A. Species within a Genus.

B. Families within an Order.

C. Phyla within a Kingdom.

It is easier to study the evolutionary relationships among related…

A. Species within a Genus.

B. Families within an Order.

C. Phyla within a Kingdom.

It is easier to study the evolutionary relationships among related…

WHY? Deep phylogenetic splits are usually heavily impacted by convergence and heterochrony. At this scale how valuable are outgroups?

WHY NOT NEWLY DIVERGED TAXA? Recent splits are difficult to study because of a lack of informative characters? Also, this scale suffers from parallel evolution and vicariance.

Origin and Relationships of Modern Amphibians

Ray-finned Fish

Coelocanths

Lungfish

Modern Amphibians

Modern Reptiles +

Birds/Crocs (By Craggy)

Things I actually know

something about(I’m no herpetologist)

This is like a detective novel where we are trying to find out what happened 400+ MYA.

Don’t forget there are plenty of false clues—many groups evolved in a short period of time, and the available fossils

are often side roads of evolution.

Sarcopterygii—Lobe Fin Fishes

a. Appendages are Similar in Structure to Amphiansb. Most Modern Forms Use Them for Locomotion

1) Walk on Bottom2) Swim

c. Two Major Groupsd. Coelacanths—2 Living Fossils from Indian Oceane. Lungfish

1) 1 Species each in Australia, Africa, and South America2) Sister to Terrestrial Vertebrates3) Australian Species is Very Different

a) Walks on Bottom of Ponds/Streamsb) Very similar to Paleozoic and Mesozoic forms

4) South American + African Formsa) Gills Mostly Remove Carbon Dioxideb) Drown Without Airc) African Form Aestivated) Both Originally Considered Salamanders

(Images from Pough et al., Vertebrate Life)

Pugh et al., 2002. Vertebrate Life, Fig 7-5

Late Carboniferous of Europe--Any place to look for this around here?

2 Competing Hypotheses for Terrestrial Vertebrates

1. Drying pond hypothesisa. lobe-finned fish in drying pondsb. fish crawl to deeper pondsc. problems

1) fish go back to water?2) African lung fish aestivate3) Fossilized remains in burrows4) Oldest fossils are in brackish areas

2. Edge of the sea hypothesisa. lobe-finned fish at the edge of the waterb. feed on prey that falls inc. become more agile at darting out of the surfd. dry land is free of competitorse. Problems

1. Some modern fish do jump ponds2. Why are they gone?

Here is One Recent Idea of Relationships

Modern Lungfish

“Lepospondyls”

Stegacephalians

Lissamphibia“Temnospondyls”

(Images from Pough et al., Vertebrate Life, and

Herpetology)

Modern Lungfish

Stegacephalians

Lepospondyls + Lissamphibia

Amniotes

Here is Competing Idea of Relationships

Why do we see these differences

The traditional view has always assumed a close relationship between temnospondyls and modern Amphibians. Thus outgroup

and character selection may be biased

How do these biases impact the results of the study?

Maybe it was ……a “Branchiosaur (a “temnospondyl” ……in the Permian…..via paedomorphosis.

LET’S PLAY CLUE

Explains: Small size, Combination of Primitive + Derived Characters, Difficulty Pinning Things Down, Absence of Last Bones to Develop in Branchiosaurs (Supratemporals, Pre+Postfrontals, Jugals, Parietal, Lacrimals), Large Orbits, Tooth Structure.

Matches Fossil Developing BranchiosaursBUT—Testing requires complete phylogenetic information.

SO WHAT ABOUT LISSAMPHIBAINS

AnuraUrodela Gymnophonia

Can We Do Any Better?Are they Monophyletic?

Synapomorphies Supporting Lissamphibian Monophyly

1. Teeth are Pedicilate and Bicuspid

2. Ears are unique having a stapes and operculum (not present in caecillians) and a

unique patch of sensory epithelial cells(papilla amphibiorum--detects low frequency sounds)

3. Stapes is directed dorsolaterally vs ventrolaterally(shared by some probable relatives)

4.Fat bodies develop from different germ layer (germinal ridge)

5. Skin contains Mucus and poison glands

6. Green Rods Present in Frogs and Salamanders

7. Muscle beneath Eye Allows Elevation (used in breathing + Swallowing)

8. Buccopharyngeal Pump for Respiration (use throat like a billows). Means air is pushed into the lungs

9. Short Strait Ribs

10. 2 Occipital Condyles (Shared with Mammals)

11. Reduction of Many Cranial Elements

SO WHAT ABOUT LISSAMPHIBAINS

AnuraUrodela Gymnophonia

This arrangement supported by: Soft Anatomy(Presence of a tail, costal groves)

SO WHAT ABOUT LISSAMPHIBAINS

AnuraUrodela Gymnophonia

This arrangement supported by: Skeletal Anatomy + Combined Morphological and Genetic Data

(What does this tell you about the # of soft characters used?)(What would a combined morphological + genetic analysis say?)

Frogs + Salamanders=Batrachia

ORDER: URODELLA

I. CharactersA. Long TailB. Four LimbsC. Costal GroovesD. Paedomorphosis is Common (aquatic salamanders)

II. Fossil Record Dates to Middle Jurassic (170-159 MYA)A. Use of CaudataB. Difficulties of Metamorphosis

III. BiodiversityA. 515+ SpeciesB. Many Cryptic SpeciesC. Mainly Holoarctic (recent invasion of Neotropics)

Sirenidae—Sirens

•2 Genera + 4 Species

•Primarily Indiana south and East

•Eel-Like and Aquatic

•Keratinous Beak

•No Hind Limbs

•Some of the Largest Salamanders

•Prey Primarily on Inverts

•Siren intermedia

Cryptobranchidae—Hellbenders

•2 Genera + 3 Species

•Eastern NA, China, Japan

•Mostly Aquatic

•Incomplete Metamorphosis

•Largest Indiana Salamander

•Prey Primarily on Crayfish

•Cryptobranchus alleganiensis

Amphiumidae—Amphiumas

•1 Genus + 3+ Species

•Mississippi River System

•Eel-Like and Aquatic

•Reduced Limbs

•Nasty Biters

•Prey Primarily on Aquatic Animals

•Amphiuma

Plethodontidae—Lungless Salamanders

•27 Genera + 360 Species

•Mostly NA with some in SA and Europe

•Most specious group of salamanders

•Full Metamorphosis (Mostly)

•Typically Small

•Prey Primarily on Small Inverts

•Plethodon, Eurycea, Psudotriton, Eurycea, Desmognathus

Proteidae—Mudpuppies and Kin

•2 Genera + 6 Species

•Mostly Central Europe + Necturus

•Aquatic Salamanders with Well-developed Gills+ 4 Legs

•Prey Primarily on Inverts (occasionally caught on worms)

•Necturus maculosus

Salamadridae—Newts

•15 Genera + 62 Species

•Holoarctic

•Eft Stage and Return to Water

•Complete Metamorphosis

•Highly Toxic

•Bad News for Frog Eggs

•Notophothalmus viridescens

Ambystomidae—Mole Salamanders

•1 Genus + 30 Species

•Mostly US

•Robust Bodies made for Digging

•Most Have Full Metamorphosis (Axotyls)•Some Paedomorphic Forms

•Prey Primarily on Inverts

•Ambystoma jeffersonianum, tigrinum, and texanum

ORDER: GYMNOPHONIA

I. CharactersA. Short Post-Anal TailB. No LimbsC. Costal Grooves?D. Paedomorphic

II. Fossil Record Dates to Early Jurassic (190 MYA)A. Fossils from NA (What does this mean)B. Had Legs in Fossil RecordsC. Very Similar to Salamander LegsD. Snakes Before Snakes

III. BiodiversityA. ~170B. Pantropical Except Central AfricaC. Systematics are a Mess

ORDER: ANURA

I. CharactersA. No Post-Anal TailB. No LimbsC. No Costal GroovesD. Caudal Vertebra Fused Urostyle (rod)E. Vertebral Column ReducedF. Elongate Hind Limbs

II. Triadobatrachus from Lower Triassic (230 MYA)A. Madagascar B. PolandC. Same Arizona Deposit as a Caecilian

III. BiodiversityA. ~4300 SpeciesB. Cosmopolitan Except Deserts and TundraC. Very Diverse In Tropics

Triadobatrachus massinoti

Modern Leptodactylus

Ascaphidae—Tailed Frogs

•Monotypic

•Ascaphus truei

•Tail is an Intermittent (“Penile”) Organ

•Highly Aquatic

•Fast Flowing Streams

•Pacific Northwest

•Tadpoles have oral suckers, which are sometimes used to climb

Paleobatidae—Spadefoot Toads

•3 Genera + 11 Species

•NA, Europe, and North Africa

•Keratin Spade on Foot•Used to Dig•Animals Emerge During Heavy Rains•Explosive Breeders

•Rapid Metamorphosis

•Scapheopus holbrooki, Spea bombifrons

Bufonidae—Toads

•33 Genera + 455 Species

•Once a Trashcan

•Nearly Cosmopolitan

•Many are Terrestrial as Adults

•Highly Toxic Skin Glands (Parotid)

•Maintain Bidder’s Organ (Rudimentary Ovary

•No Teeth

•Bufo woodhousi and americanus and maritimus

Pipidae—Clawed Frogs

•5 Genera + 30 Species

•Sub-Saharan Africa, Panama, Tropical South America

•Aquatic as Adults

•Odd Morphology•Lack Tongues•Claw-like Tips to Toes•Dorsoventral Compression•Well-developed Lateral Lines

•Official Lab Rat of Developmental Biology

•Xenopus

Myobatrachidae

•23 Genera + 122 Species

•Australia, New Guinea, Tasmania

•Highly Variable Reproduction•Young in Inguinal Pouches of Males•Young in the Stomach

•Many falling victim to chytid fungal infections

Hylidae—Tree Frogs

•40 Genera + 835 Species

•Paraphyletic with “Psuedidae” excluded

•Mostly Arboreal

•Toe Pads and claw-like terminal phalanges

•2 Hyla, 2 Psuedacris, Acris

Microhylidae—Narrowmouth Toads

•69 Genera + 350 Species

•Eastern US, South America, Southern Africa

•Small Palatal Folds--Head Vail

•Very Small Frogs

•Local Versions are Fossorial

•Other places get Terrestrial and Arboreal Forms

•2 Form Commensal Relationships with Spiders

•Often Found Under Cow Poop

•Gastrophryne

Dendrobatidae—Poison Dart Frogs

•8 Genera + 205 Species

•Central and South America

•Terrestrial or Arboreal

•Parents Cary Tadpoles on Backs

•Highly Toxic Skin Glands•Used to Poison Blow-gun Darts•Probably Diet Related•Common in Pet Trade

•Official Lab Rat of Developmental Biology

•Dendrobates

Mantelliidae—Madagascar Poison Frogs

•5 Genera + 140 Species

•Madagascar

•Have Aposematic Coloration and Poison in Mantellus

•Some Mantellus also resembles Rana and Bufo

•2 Genera Converge on Spea

•Boophis resembles Hyla

•Why do we see these patterns?

•What is the difference between convergence and parallelism?

Ranidae—Pond Frogs

•38 Genera + 600+ Species

•Cosmopolitan

•Highly Variable and Para/Polyphyletic

•Trashcan taxon

•Economically Important

•Rana catesbienna widely Introduced

•8 Local Species

ILLUSTATION OF DIVERSITY: OTHER FAMILIES

•Leiopelmatidae•Bombinatoridae•Discoglossidae•Megaphyridae•Pelodytidae•Rhinophrynidae•Brachycephalidae•Heleophrynidae

•Racophoridae•Leptodactylidae•Rhinodermatidae•Pseudidae•Allophrynidae•Hemisotidae•Artholeptidae•Petropedetidae•Hyperoliidae

Mostly in African, SA, and Asiatic Tropics