Stenostomum grande Child 1902

Stenostomum grande Child, 1902 Fig. 4 E, F Sampling sites. Display case with vegetation – Tank 2, Display case with vegetation in a Palmhouse. Description. A large Stenostomum reaching the length of 1100 μm in a two-zooid individual. The body shape is cylindrical and compact with pointed anterior and posterior parts (Fig. 4 E). The sensory pits are elongated and open to the environment, similar to the ones in S. paraguayense. They are enclosed shallowly in the anterior brain, which is composed of many metamers (Fig. 4 F). The posterior brain is made from four lobes with the posterior ones connecting through protrusions with refracting bodies, which are tear-shaped and consist of many granules (Fig. 4 F). The mouth opening is small but clearly visible and followed by a long pharynx, with strong circular musculature and a large number of glandular cells along the anterior two-thirds of its length (Fig. 4 F). The gut is dark brown and does not reach the caudal end of the body, which ends in a small, triangular tail (Fig. 4 E). The protonephridium is clearly visible, even at the dissecting scope, and ends after the gut, but does not reach the posterior extremity of the body. The worms can be cultured on Chalkley’s Medium with wheat at 20 ° C, where the animals stay at the bottom of a dish, feeding on decomposing organic matter. Distribution. US, New York and Massachusetts (Graff 1913); Russia, Kola Peninsula (Nassonov 1924); US, Virginia (Nuttycombe and Waters 1938); Brazil, São Paulo (Marcus 1945); Surinam, Onverwacht (van der Land 1970); Poland, heated Konin Lakes (Kolasa 1977); US, New York (Kolasa et al. 1987); Japan, Ikeura rice field (Yamazaki et al. 2012); Argentina, Buenos Aires (Noreña et al. 2005); Lake Mangueira and Lake Nicola (Reyes et al. 2021).