Lecture 07 PART2 Handout PDF 14/10/2012

14/10/2012 Lecture 07 Part 2: early diversification of tetrapods ERA Period mya Land Plants Quaternary 2 CENOZOIC Tertiary 5 66 Cretaceous...

14/10/2012 Lecture 07 Part 2: early diversification of tetrapods ERA Period mya Land Plants Quaternary 2 CENOZOIC Tertiary 5 66 Cretaceous Flowering plants MESOZOIC 145 Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Gymnosperms Devonian Seed plants PAEOZOIC 416 Silurian Vascular plants 444 Ordovician Land plants 488 Cambrian 542 PROTEROZOIC 2500 1  14/10/2012 ERA Period mya Land Plants Animals Quaternary 2 CENOZOIC Tertiary 5 66 Cretaceous Flowering plants MESOZOIC 145 Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Gymnosperms Devonian Seed plants Land tetrapods (mid to late Devonian) PAEOZOIC 416 Silurian Vascular plants Bony fish appear (late Silurian) 444 Ordovician Land plants 488 First vertebrates in late Cambrian or early Ord. Cambrian 542 Cambrian explosion of animal phyla PROTEROZOIC Earliest animals in Ediacaran 2500 ERA Period mya Land Plants Animals Quaternary 2 CENOZOIC Tertiary 5 66 Cretaceous Flowering plants MESOZOIC 145 Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Gymnosperms Devonian Seed plants Land tetrapods (mid to late Devonian) PAEOZOIC 416 Silurian Vascular plants Bony fish appear (late Silurian) 444 Ordovician Land plants 488 First vertebrates in late Cambrian or early Ord. Cambrian 542 Cambrian explosion of animal phyla PROTEROZOIC Earliest animals in Ediacaran 2500 2  14/10/2012 ERA Period mya 1) Early Tetrapods Quaternary 5 Tertiary Early tetrapods flourished during the Carboniferous CENOZOIC and Permian producing a diversity of forms. Here are a few examples (which you do not need to remember) 66 Cretaceous 145 MESOZOIC Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 Colosteidae Crassigyrnius Whatcheeriidae Seymouriamorpha Westlothiana Keraterpetontidae Aistopoda 3  14/10/2012 ERA Period mya 1) Early Tetrapods Quaternary 5 Most early tetrapod lineages went extinct at the Tertiary beginning of the Triassic CENOZOIC Two main lineages survived: 66 1) The Lissamphia – Amphibians (frogs, Cretaceous salamanders, caecilians etc.) 145 MESOZOIC Jurassic 200 2) The Amniotes – (reptiles, mammals, birds) Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 Colosteidae Crassigyrnius Lissamphibia Whatcheeriidae Seymouriamorpha Amniotes Westlothiana Keraterpetontidae Aistopoda 4  14/10/2012 ERA Period mya 2) Lissamphibia Quaternary 3 groups of living amphibians: 5 1. Caecilians = 174 species Tertiary CENOZOIC 2. Urodeles (salamanders and newts) = 517 species 3. Anurans (frogs and toads) = 5602 species 66 Cretaceous 145 MESOZOIC Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 ERA Period mya 2) Lissamphibia Quaternary 5 3 groups of living amphibians: Tertiary CENOZOIC 1. Caecilians Wormlike amphibians Completely lack limbs 66 Reduced eyes, covered by skin for Cretaceous protection and see only light and dark 145 MESOZOIC Jurassic Burrowing lifestyle 200 Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 5  14/10/2012 ERA Period mya 2) Lissamphibia Quaternary 5 3 groups of living amphibians: Tertiary CENOZOIC 2. Urodeles (salamanders and newts) 66 Cretaceous 145 MESOZOIC Jurassic 200 Triassic 251 Permian Newly discovered species 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian Giant Salamander 542 ERA Period mya 2) Lissamphibia Quaternary 3 groups of living amphibians: 5 Tertiary 3. Anurans (frogs and toads) CENOZOIC 66 Cretaceous 145 MESOZOIC Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 6  14/10/2012 Caecilians (174 species) Urodeles (517 species) Triadobatrachus Early Triassic Anurans (5600+ species) Intermediate between frogs Prosalirus and salamanders Early Jurassic Prosalirus other tetrapods Tailed Frog Triadobatrachus 7  14/10/2012 Colosteidae Crassigyrnius Lissamphibia Whatcheeriidae Seymouriamorpha Amniotes Westlothiana Keraterpetontidae Aistopoda 3) Evolution of Amniotes The amniotic egg unites all amniotes as a taxonomic group, the Amniota Frog egg All vertebrates have a yolk sac membrane like these frog eggs albumin yolk 8  14/10/2012 3) Evolution of Amniotes The amniotic egg unites all amniotes as a taxonomic group, the Amniota All vertebrates have a yolk sac membrane Amniotic embryos produce an additional membrane that folds around the embryo called the amnion The amniotic fluid inside the amnion a similar composition to sea water The Amniotic egg functions like a spaceship in an alien environment: The shell is the outer hull The amnion is the crew quarters where the embryo develops The yolk is the food source The albumin is the water supply The Allantois is the gas exchanger bringing oxygen to the embryo and expelling CO2. 3) Evolution of Amniotes The amniotic egg unites all amniotes as a taxonomic group, the Amniota Most amphibians lay soft eggs in water and the young are reared in water until they metamorphosize into adults and come onto land. The hard shell of the amniotic egg allowed amniotes to be fully terrestrial without desiccating. Amniotic young develop to a further stage than amphibians while in the egg and hatch as terrestrial animals, often as miniature versions of adults. 9  14/10/2012 QUESTION: Why might the amniotic egg have been revolutionary for those tetrapods which possessed them? 3) Evolution of Amniotes The amniotic egg unites all amniotes as a taxonomic group, the Amniota Most amphibians lay soft eggs in water and the young are reared in water until they metamorphosize into adults and come onto land. The hard shell of the amniotic egg allowed amniotes to be fully terrestrial without desiccating. Amniotic young develop to a further stage than amphibians while in the egg and hatch as terrestrial animals, often as miniature versions of adults. The hard shell of the amniotic egg (lost in most mammals) meant that eggs no longer had to be placed in water. Consequently amniotes radiated to fill a greater variety of terrestrial environments that earlier tetrapods could not occupy. 10  14/10/2012 3) Evolution of Amniotes Vertebrate phylogenetic tree Eusthenopteron Panderichthys Tiktaalik Acanthostega Ichthystega Balanerpeton Caecilians Urodeles Anurans 1 Amniotic egg, able to Amniotes be fully terrestrial ERA Period mya 3) Evolution of Amniotes Quaternary Amniotes came to be dominant land animals in 5 all terrestrial environments from the Permian to Tertiary CENOZOIC the present. 66 Cretaceous 145 MESOZOIC Jurassic 200 Triassic 251 Permian 299 Carboniferous 359 Devonian PAEOZOIC 416 Silurian 444 Ordovician 488 Cambrian 542 11  14/10/2012 3) Evolution of Amniotes i) Skull structure Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids 3) Evolution of Amniotes i) Skull structure Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Diapsids 12  14/10/2012 3) Evolution of Amniotes i) Skull structure Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Diapsids Synapsids 3) Evolution of Amniotes i) Skull structure Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Turtles Diapsids Lizards, Crocodiles, Dinosaurs, Birds Synapsids Mammals 13  14/10/2012 3) Evolution of Amniotes i) Skull structure Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Turtles Diapsids Lizards, Crocodiles, Dinosaurs, Birds Synapsids Mammals 3) Evolution of Amniotes i) Skull structure Morphological phylogenetic analyses support this tree Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Turtles Diapsids Lizards, Crocodiles, Dinosaurs, Birds Synapsids Mammals 14  14/10/2012 3) Evolution of Amniotes i) Skull structure Molecular phylogenetic analyses support this tree Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Fish Lissamphibia Anapsids Turtles Secondarily derived Anapsid state Diapsids Lizards, Crocodiles, Dinosaurs, Birds Synapsids Mammals Carbon. Permian Triassic Jurassic Cretaceous Cenozoic 4) Anapsids Turtles 15  14/10/2012 Permian Triassic Jurassic Cretaceous Cenozoic 4) Anapsids 10 trunk vertebrae Eunotosaurus Odontochelys ? Proganochelys and modern turtles Permian Triassic Jurassic Cretaceous Cenozoic 4) Anapsids 10 trunk vertebrae Eunotosaurus Odontochelys ? Has teeth, long tail, lack of shell on back, shell only ventrally Proganochelys and modern turtles 16  14/10/2012 QUESTION: Why might this sea turtle from the Cretaceous have grown to such monstrous sizes and why do turtles not grow to such sizes today? the giant Cretaceous sea turtle, Archelon 5) Diapsids Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Turtles Turtles Squamates Tuatara Plesiosaurs Ichthyosaurs Champsosaurs Archosaurs 17  14/10/2012 5) Diapsids Carbon. Permian Triassic Jurassic Cretaceous Cenozoic Turtles Turtles Squamates Tuatara Plesiosaurs Ichthyosaurs Champsosaurs Archosaurs Permian Triassic Jurassic Cretaceous Cenozoic Squamates Tuatara Lepidosauromorpha Plesiosaurs ? Ichthyosaurs ? Champsosaurs Archosauromorpha Trilophosaurs Archosaurs 18  14/10/2012 Permian Triassic Jurassic Cretaceous Cenozoic Squamates Lepidosauromorpha Tuatara 5) Diapsids a) Lepidosauromorpha i. Squamates Squamate Phylogeny 19  14/10/2012 Squamate Phylogeny What are snakes? 2 hypotheses for origin: Monitor Lizard Squamate Phylogeny What are snakes? 2 hypotheses for origin: 1) Sea origin: They are descendants of Cretaceous Mosasaurs, a group of Marine reptiles related to Monitor Lizard modern day monitor Mosasaur lizards Monitor lizard Mosasaur 20  14/10/2012 Squamate Phylogeny What are snakes? 2 hypotheses for origin: 2) Terrestrial origin: They are descendants of a terrestrial group with adaptations to burrowing way of life. Squamate Phylogeny other families Bipedidae worm lizards snakes legless lizards (burrow in soil) 21  14/10/2012 Recently discovered fossil of Najash from 90 Mya in mid-Cretaceous is the most primitive snake known. Fossils are from a terrestrial deposit This fossil know as Najash dates to 90 Mya and has transitional features between lizards and snakes which suggest the terrestrial hypothesis for snake origins.. It has hind limbs which appear to have been adapted to a burrowing lifestyle much like legless lizards. Unlike modern snakes, it still had a sacrum and pelvic girdle like in lizards Najash Permian Triassic Jurassic Cretaceous Cenozoic Squamates Lepidosauromorpha Tuatara 5) Diapsids a) Lepidosauromorpha i. Squamates ii. Tuatara 22  14/10/2012 Vertebrate phylogenetic tree Eusthenopteron Panderichthys Tiktaalik Acanthostega Ichthystega Balanerpeton Lissamphibia Caecilians Urodeles Tetrapoda Anurans 1 Synapsids Amniotic egg, able to be fully terrestrial Anapsids Amniotes Squamates Diaspids Tuatara Archeosauromorpha Vertebrate phylogenetic tree Eusthenopteron Panderichthys Tiktaalik Acanthostega Ichthystega Balanerpeton Caecilians Urodeles Anurans 1 Turtles Amniotic egg, able to Squamates be fully terrestrial Tuatara Archeosauromorpha Synapsids 23  14/10/2012 For in depth review: Chapter 9 of Cowan 30 min 24