Taxonomy of Finfish (1+2)

4.2.2. Testudines - Sea Turtles

4.2.2 sea Turtles

 

Kingdom          : Animalia

  Phylum            : Chordata

    Subphylum      : Vertebrata

Class              : Reptilia

  Subclass         : Anapsida

    Order               : Testudines

       Family            : Cheloniidae

 Subclass: Anapsida

They are primitive reptiles with a solid skull roof. 

 

ORDER - TESTUDINES 

 This order includes all turtles and tortoises. It is divided into three suborders: 

1.      Pleurodira (side-necked turtles)

2.      Cryptodira (freshwater turtles, snapping turtles, tortoises, soft-shelled turtles, and sea turtles)

3.      Amphichelydia (a suborder of turtles that is now extinct).

 FAMILIES  

Most scientists recognize seven species of sea turtles under two families: 

1.      Cheloniidae (all sea turtles with scutes (horny plates) covering their shells)  

• Upper shell, or carapace quite flat rather than highly rounded; oval or heart-shaped
• Lower shell, or plastron, a bit smaller than in most turtles and attaches to the upper shell by tough but flexible tissues called ligaments
• Limbs are modified into flippers for swimming
• Unlike many other turtles, they cannot retract, or pull back, their limbs or heads into their shells.
• The family Cheloniidae contains six species under six genera.

Cheloniids are large turtles, ranging between 71 cm (Lepidochelys olivacea) and 213 cm (Caretta caretta) in maximum carapace length.  

Species: 

1. Green (Chelonia mydas); two subspecies of the green (Chelonia mydas mydas) and the black or Eastern Pacific green turtle (Chelonia mydas agassizii)
2. Loggerhead (Caretta caretta)
3. Kemp's ridley (Lepidochelys kempii)
4. Olive ridley (Lepidochelys olivacea)
5. Hawksbill (Eretmochelys imbricate)
6. Flatback (Natator depressus)  

2.      Dermochelyidae 

• Scuteless turtles with only one modern species; the leatherback turtle - covered with leathery skin
• It is the only marine turtle whose backbone is not attached to the inside of its shell  

Species:  

1.  Leatherback (Dermochelys coriacea) - the largest living turtle.

Fresh water chelonians called terrapins.  Trionyx is a soft shelled fresh water edible terrapin.