The larva of Malacobdella siliqua collected in February 2013. Note longitudinal groove at right and posterior cirrus at left. Scale 100 µm. 

Malacobdella siliquae

Sequence Data:  16S, COI

Observed in Coos Bay: Feb

This is the larva of Malacobdella siliquae.  The adults of this species are found within the mantle cavity of the razor clam, Siliqua patula (Kozloff 1991; Roe et al. 2007). The larvae were collected once in February, are very small and show no obvious hoplonemertean larval characteristics –there is no apical tuft, no conspicuous cerebral organs and no eyes. Instead, larvae may be recognized by a long (1/4 body length) mid-ventral groove at the anterior end. They have a rounded anterior and blunt posterior with a posterior cirrus (above). The larvae we collected were young and superficially resembled small palaeonemertean larvae.