Modern Amphibians = Lissamphibia Urodela (Caudata) (salamanders and newts) Apoda (caecilians) Anura (frogs and toads)

Shared derived traits of Lissamphibia Table 10-1 Pedicellate teeth

Operculum-columella complex – Transferring air waves into fluid waves and ground vibration into sound.

Levator bulbi muscle Closed Eye

Thin skin with mucus and poison glands Implications for physiology and ecology

Breathing via the skin

Water through the skin – a boon and a bane

The skin as a storehouse for toxins Chapter 10.5 And warning and cryptic pigments Aposematic coloration

Apoda (Gymnophiona) Caecilians Reduced eyes, sensory tentacles, dermal folds

Apoda Reproduction Internal fertilzation with phallodeum Oviparous (egg guarding) or viviparous Cloaca

Adult teeth Baby teeth grappling

Urodele – Caudata Distribution Holarctic Aquatic Terrestrial

Reproduction Visual displays and olfaction Nasolabial groove Sexual dimorphism Hedonic (scent) glands

Fertilization external (few) or internal (most) Spermatophore Fire salamander - viviparous Egg mass

Anura most diverse, most widespread Highly derived body form Urostyle Illia

Anura Reproduction dominated by vocalization Expense? See text Functions of reproductive calls? Explosive versus prolonged breeding?

WhineChuck Tungara frogs Males alone – whine only Males with males – Whine- chuck Females prefer whine- chuck call Explain the pattern

External fertilization via amplexus Function of sexual dimorphism? Male Female

Biphasic Lifestyle Advantages? Disadvantages?

Amphibian Conservation Issues Cane Toads (Bufo marinus) Introduced into Australia Conservation concerns?

Bullfrog (Rana catesbiana) introductions

Major Conservation Concern: Amphibian Declines 2006 report: 1,856 species, 32.5 percent of the known species of amphibians, are “globally threatened,” (vulnerable, endangered or critically endangered). By comparison, 12 percent of bird species and 23 percent of mammal species are threatened. 435 amphibian species are in rapid decline, at least 9 species have gone extinct since 1980 and another 113 species have not been reported from the wild in recent years and are considered to be possibly extinct. Causes?

Amphibian characteristics that increase susceptibility to environmental changes??

Habitat Loss

Over-exploitation as: Food Pets - Goliath frog 6 million into Hong Kong/yr

Introduced Species 99% of lakes in Sierra Nevada originally without trout. Rana mucosa (native frog) declining in part due to trout predation

Amphibian egg survival and ultraviolet light at high elevations

Rana Hyla Bufo

UV protectedNo UV protection Increased ultraviolet radiation due to reduced ozone Worldwide studies of UV on amphibians Red = negative effect of UV

Pollutants Nitrogen, pesticides, acidification,

Deformities

Trematodes parasites cause abnormalities Eggs Meracidium Cercaria Cysts

Chytrid Fungus

Global Climate Change? Direct: Loren’s paper Interaction with: disease susceptibility to toxins susceptibility to parasites Species Introduction?