Umbo bivalve meaning Each valve can be regarded as having; dorsal, ventral, anterior and posterior margins. The region opposite is the ventral margin. If the adductor muscles are relaxed, the shell is pulled open by ligaments located on each side of the umbo. The area surrounding the beak is known as the umbo although some regard these terms as interchangeable. In Brachiopoda and Bivalvia, the first part of the shell to be formed; it occurs at the posterior of each valve in brachiopods and forms the dorsal part of the shell in bivalves. Mar 3, 2023 · La plupart des bivalves primitifs (protobranches) sont des détritivores sélectifs et aucun d'entre eux possèdent une radula, mais ils restent toutefois au contact avec le substrat grâce à une paire de tentacules recouverts de mucus qui fonctionnent comme des extensions de la bouche. The beaks effectively divide the dorsal margin into anterodorsal and posterodorsal parts. Jan 5, 2023 · Right and left valves. In Brachiopoda [1] and Bivalvia [2], the first part of the shell to be formed; it occurs at the posterior of each valve in brachiopods and forms the dorsal part of the shell in bivalves. This type of larva looks like a miniature bivalve with a row of L'umbo (pluriel umbones ou umbos, du latin umbo, « bosse, protubérance »), est l'extrémité saillante des valves d'un mollusque bivalve ou univalve. xdxmugflnyobmwtrumqsatlmyzaidkudjgbrxnzjlldqawyzekcztsdgdmlbrcoxeilqvsitaqyyagbwq