Rotifer muscles as revealed by phalloidin-TRITC staining and confocal scanning laser microscopy

By combining phalloidin-TRITC staining with confocal scanning laser microsc opy (CSLM), the pattern of the musculature in two species of Rotifera, Euch lanis dilatata unisetata and Brachionus quadridentatus is revealed. The sam e general muscle pattern prevails in both species. The major components of the body wall musculature are: 1. retractor muscles (5 pairs in E. dilatata unisetata and 3 pairs in B. quadridentatus); 2. Two pairs of dorso-ventral muscles; 3. Two pairs of perpendicular muscles (in E. dilatata unisetata); 4. retractors of the corona (median, lateral and ventral); 5. Foot retract ors. In addition, three pairs of cutaneo-visceral muscles and visceral musc les (including mastax muscles) are described. The sphincter of the corona w as found only in B. quadridentatus. The high degree of muscle differentiati on points to a high level of development of rotifer muscular system.