part of part of overlaps overlaps in taxon develops from develops from Amphibia Aves neurocranium chondrocranium neurocranial trabecula endochondral element mesethmoid element absent in primitive mammals, ungulates, amphibians, reptiles/birds ventral nasal capsule mesethmoid UBERON:0010892 An endochondral element of the nasal capsule that forms septum between nasal capsules and usually remains unossified in mammals. relationship loss: part_of braincase and otic capsule skeleton (AAO:0000052)[AAO] AAO:0000303 Endochondral ossification of the anteromedial portion of the braincase.[AAO] ethmoid region