PHYLUM CHORDATA

  • Learn  more about chordates from the UCMP or from the Tree of Life
  • 45,000 species
  • Chordates and echinoderms are deuterostomes
  • Characteristics of the Phylum Chordata
    1. Notochord (usually replace by vertebral column)
    2. Dorsal hollow nerve cord
    3. Pharyngeal gill slits
    4. Postanal tail
    5. etc.

Subphylum UROCHORDATA

  • tunicates [fig. 26.6-26.8]
    1. mainly sessile & solitary adults
    2. filter feeders
    3. mobile "tadpole" larva.  
    4. paedomorphosis
    5. more from Maureen Gramaglia's Webpage on Urochordata; Penn State 

 


solitary adult tunicate left, photograph courtesy of BIODIDAC; "tadpole" larva,  right photograph courtesy of BIODIDAC

Subphylum CEPHALOCHORDATA

  • lancelets [fig. 26.9]
  •  45 species
  • filter feeders
  • no obvious head, no eyes
  • more from Maureen Gramaglia's Webpage on Cephalochordata; Penn State 
  • Branchiostoma: External features of a lancelet amphixous; drawing courtesy of BIODIDAC

 


SUBPHYLUM VERTEBRATA 

Superclass AGNATHA

Class MYXINI

 


image courtesy of BIODIDAC

Class CEPHASPIDOMORPHI (Petromyzontiformes)

 


lamprey parasitizing bony fish;  image courtesy of BIODIDAC


Superclass GNATHOSTOMATA


CLASS CHONDRICHTHYES - 750 spp.

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CLASS OSTEICHTHYES

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Subclass Actinopterygii

  • ray-finned fish [Fig. 27.12-27.13]
  • most fish (most vertebrates)
  • Alligator gar, photograph by John White, California Academy of Sciences

 

 Subclass Sarcopterygii

  • fleshy-finned fishes including lungfish [Fig. 27.10] and the coelacanth [Fig. 27.11]
  • fleshy finned fish gave rise to amphibians in the Devonian; Devonian lungfish drawing BIODIDAC used with permission
  • more from the UCMP
  • David Atkins Chordate Biology

 


Tetrapods


CLASS AMPHIBIA: 4,000 spp.


AMNIOTES AND THE AMNIOTIC EGG

CLASS REPTILIA

Chelonia: turtles (225 species)

bigtort.jpg (3338 bytes)

Squamates

  • Lizards (3300 species) [Fig. 29.6-29.7]
    1. diapsids with lower temporal bar lost
    2. Sceloporos jarrovii --photograph 2001by Dr. Allan H. Chaney,  used  with permission
  • Snakes (2300 species)
    1. kinetic skull:  middle and lower temporal bars lost
    2. vestigial pelvic girdle in booids
    3. Masticophis flagellum testaceus western coachwhip, red color phase, photograph 2001by Dr. Allan H. Chaney,  used  with permission

 

 

Crocodilia: alligators and crocodiles (21 species)


American alligator; photograph taken at Aransas National Wildlife Refuge 2001by Dr. Allan H. Chaney,  used  with permission


Class AVES

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Class MAMMALIA: 4,500 spp.

RHINOFULL.JPG (4434 bytes)

Monotremes [Fig. 31.4a,b]

Marsupials (Subclass Metatheria):

Placental Mammals (Subclass Eutheria):

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