lissamphibia ~4,900 species (more than number of extant mammal species) >4,300 species frogs...
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Lissamphibia ~4,900 species
(more than number of extant mammal species) >4,300 species frogs (Anura) >415 species salamanders (Urodela) >165 species caecilians (Gymnophiona)
Lissamphibia Gymnophiona (caecilians)
Typhlonectes
Typhlonectes
CAECILIANSThe Unknown Amphibian
Who are they?
• Order: Gymnophiona• Family: 6 families• Genus: 34• Species: 165• Habitat: loose soil,
leaf litter in tropical forests or rivers and streams
• Length: up to 2.4m;
shortest 3.5 in.• Up to 2.2 lbs• Life span: up to 13 yrs • Offspring: 30 – 60
eggs; 2 - 25 young
born
Range
Central Africa, Southeast Asia, Southern Mexico to Argentina
Description
• Caecilians are tropical amphibians that look like large worms or slick snakes. They have no arms or legs, and sometimes it’s hard to tell which end is the head and which is the tail! Their shiny skin is ringed with skin folds called annuli, and they usually come in shades of gray, brown, black, orange, or yellow. Some species have tiny, fishlike scales (dermal scales) within the rings.
Gymnophiona (caecilians) (see Pough CH3)
- elongate, distinctly annulated -primary etc.
- terrestrial, burrowing, or aquatic (derived)
- tails reduced or absent
- eyes reduced (covered by skin or even bone)
- limbs and girdles absent in all extant taxa (still present in fossil ancestor)
Fig. 3-11 Pough et al. 2001
Fossil Gymnophiona ancestor (Eocaecilia)
evidence of tentacles
Annuli and Smooth
Dermal Scale Present in Some Caecilians
Gymnophiona (caecilians) dermal scales in some spp. - pouches in dermis below annular groove - scales like this not found in other Lissamphibia
Fig. 3-9 Pough et al. 2001
Caecilian Head
Gymnophiona (caecilians) - Skulls unique - Well ossified (but openings for eyes, nares, tentacles)
stegokrotaphic = skull completely roofed zygokrotaphic = skull weak in temporal region
vs. gymokrotaphic = temporal region open (anurans + urodelans)
zygokrotaphic = skull weak in temporal region
Lots of bones fused
stegokrotaphic = skull completely roofed
stegokrotaphic
Fig. 3-10 Pough et al. 2001
Fig. 13-12 Duellman and Trueb, 1986
Fig. 13-15 Duellman and Trueb, 1986
Caecilian skulls vs. Anuran skullZ
S
G
S S
S S
Gymnophiona (caecilians) - many bones of skull fused - Why have well ossified skull? - unique dual jaw closing mechanism
Fossorial
Adult caecilian can bury itself in a matter of minutes. Fossorialanimals spend most of their time underground.
Aquatic Species
Gymnophiona (caecilians) - left lung often reduced or absent
- aquatic eggs and larvae, or terrestrial oviposition with female parental care
- some species viviparous- internal fertilization (phallodeum)
Male Typhlonectes (cloaca)
Typhlonectes (mating)
Oviparous Species
Some female caecilians lay eggs in damp holes near water. When the larvae hatch they have gills and a short, finned tail to help them swim in the water, feeding on plankton. Through a series of changes the gills are replaced by a single lung, the skin becomes thicker, the annuli develop, and sensory tentacles appear. At this point the newly developed adult returns to the land and goes underground.
Caecilian EmbryoEmbryo removed fromegg. Yolk is visible aswell as sensory structures along headand side of body. These include mechano- and electrical receptorsof the lateral line.Eggs are laid inburrows near streams.hatch, larval stage livesin streams until metamorphosis a yearlater.
Icthyophis kohtaoensis
Viviparous Species• Some species give birth to live young that
are fully developed inside the mother before they are born.
Gymnophiona (caecilians) In viviparous species,
- young nourished by secretions from oviduct
- mother’s skin may produce edible secretions after birth
Fig. 5-5 Duellman and Trueb, 1986
Fig. 17-13 Stebbins and Cohen, 1995
Larval Caecilian
Aquatic stage with gills that are transient.
Senses
• A hard, thick, pointy skull helps these amphibians dig in soft dirt. Because of their underground lifestyle, caecilians have little need to see or hear. Therefore, their eyes are very tiny in some species, or hidden under the skin or skull in other species, making just tiny gray bumps for eyes. Some species in South America spend their lives in water instead of on land. Caecilians don’t have ear openings, so it is doubtful they can hear sounds.
Tentacles
• Tentacles, located between the nostrils and the eyes, are used to locate prey and detect surroundings.
Gymnophiona (caecilians) TENTACLE - chemoreception - between eyes and nostrils - protrusible in some taxa - involves structures normally associated with eye and Jacobsen’s organ
Diet
• Inside a caecilian’s mouth are dozens of needle-sharp teeth. The teeth are used to grab worms, termites, beetle pupae, mollusks, small snakes, frogs, lizards, and even other caecilians. All food is swallowed whole.
Eating tubifex worms
Skin Glands
• Caecilians have toxic glands in their skin that sometimes protect them from being eaten by other animals.
Toxic glands
Mucus glands
Families of Caecilians
• Rhinatrematidae South America
• Ichthyophiidae Southeast Asia
• Uraeotyphlidae Southern India
• Scolecomorphidae Subsahara Africa
• Caeciliaidae South and Central America,
Subsahara Africa, Southern Asia
• Typhlonectidae South America
Gymnophiona
Pough et al. 2001
Fig.3-12 Pough et al. 2001
Lissamphibia Gymnophiona (caecilians) 6 families, 34 genera, 165 spp.
Gymnophiona (caecilians) Rhinatrematidae (2 genera, 9 species; northern South America)
- ancestral (‘primitive’) lineage - true tail - mouth at tip of snout - tentacle next to eye - zygokrotaphic skull (weaker) - many scales - not well-known - likely not fossorial - relatively small - oviparous (egg-laying), with aquatic larvae
Rhinatrematidae
• Small, terrestrial caecilian with aquatic larvae
@1998 MarvaleeH. Wake
Gymnophiona (caecilians)
Uraeotyphlidae
1 genus, 5 species; Southern India
Stegokrotaphic skulls
oviparous (with aquatic larvae)
small (300 mm)
true tail
Tentacle underneath the nostril
Uraeotyphlidae
Gymnophiona (caecilians)
Ichthyophiidae2 Genera, 38 species+; SE Asia, India, Islands of
the Indo-Pacific, and the PhilippinesTerrestrialOvivparous (up to 100 eggs)True TailTentacle closer to eye than nostril500 mmStegokrotaphic skullDermal Scales
Ichthyophiidae
• Large terrestrial caecilian with aquatic larvae
Gymnophiona (caecilians) Scolecomorphidae (2 genera, 5 species; parts of central Africa)
- unusual lineage - vestigial eyes attached to tentacles - orbits absent - zygokrotaphic skull lacking elements - calcified spines on male phallodeum - no scales - oviparous or viviparous
Scolecomorphidae
Gymnophiona (caecilians) “Caeciliidae” (21 genera, 90 species; central and S. America, parts of Africa and Asia)
- no tail - mouth recessed under snout - tentacular location varies - scales variable - mostly burrowers - wide range of sizes - some brightly colored - life history variable
Caeciliaidae
• Very varied with small (10cm) to large (1.5m) organisms.
• Terrestrial, aquatic, oviparous, viviparous.
• Most are gray – black but some are more colorful.
Gymnophiona (caecilians) Typhlonectidae (5 genera, 13 species; South America)
- often aquatic - tracheal lungs - narial plugs - secondarily zygokrotaphic skulls
- includes largest lungless tetrapod - nocturnal - viviparous with aquatic larvae
Typhlonectes
Sometimes soldin fish stores.Aquatic.Female withyoung.
Typhlonectidae
• Aquatic caecilian, viviparous
• Larval gills
Ambystoma californiense
Lissamphibia Urodela
(salamanders) 10 families, 61 genera, 415 spp.
Ambystoma californiense
Ambystoma tigrinum
Unken reflexFig. 13.5
Stebbins and Cohen, 1995
Urodela (salamanders) (see Pough CH3) - Urodela (extant) - Caudata (extant plus fossil relatives)
- North America and temperate Eurasia - Plethodontids have radiated in tropics
- extensive salamander fossil record (unlike Gymnophiona)
Urodela (salamanders) - typically 4-limbed, short bodied, long tail
some with limbs reduced or lost
- costal grooves - most species terrestrial,
but need water for reproduction (some fully aquatic or terrestrial)
- some arboreal
Urodela (salamanders) - unique jaw musculature
- skulls reduced (bones absent) - skull bone ossification sequence - late appearance of maxillae in skull
Urodela (salamanders) - lack middle ear cavities and tympana (drum) - various opercular components missing
Pough et al. 2001
Urodela (salamanders) - mucous and poison glands
(pheromones) - aggregations of mucous glands =
courtship glands (e.g., mental glands)
mental glands
Fig. 17.3 Stebbins and Cohen, 1995
Urodela (salamanders) - some external fertilization - mostly internal fertilization
(via spermatophore)
Duellman and Trueb, 1986
female
male
Urodela (salamanders) - large genomes (and large cell nuclei)
- usually have larval stage larvae with true teeth, gill slits, external gills
- larvae rather similar to adults (compared to anurans)
palate is remodelled during metamorphosis
- many with direct development
Sala
man
der
Larv
ae
Pond
Stream
Terrestrial
Stebbins and Cohen, 1995
Urodela (salamanders) - Paedomorphosis common
all adults retain larval characteristics
OR some retain larval characteristics
(facultative) OR
none retain larval characteristics - makes phylogenetic reconstruction difficult
Urodela (salamanders)
- Unique defensive
adaptations Duellman and Trueb, 1986
Fig. 10-7 Duellman and Trueb, 1986
Urodela (salamanders) - Unique defensive adaptations
Fig. 3-1 Pough et al. 2001
Lissamphibia Urodela
(salamanders) 10 families, 61
genera, 415 spp.
Fig. 10-7 Duellman and Trueb, 1986
Urodela (salamanders) - Unique defensive adaptations
Echinotriton chinhaiensis Chinhai Salamander Salamandridae © Max Sparreboom
Urodela
Pough et al. 2001
Sirenidae Hynobiidae
Salamandridae
Pough et al. 2001
Urodela
Urodela
PlethodontidaeProteidae
Pough et al. 2001
Urodela (salamanders) Sirenidae
(2 genera, 4 species; SE U.S., NE Mexico)
- ancestral lineage (sister to all other
salamanders) - long, slender, eel like - lack pelvic girdle and hindlimbs - keratinized beak - fully aquatic - prey on invertebrates (insects,
crayfish, worms) - Paedomorphic (no eyelids, external
gills, non-pedicillate teeth, reduction in number of
digits on forelimbs)
- mucous cocoon and aestivation - external fertilization? - oviparous
The dwarf-siren Pseudobranchus striatus (photo J. White)
Urodela (salamanders) Cryptobranchidae
(2 genera, 3 species; Japan, China, E N. America)
- incomplete metamorphosis adults lack eyelids, retain one pair gill slits - flattened bodies and heads - aquatic - asymmetrical suction
feeding - cutaneous respiration - largest salamanders (up to
1.8 m) - cold mountain streams - external fertilization - males make nests and guard eggs (Den Master)
The Hellbender Cryptobranchus alleganiensis (photo M.A. Donnelly)
© Dr. Eric J. Routman
Urodela (salamanders) Hynobiidae
(7 genera, 36 species; disjunct Asia)
- complete metamorphosis eyelids, lack gill slits as adults
- lungs may be reduced or absent - some fully aquatic - some with terrestrial adults and migration to breed
- relatively small (100-250 mm) - some breed while wetlands still ice and snow covered - males have territories - males may compete (mating ball) - external fertilization
Batrachuperus mustersi Photo by Max Sparreboom
Urodela (salamanders) Amphiumidae
(1 genus, 3 species; S, SE U.S.) - elongate, paedomorphic
lack eyelids, lack external gills (but have slits)
- pedicellate teeth - retain both pairs of limbs (and
girdles), but small limbs
- aquatic - eat invertebrates and
vertebrates- ocassionally move overland or
aestivate - up to 1.1 m long - internal fertilization - oviparous on land (alligator nest
mounds?) female parental care
Two-toed amphiuma Amphiuma means © John White
Urodela (salamanders) Plethodontidae
(28 genera, 266 species; disjunct N, Central, S America, ~ Italy) - diverse and specious
(only group to radiate in tropics) - lungless
(adaptation to mountain streams) - nasolabial groove (chemoreception) - subterranean, aquatic, terrestrial, arboreal - variable body forms
(arboreal often with webbed feet and prehensile tails) - variable life history strategies - include smallest and
~largest terrestrial Urodela
Batrachoseps stebbinsi Tehachapi Slender Salamander © Tim Manolis
Fig.3-6 Pough et al. 2001
Plethodontidae
Figs 7.2 and 6.1 Stebbins and Cohen, 1995
Urodela (salamanders) Rhyacotritonidae
(1 genus, 4 species; Pacific Northwest U.S.)
- inhabit old-growth forest (indicator species)
- very old lineage
Rhyacotriton olympicus Olympic Torrent Salamander © William Flaxington
Urodela (salamanders) Proteidae
(2 genera, 6 species; NE U.S., S Central Europe)
- diploid chromosome count of 38 - paedomorphic
large gills and caudal fins - lack maxillary (~upper jaw) bone - mostly aquatic - Proteus live in caves
(slender; whitish skin; reduced eyes)
Proteus anguinus
Urodela (salamanders) Salamandridae
(15 genera, 55 species; N America, Europe, Asia, N Africa)
- includes ‘newts’ - may have extremely rugose skin - life history variable - some species with efts (terrestrial immature)
Fig. 13.5 Stebbins and Cohen, 1995
- defensive displays - aposematic coloration
(bright warning) - tetrodotoxins (neuro)
Unken reflex
Newts Taricha spp.
Salamandra salamandra Fire Salamander © Arie van der Meijden
Taricha granulosa Rough-skinned Newt © Harry Greene
Urodela (salamanders) Ambystomatidae
(1 genus, 32 species; N America)
- several hybrids and unisexual forms variable ploidy and number of parental species
- hybrids generally of ancient origin - Ambystoma mexicanum often used in research - variable metamorphosis (none, some, all)- robust and ‘medium sized’
Ambystoma californiense
Urodela (salamanders) Dicamptodontidae
(1 genus, 4 species; ~NW U.S.) - similar to Ambystomatidae - relatively large - inhabit coniferous forest habitats
cold streams and cold mountain lakes
- species very difficult to differentiate morphologically
Dicamptodon tenebrosus Pacific Giant Salamander © Henk Wallays
Rana pipiens
Lissamphibia
Anura (frogs)
~28 families, 310 genera, 4,300 spp.
Fig. 3-20 Pough et al. 2001
Zug et al. 2001
caecilian
salamander
frog
Anura (frogs) (see Pough CH3) - Salientia (clade that includes extinct
Triadobatrachus)
Pough et al. 2001
tail
extra vertebrae
Anura (frogs) - most extant families first appear in the Cretaceous - radiation in the early Cenozoic
Ascaphus truei
Anura (frogs) (see Pough CH3)
GENERAL- tail absent
- metamorphosis larvae and adults very different
- specialized skin...
- jumpers (saltation)
- 88% of Lissamphibia are Anura
- found ~worldwide except Antarctica, poles, and very dry deserts
Anura (frogs)
Jumping
Most anurans jump
Stebbins and Cohen, 1995
Derived jumper
Likely ancestral state was terrestrial protofrog that moved into water in riparian system to avoid danger.
‘Jumping’ is fast way to get to safety.
Anura (frogs)
Jumping(lose mass, add rigidity)
- inflexible vertebral column - caudal vertebrae fused to form urostyle - loss and reduction of skull bones
- loss of teeth in lower jaw (except one species) - anterior ribs reduced or lost
- radius-ulna and tibia-fibula fused - elongate ankle bones (astragulus-calcaneum)
transfers energy to trunk during push-off - limbs folded under body (greater propulsion)
Anura (frogs) Jumping etc. - skull reduced
Fig. 3-16 Pough et al. 2001
- 9 or fewer vertebrae
- fused bones limbs, urostyle
- no tail
- elongate hindlimbs ankles, feet
Anura (frogs)
Pectoral Girdles
1. arciferal - widespread - ancestral
2. firmisternal - derived
- systematics- intermediate conditions - reversals
Anura (frogs)
Reproduction (typically external) Amplexus:
1. inguinal 2. axillary ------> 3. cephalic
Stebbins and Cohen, 1995
Eggs deposited: - in water - on land - suspended in air
Development: - complete metamorphosis - direct development - viviparity
Anura (frogs)
Reproduction Parental Care:
not typical, but...
Stebbins and Cohen, 1995
Stebbins and Cohen, 1995
Darwin frog, vocal sac
Anura (frogs) Reproduction Metamorphosis:
Tadpole (Larvae) - herbivorous filter feeders - some carnivorous - or cannibalistic - some don’t feed at all
Stebbins and Cohen, 1995
Modify gut, body plan, mouth, jaws, limbs etc.
Adult - mostly carnivorous - two frugivorous species - tongue attachment
Lissamphibia
Anura (frogs)
~28 families, 310 genera, > 4,300 spp.
Fig. 3-20 Pough et al. 2001
Anura (frogs)
Larvae
Stebbins and Cohen, 1995
Stebbins and Cohen, 1995
Surface film
Suctorial scraper
Carnivore
Use to ID
Internal Gills
Anura (frogs)
Larvae General types based on morphology and diet
1 2 3 4
Pough et al., 2001
spiraclespiracles
Keratinous mouth parts
Anura (frogs)
SoundMost important anuran communication tool
- Most anurans vocalize - Usually male - Inflate throat sacs
- species specific calls - mate attraction - territoriality - alarm calls
- more later...
Anura (frogs)
Skin Specialized for multiple functions
- hydration, defense, locomotion, thermoregulation, reproduction, respiration etc.
glands - mucus (2 types) - poison = granular pigmentation
Fig 2.1 Stebbins and Cohen, 1995
12
Anura (frogs)
Skin Specialized glands A. mucus
-1 moist coating prevent dehydration
-2 sexual dimorphism nuptial pads
Nuptial pads
Pough et al., 2001
B. poison = granular -defensive secretions (sticky, antibiotics, toxic, etc.)
Dendrobates tinctorious
Anura (frogs)
Skin Pigmentation (Chromatophores)
Xanthophores Iridophores Melanophores
Stebbins and Cohen, 1995
Pigmentation under hormonal control
-reflectance -infrared -aposematic
Anura (frogs) Skin
Respiration - blood vessels
Stebbins and Cohen, 1995
- epidermal thickness
- versus hydration gas transfer requires ‘solution’
Lissamphibia
Anura (frogs)
~28 families, 310 genera, 4,300 spp.
Fig. 3-20 Pough et al. 2001
Anura (frogs) Ascaphidae
(1 species; ~NW U.S., into Canada)
- monotypic Family and Genus
- ‘tailed frog’ - tail is extension of cloaca - internal fertilization (1 of ~3 spp.) - do not call - no tympana - highly turbulent aquatic habitat Ascaphus truei
Anura (frogs) Leiopelmatidae
(1 genus, 3 species; New Zealand)
- only amphibians native to NZ - ribs embedded in ventral musculature - lack ear components and vocal sac - direct development - male parental care in 2/3 species
Leiopelma hochstetteri
Leiopelma hamiltoni
Anura (frogs) Bombinatoridae
(2 genera, 8 species; Europe, E Asia)
- Bombina toxic skin secretions aposematic coloration (~orange + yellow) unken reflex
Bombina orientalis
Lissamphibia
Anura (frogs)
~28 families, 310 genera, 4,300 spp.
Fig. 3-20 Pough et al. 2001
Anura (frogs) Pelobatidae (3 genera, 11 species; N America, Eurasia)
- include ‘spade foots’ - well-developed keratinous, spade-like
metatarsal tubercle on hind feet
- fossorial - often with enlarged parotoid glands on dorsum - desert adapted
aestivate explosive breeders egg to metamorph in ~8 days
Anura (frogs) Pelobatidae (con’t)
Scaphiopus couchii
spade
Anura (frogs) Rhinophrynidae
(1 species; Texas to Costa Rica)
- monotypic family and genus - ultra fossorial
spade tubercles pointed head with cornified skin small eyes no tympanum reinforced skull
- feed on ants and termites underground
- unique tongue
Rhinophrynus dorsalis
Anura (frogs) Pipidae
(5 genera, ~30 species; Panama, S America, sub-Saharan Africa)
- no tongue - keratinous ‘claws’ - aquatic - modified ears and calling - Xenopus laevis
research polyploids
- Pipa spp. eggs in dorsal skin of female
X. tropicalis
Lissamphibia
Anura (frogs)
~28 families, 310 genera, 4,300 spp.
Fig. 3-20 Pough et al. 2001
Anura (frogs) Bufonidae
(33 genera, ~400 species; widespread, not in Australopapuan region)
- Bidder’s organ rudimentary ovary on male testes (paedomorphic)
- no teeth - parotoid glands
toxins - Bufo marinus
pest
Anura (frogs) “Leptodactylidae“
(49 genera, > 900 species; Americas, West Indies)
- not monophyletic - variable - Eleutherodactylus
> 500 species!! most species rich genus of vertebrates some with direct dvpt. 2 spp. with internal fert.
Eleutherodactylus auriculatus
Ceratophrys cornuta
Anura (frogs) Myobatrachidae
(21 genera, 120 species; Australia, New Guinea, Tasmania)
- variable
- one species with male inguinal pouches for brood rearing - two species with gastric brooding in female Rheobatrachus (extinct?) Rheobatrachus vitellinus
Anura (frogs) Rhinodermatidae
(2 species; Argentina and Chile)
- fleshy proboscis at tip of snout
- males carry larvae to water, or brood in vocal pouch
Rhinoderma darwinii
Anura (frogs) Hylidae
(38 genera, 760 species; Americas, W indies, Australopapuan region) (Hyla in Americas, Eurasia, Japan, N Africa)
- arboreal generally - well-developed toe discs - claw-shaped terminal phalanges - many spp. with females that
transport young dorsally - Phyllomedusa
toxin for native rituals lipid glands in skin wiping behavior
Phyllomedusa sauvagi
Anura (frogs) Centrolenidae
(3 genera, > 130 species; Mexico to S America)
- medial process on 3rd metacarpal - toe discs - terminal phalanges T-shaped - eggs attended by males - transparent venter =
‘glass frogs’
Centrolenella oyampiensis
Centrolenella fleischmanni
Lissamphibia
Anura (frogs)
~28 families, 310 genera, 4,300 spp.
Fig. 3-20 Pough et al. 2001
Anura (frogs) Dendrobatidae
(6 genera, 185 species; Cent. America, N South America)
- pair of dermal scutes on dorsal surface of fingers - generally diurnal and terrestrial - cephalic amplexus (if amplex) - parental care
move larvae around
- Dendrobates may feed tadpoles eggs
- Phyllobates terribilis lipophilic alkaloids dietary origin
Dendrobates tinctorious
Anura (frogs) Arthroleptidae
(7 genera, 75 species; sub-Saharan Africa)
- includes Trichobatrachus robustus (hairy frog) male sits on clutch and aids aeration?
Stebbins and Cohen, 1995
Anura (frogs) “Ranidae”
(46 genera, > 700 species; most everywhere, except many islands)
- likely not monophyletic - variable - some unique Rana esculenta hybrids both sexes represented alternate generations sexual <---> asexual
Rana pipiens
Anura (frogs) Hyperoliidae
(19 genera, 230 species; sub-Saharan Africa, Seychelles, Madagascar)
- many arboreal - toe discs - ~ brightly colored - Afrixalus eggs on leaf then ‘taco’
Afrixalus osorioi congicus
Anura (frogs) Rhacophoridae
(15 genera, 315 species; Africa, Madagascar, Asia)
- mostly arboreal - enlarged toe discs - some with foam nests - some communal nests
- Mantella with skin alkaloids and aposematic coloration
Buergeria japanicus