biology

Proexochokefalos

Proexochokefalos is a biology 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 Proexochokefalos rather than just read about it. In short: Proexochokefalos (meaning "big head with big tuberosities") is an extinct genus of machimosaurid teleosauroid from the Middle to Late Jurassic of France and Switzerland. In life, it was a large marine reptile that would have fed on other large animals.

Key takeaways

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

Reference excerpt

Proexochokefalos (meaning "big head with big tuberosities") is an extinct genus of machimosaurid teleosauroid from the Middle to Late Jurassic of France and Switzerland. In life, it was a large marine reptile that would have fed on other large animals.

History The type species, P. heberti, was originally named "Steneosaurus" heberti by Morel de Glasville in 1876 from a roughly 1.1 meter (3.6 foot) long complete skull and mandible (MNHN.F 1890-13) found in the Callovian aged Marnes de Dives near Villers-sur-mer in the Calvados department of Normandy, France. The genus Steneosaurus was used as a longtime wastebasket taxon for various teleosauroid specimens and had more than a dozen species. The type species, Steneosaurus rostromajor is undiagnostic, making the genus and species dubious and invalid. Additionally, many species of so called "Steneosaurus" were found to be quite different and unrelated to one another, thus needing new generic names. In a study by Michela Johnson and colleagues in 2020, "Steneosaurus" heberti was reclassified into the new genus Proexochokefalos, resulting in the new combination Proexochokefalos heberti. The species "Steneosaurus" depressus was also found to be a junior synonym of P. heberti. Another species referred to the genus, Proexochokefalos cf. bouchardi is known from remains from the Calcaire de Caen, France, and Reuchenette Formation, Switzerland.

Classification Proexochokefalos is a member of the family Machimosauridae, a group of large-bodied sea going reptiles. They are known for their robust skulls, powerful jaws, and heavily built bodies, and were among the top predators in their ecosystems. Proexochokefalos possesses an intermediate morphology between more basal and gracile machimosaurids and the larger and more heavily built members of the tribe Machimosaurini. The cladogram below is from an analysis conducted by Johnson and colleagues in 2020.

Ecology Proexochokefalos possessed a mandible well adapted for handling large prey, featuring some of the largest muscle attachment sites among machimosaurids. Its tooth morphology is also intermediate between that of typical "longirostrine" species such as Charitomenosuchus and the more durophagous Machimosaurus. These adaptations point to a shift towards feeding on larger prey items in Proexochokefalos and more derived machimosaurids. However it was not adapted for durophagy to the same extent as Machimosaurus, instead being more of a generalist of large fish and marine reptiles.

References

Illustrations

Worked examples

Example 1 — a first encounter with Proexochokefalos

Start with the simplest possible case. Write down what Proexochokefalos claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Proexochokefalos 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 Proexochokefalos 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 Proexochokefalos

In research: Proexochokefalos appears in biology 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 Proexochokefalos 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: Proexochokefalos is common in secondary-school and first-year university syllabi. It links to neighbouring topics Callovian life, Fossil taxa described in 2020, Fossils of France, so understanding it makes those chapters shorter.
In everyday life: Look for Proexochokefalos 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 Proexochokefalos in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Proexochokefalos 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.
Explain Proexochokefalos out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Proexochokefalos in simple terms?

Why does Proexochokefalos matter?

Because it connects several biology 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 Proexochokefalos?

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 Proexochokefalos.