Data from: Xianella: a new mat-forming calcified cyanobacterium from the Middle–Late Ordovician of North China

Xianella hongii gen. et sp. nov. is described from the Middle–Late Ordovician of Shaanxi, China and interpreted as a calcified cyanobacterial sheath. Xianella filaments formed cable-like strands that constructed thick fenestral layers. The specimens occur in metre-sized limestone blocks, possibly derived from local collapse of a reefal platform margin. In combination with micrite, some of which is intraclastic and peloidal, Xianella created thick and extensive stacks of layered calcified fenestral fabric that appear to be synsedimentarily calcified open-frame mat deposits. The fenestrae range from small, laminose and very irregular, to large equidimensional areas ~2 cm across. Fenestrae with rounded outlines resemble primary gas bubbles observed in present-day microbial mats. These delicate fabrics are comparable in structure and quality of preservation with those of some Proterozoic silicified stromatolitic mats.

本研究记述了产自中国陕西中奥陶世至晚奥陶世的红氏仙莱拉菌（Xianella hongii gen. et sp. nov.），该化石被解释为钙化蓝细菌鞘。红氏仙莱拉菌的丝状体形成缆状丝束，构建出厚实的孔隙层。该类标本赋存于米级石灰岩块体中，这些块体可能源自礁坪边缘的局部垮塌。红氏仙莱拉菌与部分为内碎屑球粒微晶灰岩共生，共同形成了厚实且分布广泛的层状钙化孔隙组构，此类组构应属于同沉积钙化的开放框架席状沉积物。窗孔的形态从小型层状且极不规则，至直径约2厘米的大型等轴状区域。轮廓圆润的窗孔与现代微生物席中观察到的原生气泡构造相似。这些精细的组构在结构与保存质量上，可与部分元古宙硅化叠层石席相媲美。