Zool 325 Phylogeny

Hemichordata: Enteropneusta

‘Acorn worms’

Cephalocordata

‘Lancelets’ “Amphioxus’

Urochordata

‘Sea squirts’

Ascidiacea, Larvaceae, Thaliaceae

 Agnathans

‘Jawless fish’

Paraphyletic lineage → Ancestral to gnathostomes

 Cyclostoma

Living Agnathans; (Hagfish and Lampreys)

Monophyletic

Myxiniforms

‘Hagfish’

Petromyzontiforms

 ‘Lampreys’

Ostracoderms

‘Armored agnathans’

Paraphyletic → Ancestral to gnathostomes

Gnathostomata

‘Jawed Vertebrates’

Monophyletic

Placoderms

‘armored fish’

Paraphyletic → ancestral to all other gnathostomes

Acanthodians

 ‘Spiny Sharks’

Paraphyletic 

 Chondrichythes

‘Cartilaginous fish’

 Oestiechthyes

 ‘Bony Fish’

Actinopterygians + Sacoptergians

Actinopterygii

 ‘Ray finned fish’

Primitive Actinopterygians

Polypteridiae → Bichirs and Reedfish

• Small slender-bodied fish

Acipensiseriformes → Sturgeons and paddle fish

• Larger fish with heterocercal tails

‘Teleostei’

Derived Actinopterygians

Sarcopterygii

‘Lobed-finned fish’

Includes coelacanths, lungfish, tetrapods and osteolepiforms

Osteolepiforms

Paleozoic sactoptergynains that are more closely related to tetrapods than are coelacanths or lungfish

Acanthostega

‘Devonian sortapod’

→Stem tetrapods

Tetrapoda

‘four footed’ ‘terrestrial vertebrates’

Amphibians

Paraphyletic

All tetrapods that are not amniotes

Labrinthodont Amphibians

Paraphyletic

Amphibians with Labrinthodont teeth; ancestors of lissamphibians and amniotes

Lissamphibia

‘modern amphibians’

Frogs, salamanders and caecilians

Urodela

Salamanders and Newts

→ Least specialized lissamphibian clade

Gymnophiona

‘Caeilians’

Anura

Frogs and Toads

→ Most diverse lissamphibian clade

Amniota

Reptiles + mammals + their fossil relatives

Sauropsida

living reptiles, including birds plus their extinct relatives

Synapsids

 mammals and their extinct relatives

Parareptilia

Early sauropods

Anapsid skull

Sauropterygia

Extinct marine reptiles related to lepidosauria

Euryapsid skull

Lepidosauria

Modern reptiles and their realatives

Squamates

lizards, including snakes and amphisbaenians. Limblessness is not unusual in this group

Rhynchocephalian

lizard-like but with specific defining anatomical details that distinguish them from true lizards. The only living representative is Tuataras from New Zealand

Archosauria

‘Ruling reptiles’

Includes the common ancestors of birds and crocodilians and its descendants

Also includes pterosaurs, non avian dinosaurs and many triassic groups related to crocodilians

Crocodylia

Common ancestor of modern alligators, crocodiles and gharial

→ Part of a much larger and more diverse group crocodylomorpha going back o the triassic

Pterosauria

Triassic cretaceous flying archosaurs

Ornithischia

Diverse herbivores

Pubis and Ischium directed posteriorly

Saurischia

long neck herbivores (sauropodomorphs) and carnivores (theropods)

Pubic directed anteriorly

Ilium directly posteriorly

Avialae

‘Birds’

Theropod dinosaurs with feathers 

Aves

‘Advanced birds’

Palaeognathae

‘flightless birds’

ratites (rheas, ostriches, emus, kiwis, cassowaries) and tinamous

Neognathae

‘flying birds’ have a keeled sternum

Pelycosaurs

Paraphyletic → ancestral to therapsids

Early synapsids

Therapsida

Derived synapsids, including mammals

Mammalia

Appeared in the Jurassic 

→ Greater diversity of habitats and lifestyles than other tetrapod groups

Monotrema

2 Surviving types → Platypus, Echidnas

Primate groups

1. Strepsirrhini: lemurs and lorises

2. Haplorhini: tarsiers, platyrrhines and catarrhines

2 Main Haplorhini groups

Platyrrhini: New world monkeys

Catarrhini: Old world monkeys (includes humans)