Description of unionacean glochidia in Finland, with a table aiding in their identification

Abstract

Colour and anatomy of the glochidial larvae of Anodonta anatina (L.), Anodonta cygnea (L.), Pseudanodonta complanata (RossM.), Unio pictorum (L.) and Unio tumidus (PHILIPSSON) were studied by using light and scanning electron microscopy. The structures which were considered were the shell, hooks and their spines, larval thread and sensory hair cells. Characteristic features helpful in the identification of the glochidia of the five species described in this paper and those of Margaritifera margaritifera (L.) are summarised in a table. The features are compared with those reported in other descriptions of unionacean glochidia.