zoo301 parade of vertebrates
DESCRIPTION
Comparative AnatomyTRANSCRIPT
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Parade of the
Comparative Vertebrate Anatomy
VertebratesVertebrates
~60,000 known species Most successful animal group in terms of
survival One of the largest group of taxa in animal
kingdom Found in various types of environments Evolved for 590M years Unique characteristics:
Presence of vertebral column Formation of cranium
TheGeologicTimeScale
Vertebrate Classification1. Agnatha2. Acanthodii3. Placodermii4. Chondrichthyes5. Osteichthyes6. Amphibia7. Reptilia8. Aves9. Mammalia
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The Vertebrates Agnathans
Ostracoderms Cysclostomes
Placoderms Acanthodians Chondrichthyans
Elasmobranchs Heterocephalans
Osteichthyans Actinopterygians Sarcopterygians
Amphibians Labyrinthodonts Temnospondyls Microsaurs Lissamphibians
Reptilians Anapsids Squamates Crocodilians
Avians Archeornithes Neornithes
Mammals Monotremata Marsupialia Insectivora Xenarthra Tubulidentata Pholidota Chiroptera Primates Lagomorpha Rodentia Carnivora Pinnepedia Perissodactyla Artiodactyla Hyracoidea Proboscidea Sirenia Cetacea
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Class Agnatha
Order: Heterostraci Order: Osteostraci Order: Anapsida Order: Coelolepida Order: Petromyzontiformes (lampreys) Order: Myxiniformes (hagfishes)
Ostracoderms
Cyclostomes
(Jawless fishes)
Ostracoderms Oldest known vertebrates (Cambrian period) Body covered with bony dermal armor (plates and tile-like
scales) – armored fishes Mostly 2-30 cm in length (longest: 2 m) Mostly freshwater habitat (few marine during Silurian period) With sense organs (eyes) and pineal body (3rd eye); nostril
(leads to olfactory sac) Filter feeders
Ostracoderm fossil from Canada(Silurian-Devonian Period)
Cyclostomes Living jawless fishes Notochord retained in adults Single median nostril No paired fin Naked skin (slime glands) With buccal funnel (adaptation to
parasitic life) – with rasping tongue andhorny denticles (lamprey)
Seven gill slits Some marine, some freshwater Lampreys are anadromous organisms
(marine but lay eggs in freshwater) Hagfishes: both gonads are present but
only one is functional
Myomyzon (Lamprey)Fossil dated during theCarboniferous period
Eptatretus (Hagfish)
Tentacles Gill slits (twelve pairs) Mucous glands
Gill openings (seven pairs) Petromyzon(Lamprey)
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Class ChondrichthyesSubclass Elasmobranchii (naked gill slits) *Order Cladoselachii (primitive paleozoic sharks) *Order Plueracanthodii (freshwater paleozoic sharks with lobed
fins) Order Squaliformes (sharks) Order Rajiformes (sawfish, skates and rays)
Subclass Holocephali (gills covered with operculum) Order Chimaeriformes (Chimaeras)
Elasmobranchs Cartilaginous fishes Placoid scales Ventral mouth With claspers (internal
fertilization) Macrolecithal egg Oviparous organism (eggs
with horny leathery shellwith tendrils)
Presence of spiracle (1st gillslit) except chimeras
Mostly marine
Elasmobranchs Squaliformes with fusiform bodies (swift swimmers) Rajiformes with dorsoventrally flattened body (bottom
dwellers) Long gestation period (2 yrs) Cranium without sutures Several sets of teeth Large animals (20 m-whale shark) Absence of swim bladder
Heterocercal tailLarge livers (bouyant oils)Pectoral fins as hydrofoilsAbsence of bones
Class Osteichthyes Subclass Sarcopterygii (Choanichthyes) – lobe-finned fishes,
fins attached to appendage (give rise to tetrapods) Actinistians – mostly extinct except Latimeria Rhipidistians – ancestors of amphibians Dipnoans – lungfishes
Subclass Actinopterygii – ray-finned fishes, modern fishes Superorder Chondrostei – chiefly paleozoic Superorder Holostei – dominant Mezoic fishes with ganoid scales Superorder Teleostei – present forms of bony fishes
Chanos chanos
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Class Osteichthyes Largest group of
extant vertebrates Bony fishes With operculum Terminal mouth With swim bladders
(air sacs)-neutralbouyancy
With cloaca Overlapping scales
(ganoid, ctenoid,cycloid,)
Fins stiffened bylepidotrichia
Actinopterygii Ray-finned fishes Fin rays joined by membranes Absence of internal nares Main distinguishing characteristic:
endoskeleton composition Superorder Chondrostei-cartilaginousSuperorder Holostei-cartilage & bones Superorder Teleostei-bone
Chondrosteans Most primitive ray finned
fishes With ganoid scales Largely cartilaginous With spiracle Ex. Sturgeon, paddlefish
can reach 8 m marine and freshwater toothless (bottom feeders) can reach up to 100 years Roe (egg) – sold
commercially as Russiancaviar
Holosteans Intermediate form of ray-finned
fishes
Freshwater
Ganoid scales; No spiracles
Single air bladder
Endoskeleton is ossified
Braincase is largelycartilaginous
Examples: Bowfin
Garpike
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Teleosts Modern fishes
Ossified skeleton
With cycloid or ctenoid scales(flexible and overlapping)
~20,000 species
Found in any body of water
With swim bladders
Homocercal (equal lobe),protocercal (single lobe,vertebral column at center) ordiphycercal tail (single lobe andvertebral column turns dorsally)
No spiracle
Teleosts
caudalfin
dorsal fin
pectoral fin(one of two)pelvic fin
(one of two)
anal fin
muscle segmentsfin supports
brain
olfactorybulbheart
livergallbladder
stomachintestineswim bladder
kidneyanusurinary
bladder
Sarcopterygii Lobed-finned fishes Bony and fleshy lobe at the base of their paired fins With internal nares that open into oropharyngeal cavity Gill slits covered with operculum Give rise to the ancestors of tetrapods Some with cosmoid scales 2 major groups:
Actinistians – mostly extinct except Latimeria Rhipidistians – ancestors of amphibians Dipnoans – lungfishes
Latimeria
Coelacanth Only extant species discovered in Madagascar coast (originally
believed to be extinct for more than 65 M years) Skull and lower jaw architecture resembles of tetrapods
(powerful jaw suspension) Predatory
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Dipnoans “True” lungfishes Only 3 living genera Non-functional gills Undergo aestivation
during dry season Similarity with
amphibians: Swim bladder connected to
pharynx Swim bladder supplied with
blood via 6th aortic archinstead of dorsal aorta
Larvae with external gillslits
Presence of internal nares
Origin of tetrapod limbs
Class Amphibia Start of tetrapods Anthracosaurs – ancestors of amniotes (mississippian
to triassic period) Cold blooded; Can live both in land and water With lungs; can respire thru skin, mouth, pharynx,
lungs
Subclasses:Labyrinthodontia- Stegocephali – 1st tetrapodsLepospondyli -Lissamphibiaa
LissamphibiansOrder: Anura
(tailless) Frogs (elongated
urostyle)
Order: Urodela(Tailed) Salamander
(perenibranchiate (retainlarval gills); neotenous
Order: Apoda(Legless) Caecilians (borrow-
dwelling; short tail;~30cm long)
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Class Reptilia Cold blooded (aquatic,
terrestrial) Scaly; with claws Breathe thru lungs Developed long neck
(cervical vertebrae) Pelvic girdle articulates
with 2 sacral vertebrae Internal fertilization Paired limbs usually
pentadactyl Heart with right and left
atria Cotylosaurs = stem
reptiles
Class Reptilia Subclasses (based on type of skull)
Anapsida Absence of temporal arch Cotylosaurs, turtles (chelonia) LepidosauriaWith 2 temporal fossae; Powerful jaw suspension Sphenodon sp. or tuatara
Archosaurs Diapsid skull (2 temporal arches); Extinct Thecodonts (dinosaurs, crocodiles and alligators)
Class Reptilia Subclasses (based on type of skull)
EuryapsidsWith single dorsal temporal fossae; modification of diapsids Descendants of birds (plesiosaurs, ichthyosaurs)
SynapsidsWith single lateral temporal fossae; descendants ofmammals Heterodont dentition; dentary bone as the largest bone ofthe lower jaw Therapsids
Order Chelonia Cyclenis amboinensis (land
turtle) Jaws lacks teeth Covered with hard horny
beaksTortoise
Enormous size Large head shields Limbs modified into
swimming flippers Chelonia sp. (sea turtle) Gopherus sp. (desert turtle) Eretmochelis inbricata
(hawksbill turtle)
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Order Squamata Represent the most recent reptiles
Suborder Lacertilia (Lizards) 2 pairs of pentadactyl limbs Upper and lower eyelids Nictitating membrane Hemiphyllodactylus sp. (Houselizard)
Expanded digits for climbingwalls and trees
Gecko gecko (tree lizard) Nocturnal; eyes are large,
pupils vertical Eyelids are lost Adhesive toe pads Capable of loud vocalization
Varanus sp. (Giant or monitorlizard)
Large lizard with tail longerthan head and body
Draco rizalis (flying lizard) Lateral folds of the trunk
Order Squamata Suborder Ophidia (Snakes) Limbs are absent Eyelids are immovably fused Eyes are covered by transparent scales Ophidia sp. (snake) Crawl by bending into a series of S-shaped
curves Some have fangs connected to poison sacs
Cobra Long cervical ribs that can be rotated outward Has hollow non folding fangs connected to
poison sacs
hollowfang
venom gland
Order Crocodilia Modified descendants of a group of bipedal archosaurs Giants of the living reptiles Crocodylus sp. (crocodiles)
Infest rivers and lakes in tropical region Snout is narrow and pointed 4th tooth of the lower jaw is exposed when the mouth is
closed Aggressive
Alligator sp. (alligator) Most abundant in the coastal regions of the southern US Snout is broad and blunt 4th tooth of the lower jaw fits into a pit in the upper jaw Passive
The Vertebrates Agnathans
Ostracoderms Cysclostomes
Placoderms Acanthodians Chondrichthyans
Elasmobranchs Heterocephalans
Osteichthyans Actinopterygians Sarcopterygians
Amphibians Labyrinthodonts Temnospondyls Microsaurs Lissamphibians
Reptilians Anapsids Squamates Crocodilians
Avians Archeornithes Neornithes
Mammals Monotremata Marsupialia Insectivora Xenarthra Tubulidentata Pholidota Chiroptera Primates Lagomorpha Rodentia Carnivora Pinnepedia Perissodactyla Artiodactyla Hyracoidea Proboscidea Sirenia Cetacea
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Class Aves Endothermic with feathers Bipedal locomotion Scales on their beak, legs and feet Single occipital condyle and diapsid skull Reduced body weight
Slender long bones with air cavities No teeth Has a large sternal keel (carina) for
attachment of massive flight muscle Presence of air sacs Reduced wrist bones, palm digits Fusion of bones (synsacrum) Absence of urinary bladder
Uropygial gland Forelimbs for flying Has a crop for storage of seeds and grain Stomach is gizzard Females with left ovary and left oviduct
only External incubation
Archeornithes Subclass:
Archeonithes(Archeopteryx sp)oldest known birdhad a long reptilian
tailthecodont teeth on
both jawsForward nostrilsSkull was more
reptilian than avianabsence of beaksunfused synsacrumhad smaller wings
Neornithes Subclass: Neornithes (Modern Birds)Superorder: Odontognathae (with
teeth)Superorder Neognathae (without teeth) Ratites - can’t fly Carinates – can fly
Class Mammalia with mammary gland (except
monotremes) with hairs Synapsid skull 1 dentary bone articulating with
squamosal bone 3 middle ear bones With diaphragm (separates
thoracic from abdominal cavities Sweat glands Absence of cloaca (except
oviparous mammals) Heterodont dentition 2 sets of teeth Biconcave, non-nucleated RBC Ear with pinna Specialized voice box Developed cerebral cortex
Major Divisions:OviparousProtheria (monotremes) lays egg and with cloaca
ViviparousMetatheria (marsupials) yolk sac as placenta
Eutheria (placentals) with chorioallantoicplacenta
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Mammalian Orders1. Monotremata2. Marsupialia3. Insectivora4. Xenarthra5. Tubulidentata6. Pholidota7. Chiroptera8. Primates9. Lagomorpha10. Rodentia11. Carnivora12. Pinnepedia13. Perissodactyla14. Artiodactyla15. Hyracoidea16. Proboscidea17. Sirenia18. Cetacea
MonotremesPlatypus (ductbill), Echidna (spiny anteater)Lay eggsAbsence of nipples (modified sweat glands sucked by
youngs)With cloacaTestes within abdomen (absence of scrotal sac)No pinna of ear
MarsupialiaYolk sac serve as placentaYoung nursed in marsupiumGeographically isolated in
AustraliaEx. Kangaroo, koala, wallaby,
opossum, phalanger,Tasmanian wolf
InsectivoraSubsist on insectsPlantigrade (flat footed)Absence of scrotal sacWith shallow cloacaSharp, pointed teeth
with incisorsPremolars poorly
developed
Albino hedgehoghedgehog
Moles
Tree shrew
shrew
Mole
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ChiropteraAbility to flyPresence of patagiumHindlimb digits with claws
(clinging)With keel (sternum)With pinnaSanguinivorous
PrimatesPrimarily arboreal mammalsGrasping handOpposable thumbPresence of nails (instead of
claws)Large cerebral hemisphereDuplex uterusOne pair of nipples (thoracic
region)PlantigradeHigher primates:
Platyrrhine – nostrils openon sidesCatarrhines – nostrils open
anteriorly
CarnivoraFlesh eatersTerrestrialLong sharp
caninesPowerful jawsFeet with tori
PinnipediaMarine flesh-eatersNo pinna of earsWith flippersAnadromous organisms
walrus
Sea Lion
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CetaceaAquatic marine mammalsWith tail fin similar to fishes (2
lobes)With flippersOne nostril (dorsal side)Ex. Dolphin, whale, porpoise
EdentataAdvance insectivorousToothlessArmored mammals (bony
plates)Can roll into a ball (defense
mechanism)NocturnalEx. armadillos
Peba(9-banded armadillo)
TubulidentataColumnar teeth
with tube-like pulpcavityanteatersLast surviving
ancient line ofhoofed mammalsDerived from
ancestral ungulatelineageDigitigradeEx. Aadvark
Pholidota Toothless scaly anteatersOverlapping horn scales Ventral and inside extremities have
exposed skin with hairsManus and pes with long curved
claws Skull is conical without a
zygomatic arch. Jaw muscles are weak. Tongue sticky & long, vermiform,
connected to long xiphisternumprocess of sternum
Muscular stomach wall.Grinding of food assisted by
pebbles (similar to gizzard ofbirds)
Pangolin
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RodentiaLargest group of
mammalsA pair of long curved
incisors (knawing)No caninesWith diastemaCan digest cellulose
(due to commensals)With long coiled
caecumCellulose eatersPlantigrade gaitClawed feetEx. mouse, hamster,
guinea pig, squirrel
LagomorphaHerbivores2 pairs of incisors (on
upper jaw)Split upper lipStrong hind legsEx. Rabbits, hares, pikas
PerissodactylaUnguligrades (walks on the
hoofed tips of 1 or 3 or 4 toes)most of the body weight is
borne in a single digithas a mexasonic foot – walk on
single digit (rhino and horses)Ex. horses, tapirs and
rhinoceros, zebras
ArtiodactylaUngulates (walk using 2
toes – paraxonic foot)Most diverseChambered stomach (at
least 3)Ruminants (chew cud)Ex. pigs,
hippopotamuses, cattles,camels, peccary, deer,antelopes, giraffe
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ProboscideaWith proboscisIncisor form tusksScanty hair on thick,
wrinkled skin5 toes ending hoof-like
nailsMolar are grindersBulky animalSubungulatesEx. elephants and
mastodons
Hyracoidea Hunchback when at rest Harelip Plantigrade 4 digits on forefeet and 3 digits on
the hind feetWith small flat hoofs (except 1 digit) Crowned teeth (similar to
ungulates) Ex. Hyrax
SireniaFreshwater or marineStrictly vegetariansFew hairsPaddle-like forelimbsHindlimb absent
(vestiges presentinternally – attachedpelvic girdle)Naked skinVestigial nails on
flippers (manatee)Ex. Manatees,
dugongs (sea cows)