4 dpf Development
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By 96 hpf, the hyosymplectic (hs) has grown considerably from that seen at 72 hpf and now can be discerned easily from the interhyal (ih) ventrally. The hyomandibula region of the hyosymplectic articulates with the anterior portion of the otic capsule (ot) in a synchondrosis, which makes it difficult to distinguish the separate elements with fluorescent labeling of chondrocytes (darker area in hyomandibula region is an overlying melanocyte). The opercle (op) projects ventrally from its articulation at the posterodorsal aspect of the hyomandibula region. The symplectic region of the hyosymplectic overlaps considerably with the palatoquadrate (pq) anteriorly.