EEB267H1 Lecture Notes - Lecture 10: Shoulder Girdle, Gymnophiona, Cloaca
7 Feb 2017
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Synapomorphy: four digits or fewer on hand. 205 species: most species are terrestrial burrowers difficult to find, one family is entirely aquatic. Long and limbless: no legs, arms, pelvic girdle or pectoral girdle unusual, lost through time, basal species have reduced tails, more derived species have no tails, extinct species had legs and a short tail. Autapomorphy: annuli: rings of skin on the outside (not internally segmented like earthworms) different from earthworms as they are vertebrates, some species have tiny scales embedded at bottom of annuli. Predators: robust, solid skull; upper jaws are fused, backwards-pointing teeth helps caecilians hold on to struggling prey, feed on insects, termites, earthworms (invertebrates) Reduced eyes: no colour vision, could be covered with skin protected, vision is not as important as other senses, see in contrast eyes extremely sensitive to light. Autoapomorhy: tentacles: small projections sticking out from sides, chemosensory organ, sensitive to chemical cues.
