Lecture 24 Vertebrates - Reptiles Flashcards
Reptilia evolved from ____ about _____
Amphibians; 320 mya
Majority of reptilia species that evolved are now
Extinct
Modern reptiles are derived into two lineages
- Parareptilia (turtles and tortoises)
- Eureptila
Eureptilia is further subdivided into two lineages
- Lepidosauromorpha (snakes, lizards, tuatara)
- Archosauromorpha (dinosaurs, crocodiles, birds)
Four extant orders of Reptilia
- Testudines (turtles and tortoises)
- Sphenodonta/Rhyncocephalia (tuatara)
- Squamata (lizards and snakes)
- Crocodilia (crocodiles, alligators, caimans, gharials)
Testudines include
Turtles and tortoises
The largest species of testudines is
Leatherback
Turtles inhabit ____ while Tortoises inhabit ____
Marine and freshwater; terrestrial
Cryptodira and Pleurodira refer to
How testudines withdraw their neck into the shell
Marine turtles, most freshwater turtles, and tortoises are
Cryptodira - contract their neck
Testudines that contract their neck are referred to as
Cryptodira
Testudines that flex their neck laterally are referred to as
Pleurodira
Some species of freshwater turtles are
Pleurodira - flex their neck laterally
Testudines lack ___, instead they have
Teeth; keratinous ridges for grinding and slicing
A unique feature of turtles is
The position of limbs within a shell (ribs encapsulate the scapulae)
Recent turtle fossils suggest that
The plastron (bottom shell) evolved before the carapace (upper shell)
Hox Genoese refer to
The fleshy fin of fish to a tetrapod limb
Rhyncocephalia / Sphenodonta are
Tuataras
Which species is native to New Zealand and surrounding islands?
Tuatara (Rhyncocephalia/Sphenodonta)
Two species of tuatara are
-Sphenodon punctatus
-Spehnodon guntheri
Tuataras are a ___ species because ___
Vulnerable; sexually mature at 20 years and females can only breed every 4-5 years
Tuataras have a lifespan of ____ and are sexually mature at ____
100 years; 20 years
The most ancestral of amniotes is the
Rhyncocephalia / Sphenodonta
The unmodified diapsid skull of Tuataras is
Redeveloped, not retention
Teeth of Sphenodonta / Rhyncocephalia are (4)
-fused to bone during early development
-new teeth are added caudally as body size increases
-double row on maxilla
-single row on mandible
Turtles and Tuatara lack
An outer aperture and tympanic membrane
Squamates include
Lizards and snakes
Snakes evolved from
Lizards
Venom in squamata evolved
Early
___ of squamates are ____
60% ; venomous
Two species of lizards that are venomous are
-Gilda monster
-Mexican beaded lizard
Squamates have movable ___ which allows for ____
Quadrate bones; greater range of motion of mandibles
Crocodilia include
-crocodiles
-alligators
-caimans
-gharials
The closest living relatives of birds are
Crocodilia
There are ____ species of Crocodilia
22
The Australian saltwater crocodile is
The largest species of Crocodilia
A derived trait (not ancestral) of Crocodilia is
Semi-sprawled posture which allows for galloping
Two main lineages of Dinosaurs are
-Ornithischia (“bird hipped”)
-Saurischia (“lizard hipped”)
Ornithischia are
Herbivores
Saurischia can be divided into
-Sauropods (herbivores)
-Therapods (carnivores)
Oviraptor is a misnomer for ___ and actually means ___
Egg thief; incubation of eggs (evidence of maternal care and endothermy)
Therapods have embryos that are
Hatched from eggs (similar to modern birds)
Dinosaurs were, without a doubt,
Feathered
Reptiles have adapted to ____ and some have re-adapted to ____
Drier environments; aquatic environments
All reptiles must ____ with the exception of ____
Return to land to lay eggs / live young; sea snakes
Sea snakes are
Viviparous
Distribution of reptiles is limited by being
Ectothermic
Ectothermic means
Body temperature is determined by the environment
Endothermic
Body produces heat
Ectothermic
Heat absorbed from environment
Homeothermic
Body temperature is constant
Poikilothermic
Body temperature varies
Reptilia transition from water to land required
A waterproof skin to minimize water loss
Waterproof skin of reptiles is due to
Thick, heavily keratinised stratum corneum
Reptile scales are used to
Identify and classify
Epidermal scales are
keratin structures
Scutes
Large, plate-like scales
Modified scales form
Horns, spikes, and crests
Which species of reptilia posses osteoderms (3)
-crocodialians
-testudines
-some lizards
Osteoderms means
Osteo = plates of bone
Derms = within dermis
What structure provides additional support to reptilia epidermis
Osteoderms
Dorsal shell of turtles and tortoises is called
Carapace
Ventral shell of turtles and tortoises is called
Plastron
In turtles and tortoises, osteoderms are
Fused with ribs and vertebrae
Reptilia have a ____ compared to amphibians
Stronger skeleton
The pectoral girdle of reptilia includes (4)
-scapula
-coracoid
-clavicle (not all species)
-inter-clavicle
The pelvic girdle of reptilia includes (4)
-ilium
-ischium
-pubis
-small epipubic bone may be present
The limb bones of reptilia are (2)
-similar to mammals
-5 digits on each manus (hands) and pes (foot)
Two reptilian skull types are
-anapsid (lacks a fenestrae)
-diapsid (contains two fenestrae)
Reptilia with anapsid skulls include
-ancestral reptiles
-turtles
-tortoises
Reptilia with diapsid skulls include (4)
-snakes
-lizards
-dinosaurs
-crocodilians
Reptiles posses ___ lungs
Paired
Many lizards have a ____ lung
Reduced left
Snakes have ___ lungs
Long, thin
Crocodialian respiration is similar to
Birds - unidirectional flow
The heart of reptilia evolved from
Amphibians
There is no typical reptilian ___
Heart
Reptilia hearts have a separate
Pulmonary and systemic circulation
Sexual dimorphism in reptiles is
Minimal or non existent
Viviparous means
Produce live young
An advantage to viviparous is
Protection of young from predators and environment
Oviparous means
Produces an egg
The yellow bellied three-toed skink displays both
Viviparous and oviparous reproduction
Parthenogenesis means
The embryo is derived solely from the fusion of 2 eggs (occurs in solitary animals and is not ideal)
Pterosaurs means
Winged lizard
