AMPHIBIA Two stages: many Paleozoic-Triassic groups and 3 modern groups with no claear connections from the ancient to the modern modifications for support, feeding, respiration, locomotion, water balance, senses, reproduction Beginnings: Late Devonian Ichthyostega head support; opercle and gill loss in adults shoulder girdle separate from skull vert neural arches with zygapophyses loss of fins except caudal cranial kinesis mostly lost limbs with flexible elbow and knee joints; humerus, radius, ulna, femur, tibia, fibula, fingers and toes Panderichthys, Russia, head only 2 Palezoic grades Labyrinthodonts (e.g. Ichthyostega near the base of the tree) later forms have otic notch for tympanum 2 part occipital condyle infolded tooth enamel fangs in second row of teeth on palate 2 groups of Labyrinthodonts 1) Temnospondyls (100+ genera; Miss - Triass; large intercentra (AV), small pleurocentra (postdorsal) 4 toed manus Miss: elongate Greererpeton Penn Trimerorhachus advanced Temnospondyls (including Stereospondyls) Eryopids \ (TX, Perm, 2m) Capitosaurs \ Metoposaurs > examples on exhibit Plagiosaurs / Trematosaurs long snouted, marine Branchiosaurs are early growth stages or neotenic including Anthracosaurs, possible ancestors to Seymouriamorphs, Diadectes, and reptiles, with deep otic notch short trunk, well developed limbs trend to small, impedence matching stapes e.g., Proterogyrinus (primitive, Miss); Seymouria (TX, Perm, large, terrestrial, reptilian) 2) Lepospondyls no fangs, no labyrinthine dentine, no otic notch pleurocentrum in most "husk vertebrae" single or wide 3-part occipital condyle e.g. Aistopoda (few; Miss-Perm; long body, small limbs) Nectridia (few; Penn-Perm; aquatic, e.g., Diplocaulus) Microsauria (Miss-Perm; terrestrial; small with small limbs) -->Modern Amphibia (Lissamphibia: Anura, Uodella, Gymnophiona)