes (Naumova) Potonie et Kremp. Considering the overall preservation and the precocious hooked tendrils and aphlebiae, the growth habit of IL uncinatus is suggested to be a vine, although its stem is still unknown (C) 2020 Elsevier B.V. All rights reserved.