Lobe-finned fish one meter long developed into four-legged fish {tetrapod}| (Tetrapoda) in shallow, plant-filled, fresh or brackish water, in tropics and subtropics. Perhaps, front limbs helped lift head above water to get more oxygen.
fins
Pectoral and pelvic fins gained feet and toes. Tetrapods have no tail fins.
bone
Vertebrae became interlocking. Neck became flexible after losing bones that joined head and shoulders. Snout became longer and head flatter. Gill and neck bones {opercular bone, tetrapod} disappeared. Longer ribs appeared. Pelvis became larger.
evolution
Most early lobefin fish were not tetrapod ancestors: Kenichthys [-400000000], Osteolepidids [-394000000], Eusthenopteron [-388000000], Panderichthys [-385000000], Elpistostege [-384000000], and Livoniana [-384000000]. Most early tetrapods are extinct and were not living-tetrapod ancestors: Elginerpeton [-378000000], Ventastega [-370000000], Acanthostega [-368000000], Ichthyostega [-366000000], and Tulerpeton [-364000000].
Biological Sciences>Zoology>Kinds>Fish>Teleost>Lobe-Finned>Fresh Water>Tetrapod
4-Zoology-Kinds-Fish-Teleost-Lobe-Finned-Fresh Water-Tetrapod
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Date Modified: 2022.0224