Research on taxonomic characters and one new recorded species of genus Macrostomum (Platyhelminthes, Macrostomida) from China [In Chinese with English summary]

Macrostomum saifunicum Nasonov, 1929, a species belonging to the family Macrostomidae of the Order Macrostomida, was reported in China for the first time. The relationship between ontogenesis and penis development of M. saifunicum was studied in detail. The results indicated that: 1) The tip structure of the penis stylet of M. saifunicum formed and stabilized at 9 days old and was a reliable morphological characteristic. 2) The length of the individual penis stylet reached 140 µm after 20 days' growth, and increased to more than 160 µm after 40 days of growth when the individual reached senescent stage, showing that the length of the penis stylet was not a stable taxonomic characteristic. 3) M. saifunicum had been found in Beijing, Anhui, Hunan, Jiangxi, and Guangdong based on the author's collections for many years, indicating that M. saifunicum was a common and widespread species in China. The study also showed that Macrostomum was an ideal experimental animal in the fields of education and scientific research.