Two undescribed species of polychaetes in Mediomastus (Annelida: Capitellidae) were collected from intertidal to shallow habitats in Tokyo Bay, Japan. These are M. duobalteus sp. n. and M. hanedaensis sp. n. Mediomastus duobalteus sp. n. is distinguishable from all congeners by the following characters: 1) segments 3, 4, 8-11 stainable with methyl green, 2) thoracic capillary chaetae unilimbate...

Estuaries provide valuable ecosystem services, but they are also subject to environmental pressures due high anthropogenic activities. The diversity and abundance of Polychaete can be used as indicators the health Kapuas estuary, supporting data currently lacking. objective this research is assess quality estuary through a community approach. study employed survey method by selecting ten sampli...