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苔藓动物是一类多为海生、滤食性的群体生物。奥陶纪是苔藓动物发生、演化辐射和灭绝的重要时期,也是苔虫礁形成的最早时期。已知最老的化石苔藓动物发现于中国特马豆克晚期。构成苔藓动物基本分类框架的狭唇纲(包括变口目、隐口目、泡孔目和管孔目)和宽唇纲(包括窗孔目和栉口目)也都是在奥陶纪时期逐步形成的,其中,变口目出现于特马豆克期Tr2时间段,在弗洛期和大坪期,多样性较低,但从达瑞威尔期开始,经桑比期至凯迪期,多样性不断增高,并出现辐射。隐口目(特别是“双叶类隐口目苔虫”)也经历了与变口目相类似的发展过程,但它首次出现的时间要相对略迟于变口目。这两个目在整个奥陶纪苔藓动物群中一直占据主导地位。泡孔目、管孔目和窗孔目,先后首次出现在弗洛期Fl2时间段、大坪期Dp1和Dp2时间段,但它们在整个奥陶纪期间一直处于低多样性态势。至于栉口目,它首次出现的时间可能更迟,在凯迪期Ka4时间段,犹如昙花一现。苔藓动物的演化在接近奥陶纪末时呈两幕式灭绝,一次发生在凯迪期Ka2时间段(可能相当于塔凯和安斯蒂的“拉夫塞伊灭绝”),另一次发生在赫南特期Hi2时间段(可能相当于塔凯和安斯蒂的“赫南特灭绝”)。分子生物学和形态学证据表明,苔藓动物属原口动物,而不是以前长期认为的后口动物,或介于原口动物和后口动物之间的过渡类型;而且,苔藓动物与腕足动物、帚形动物之间没有直接的亲缘关系。苔藓动物可能起源于一种叫原内肛动物的生物,它们的目一级分类单元之间的系统发育关系目前尚未形成共识,本文绘制的谱系图还有待于化石记录的不断补充和分子生物学研究的逐步介入以使其日趋完善。
Bryophytes are a group of mostly marine, filter-feeding group organisms. Ordovician is an important period of the occurrence, evolution and extinction of mosses, and also the earliest period of the formation of the moss reef. The oldest known fossil bryozoan was found in the late Tematogs in China. The order of the lip class (which includes the order of the order, order of the order, the order of the order of the order of the order of the order), the order of the order of the order of the order of the lip (including the order of the order of the order of the order) Gradually formed, of which, the change of mouth appears in the Tr2 period of the Temazek period, in the Floyd and Daping phases, the diversity is low, but from the Daruiweier period, the Sambi period to the Kaidi period, Increasing diversity and radiation. Hidden eyesight (especially “double-leafed hidden mouth bug ”) also experienced a similar process of change, but it is the first time it appears relatively late. These two orders have always dominated the entire Ordovician moss fauna. For the first time in the Fl 2 Fl 2 and Dap 1 Dp 1 and Dp 2 periods, they were first seen in the low diversity period throughout the Ordovician period. As for the duration of the first occurrence, it may be later, in Kaidi Ka4, as a blip. The evolution of the bryozoan showed two episodes of extinction near the end of Ordovician, one at Ka2 Kaidi (possibly equivalent to the “Raschuai extinction” of Thaki and Ansty) and another at Hennan period Hi2 time period (which may be equivalent to “Thainter extinction” of Thaki and Ansty). Molecular biology and morphological evidence indicate that the mosses are protozoa rather than the later-considered posterior animals or transitional types between primitive and posterior animals; furthermore, the bryozoans and brachiopods, There is no direct relationship between animals. The bryozoans may have originated from an organism called protozoan, and their phylogenetic relationships have not been established yet. The pedigree drawn in this paper needs to be further supplemented by fossil records and molecular biology The gradual intervention of research to make it more and more perfect.