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Anatomy Of The Box Turtle
(Includes Definitions For All Those Technical Turtle Words)

.Outer Anatomy: Explained

.Inner Anatomy Is Coming Soon
.Turtle-Word Dictionary
 
 

 

 


Outer Anatomy: Explained
Carapace and Plastron

Carapace Description
The carapace is the top shell of chelonians. Is the dorsal (back) of a box turtle. The size and shape can vary depending on the subspecies, but usually in adults it is long (head to tail), and almost dome shaped (sometimes flat on the top).

Nuchel Scute: A small, single scute at the front of the carapace.
Central Scutes: Five large scutes extending down the middle of the carapace.
Costal Scutes: Four large scutes running along each side of the centrals.
Marginal Scutes: Several small scutes along the edge of the carapace.
Supracaudal Scutes: Two scutes (sometimes fused) at the end of the carapace.

Central Scutes are less commonly known as Vertebral Scutes.
Costal Scutes also are known as another name; Pleural Scutes.


Plastron Description

The plastron is the bottom shell of chelonians. Adult box turtles have hinge between the Pectoral and Abdominal sections, the hinge enables box turtles to close up (sometimes perfectly) into a "box" to protect against any danger.

Gular Scutes: The foremost scutes of the plastron.
Humeral Scutes - The second pair of scutes (bellow the front legs).
Pectoral Scutes: The third pair of the plastral scutes
Abdominal Scute: The middle pair of plastral scutes.
Femoral Scute: The fifth pair of scutes (bellow the opening for the back legs).
Anal Scutes: The rearmost pair of plastral scutes (bellow the tail).
Marginal Scutes: Several small scutes along the edge of the carapace.
Axillary Scutes: A small plastral scutes opposite the armpits.
Inguinal Scutes: Scutes just in front of the inguinal notch.

The Axillary and Inaguinal together is called the Bridge, it is the piece that connects the Carapace and Plastron together. The dark gray is the underside of the carapace, and where the turtles head and limps are.

 

 

 


Turtle-Word Dictionary (Click Here For Reference)

Well, I myself may not use all these terms, but incase you ever run into a word you don't know related to chelonians, here's a great place to check. In fact, now is a good time to scroll down to see what chelonian means.

(Not yet fully alphabetized, still under construction!)

A
Abdominal Scute -
The middle pair of plastral scutes
Anal Scutes - The rearmost pair of plastral scutes (bellow the tail).
Anterior - Towards the front of the shell
Aquatic - Lives in water.
Areola - The center are of a scute.
Axillary Scutes - A small plastral scutes opposite the armpits.

 

B
Bask - To sunbath in a warm atmosphere.
Beak - A horny plate covering the jaws.
Bridge - Part of the shell that connects the Carapace and Plastron together.
Brumation - Hibernate-like state.

 

C
Carapace - The top shell, the dorsal (back) of the turtle.
Carnivore - Meat-eating animal.
Caruncle - The Egg Tooth, a small horned bone on the snout of baby turtles, used to escape the egg shell.
Caudial - The tail region
Central Scute - The Vertebral Scutes, five large scutes extending down the middle of the carapace.
Chelonian - Referring to any species/family of turtle, tortoise, or terrapene.
Cloaca - The Vent, The posterior part of the intestinal tract in chelonians.
Clutch - A group of eggs laid by a female
Costal Scutes - Pleural Scutes, four large scutes running along each side of the centrals
Cruro- The thigh or leg
Cryptozoic - conducting a hidden or secluded way of life
Cusp - A sharp projection at the end of the jaw.



E
Endemic - Naturally restricted to a particular area
Epiplastron - The two anteriormost bones in the plastron
Estivation - Inactivity during long periods of drought or high temperatures
Egg Binding - A condition when a female turtle is unable to lay her eggs.
Egg Tooth - Caruncle, a small horned bone on the snout of baby turtles, used to escape the egg shell.

 

F
Fontanelle - Opening present in young turtles skull or shell, filled with maturity.

 

G
Glottis - closable opening in the floor of the mouth into which the windpipe opens
Gular scutes - The foremost scutes of the plastron.
Genetic - Pertaining to genes.
Genus - A category of biological classification ranking between family and species.
Gestation - The period between fertilization and the laying of the eggs.
Gravid - Having eggs.

 

H
Humeral Scutes - The second pair of scutes (bellow the front legs).
Hyoplastra - the second front most pair of plastral bones
Hypoplastra - the second rearmost pair of plastral bones
Habitat - An environment where an animal resides
Hatchling - The reptile just after it leaves its egg.
Herpetology - The study of reptiles and amphibians.
Hibernation - Winter inactivity where specific biological changes occur..
Hinge - A moveable joint in the shell.
Hybrid - An offspring from parents who are not the same species or subspecies.

 

I
Inguinal notch - A notch at the rear of the bridge where the hind legs protrude
Inguinal scutes - scutes just in front of the inguinal notch
Intergular scute - a sometimes present small scute which separates the gular scutes
Incubation - The phase of the egg after being laid and before hatching.


J
Juvenile - The ages between one year old and not yet sexually mature

 

K
Keel - A lengthwise ridge running lengthwise along the carapace, usually the center.
Keratin - Fibrous protein present in structures such as the carapace scutes, beaks and claws.

 

L
Lamella - A thin plate made from bone or keratin
Lateral - Pertaining to the side.

 

M
Marginal Scutes - Several small scutes along the edge of the carapace.

 

N
Nuchal bone - large bone at the front of the turtles carapace
Nuchal scute - A small, single scute at the front of the carapace.
Nares - The openings to the nasal cavity.
Nitrate - The final stage of digestive filtration, containing ammonia and nitrate. Many turtles and tortoises expel this, appearing as a white, thick substance when eliminating.
Nocturnal - Active at night.

 

O
Ocellus - A ring shaped (often with a dark center) marking
Ovipositor - A soft tubular structure extruded from the vent during oviposition of eggs

 

P
Palpate - Feeling an animal's body/bones (sometimes to see if it is gravid)
Papilla - A soft elongate protruberance
Pectorial Scutes - The third pair of the plastral scutes
Pedicle - a thickened area of bone designed to withstand weight or pressure
Plastron - The bottom part of the shell in chelonians.
Postorbital - A scale or other structure behind the eye
Pygal - the rearmost bone in turtles carapace
Pleural scutes - Costal Scutes, four large scutes running along each side of the Vertebral Scutes (centrals)

 

R
Rathke's Glants - Glants from which some turtles can exude a highly odorous secretion
Renal - Pertaining to the kidneys.
RH - Stands for 'Relative Humidity'.

 

S
Seam - The line between scutes.
Supracaudal Scutes - Two scutes (sometimes fused) at the end of the carapace
Supramarginal scutes - Scutes located between the pleural (costals) and marginals
Sympatric - Occupying the same geographic area
SCL - Means to measure the 'Straight Carapace Length' of a turtle.
Scute - The scales covering the bones of a turtles shell.
Serrated - Jagged/saw shaped edge
Subcutaneous - Beneath the skin.
Subspecies - A subdivision of a single species.
Substrate - The bedding used on the flooring of an enclosure.
Suture - The seams between two boney areas.
Systemic - Affecting the entire body.

 

T
Tachycardia - A rapid heart rate, (greater than 100 beats per minute.)
Temporal - the sides of the scull behind eyes
Tubercle - A small lump
Tuberosity - A large tubercle
Tympanum - A vibrating surface which forms the external ear in turtles
Temperate - Environments where winter and summer is experienced.
Terrestrial - Living on the ground.
Tomium - The sharp beak of a turtle.

 

X
Xeric - Term used to describe dry environments
Xiphiplastra - The rearmost pair of plastral bones