What are Bryozoans?

The bryozoa (Bryozoa = Polyzoa) is a group animal that lives on a regular basis. Individuals are small, not segmented, specific cavity. The front end of the worm body has a mouth, and there is a crown around the mouth, which is called "total burden", and there are many tentacles on it. There are many types in the geological age, the Ordovician already appeared, and modern life still exists. Belongs to building blocks.

Classification status: bryophyta, bryophytes

Fossil origin: Zunyi, Guizhou, Nanning, Guangxi and other places throughout the country

Geological age: Early Ordovician-Modern

Living environment: living on the seabed or other objects

Typical size: individuals generally do not exceed 1mm, groups from several millimeters to hundreds of millimeters ^[1]

The bryozoa (Bryozoa = Polyzoa) is a group animal that lives firmly. A bryozoan is an animal that resembles a moss plant. It looks like a plant but has a complete set of digesters, including the mouth, esophagus, stomach, intestine, and anus. So put it in the animal kingdom. This organism is often associated with seaweed. Individuals are small, not segmented, specific cavity. A layer of gelatin is secreted in vitro, forming the bones of the population. The front end of the worm body has a mouth, and there is a crown around the mouth, which is called "total burden", and there are many tentacles on it. The U-shaped digestive tract brings the mouth and anus closer. No excretion and circulatory organs. Both seawater and freshwater are produced. There were many kinds in the geological age,

Mosses live in the ocean. There are chrysanthemum dish moss, white thin moss, and whip whisker.

The hard body is calcareous, the worm tube is slender, the cross section is round and polygonal, there are gap holes, punctures, the central area (inner zone), the edge zone (outer zone), the boundaries between the inner and outer zones are unclear, and the inner zone is thick. There are few horizontal plates, thin outer wall and many horizontal plates. The worm tube wall has a parallel sheet structure surrounding the worm chamber.

The hard body is calcium, and the group is fan-shaped, funnel-shaped, branch-shaped, etc. It usually consists of many parallel branches, which are connected by transverse branches to form a grid. There are two rows of worm chambers on the two branches. The middle edge is separated. The worm chamber is rectangular, square or hexagonal, with clear inner and outer bands, narrow inner bands, wide outer bands, and puncture holes. It is dark brown under a single polarizer, and the wall has a parallel sheet structure. The moss worm is small in its population, the slender tube is different from the coral, and its worm tube does not shrink outward, and the tube wall is a conical parallel sheet-like structure with thickened places, with gap holes and punctures. Distinguish coral algae from corals. Most bryozoans live in shallow waters, and a few are in fresh water. The era is Ordovician-Modern ^[2]

Although the bryozoites are not large, about 0.5 mm, they live in groups, and a large number of bryozoans will form moss worm groups of various shapes, such as dendritic, reticulate, sheet, and hemispherical. They often live a "tourist life" in their infancy, then settle down and begin to camp on a fixed or epiphytic life. Both modern and ancient mosses can cling to hard rocky seabeds of various terrains, rolling pebbles, or dead animal shells. ^[3]

The ancestors of bryozoans that now exist in the ocean can be traced back to the early Ordovician about 500 million years ago. A Early Ordovician Temadoucus bryophyte fossil was preserved at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences (hereinafter referred to as the Nanguo Institute). ^[3]

Early Ordovician tematococcus moss fossil

The Early Ordovician Temadoucus moss fossils were discovered by researchers from the Nangu Institute in 2007 in the subdivisions of Huanghuachang and Songzi Liujiachang in Yichang, Hubei. It is not only the oldest moss fossil in the world known at the time, but also the skeleton organism that constituted the world's earliest moss reef, and is the earliest true metazoan biological reef. ^[3]

Looking for bryozoans in earlier Ordovician strata (such as the Nanjinguan Formation) is not groundless. Fossil records show that the Ordovician period was very rich in bryozoans. In particular, the evolutionary radiation of the Brachiaria bryophytes is an important component and manifestation of the paleozoic Paleozoic Ordovician Ordovician biological radiation. In the Early Ordovician Temadouq, the bryozoans had a certain diversity at this time, including 3 orders, namely the order of metamorphosis, hermit and Estonian, and 3 genera 6 Species are also relatively complicated. This indicates that there was a relatively long evolutionary period before the bryozoans were divided into different groups. ^[3]

However, this "earliest" record has not been maintained for a long time. Soon, through the continued efforts of the Bryozoan Research Group of Nangusuo, it was discovered earlier in the Nanjinguan Formation (underlying strata of the sub-township) in the Liujiachang area of Songzi Moss bug. ^[3]

The earliest pioneers of moss research

In addition to the Early Ordovician Temadoucus bryozoite fossils, the Nanguo Institute also has another layer of indissoluble bond with moss fossils: Researcher Yang Jingzhi is the first pioneer of moss fossil research in China. ^[3]

Big energy in a small body

Modern research shows that the earliest moss fossils were found in the strata of the Early Ordovician. Among the bryozoans, the larvae do not have calcium carbonate skeletons like other marine bryozoans, but have organic matter. Moreover, this group is considered to be a relatively primitive group, and other bryophytes may be derived from groups similar to the larvae. They have continued to the modern era since the emergence of the Ordovician period, but there are few changes and not many fossils. ^[3]

In the Paleozoic era, bryozoans had three important evolutionary periods. ^[3]

The first is the Ordovician, the first flourishing period of bryozoans. In this period, the moss worms appeared in the order of metamorphosis, pore order, crypt order, and ring order, in addition to the order of the order. Among them, the mosquitoes of the morphophora and hermitidae are in absolute superiority in both diversity and biomass. ^[3]

The Devonian to Carboniferous period was the second flourishing period of bryozoans. The above orders still existed, but the hermitia appeared to be particularly prosperous, and the Porphyra moss gradually increased. ^[3]

But in the third evolutionary period, the Permian period, the bryophytes had undergone major changes. At the end of the Permian period, a large-scale extinction occurred. The metamorphosis, hermitaceae, and pane panes that were once dominant groups gradually became extinct. The Orchidoptera and Labiata began to diversify, becoming the dominant group of bryozoans. In addition to the Oraloptera and Labiata, which have calcium carbonate skeletons, the bryozoans also include freshwater types of non-mineralized bones, Lamiaceae and Lacaria. ^[3]

The evolution of the bryozoan's morphology and diversity is one of the important reasons that has attracted researchers' interest. Another important reason is that bryozoans are a class of animals with mineralized bones that did not appear in the Cambrian biological radiation. "Therefore, the study of bryozoan paleontology is of great significance for us to understand the origin of metaphytes. ^[3]

Moreover, bryozoans experienced considerable biodiversity in the Paleozoic and Cenozoic, which is of great significance for modern people to understand the co-evolution of biology and the environment in the process of geological history. ^[3]

In addition, in some geological periods, bryozoans have a faster evolution rate and can play an important role in stratigraphic correlation. ^[3]