INTRODUCTION, HABITAT AND CHARACTERS OF FISHES ARE DESCRIBED

1. Pisces – general characters
G RAVITEJA
LECTURER IN ZOOLOGY
YVNR GDC, KAIKALUR.
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2. Introduction
 First Jawed vertebrates
 Completely aquatic and gill breathing animals
 Ostracoderms
 Consists most diverse and largest vertebrate group
 Ichthyology
 Paedocypris progenetica(7.9mm)
 Rhynodon typhus (whale shark)
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3. Pisces - general characters
Poikilothermic animals
Body- streamlined and
differentiated into
head trunk hand tail.
Exoskeleton –
mesodermal scales or
Bony plates
Endoskeleton –
cartilaginous or Bony.
Skull is monocondylic,
Vertebrae are
amphicoelous.
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BY-SA

4.  Locomotion – unpaired (median and caudal) and paired (pectoral and pelvic)
fins.
 Mouth is ventral and terminal
 Teeth are acrodont homodont and polyphyodont
Pisces - general characters

5. Pisces - general
characters
 Exchange of respiratory gases - gills

6.  Heart is two chambered – branchial and venous heart.
 Single circuit circulation.
Pisces - general characters

7. Pisces - general
characters
 Kidney are mesonephric
 Mostly ammonotelic and some
are ureotelic.
 Cranial nerves are 10 pairs.
 Menix primitiva.

8.  Internal ear consists of three semicircular canals.
 Lateral line sensory system – Neuromast organs – Rheoreceptor.
Pisces - general characters

9.  Eyes are without eyelids – Nictitating membrane.
 Unisexuals
 Fertilization is internal or external
 Development may be direct or indirect.
Pisces - general characters