The document discusses the class Chondrichthyes, which includes cartilaginous fishes such as sharks, rays, and skates. Key characteristics include a cartilaginous skeleton, placoid scales, ventral mouth and nostrils, jaws, paired appendages, and male claspers. The class contains two subclasses: Elasmobranchii containing sharks and rays/skates, and Holocephali containing chimaeras. Elasmobranchii have a four-chambered heart and seasonal reproduction cycles, while Holocephali have smaller mouths bounded by three lips and tooth plates instead of scales.

1. Class Chondrichthyes
Mirabel, Camille Joyce Mercado,
Pia Alyssa
Rivera, John David

2. ETYMOLO
G Y - Cartilages
“Chondros’’
“Ichthyos’’
- Fish

3. Class Chondrichthyes
Characteristics:
 Cartilaginous
fishes
 Streamlined form with heterocercal tail
 Cartilaginous skeleton
 Leathery skin
 With placoid scales ( dermal denticles )
 Restricted notochord
 Mouth and two nostrils ventral
 Jaws and paired appendages
 Male claspers
 Eggs with large yolk

4. M O R P H O L O
G Y

5. Taxonomical Hierarchy

Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Infraphylum Gnathostomata
Class Chondrichthyes
Subclass Elasmobranchii
Orders Cladoselachii,
Pleuracanthodii ( extinct sharks )
Orders Squaliformes
Order Rajiformes
Subclass Holocephali

6. Subclass
Elasmobranchii
 Sharks (Selachii) and the rays & skates
(Batoidea)
 lives in most oceans in the world

7. Circulatory System
Four chamber heart: sinus venosus,
atrium, ventricle, and conus
arteriosus.
One direction of flow: Heart Gills
Body
Ectotherms/Endotherms

8. Reproductive System
(Male)
 Both testes
functional

Seasonal
reproduction
cycle

Sperm
stored in
seminal
vesicles

Both
claspers
functional

9. Reproductive System (Female)

One functional ovary in most
viviparous species

Seasonal reproductive cycle

Fertilization in nidamental gland

10. Shark Mating

One clasper will rotate 90º and
will be inserted into the female’s
cloaca

Clasper will expand cartilaginous
spurs to anchor in the female

11. Subclass Elasmobranchii:
Orders Cladoselachii,
Pleuracanthodii

extinct sharks

12. Order Squaliformes
 sharks,
body spindle-shaped; 5-7 pairs of
lateral gills not covered by operculum,
pectoral fins not enlarged example:
Squalus

13. Order Rajiformes
 skates,
rays and sawfishes, body
spreadout, pectoral fins enlarged and
attached to head and body; five pairs of
gill slits on ventral side, spiracles large

14. Subclass Holocephali
•
•
•
•
chimaeras or ghost fish , gill slits covered with
operculum;
spirally closed; aberrant shaped; jaws with tooth
plates;
single nasal opening without scales; accessory
clasping organs in male ;
lateral line an open groove, Chimaera

15. Nervous System
 Cerebellum
is small
 Medulla Oblongata is produced laterally
into restiform bodies

16. Digestive System
 The
mouth in holocephali is small as
compared to the wide mouth of
Elasmobranch
 It is bounded by three lips-like fold and
equipped with the tooth plate having
irregular surface and sharp cutting Edges

17. Urogenital System
 The
kidney of holocephalians is
opisthonepric having a large number of
uriniferous tubules and built upon the
basic pattern other fishes.

18. Circulatory System
 Heart
is Built upon the pattern similar to
other fishes.
 The Heart is consists of a sinus venosus,
artrium, ventricle and conus with three
rows of valves.

19. Respiratory System
A
Mandibular pseudobranch is absent and
hyoid bear only a Posterior Hemibranch.
 The first,second and the third branchial
arches have Holobranch but the forth Has
a hemibranch.