Feeding morphology of juvenile Utterbackia imbecillis (Bivalvia:Unionidae)

The ontogeny of the feeding morphology of juvenile U. imbecillis was examined to provide information about this relatively little studied stage of unionid mussel development. Glochidia larvae were induced to metamorphose to juveniles by using in vitro culture techniques. Juveniles were reared in a recirculating flow through trough system. Specimens were collected weekly from 0-130 days, and the progression of development of gill filaments, ciliation of the gills, foot and mantle, formation of the labial palps, and the ciliation of the oral field and mouth was followed with scanning electron microscopy. Newly metamorphosed juveniles possessed one pair of fully formed gill filaments with the full suite of lateral and frontal cilia and latero-frontal cirri, plus two pairs of gill buds – incompletely formed filaments. New filaments first appeared as buds at the posterior margin of the developing gill lamellae. As the juveniles grew, interfilamentary ciliary connections appeared at the tips of the filaments, to be followed by formal tissue connections. Subsequently the lamellae of each side of the animal joined at their ventral margins forming a basket-like array that effectively separated the ventral infrabranchial aspect of the mantle cavity from the dorsal suprabranchial space. This arrangement, coupled with the posterior-ward growth of the labial palps contacting the anterior of the paired lamellae, had the rudiments of a food groove that may enable juvenile mussels to filter feed prior to development of the ascending lamellae and the outer demibranch characteristic of adult mussels. With this morphology of the gills and related pallial structures, juvenile U. imbecillis may efficiently sort particles much earlier than previously thought. The early onset of filter feeding could augment the commonly described behavior of deposit feeding through pedal sweeping by juveniles of this and other species of unionid mussels.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2010

Author dc:creator

• Trump, Matthew

• Ultrastructure

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10339/14728

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/14728