记者4月10日从中国科学院古脊椎动物与古人类研究所获悉，此所研究人员在江西德安志留纪地层发现了盔甲鱼类的新属种，已命名为隆平德安鱼。这一最新研究成果最近在线发表于国际学术期刊《系统古生物学杂志》。

中国科学院古脊椎动物与古人类研究所研究员盖志琨介绍说，隆平德安鱼是一种非常小、头甲不足2厘米的无颌鱼类，生活在距今4.36亿年前的志留纪早期。研究团队通过对包括隆平德安鱼在内的67种盔甲鱼类进行详细的形态学分析以及解剖学对比，建立了迄今为止最完善的盔甲鱼类系统发育数据矩阵，并建立了基干盔甲鱼类新科——德安鱼科。

On a well-preserved fossil brain, researchers identified sensory organs such as brain cavities, nerves, gill sacs, nasal sacs, eye sacs, and auricular sacs, indicating that Longping De'an fish has a longitudinal middle dorsal foramen, 6 pairs of gill sacs, and a posterior gill structure.

The middle dorsal hole of the armoured fish is the nostrils of the armoured fish, which has both the functions of smell and breathing. "Previously, the longitudinal oval middle dorsal foramen has been thought to be a unique feature of all true armoured fishes, and the longitudinal slit middle dorsal hole evolved from this feature." Gai Zhikun said that this is the first time that an elongated oval middle dorsal hole has been found in a group of basal armoured fishes, which further complicates the study of the evolution of the middle dorsal hole in armoured fishes. The longitudinal oval middle dorsal hole may represent the original features of armoured fishes.

The structure of the posterior gill region of Longping De'an provides a key clue to the origin of jawed body carapace. The posterior gill region is a cavity that opens backwards behind the gill area of the armoured fish, and is presumably used to protect the internal organs and other critical organs of the armoured fish. Recent research results suggest that the posterior branchial region located in the posterior segment of the cephalic carapace is a common ancestral feature of some early armor fishes. (Reporter Yuan Huijing, Wen Jinghua)