Herpetology Unit 1

Herpes

“Crawling things”

Reptiles:1, amphibians:2

Occipital condyle

Herp hearts

3 chambered except crocs

Caudata

Salamanders and newts

Anura

Frogs

Gymnophioma

Caecillians

Testudines

Turtles

Crocodilia

Duh

Rhynchocephalia

Tuataras

Squamata

Lizards + snakes

Poikliothermic

Body temp very variable

Ectothermy

Temp regulated by external factors

Amphibian activity

Concentrated at night

Reptile activity

Concentrated at day

Synonymy

Multiple names for the same species

Homonymy

The same name for multiple species

Holotype

Original description specimen

Allotype

A type specimen of the opposite sex of holotype

Paratype

A specimen other than the holotype used to solidify description

Cladistics

A systematic approach that infers phylogeny according to shared characteristics from a common ancestor

Plesiomorphs

Ancestral characteristics

Apomorphy

Derived characteristics

Synapomorphy

Shared derived characters from a common ancestor

Reasons for colonizing land

More food, less competition, no predators, more O2

Adaptations for land colonizations

1) Strong skeletal muscular system

2) Toleration of seasonality

3) Dietary alterations

4) Desiccation resistance

5) Breathing alterations

6) Sensory upgrades

Tongue

Tetrapod adaptation for manipulating food

Skin wax

Amphibian desiccation resistance

Tetrapod ancestor group

Sarcopterygians

Tetrapodomorpha

All taxa more related to modern mammals, reptiles, and amphibians

Panderichthys

Fewer fins, reduced tail, robust pelvic girdle

Tiktaalik

Flexible neck, mobile head, strong pelvic girdles

Temnospondyl hypothesis

All modern amphibians evolved from a Temnospondyl ancestor. Pedicellate teeth, wide palate openings allowing eye retraction, 2 occipital condyles, and reduced ribs

Lepospondyl hypothesis for amphibian evolution

Lack many skull bones associated with miniaturization, widely disregarded

Paedmorphosis

Supports Temnospondyl origin, assumed to be apomorphy

Amniota

Reptiles and mammals

Amniotic eggs

Eggs compartmentalized into multiple layers

Amnion

Contains embryo

Chorion

Outer membrane

Allantois

Nitrogenous waste

Evidence for supporting Amniotic monophyly

Egg, skull, pectoral girdle, appendicular skeleton, and molecular data

Amniote ancestors

Late Cretaceous reptilomorphs

Lissamphibia and Amniota divergence

30my after emergence of Tetrapoda

Lepidosaur Synapsids

Squamata and Rhynchocephalia, transverse cloacal slit and loss of single penis

Archosaur Synapsids

Crocodilia, Testudines, and Aves. Cranial musculature

Turtle origins

Archosaur ancestors, temporal fenestrae loss

Stratum corneum

Keratinous and protective layer of epidermis, periodically shed

Stratum germinaturum

Innermost layer of epidermis, skin cells replicate

Stratum spongiosum

Loose matrix of glands, vessels, and pigments in dermis

Stratum compactum

Densely knit connective tissue in dermis

Amphibian glands

Produce mucus to prevent desiccation and produce mucus cocoons

Glandular glands

Produce toxins in amphibians

Melanophores

Black/brown/red

Xanthophores

Yellow/orange/red

Chromatophores

Color cells of dermis

Blue frogs

No xanthophores!

Green frogs

Possess xanthphores

Amphibian retinas

Single and double cones

Amphibian eyes

Retractable due to special muscles!

Pedicellate

Layer of dentine separates tooth crown from base, unique to modern amphibians

Acrodont

Rootless teeth fastened with no sockets on jaw, some reptiles

Pleurodont

Teeth connected to side of jaw, most Squamatans

Thecodont

Tooth embedded in bone sockets (Crocs!)

Opistocoelous vertebrae

Concave end posterior

Procoelous vertebrae

Concave end anterior

Amphicoelous vertebrae

Concave on both ends

Caecillian lungs

Left lung smaller than right

Frog pupils

Never round

Pectoral girdle bones of frogs

Suprascapula, scapula, coracoid, clavicle

Arciferal girdle

Coracoid caps overlap, can slide past one another, and can be compressed laterally. Ancestral condition of frogs

Fermisternal girdle

Derived characteristic where coracoids are joined together. Ranids

Urostyle

Rod of caudal vertebrae in frogs

Radioulna

In frog forelimbs for strong landings

Frog carpal elements

Bony and reduced by fusion

Frog skulls

Broad and fenestrated. Cranial elements reduced, cannot move left-right

Salamander bodies

Are largely cartilaginous

Caecilian reproduction

Facilitated by phallodeum

Alpha keratin

Soft and pliable

Beta keratin

Hard and rigid (unique to reptiles!)

Lenticular organs

Embedded in skin for tactile sensation

Columnella

Single reptile ear bone

Lizard columnella

Rests on tympanum

Snake columnella

Attached to quadrate of jaw

Tuatara

Sagittal crest, cloacal outpockets (pseudo-hemipenes), deciduous tails, rib hooks, akinetic skulls, two rows of acrodont teeth on upper jaw

Autonomy

Fracturing of transverse planes to drop tails

Femoral glands

Secrete lipids to scent mark for reptiles

Lizard skulls

Highly kinetic

Climbing lizards

Possess lamellae, chemically sticky!

Snake lungs

Left reduced

Labial glands

Produce mucus in snakes

Duvernoy gland

Rear venom gland

Aglyph

Homodont teeth (Colubrids)

Opistroglyph

Posterior pair of teeth enlarged as fang

Proteroglyph

Front fangs fixed (Elapids)

Solenoglyphs

Maxilla reduced with no teeth, except collapsible fangs (Viperids)

Pits

Allow overlay of visual and thermal cues

Scutes

Dermal components covering skeletal components

Suborder Pluerodira

Side-necked turtles

Suborder Cryptodira

Hidden-necked turtles

Turtle girdles

Contained within rib cage

Plastron

Rib and backbone components. Solid or articulate