Schierwater Bernd
ITZ, Ecology and Evolution, Tierärztliche Hochschule Hannover, Germany.
Bioessays. 2005 Dec;27(12):1294-302. doi: 10.1002/bies.20320.
Trichoplax adhaerens is more simply organized than any other living metazoan. This tiny marine animal looks like a irregular "hairy plate" ("tricho plax") with a simple upper and lower epithelium and some loose cells in between. After its original description by F.E. Schulze 1883, it attracted particular attention as a potential candidate representing the basic and ancestral state of metazoan organization. The lack of any kind of symmetry, organs, nerve cells, muscle cells, basal lamina and extracellular matrix originally left little doubt about the basal position of T. adhaerens. Nevertheless, the interest of zoologists and evolutionary biologists suddenly vanished for more than half a century when Trichoplax was claimed to be an aberrant hydrozoan planula larva. Recently, Trichoplax has been rediscovered as a key species for unraveling early metazoan evolution. For example, research on regulatory genes and whole genome sequencing promise insights into the genetics underlying the origin and development of basal metazoan phyla. Trichoplax offers unique potential for understanding the minimal requirements of metazoan animal organization.
黏丝盘虫比其他任何现存的后生动物结构都更简单。这种微小的海洋动物看起来像一个不规则的“毛盘”（“tricho plax”），有一层简单的上表皮和下表皮，中间有一些松散的细胞。自1883年被F.E.舒尔茨首次描述后，它作为后生动物组织基本和原始状态的潜在代表而备受关注。由于缺乏任何形式的对称性、器官、神经细胞、肌肉细胞、基膜和细胞外基质，黏丝盘虫最初被认为处于基部位置几乎毫无争议。然而，当黏丝盘虫被认为是一种异常的水螅虫浮浪幼虫时，动物学家和进化生物学家对它的兴趣突然消失了半个多世纪。最近，黏丝盘虫作为解开早期后生动物进化之谜的关键物种被重新发现。例如，对调控基因和全基因组测序的研究有望深入了解基部后生动物门起源和发育的遗传学基础。黏丝盘虫为理解后生动物组织的最低要求提供了独特的潜力。
