1. Crocodylians -diapsid skulls Oviparous; internal fertilization Semi-aquatic; bask on shorelines -12-60 eggs per clutch nest in mounds of vegetation mostly adapted well to an aquatic niche Montealtosuchus – a ‘missing link’ in crocodylian paleohistory. (discovered in 2008 near Rio de Janerio)

3. CharacterFamily AlligatoridaeFamily CrocodilidaeFamily Gavialidae Popular NameAlligators and Caimans True crocodilesGharial Head & SnoutMore oval than triangular Broad, triangular head with a short SnoutBeak-like extension of the snout 4 th lower tooth (when the mouth is closed) Not visible from outside Visible from outside Mandibular Symphysis (joint between two halves of lower jaw) Extends to a level less than 23 rd tooth Extends to a level of 23 rd or 24 th tooth DistributionS. America, China, USA Asia, Africa, Australia & Pacific Islands & USAAsia (India & Nepal) No. of Genera (No. of species given in brackets) Alligator(2) Caiman(2) Paleosuchus(1) Melanosuchus(2) Crocodylus (11) Osteolaemus(1) Tomistoma(1)Gaviali

5. Family Gavialidae Gharials monotypic Gavialis gangeticus -SW Asian River Basins longest and narrowest jaws of all crocodylians -males grow a boss on snout tip -most aquatic of crocodylians -impale fish by swiftly moving head -4 m in length (not really dangerous to man)

6. Family Alligatoridae Subfamily Alligatorinae 2 species Alligator mississippiensis American Alligator SE USA 4 meters opportunistic carnivore breed at 2.1 meters in length young have a very different coloration AR Post National Memorial females show parental care A. sinensis Chinese Alligator 2.1 meters 40% of diet is mollusks hibernates similar reproduction to American lower jaw fits within mouth upon closure

7. Subfamily Caimaninae 3 genera; 7 species -Central to south America, Amazonia -small to large 1.7m to 5m -freshwater -mound nest builders -harvested and habitat destruction Caiman crocodilus introduced into south FL. interaction with FL crocs? Dwarf Caiman (Paleosuchus)

8. Family Crocodylidae Crocodiles and False Gharials 2 subfamilies pan - tropical moderately long and broad jaws when mouth is shut, fourth mandibular tooth is exterior

9. Subfamily Crocodylinae 2 genera; 14 species Crocodylus acutus - American crocodile -up to 15 ft. -habitat destruction, moving into salt water -400 left in Everglades C. porosus - Estuarine crocodile -up to 20 feet -often seen at sea -opportunistic predator C. niloticus - Nile Crocodile -16 feet -quite dangerous, heavily populated Nile Valley -perhaps 5,000 people a year could be eaten -can build a sand nest but prefers mounds Osteolaemus Dwarf crocodile exclusively nocturnal

10. Subfamily Tomistominae False Gharial monotypic Tomistoma schlegelii -Borneo and Sumatra, Malay Peninsula -fish eater like gharial, can also ambush poorly known, overhunted, habitat destruction