biology

Rhabdognathus

Rhabdognathus 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 Rhabdognathus rather than just read about it. In short: Rhabdognathus is an extinct genus of dyrosaurid crocodylomorph. It is known from rocks dating to the Paleocene epoch from western Africa, and specimens dating back to the Maastrichtian era were identified in 2008.

Key takeaways

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

Reference excerpt

Rhabdognathus is an extinct genus of dyrosaurid crocodylomorph. It is known from rocks dating to the Paleocene epoch from western Africa, and specimens dating back to the Maastrichtian era were identified in 2008. It was named by Swinton in 1930 for a lower jaw fragment from Nigeria. The type species is Rhabdognathus rarus. Stéphane Jouve subsequently assessed R. rarus as indeterminate at the species level, but not at the genus level, and thus dubious. Two skulls which were assigned to the genus Rhabdognathus but which could not be shown to be identical to R. rarus were given new species: R. aslerensis and R. keiniensis, both from Mali. The genus formerly contained the species Rhabdognathus compressus, which was reassigned to Congosaurus compressus after analysis of the lower jaw of a specimen found that it was more similar to that of the species Congosaurus bequaerti. Rhabdognathus is believed to be the closest relative to the extinct Atlantosuchus.

Description Rhabdognathus has an extremely elongated snout that makes up around 75% of the length of the entire skull. The total skull length of R. keiniensis is 73.1 centimetres (28.8 in), while the length of the skull of R. aslerensis is unknown because the front of the snout is not preserved in the only known skull, CNRST-SUNY-190. The mandible of Rhabdognathus is as high as it is wide or higher, which distinguishes it from Hyposaurus. The mandible is dorsally directed toward the tip, and the first pair of alveoli (tooth sockets) at the very tip of the jaw are higher than the others. Another distinguishing feature is the extreme length of the mandibular symphysis, which extends past the nineteenth mandibular alveolus. The splenial also extends beyond this point, although the position of its symphysis varies during growth. The alveoli of Rhabdognathus are rounded and directed slightly laterally, causing the teeth to project at an angle. The skulls of R. aslerensis and R. keiniensis possess numerous characters that distinguish Rhabdognathus from other dyrosaurids. The posterior wall of the supratemporal fenestra inclines dorsally so that it is visible when the skull is viewed in dorsal aspect. In Dyrosaurus phosphaticus, the wall is vertical and thus not visible in dorsal aspect. In both species of Rhabdognathus, the space between the occipital condyle and the basioccipital tubera (both located in the back of the skull where the vertebrae articulate) is anteroposteriorly longer than in D. phosphaticus. In the skulls of both species of Rhabdognathus, the posterior margin is inclined so that both the occipital condyle and the basioccipital tubera below it are visible in occipital view.

References

External links Rhabdognathus at the Paleobiology Database

Worked examples

Example 1 — a first encounter with Rhabdognathus

Start with the simplest possible case. Write down what Rhabdognathus 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 Rhabdognathus 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 Rhabdognathus 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 Rhabdognathus

In research: Rhabdognathus 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 Rhabdognathus 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: Rhabdognathus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dyrosauridae, Fossils of Mali, Late Cretaceous crocodylomorphs of Africa, so understanding it makes those chapters shorter.
In everyday life: Look for Rhabdognathus 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 Rhabdognathus in 20 minutes

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

Frequently asked questions

What is Rhabdognathus in simple terms?

Why does Rhabdognathus 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 Rhabdognathus?

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 Rhabdognathus.