PAOLA ESCOBAR RAMOS
BILOGO
MSC. CIENCIAS BOLGICAS
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FIGURE 3.22 Acanthostega, early tetrapod. A tetrapod from the Devonian showing transitional features from fish to
tetrapod. Note the polydactyl feet. About 60 cm overall length.
Presencia
Based on Coates, 1996.
de Quiridio
Anthracosaur skulls tended to be deep, and they also
Extremidad muscular con
y dedos
tended toarticulaciones
be terrestrial as adults.
(a) Ichthyostega
1 cm
Unlike their rhipidistian ancestors, early tetrapods
were soon adapting to sojourns onto land. The limbs and
supportive girdles were generally more ossified and stronger,
and the vertebral column tended to increase in prominence.
In early tetrapods, as in a few rhipidistian fishes before them
(e.g., Tiktaalik), the connection of the shoulder girdle with
the skull was absent and a mobile neck region developed,
allowing the head to move in all directions relative to the
body. The opercular bones were lost along with the internal
earlier during an ill-fated attempt to reach the North Pole by a hotair balloon. Later expeditions by Gunnar Sve-Sderberg uncovered
skulls of Ichthyostega, but Sve-Sderberg died at age 38 before he
could study the skulls. After Swedish paleontologists returned to the
Greenland site where they found the remainder of Ichthyostegas
skeleton, Erik Jarvik, one of Sve-Sderbergs assistants, examined
the skeleton in detail. This research became his lifes work, producing a description of Ichthyostega that remains the most detailed of
any Paleozoic tetrapod. Jarvik suffered a crippling stroke at age 88 in
1994, but had by then virtually completed an extensive monograph
on Ichthyostega, which was published in 1996.
Escamas
forelimb rather than the five characteristic of most tetrapods. Lissamphibians arose during the Carboniferous and later diversified, probably by early Triassic, to produce ancestors of the three
major groups of amphibians alive today, frogs (Anura or Salientia), salamanders (Caudata or Urodela), and caecilians (Apoda
or Gymnophiona).
Two additional generally recognized but nonetheless controversial groupings of Carboniferous and Permian tetrapods, lepospondyls and anthracosaurs, are judged from skull structure
to be closer to amniotes than to temnospondyls (Figure 25.3).
We cover the amniote branch of tetrapod phylogeny in Chapters
26 through 28.
seas
ventrales
Crneos grandes
Vertebras macizas
Metamorfosis
Articulacin del
cuello
See Chapters 26 through
28 for details
Frogs and
toads
Anthracosauria
Amniota
Lepospondyli
Salamanders
Ichthyostega
Lissamphibians
Caecilians
Dipneusti
Diverse
Devonian groups
Sarcopterygian
ancestor
Diverse
temnospondyl groups
Coelacanth
Devonian
Carboniferous
Permian
PALEOZOIC
395
Geologic time (My ago)
MESOZOIC
225
CENOZOIC
65
Figure 25.3
Early tetrapod evolution and the descent of amphibians. Tetrapods share most recent common ancestry with diverse Devonian groups. Amphibians share
most recent common ancestry with diverse temnospondyls of the Carboniferous and Permian periods of the Paleozoic, and Triassic period of the Mesozoic.
earlier during an ill-fated attempt to reach the North Pole by a hotair balloon. Later expeditions by Gunnar Sve-Sderberg uncovered
skulls of Ichthyostega, but Sve-Sderberg died at age 38 before he
could study the skulls. After Swedish paleontologists returned to the
Greenland site where they found the remainder of Ichthyostegas
skeleton, Erik Jarvik, one of Sve-Sderbergs assistants, examined
the skeleton in detail. This research became his lifes work, producing a description of Ichthyostega that remains the most detailed of
any Paleozoic tetrapod. Jarvik suffered a crippling stroke at age 88 in
1994, but had by then virtually completed an extensive monograph
on Ichthyostega, which was published in 1996.
samphibians arose during the Carboniferous and later diversified, probably by early Triassic, to produce ancestors of the three
major groups of amphibians alive today, frogs (Anura or Salientia), salamanders (Caudata or Urodela), and caecilians (Apoda
or Gymnophiona).
Two additional generally recognized but nonetheless controversial groupings of Carboniferous and Permian tetrapods, lepospondyls and anthracosaurs, are judged from skull structure
to be closer to amniotes than to temnospondyls (Figure 25.3).
We cover the amniote branch of tetrapod phylogeny in Chapters
26 through 28.
Temnospondylis,
See Chapters 26 through
28 for details
Lisamphibia
Extremidades
Frogs and
toads
Anthracosauria
anteriores
Cuatro dedos
Amniota
Lepospondyli
Lisamphibia
Ranas, Anuros o
Salamanders
Ichthyostega
Lissamphibians
Salientia
Salamandras, Caudata
o Urodela
Caecilios, Apoda o
Gymnophiona
Caecilians
Dipneusti
Diverse
Devonian groups
Sarcopterygian
ancestor
Diverse
temnospondyl groups
Coelacanth
Devonian
Carboniferous
Permian
PALEOZOIC
395
Geologic time (My ago)
MESOZOIC
225
CENOZOIC
65
Figure 25.3
Early tetrapod evolution and the descent of amphibians. Tetrapods share most recent common ancestry with diverse Devonian groups. Amphibians share
most recent common ancestry with diverse temnospondyls of the Carboniferous and Permian periods of the Paleozoic, and Triassic period of the Mesozoic.
Caractersticas compartidas
Huevos sin cscara ni membranas
extraembrionarias
Sistemas sensoriales, olfato y odo
Mitad del ciclo de vida, tierra
Huevos y larvas acuticas, desarrollo de agallas
Metamorfosis, prdida de agallas
Pulmones
Animales ectotrmicos
Glndulas mucosas o venenosas
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Ranas, salamandras
and caeciliansinclude almost 4,000 species displaying a
wide range of life histories (figure 3.24ac). Except for an
absence from some oceanic islands, they occur throughout
the tropical and temperate regions of the world. Amphibian eggs, which lack shells and amniotic membranes, are
laid in water or moist locations. External fertilization
characterizes frogs, whereas internal fertilization characterizes most salamanders and probably all caecilians. Typically, paired lungs are present, although they may be
reduced or even absent entirely in some families of salamanders. Mucous glands of the skin keep amphibians
moist, and granular (poison) skin glands produce chemicals unpleasant or toxic to predators.
Modern amphibians in some ways stand between
fishes and later tetrapods; therefore, they supply us with
approximate living intermediates in the vertebrate transition from water to land. In their own right, however, living
amphibians are specialized and represent a considerable
departure in morphology, ecology, and behavior from the
ancient Paleozoic tetrapods (figure 3.25). Many bones of
the ancient skull and pectoral girdle are lost. Scales are
absent, except in caecilians, which allows respiration to
occur through the moist skin. Living amphibians are small.
The fossil record preserves no intermediate common
(b) Ambystoma
(a)
Rana
(c) Caecilian
FIGURE 3.24 Lissamphibia. (a) Frog (Rana).
(b) Salamander (Ambystoma). (c) Gymnophiona (Caecilian).
nozoic
y caecilios
4000 especies
Amplia distribucin
Excepto, algunas
islas ocenicas
Fecundacin
externa (ranas o
sapos) interna
Salientia
(frogs)
Urodela
(salamanders)
Gymnophiona
(caecilians)
Escalon
intermedio
entre agua tierra
Respiracin a travs
de la piel
Dientes pedicelados
Operculo auricular
Reproduccin
Control hormonal y medio ambiente:
micorhabitat, talla, modo reproductivo, cuidado
parental
Caecilios, reproduccin cada dos aos
Salamandras, reproduccin annual
Anuros, reproduccin continua
Temperatura, salamandras
Lluvias, anfibios
Comunicacin
visual, restringidas para
especies diurnas
Seales visibles, cortejo, movimientos y
coloracin
Comunicacin vocal, indispensables para
el cortejo, llamado a la hembra
Estimulacin tctil
Captura fsica, amplexus
Courtship and Mating
69
! 3-25. Amplectic positions in anurans (males shaded). A. Inguinal (Alytes obstetricans). B. Axillary
VEJeutherodactylus danae). C. Cephalic (Colosthetus inguinalis). D. Straddle (Mantidacfylus lber). E. Glued
Breviceps adspersus). f. Independent (Dendrobates granuliferus). Drawing C adapted from Wells (1980a); D
adapted from Blommers-Schlosser (1975a), and E adapted from Wager (1965).
Importantes, metamorfosis
Grupos
modernos, piel especializada
Intercambio gaseoso
Dermis y epidermis, con capilares
Algunas
salamandras carecen de
pulmones, respiracin cutnea
Necesidades metablicas
PIEL
Carentes de escamas
Excepto algunos Apodos
Dentro de la epidermis, capa basal profunda y
superficie apical
Cel. De Leydig, proteccin virus y bacterias
Adultos, piel es similar al de las larvas con tejido
conectivo fibroso
Clulas de Leydig ausentes en epidermis
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Epidermis
Dermis
Estrato
crneo,
proteccin
Almohadillas
nupciales, forma de
dedo
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Stratum corneum
Chromatophores
Transitional layer
Stratum germinativum
Poison
gland
Mucus
gland
Muscle
amp
lary
into
serv
(a)
Stratum
corneum
Leydig cell
Rep
Transitional
layer
Epidermis
Stratum
basale
Mucous
gland
Callo
two
Both
conn
be sm
relea
(gra
secre
glan
ever
secre
harm
Chromatophore
Poison
gland
Dermis
(b)
FIGURE 6.12 Amphibian skin. (a) Section through an
adult frog skin.A basal stratum basale and a thin, superficial
stratum corneum are present.The transitional layer between
them includes a stratum spinosum and a stratum granulosum.
(b) Diagrammatic view of amphibian skin showing mucous and
poison glands that empty their secretions through short ducts to
the surface of the epidermis.
The
terre
and
pres
mal
orig
port
mis.
epid
scale
scale
Add
spin
bon
of bo
bon
kar24239_ch06_212-239.qxd
Epidermis
Glndulas
Mucosas, pequeas
Venenosas, grandes
Localizadas
en la
dermis y abren a
travs de unos
conductos
No venenosas al
humano
Dermis
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Page 220
Stratum corneum
Chromatophores
Transitional layer
Stratum germinativum
Poison
gland
Mucus
gland
Muscle
two
Both
conn
be sm
relea
(gra
secre
glan
ever
secre
harm
amp
lary
into
serv
(a)
Stratum
corneum
Leydig cell
Rep
Transitional
layer
Epidermis
Stratum
basale
Mucous
gland
Chromatophore
Poison
gland
Dermis
(b)
FIGURE 6.12 Amphibian skin. (a) Section through an
adult frog skin.A basal stratum basale and a thin, superficial
stratum corneum are present.The transitional layer between
them includes a stratum spinosum and a stratum granulosum.
(b) Diagrammatic view of amphibian skin showing mucous and
poison glands that empty their secretions through short ducts to
the surface of the epidermis.
The
terre
and
pres
mal
orig
port
mis.
epid
scale
scale
Add
spin
bon
of bo
bon
It
J
St
Qj
Sq
Po
Pf
Pro
Pp
T
Qj
It
Sq St
P
T
Op
Se
reducen los
huesos de la nariz
Hiomandibular,
implicado en la
audicin (estribo)
Prdida de los
huesos operculares y
extraescapulares
FIGURE 7.28 Diagrammatic
views of skull modifications from
rhipidistian to early tetrapod to
modern amphibian (salamander).
(a) Dorsal views. (b) Ventral (palatal) views.
Skull bones lost in the derived group are
shaded in the skull of the preceding group.
Abbreviations: basioccipital (Bo),
basisphenoid (Bs), ectopterygoid (Ec),
exoccipital (Eo), frontal (F), intertemporal
(It), jugal (J), lacrimal (L), maxilla (M), nasal
(N), opercular (Op), opisthotic (Ops),
parietal (P), palatine (Pal), postfrontal (Pf),
premaxilla (Pm), postorbital (Po), prefrontal
(Prf), prootic (Pro), postparietal (Pp),
parasphenoid (Ps), pterygoid (Pt), quadrate
(Q), quadratojugal (Qj), supratemporal (St),
squamosal (Sq), tabular (T), vomer (V).
Ops
Pp
Eo
Sq
Extrascapulars
(a) Dorsal
Rhipidistian
Internal
naris
Pm
Pm
M
Modern amphibian
(salamander)
Early tetrapod
Pm
Pal
V
M
Pal
Ec
Ec
Ps
Pt
Ps
Qj
Ps
Pt
Qj
Q
Pro
T Ops Bs
Eo
Bo
Pt
Pro
Ops
Sq Eo
(b) Ventral
Prdida de la fijacin
openings for eyes, pineal organ, and nostrils (figure 7.33ad).
Robust attachment flanges and processes are evidence of
strong jaw-closing muscles. The palatoquadrate of the
mandibular arch was reduced to the small epipterygoid and
separate quadrate. The hyoid arch produced a stapes, a
stout bone that braced the back of the dermatocranium
against the chondrocranium. These early tetrapods lacked
a temporal notch. Sound transmission to the inner ear may
have occurred along bones of the lower jaw.
de la cintura pectoral
con la parte posterior
del crneo
Skull Fenestrae As mentioned earlier, the temporal region
fenestrae. In recent turtles, emarginations often encroach
upon the posterior margin of the skull roof. These emarginations are large notches that function like fenestrae, but they are
independent phylogenetic derivatives. The diapsid skull
includes two temporal fenestrae, a condition carried forward in
Sphenodon and in crocodiles and their allies. However, the
lower and/or upper temporal bars are often lost in other modern forms. This gives us several contemporary varieties of a
modified diapsid skull in which the diapsid condition is substantially altered, such as birds, lizards, and especially snakes.
The synapsid skull of pelycosaurs, therapsids, and
Sistema
digestivo
Esophagus
Gallbladder
Esfago es corto,
clulas mucosas y
ciliadas
Estmago, glndulas
gstricas
Intestino, duodeno
corto
Pancreas
covering
bile duct
Liver
Stomach
Small
intestine
Pylorus
Large
intestine
Urinary
bladder
Sm
in
Cloaca
Cloaca
(a) Frog (Rana)
Liver
Gallbladder
Esophagus
Caecilios
Cuerpo
elongado
Sin extremidades
Excavadores
Escamas pequeas,
algunas
Costillas
Ano terminal
Figure 27-5
Female caecilian coiled around eggs in burrow.
Bosques
tropicales
de Sur America,
Africa y sur de Asia
Ojos pequeos
Adultos ciegos
Organos sensoriales,
hocico
Figure 27-5
Female caecilian coiled around eggs in burrow.
Poco
frecuentes
Lombrices y
pequeos
invertebrados
Fecundacin es
interna
Macho, organo
copulador protusible
Figure 27-5
Female caecilian coiled around eggs in burrow.
Huevos, cerca
del
agua sobre tierra
hmeda
Larva acutica
Huevos entre los
pliegues del cuerpo
Viviparos
Figure 27-5
Female caecilian coiled around eggs in burrow.
Salamandras
Anfibios
con cola
Diversos y
abndantes en Norte
America
Clima templado
Pequeo, 15 cm
Figure 27-9
Longtail salamander Eurycea longicauda, a
common plethodontid salamander.
Extremidades,
algunas
rudimentarias, otras
ausentes
Carnvoras, larvas y
adultos
Larvas acuticas y
adultos terrestres
Figure 27-9
Longtail salamander Eurycea longicauda, a
common plethodontid salamander.
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546
hmedos
Fecundacin interna
La hembra recoge en
A
la cloaca el
espermatoforo
Desarrollo directo,
salamandras
terrrestres
B
PART 3
Lugares
The Diversity of Animal Life
Female
Male
Spermatophore
Base of spermatophore
beneath female's vent
Figure 27-6
Courtship and sperm transfer in pygmy salamanders Desmognathus wrighti. After judging the females
receptivity by the presence of her chin on his tail base, the male deposits a spermatophore on the
ground, then moves forward a few paces. A, The white mass of the sperm atop a gelatinous base is
visible at the level of the females forelimb. The male moves ahead, the female following until the
spermatophore is at the level of her vent. B, The female has recovered the sperm mass in her vent,
Respiracin
Piel
Agallas
Pulmones
Ambos
Ninguna
Amphiumidae, sin
agallas en etapa
larval
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CHAPTER 27
Paedomorfisis
Early Tet
Retencin de caracteres
ancestrales
Siempre joven
sexual,
etapa larval
Perennibranchiados
Common mud puppy
(Necturus maculosus)
Madurez
Figure 27-9
Longtail salamander Eurycea longicauda, a
common plethodontid salamander.
Axolotl
(Ambystoma mexicanum)
probably originated in swift streams
Figure 27-10
Paedomorphosis in salamanders. A, The mud
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PART 3
The Diversity of Animal Life
3450
ranas y sapos
Mejor conocidos
del grupo
Reproduccin
acutica
Piel permeable al
agua
Anura, sin cola
e 27-11
Excepto las larvas y
Ascaphus
ructure of representatives of three different species of the tropical plethodontid salamander
Bolitoglossa. These specimens have been treated chemically to clear the skin and muscles and
n the bone red and cartilage blue. The species having the most fully ossified and distinct digits
ive primarily on the forest floor. The species having the padlike foot caused by restricted digital
(B) climbs smooth leaves and stems using the foot surface to produce suction or adhesion for
ment. The padlike foot evolved by paedomorphosis; it was derived evolutionarily by truncating
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PART 3
The Diversity of Animal Life
Adaptados
para
saltar
Huevo
larva con
agallas y
herviboras
Perennibranchias
no ocurre
B
e 27-11
ructure of representatives of three different species of the tropical plethodontid salamander
Bolitoglossa. These specimens have been treated chemically to clear the skin and muscles and
n the bone red and cartilage blue. The species having the most fully ossified and distinct digits
ive primarily on the forest floor. The species having the padlike foot caused by restricted digital
(B) climbs smooth leaves and stems using the foot surface to produce suction or adhesion for
ment. The padlike foot evolved by paedomorphosis; it was derived evolutionarily by truncating
CHAPTER 27
Variados
tamaos
Ecosistemas
tropicales y
templados
Habitos solitarios,
excepto poca de
reproduccin
Figure 27-13
Machos
ruidosos
American toad
Bufo americanus (family
Bufonidae). This principally nocturnal yet familiar
amphibian feeds on large numbers of insect
pests and on snails and earthworms. The warty
skin contains numerous glands that produce a
surprisingly poisonous milky fluid, providing
excellent protection from a variety of potential
Figure 27-14
Early Te
550
PART 3 The Diversity of Animal Life
is derived from glycogen and fat stored
in their bodies during the spring and
summer months. More terrestrial frogs,
such as tree frogs, hibernate in humus
of the forest floor. They are tolerant of
low temperatures, and many actually
survive freezing all extracellular fluid,
representing 35% of the body water.
Such frost-tolerant frogs prepare for
winter by accumulating glucose and
glycerol in body fluids, thereby protecting tissues from the normally damaging effects of ice-crystal formation.
Posesin
de una
charca
Habitos silenciosos
Durante el invierno,
anuros hibernan
Toleran bajas
temperaturas
While native American amphibians continue to disappear as wetlands are drained,an
Reptiles,
aves y
exotic frog introduced into southern California has found the climate quite to its likhumanos
ing. African clawed frogs,Xenopus laevis
(Figure 27-15),are voracious,aggressive,primarily aquatic frogs that rapidly are displac-
Figure 27-15
hic09617_ch27.qxd 6/7/00 12:00 PM Page 552
Columna
con siete
vertebras
Urostilo (coxis)
Esqueleto ligero y
aplanado
Patas pentadactilas
Piel, boca y
pulmones para
respirar
552
PART 3
The Diversity of Animal Life
Pterygoid
Frontoparietal
Nasal bone
Supra scapula
Premaxilla
Nares
Parasphenoid
Exoccipital
Prootic
Squamosal
Auditory capsule
Sacral vertebra
Tibiofibula
Astragalus
Maxilla
Calcaneum
Coracoid
Epicord
Mesosternum
Xiphisternum
Urostyle
Ilia
Ischium
Femur
Prehallux
Tibiofibula
Scapula
Clavicle
Phalanges
Metacarpals
Carpals
Prepollux
Radioulna
Humerus
Figure 27-19
Skeleton of a bullfrog, Rana catesbeiana.
second set of posterior and dorsal
muscles that draws the limb back and
away from the body (retraction and
abduction).
Trunk musculature, which in fishes
is segmentally organized into powerful
muscular bands (myomeres, p. 525) for
locomotion by lateral flexion, has been
Lungs are supplied by pulmonary
arteries (derived from the sixth aortic
arches) and blood returns directly to
the left atrium by the pulmonary veins.
Frog lungs are ovoid, elastic sacs with
their inner surfaces divided into a network of septa that are subdivided into
small terminal air chambers called alve-
hic09617_ch27.qxd 6/7/00 12:03 PM Page 556
Cuerdas
vocales
556
PART 3
The Diversity of Animal Life
Sexually mature
frog at 3 years
Tail shortens by
reabsorption, metamorphosis
nearing completion
Macho mejor
desarrolladas
Laringe o caja vocal
Carnvoros
Amplexo
Hindlimbs, then
forelimbs emerge
Male clasps female
(amplexus); eggs
fertilized as they
are shed
Skinfold grows over
external gill, water
exits through spiracle
Eggs surrounded
by jelly coats
Spiracle
Tail bud
External
gills
Tadpole begins
feeding on algae
Embryo nourished
by yolk
Cleavage
Figure 27-26
Life cycle of a leopard frog.
Males usually return to a pond or
stream before females, which they
then attract by their calls. Some salamanders also have a strong homing
Classification of Class
instinct, returning each year to reproduce in the same pool, to which they
are guided by olfactory cues. The initial stimulus for migration in many
pantropical, 6 families, 34 genera,
cases is attributable to a seasonal cycle
in the gonads plus hormonal changes
that increase the frogs sensitivity to
changes in temperature and humidity.
Order Anura (uh-nur!uh) (Gr. an, with-
