Comparative AnatomyComparative Anatomy

Vertebrate Phylogeny: Vertebrate Phylogeny: Amphibians, Reptiles, and BirdsAmphibians, Reptiles, and Birds

Kardong Kardong Chapter 3Chapter 3

Part 5 Part 5

Amphibian CharacteristicsAmphibian Characteristics

11stst vertebrates to possess cervical vertebrae vertebrates to possess cervical vertebrae Lost scalesLost scales Some primitive frogs have dermal scalesSome primitive frogs have dermal scales Anamniotic eggsAnamniotic eggs 3 chambered heart3 chambered heart MetamorphosisMetamorphosis 10 pairs of cranial nerves10 pairs of cranial nerves 2 occipital condyles2 occipital condyles

Modern AmphibiansModern Amphibians

Order CaudataOrder Caudata Order AnuraOrder Anura Order Gymnophiona Order Gymnophiona

(Apoda)(Apoda)

Figure 5.1.

Reptiles (the Parareptilia and Reptiles (the Parareptilia and Eureptilia)Eureptilia)

Mesozoic Era - Age of ReptilesMesozoic Era - Age of Reptiles Carboniferous - Divided into Pennsylvanian (upper) Carboniferous - Divided into Pennsylvanian (upper)

and Mississippian (lower)and Mississippian (lower) Extinction took place at end of Paleozoic Era with Extinction took place at end of Paleozoic Era with

placodermsplacoderms

Figure 5.2. Carboniferous Period.

Labyrinthodont amphibians led to stem reptiles- Labyrinthodont amphibians led to stem reptiles- cotylosaurs (p. 109)cotylosaurs (p. 109) Which gave rise to all reptiles and mammalsWhich gave rise to all reptiles and mammals

Figure 5.3. Cotylosuars, stem reptiles.

Figure 5.4. Phylogenetic grouping of amniotes (bookfigure 3.30.).

Phylogeny of Amniote GroupsPhylogeny of Amniote Groups

Figure 5.5.

Reptilian CharacteristicsReptilian Characteristics

True clawsTrue claws Amniotic eggsAmniotic eggs NoNo metamorphosis metamorphosis 12 pairs of cranial 12 pairs of cranial

nervesnerves Single occipital condyleSingle occipital condyle

Figure 5.6. Nile monitor.

Figure 5.7. Reptile egg.

Reptilian ClassificationReptilian Classification Parareptilia - anapsida (today applies to skull type) Parareptilia - anapsida (today applies to skull type)

Order Testudines (Order Testudines (ChelodinaChelodina)) Ex: turtlesEx: turtles

Diapsida (within the Eureptilia)Diapsida (within the Eureptilia) Majority of reptilesMajority of reptiles Order SquamataOrder Squamata

Ex: lizards and snakes Ex: lizards and snakes Suborders Serpentes and SauriaSuborders Serpentes and Sauria

Order SphenodontidaOrder Sphenodontida Ex: tuatara (Ex: tuatara (SphenodonSphenodon))

Order CrocodyliaOrder Crocodylia

Reptilian Oral CavityReptilian Oral Cavity

Tooth typeTooth type AcrodontAcrodont

Tooth on surface of jawTooth on surface of jaw Ex: fish and Ex: fish and SphenodonSphenodon

(tuatara)(tuatara) PleurodontPleurodont

Tooth attached on medial Tooth attached on medial surface of jaw surface of jaw

Ex: lizards and snakesEx: lizards and snakes ThecodontThecodont

Teeth embedded in jaw Teeth embedded in jaw bonebone

Ex: crocodileEx: crocodile

Figure 5.8. Jaw cross section.

Skull TypeSkull Type

Amniotes possess different skull typesAmniotes possess different skull types Anapsid- lack temporal fossaAnapsid- lack temporal fossa Diapsid- two temporal fossaDiapsid- two temporal fossa

One dorsal and one ventralOne dorsal and one ventral Synapsid- single, lower temporal fossaSynapsid- single, lower temporal fossa

Gave rise to mammal-like reptilesGave rise to mammal-like reptiles

Figure 5.9. Skull types.

Figure 5.10. Sarcopterygian skull.

Reptilian RadiationReptilian Radiation

Figure 5.12. Relationships amonghigher vertebrates.

Figure 5.11. Phylogenetic tree of reptiles.

Pliosaur (a type of plesiosaur). Mayborn Museum, Baylor University

Nothosaurus (Berlin Natural History Museum)

“Sea Serpents”

Dinosaur GroupsDinosaur Groups Morphological character of pelvis separate groups Morphological character of pelvis separate groups SaurischiansSaurischians

Triradiate pelvisTriradiate pelvis Lizard-likeLizard-like

OrnithischiansOrnithischians Tetraradiate pelvisTetraradiate pelvis Bird-likeBird-like

Figure 5.13. Pelvic of two dinosaur groups (book figure 3.35).

Figure 5.14. Size of selected dinosaurs.

SaurischiansSaurischians Gave rise to dominant Gave rise to dominant reptilesreptiles Birds evolvedBirds evolved

Parallel convergenceParallel convergence

Figure 5.15. Reptilian cladogram.

Dinosaur GroupsDinosaur Groups (cont.) (cont.)

Aves - BirdsAves - Birds

ArcheopteryxArcheopteryx- - discovered in 1861 – discovered in 1861 – ancestral bird ancestral bird Feathers and teeth Feathers and teeth

presentpresent Read “Discovery of the Read “Discovery of the

First Bird” – p. 119.First Bird” – p. 119.

Figure 5.16. Archeopteryx fossil.

Birds Birds (cont.)(cont.)

Keeled sternum in Keeled sternum in birds that fly.birds that fly.(carinates)(carinates)

Flightless birds Flightless birds (ratites)(ratites)

Figure 5.17. (a) Archaeopteryx (b) pigeon.

Relative Diversity of Terrestrial Vertebrates

Fig. 5.18.

Characteristics of BirdsCharacteristics of Birds

Feathers presentFeathers present HomeothermicHomeothermic Single occipital Single occipital

condylecondyle Scales on legs and feetScales on legs and feet

Figure 5.19.

Flier and Flightless BirdsFlier and Flightless Birds ArcheopteryxArcheopteryx- glider- glider

Reduced sternumReduced sternum

Figure 5.20. (a) Archaeopteryx (b) pigeon.

Avian ClassificationAvian Classification

Modern birds - Subclass NeornithesModern birds - Subclass Neornithes Ancient birds - Subclass ArchaeornithesAncient birds - Subclass Archaeornithes Passeriformes - largest order of birdsPasseriformes - largest order of birds Birds arose in mid-Jurassic PeriodBirds arose in mid-Jurassic Period