science

List of Testudines families

List of Testudines families is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand List of Testudines families rather than just read about it. In short: There are fourteen extant families of the order Testudines, an order of reptile. The testudines are some of the most ancient reptiles alive, with only the tuataras considered more primitive.

Key takeaways

List of Testudines families belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect List of Testudines families to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of List of Testudines families from memory before moving on to harder problems.

Reference excerpt

There are fourteen extant families of the order Testudines, an order of reptile. The testudines are some of the most ancient reptiles alive, with only the tuataras considered more primitive. There are approximately 300 extant species and 97 genera of testudines, split into two suborders: the Cryptodirans and the Pleurodirans. The distinction between these two suborders is based on the mode in which they cover their head and neck. The Pleurodirans, also called the side-necked turtles, have long necks, and fold them sideways to align them with the shell. The Pelomedusidae and Chelidae are the only extant families of pleurodires. The Cryptodirans pull their neck straight back to conceal their head within the shell. The Carettochelyidae, Cheloniidae, Chelydridae, Dermatemydidae, Dermochelyidae, Emydidae, Kinosternidae, Testudinidae and Trionychidae are all cryptodires, although the ability to retract the head has been lost in the sea turtles (Cheloniidae and Dermochelyidae). A third order, the Paracryptodirans, are extinct. Reptiles are classified according to the pattern of fenestration in the temporal region of the skull. Testudines are placed in the subclass Anapsida because they lack fenestration. There are suggestions that this lack of fenestration is a secondary characteristic and that turtles belong in Diapsida. Both sides cite strong evidence, and the conflict has yet to be resolved. The shell of testudines distinguishes them from other vertebrates. The shell is not an exoskeleton, but a modified ribcage and part of the vertebral column. Because of the shell, the pectoral and pelvic girdles are located within the ribcage. The limb bones are also modified to accommodate to the shell. The earliest known turtles are from fossils in the Upper Triassic. These fossils are nearly indistinguishable from modern turtles anatomically. In these early fossils (mostly of the genus Proganochelys), the teeth have already been lost, and a keratin beak is suggested by the mandibles. Important differences between Proganochelys and modern turtles are the presence of the palatal teeth (lost in modern species), the inability to retract the head within the shell, and the lack of a trochlear pulley in the jaw closing anatomy.

Families The following lists the family—the Latin name of the family, date in which the species was formally described and classified, and the binomial authority on the species; the number of genera belonging to the family; the name or names commonly used; an example species and an example image.

References

Further reading David T. Kirkpatrick (November–December 1995). "Platysternon megacephalum". Reptile & Amphibian Magazine. pp. 40–47. Archived from the original on 22 May 2011. Retrieved 26 June 2010. Cogger, H.G.; R.G. Zweifel; D. Kirschner (2004). Encyclopedia of Reptiles & Amphibians Second Edition. Fog City Press. ISBN 1-877019-69-0.

External links John B. Iverson; A. Jon Kimerling; A. Ross Kiester. "EMYSystems". Terra Cognita Laboratory, Geosciences Department of Oregon State University. Retrieved 26 June 2010.

Illustrations

Worked examples

Example 1 — a first encounter with List of Testudines families

Start with the simplest possible case. Write down what List of Testudines families claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to List of Testudines families before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about List of Testudines families ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of List of Testudines families

In research: List of Testudines families appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses List of Testudines families in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: List of Testudines families is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lists of reptiles, Taxonomic lists (families), Turtles, so understanding it makes those chapters shorter.
In everyday life: Look for List of Testudines families outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study List of Testudines families in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what List of Testudines families means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is List of Testudines families in simple terms?

There are fourteen extant families of the order Testudines, an order of reptile. The testudines are some of the most ancient reptiles alive, with only the tuataras considered more primitive.

Why does List of Testudines families matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study List of Testudines families?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on List of Testudines families.