Plastron (turtle)

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Belly armor of an ornamental turtle ( Chrysemys picta )

The Plastron ( frs. "Chest harness ") is the flat stomach shell of the two-part tank of turtles (Testudinata). It is connected to the dorsal part of the armor, the arched back armor or carapace , via the bony “bridge” .

Horn shields ( left ) and bone plates (right) of the plastron using the example of a false pointed-headed tortoise ( Pseudemydura umbrina ).
Labeling in English

The plastron and carapace each consist of an underlying layer of solid bone plates. The bone is covered by a layer of skin which - with the exception of the softshell turtles - is covered with shields (Scuta, singular Scutum = arched wooden shield of Roman legionaries) made of horny substance . However, the borders of the horn and bone plates are not congruent. According to a general scheme, the shields can be divided into groups based on their position on the plastron:

  • In the middle are 6 pairs of shields, labeled from front to back:
    • Gular or throat shields (Gulare)
    • Humeral or arm shields (humerals)
    • Pectoral or breast shields (pectorals)
    • Abdominal or belly shields (abdominals)
    • Femoral or thigh shield (femoral)
    • Anal or anus shields (anal, syn. Subcaudale)
  • There are a row of inframarginal shields on both sides of the edge
  • Occasionally there is an unpaired intergular or throat shield in front
  • Further scuta such as the armpit shield (axillary) and the soft or hip shield (inguinals) can occur


  • U. Lehmann: Paleontological dictionary. 3. Edition. Ferdinand Enke Verlag, Stuttgart 1985, ISBN 3-432-83573-6 .