中国硅藻化石新种和新记录种
NEW SPECIES AND NEW RECORDS OF FOSSIL DIATOMS FROM CHINA
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摘要: 在对江汉平原钻孔中的化石硅藻进行鉴定时,发现1个新种类:江汉异极藻(新种)Gomphonema jianghanensis sp.nov.,该种的主要特征为:壳面狭披针形或线性披针形,端部和基部圆形,中轴区窄。中心区宽呈横矩形,在紧靠中心区的一侧具1条很短的线纹,另一侧有时有1条很短的线纹,有时没有线纹,无孤点。壳缝呈直线,在中央区附近略弯向一侧,在极节处折向另一侧。线纹轻微放射状,中部略弯曲,在近顶端处没有线纹,在10μm内,中部具6-13条。长20-30μm,宽4-7μm。4个中国新记录属:楔异极藻属Gomphosphenia Lange-Bertalot、楔月藻属(新记录属)Cymbopleura Krammer、优美藻属Delicata Krammer、尖月藻属Encyonopsis Krammer,8个中国新记录种:微小异极藻Gomphonema minutiforme Lange-Bertalot&Reichardt、较细楔异极藻Gomphosphenia tenerrima(Hustedt)Reichardt、舌状楔异极藻Gomphosphenia lingulatiforme(Hustedt)Lange-Bertalot、瑞克舟形藻Navicula rakowskae Lange-Bertalot、北方羽纹藻岛屿变种Pinnularia borealis var.islandica Lange-Bertalot,舟形盖斯勒藻Geissleria tectissima(Lange-Bertalot)Lange-Bertalot&Metaeltin、岩生楔月藻小变种Cymbopleura rupicola var.minor Krammer和法国尖月藻Encyonopsis falaisensis(Grunow)Krammer,1个种的补充说明:中华优美藻Delicata sinensis Krammer & Metzetin。Abstract: In the present paper, one new fossil diatom species, Gomphonema j ianghanensis sp.nov., is described.Its characteristic is valve narrowly lanceolate or linear- lanceolate with rounded headpole and narrowly rounded footpole.Axial area is narrow.Central area is distinct and transversely rectangular with one shortened striae on one margin, and has, or not, one shortened striae on the othermargin.It lack stigma.Raphe is linear, curved towards the proximal ends and reflexed towards the other side at the distal ends.Striae radiate throughout and slightly curved on the central margin.There are not striae near the disal ends in light microscope.Striae in themiddle port ion 6-9 in 10m, up to 11-13 in 10 m towards the ends.Length is 20-30 m and breadth is 4-7m.
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