vert zoo final phylogeny

diploblast

animals with two germ layers (ectoderm and endoderm), includes cnidarians

Parahoxozoa

clade including cnidarians and bilaterians defined by presence of Hox genes

Bilateria

animals with bilateral symmetry and three germ layers (triploblastic)

Nephrozoa

bilaterians with specialized excretory organs (nephridia)

Deuterostomia

bilaterians where the blastopore becomes the anus (includes chordates and echinoderms)

Gnathostomata

jawed vertebrates including sharks, bony fish, amphibians, reptiles, birds, and mammals

Chondrichthyes

cartilaginous fishes (sharks, rays, chimaeras)

Osteichthyes

bony fishes including ray-finned and lobe-finned fishes

Actinopterygii

ray-finned fishes; most modern fish species

Sarcopterygii

lobe-finned fishes; includes lungfish, coelacanths, and tetrapods

Actinistia

coelacanths; deep-sea lobe-finned fishes with lobed fins and intracranial joint

Dipnoi

lungfish; air-breathing freshwater fishes with lungs

Rhipidistia

clade including lungfish and tetrapods

Eusthenopteron

lobe-finned fish with tetrapod-like limb bones

Tiktaalik

transitional fossil with neck and limb-like fins

Acanthostega

early tetrapod with limbs but mostly aquatic

Ichthyostega

early tetrapod more adapted to land locomotion

Tetrapoda

vertebrates with four limbs (amphibians + amniotes)

Lissamphibia

modern amphibians (frogs, salamanders, caecilians)

Amniota

tetrapods with amniotic egg (reptiles, birds, mammals)

Anura

frogs; tailless amphibians adapted for jumping

Urodela (Caudata)

salamanders; retain tail as adults

Gymnophiona

caecilians; limbless burrowing amphibians

Batrachia

clade including frogs and salamanders

Cryptobranchidae

giant salamanders and hellbenders

Plethodontidae

lungless salamanders; rely on cutaneous respiration

Ambystomatidae

mole salamanders (e.g., axolotls)

Sirenidae

aquatic salamanders lacking hind limbs

Hyloidea

“true” frogs and many tree frogs

Ranoidea

diverse frog group including many aquatic and terrestrial frogs

Bufonidae

“true” toads with toxin-producing glands

Synapsida

amniotes with one temporal fenestra (mammals and ancestors)

Sauropsida

reptiles and birds

Diapsida

reptiles with two temporal fenestrae (includes birds)

Archosauria

crocodilians + dinosaurs + birds

Avemetatarsalia

lineage leading to dinosaurs and birds

Dinosauria

clade of dinosaurs including birds

Ornithischia

herbivorous “bird-hipped” dinosaurs

Saurischia

“lizard-hipped” dinosaurs including theropods

Theropoda

bipedal carnivorous dinosaurs; ancestors of birds

Aves

birds; living theropod dinosaurs

Mammalia

mammals with hair, milk, and specialized jaws

Monotremata

egg-laying mammals (platypus, echidna)

Theria

live-bearing mammals

Metatheria

marsupials; pouch-bearing mammals

Eutheria

placental mammals

Afrotheria

African mammals (elephants, manatees)

Xenarthra

armadillos, sloths, anteaters

Laurasiatheria

bats, whales, carnivores, hoofed mammals

Euarchontoglires

primates, rodents, rabbits

Primates

mammals with grasping hands, forward-facing eyes, and large brains

Hominidae

great apes including humans, chimpanzees, gorillas, and orangutans

Homo sapiens

modern humans with advanced cognition and language

Cetacea

whales and dolphins; aquatic mammals

Hippopotamidae

hippos; closest relatives of whales

Pikaia gracilens

early chordate fossil resembling lancelets

Haikouichthys

early vertebrate with camera-type eyes

Cephalochordata

lancelets; retain all chordate traits as adults

Urochordata

tunicates; closest relatives to vertebrates

Hemichordata

acorn worms; related to echinoderms

Ambulacraria

echinoderms + hemichordates

Ostracoderms

extinct jawless armored vertebrates

Acanthodii

extinct “spiny sharks”

Placoderms

extinct armored jawed fishes

Salmoniformes

salmon; anadromous fishes with adipose fin

Gadiformes

cod and haddock; important marine fishes

Lophiiformes

anglerfish; bioluminescent lure

Cichliformes

freshwater fish with rapid adaptive radiation

Anguilliformes

eels; elongated bodies

Siluriformes

catfish; barbels and no scales

Ampullae of Lorenzini

electroreception organs in sharks

Lateral line system

detects water movement in fish and amphibians

Neuromasts

sensory units of lateral line

Amniotic egg

egg with membranes allowing reproduction on land

Secondary palate

allows breathing and chewing simultaneously

Diaphragm

muscle for efficient lung ventilation

Gnathostomata → Osteichthyes → Sarcopterygii → Rhipidistia → Tetrapoda → Lissamphibia or Amniota

major vertebrate phylogeny pathway

Amniota → Synapsida or Sauropsida

major amniote split

Sauropsida → Diapsida → Archosauria → Dinosauria → Aves

lineage leading to birds

Sauropsida

reptiles and birds

Diapsida

reptiles with two temporal openings

Lepidosauria

lizards, snakes, and tuatara

Rhynchocephalia

tuatara lineage

Squamata

lizards, snakes, and amphisbaenians

Toxifera

squamate clade where venom evolved

Serpentes

snakes

Testudines

turtles

Archelosauria

turtles + archosaurs

Archosauria

crocodilians + dinosaurs + birds

Crocodylomorpha

crocodiles and relatives

Gekkota

squamate clade with adhesive toe pads, specialized for climbing surfaces

Scincomorpha

squamate clade including skinks, often with reduced limbs and elongated bodies

Toxifera

squamate clade in which venom evolved, includes many lizards and snakes

Iguania

squamate clade including iguanas and chameleons, often with specialized tongues for prey capture

Anguimorpha

squamate clade including monitor lizards and Komodo dragons, often active predators with strong jaws