title: Fertile structures with in situ spores of a dipterid fern from the Triassic in southern China.
abstract: Clathropteris was a typical dipterid fern with well documented fossil record and was widely dispersed during the Mesozoic; however, our knowledge of fertile structures including in situ spores for this genus is still very limited. Here we report well-preserved compression specimens of Clathropteris obovata Oishi from the Late Triassic of Guangyuan, Sichuan Province, China. The specimens show round to oval and exindusiate sori, vertical to oblique annuli in sporangia, and in situ trilete spores with verrucate and baculate sculptures, which are comparable to dispersed spore genera of Converrucosisporites and Conbaculatisporites. Comparisons of relevant fossil taxa suggest that specimens of C. obovata from Triassic of China provide for the first time in Asia the detailed fertile structures with in situ spore characters of dipterid fossil Clathropteris. Unlike living Dipteris, Mesozoic fossils of Dipteridaceae show a high diversity and a range of complex morphology of in situ spores, thus are significant for the evolutionary links between Dipteridaceae and other related fern clade, including Gleicheniaceae and Matoniaceae of the Gleicheniales.
authors.affiliation: Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China, ydwang@nigpas.ac.cn.
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Wang
authors.forename: Liqin
authors.initials: L
authors.lastname: Li
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Guignard
authors.forename: David L
authors.initials: DL
authors.lastname: Dilcher
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xie
authors.forename: Ning
authors.initials: N
authors.lastname: Tian
authors.forename: Ning
authors.initials: N
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D005075:Biological Evolution; D002681:China; D029624:Ferns / Q000502:physiology* / Q000648:ultrastructure; D005298:Fertility; D005580:Fossils; D010802:Phylogeny; D058432:Sporangia / Q000502:physiology* / Q000648:ultrastructure; D013170:Spores / Q000648:ultrastructure