摘要
在我国,先后有好几种植物被报道或记述于艾羊齿(Aipteris)或革叶(Scytophyllum)属名下(王喜富,1975,1979;黄枝高、周惠琴,1980;李佩娟、何元良,1986)。它们属于哪个分类群,与大羽羊齿植物是否有关系,这些问题,由于一块被归于Aipteris,羽片上着生种子的标本被发现,再次引起了人们的关注。现将这一标本和同时代一些被归于Aipteris的化石正式发表,并对有关上述问题的一些材料作一评述和讨论,以引起人们对此问题的注意。
Since 1975 some interesting plant fossils have been described under the generic names of Aipteris and Scytophyllum from the Upper Triassic of China, but most interesting is the finding of a seed-bearing specimen informally reported as Aipteris zhiluoensis Wang. For the purpose of attracting more attention to the question on the real systematic position of the Chinese fossil material described as Aipteris, this article gives a description of the seed-bearing specimen, under the name of Aipteridium zhiluoense Wang (sp. nov.), and come associated specimens, illustrated by photo-figures. Furthermore, this paper also gives the reason for using the generic name dipteridium instead of Aipteris, with a discussion on the relationship between Aipteridium and gigantopterids.Aipteridium zhiluoense Wang (sp. nov.) (P1. Ⅰ, figs. 1, 2)Leaf simply pinnate, about 11 cm in width. Rachis of medium size, about 3 mm in width, with uneven surface. Pinnae linear to lanceolate, with a length of 60 mm and a width of 15mm; apex blunt to rounded. Margin of the pinna crenate, with each crena representing the apex of a coherent pinnule. Anadromic margin of the pinna slightly contracted near the base, while catadromic margin decurrent on the pinna rachis. Pinnae possessed of a vasculature with three orders of veins, taking the midvein as the first order. Secondary vein with its tertiaries forming peculiar fascicles, which are arranged pinnately, set oppositely or sub-oppositely to the midvein. Midvein of the pinna about 1 mm in width, tapering toward the apex, slightly decurrent on the rachis. Sec- ondaries departing from the midvein at an acute angle; tertiaries departing from the secondaries at very acute angle, unbranched or rarely branched once even twice. Only a small part of tertiaries departing near the tip of secondary vein extending to meet the pinna margin or the apex of the coherent pinnule; most of them extending to and diminishing at the boundary of two coherent pinnules, and never extending to the pinna margin. Tertiary veins never anastomosing with each other, nor with those of the adjacent fascicles, nor with the sutural vein, if any between two fa scicles.Seed oval in form, about 6mm×4mm in dimension, arranged on both sides of the midvein. Structure of the seed unknown.Remarks: The specimen attached with seeds was first informally reported by Dr. Wang in 1979 and later cited by Li and He (1986) under the name of Aipteris zhiluoensis Wang, but the species had never been described nor figured before until it is described here as a new species.While discussing the venation types of gigantopterids, Prof. Li and Yao (1983) implied that Aipteris pinnata Sixtel disagrees with the typical illustration of A. speciosa, the type species of Aipteris, given by Zalessky (1939), and therefore it seems better to remove the former species from the original designation and place it in a new genus. For this reason, they proposed a new generic name of Aipteridium, taking A. pinnata Sixtel as its type species. Taking into consideration the presence of seeds and the differences in the epidermal structure between the Chinese material and the Russian species of Scytophyllum, here the authors ascribe the fossil material to the genus Aipteridium.Locality and horizon: Holotype specimen (PB 15532) from upper part of Middle Late Triassic Yenchang Formation, Zhiluo, Huangling district, Shaanxi.
出处
《古生物学报》
CAS
CSCD
北大核心
1991年第1期49-56,145-146,共8页
Acta Palaeontologica Sinica
基金
国家自然科学基金(4880071)
