Serpentes Titanoboa • Some 60 million years ago, well after the demise of the dinosaurs, a giant relative of today's boa constrictors, weighing more than a ton and measuring 13 meters long, hunted crocodiles in rain-washed tropical forests in northern South America, according to a new filfossil discovery. • The fossil find - a batch of super-size vertebrae pulled from an open- pit coal mine in northeastern Colombia - is remarkable enough just as a paltliltleontological extreme. ThiThe species, g iven the name Titanoboa cerrejonensis, is the largest known snake species ever discovered. Locomotion • Figure 13-5 – Lateral undulation http://www.youtube.com/watch?v=JA5PyUFGHtI – Rectilinearhttp://www.youtube.com/watch?v=Ci_OxulaWwY – Concertina – Sidewinding http://www.youtube.com/watch?v=JyXNBAHu32o Snake Skull • Snakes have 8 links in the skull with joints Prey detection Thermal prey detection • Some snakes detect prey by thermal cues • Infrared light is sensed by trigeminal- innervated blind nerve endings • Many boas and pythons have labial “pits” and cro tlitalines (iti(pit vipers )h) have “it”i“pits” in their loreal scales • Temperatures of 0.05 degrees C will elicit a response from some snakes Prey capture • Depends on prey, many species just grab their prey and eat it. • Large prey pose other problems • Constriction http://www.youtube.com/watch?v=-Evvo79ojME • Venom injection http://www.youtube.com/watch?v=_wSetsdtNfw Venomous snakes • Venom glands are Duvernoy’ s Gland • The venom delivery system consists of the gland, muscles to force venom from the gland, ducts to transport venom, and fangs to inject venom Venomous snakes •Oppgypisthoglyphous – snakes have one or more enlarged teeth near the rear of the maxilla (mainly found in Colubrids) • PlhProteroglyphous – hllhollow fangs locate d at t he front of the maxilla that are permanently erect (Elapidae) • Solenoglyphous – the hollow fangs are the only teeth on the maxilla and can rotate so that the fangs can fold up when the mouth is closed (pit vipers and true vipers) Venom Table 13-4 Snake defensive behaviors • Death feigggning • Mimicry • Warning colors • Diverting attack • Spitting • http://www. youtube.com/watc h?v=_5dtpMj9Ehs.