Exam 2 phylogeny

·         Chordata – 5 hallmarks

o    Cephalochordata -

§  Amphioxus

·         Lancelet – slender, laterally flattened, 5-7 cm long, monecious, external fertilization

o    Vertebrata (Craniata) – ventral 3-chambered heart, tripartite brain,

§  Agnatha

·         Myxini

o    Hagfish – slime pores, marine, scavengers, knot, 100:1 sex ratio,

·         Petromyzontida

o    Lamprey- parasitic, anadromous, buccal funnel, control measures

·         Ostracoderm: extinct 530-MYO fossils, armored, lacked paired fins, <30cm,

§  Gnathostomata – gill arches and jaws derived from neural crest cells

·         Placoderm – head and thorax covered by thick armored plates, up to 11 meters,

·         Chondrichthyes – placoid scales, claspers, cartilaginous skeleton

o    Elasmobranchii – rostrum, spiracle, heterocercal tail (thrust and lift)

§  Sharks – ram ventilation, lateral-line system, ampullae of lorenzini, spiral valve, large liver, nitrogen in blood

§  Skates and rays – flat disklike body, benthic, platelike teeth,

o    Holocephali – Chimaeras

§  Ratfish – jaws with flat plates, upper jaw fused to cranium

·         Acanthodii – mix of bony and cartilaginous skeleton, fins supported by spines, 1-2 m

·         Osteichthyes – bony fish

o    Actinopterygii – ray finned fish

§  Sturgeon/Paddlefish – ganoid scales, heterocercal tail

§  Bowfin/Gar – ganoid scales, heterocercal tail, Mississippi river

§  Teleost – cycloid or ctenoid scales, homocercal tail, flexible dorsal fin, swim bladder, operculum

o    Sarcopterygii – lobe finned fish

§  Lungfish- survive dessication seasons

§  Coelacanth – diphycercal tail, fleshy fins

·         Intermediate Tetrapods – oxygen, density, temperature, dessication

o    Eusthenopteron – paddle through bottom mud, lungs and walking fins

o    Tiktaalik- recently discovered, limbs support body, snout above breathing

o    Acanthostega – clearly formed digits, drug body on ground

o    Ichthyostega – bulkier limb muscles, didn’t walk efficiently

o    Limnoscelis – 5 digits, early Permian (300 MYA)

o    Temnospondyls – resemble large salamanders, 20 cm – 3 m long, aquatic

o    Lepospondyls – simple spool-shaped vertebra, small, aquatic

·         Tetrapoda

o    Lissamphibia – pedicellate teeth, mucus and poison glands, muscles elevate the eye, straight ribs, cutaneous respiration, buccopharyngeal force breathing

§  Urodella

·         Salamanders- four-limbed, long tails, costal grooves, lack scales, regenerate limbs, mythology, paedomorphosis (Axolotl)

§  Anura – cosmopolitan except oceanic islands, fused caudal vertebrae, shortened trunk, paratoids, sexually dimorphic, amplexus

·         Toads and Frogs

§  Apoda of Gymnophiona

·         Caecilians – elongate, burrowing, limbless, tropical forests, terminal anus, internal insemination, parental care, tentacle – chemosensory organ that opens to the surface of the head through an aperture in the skull located between eyes and nostril

o    Amniota: Yolk sac, amnion, allantois, chorion, shell

§  Lepidosauria – better jaws than amphibians, suck air in by enlarging thoracic cavity,

·         Sphenodonta (Rhynchocephalia):living fossil, brain and mode of locomotion like amphibians, New Zealand

·         Squamata – scaled reptiles,

o    Lizards- extremely diverse group including terrestrial, burrowing, aquatic, arboreal and even aerial

§  Helodermatidae – venom glands in low jaw

§  Beaded lizards/ Gila monsters

§  Amphisbaens – legless, moveable eyelids, external ears

o    Serpentes – Jacobson’s organ

§  Boidae – boas (new world), pythons (old world), sand boas

§  Colubridae – 63% of all snakes, gopher, corn, king, milk, garter

§  Viperidae – none in Australia and Madagascar, hinged fangs, copperheads, pit vipers, adders, rattlesnakes

§  Elapidae – hollow fixed fangs, extremely venomous, coral, cobras, taipans, sea snakes, mambas

§  Testudines

·         Turtles: carapace, scutes, plastron (concave or convex)

§  Archosauria

·         Crocodilia

o    Crocodiles – widely distributed

o    Alligators  and caiman mostly new world

·         Aves – feathers, keratinized beaks, oviparous, pneumatic

o    Archaeopteryx – Germany 1861, 147 MYO,

§  Flightless Birds - ostrich

o    Neognathous Bird – keeled sternum, migration

§  Mammalia – early synapsids were pelycosaurs, hair, endothermy, homeothermy, sweat and scent glands, fleshy external ears, produce milk for young, horns vs. antlers,

·         Monotremata

o    Duck-billed platypus, echidnas

·         Diprotodontia

o    Koalas, wombats, wallabies, kangaroos

·         Chiroptera

o    Bats

·         Lagomorpha

o    Rabbits, hares, pika

·         Primates

o    Lemurs, monkeys, apes, humans

·         Rodentia

o    Squirrels, rats, woodchucks, porcupine, beaver, lemmings

·         Carnivora

o    Dogs, bears, weasels, seal, sea lions, walruses, cats, skunks, badgers, otters

·         Proboscidea

o    Elephants

·         Sirenia

o    Manatees

·         Perissodactly

o    Horses, rhinos, zebras

·         Artiodactlya

o    Camels, deer, hippos, cattle, goats, antelopes, swine

·         Cetacea

o    Whales, dolphins, porpoises