part of part of in taxon Mammalia compound organ pineal complex parapineal organ UBERON:0015241 An unpaired left-sided accessory organ which plays a role in establishing lateral brain left right asymmetry[ZFA:0001360, ZFIN:ZDB-PUB-030206-1]. TAO:0001360 In lampreys and apparently in some fossil fish, the parapineal body and the pineal body (epiphysis) are a bilateral pair of structures rather than being located in series, one in front of the other. A pair of visual structures may have been the ancestral condition of this pineal complex (Weichert, 1970, p.622). The parapineal organs of lampreys, tadpoles, and lizards possess cells similar to rods and cones. Frogs possess a brow spot or frontal organ where ancestral pineal eye might have been (Weichert, 1970, p.622) parapineal gland ZFA:0001360