biology

Obelignathus

Obelignathus 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 Obelignathus rather than just read about it. In short: Obelignathus (meaning "Obelix jaw") is an extinct genus of rhabdodontomorph ornithopod dinosaurs from the Late Cretaceous 'Grès à Reptiles' Formation of France. The genus contains a single species, O. septimanicus, known from a right dentary.

Key takeaways

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

Reference excerpt

Obelignathus (meaning "Obelix jaw") is an extinct genus of rhabdodontomorph ornithopod dinosaurs from the Late Cretaceous 'Grès à Reptiles' Formation of France. The genus contains a single species, O. septimanicus, known from a right dentary. The species was initially classified as a species of the coeval Rhabdodon.

Discovery and naming The Obelignathus holotype specimen, MDE D30, was discovered in 1990 in outcrops of the 'Grès à Reptiles' Formation near Montouliers in Saint-Chinian commune of Hérault, southern France. The specimen consists of an isolated right dentary, missing the anterior (front) part. The specimen was first described in 1991 by Éric Buffetaut and Jean Le Loeuff. Based on the general morphology and dental anatomy, they identified it as belonging to the genus Rhabdodon, named as a hypsilophodont in 1869. However, they described it as a new species, R. septimanicus due to other differing anatomical characteristics. The specific name references Septimania, a historic region of France corresponding to Languedoc, where the type locality in Montouliers is. In 2025, Czepiński & Madzia described Obelignathus as a new genus of rhabdodontomorphs for "Rhabdodon" septimanicus based on these fossil remains. The generic name, Obelignathus, combines a reference to Obelix, a fictional character in the cartoon Asterix and Obelix, with the Greek γνάθος (gnáthos), meaning "jaw", referencing the similar strength of the character and robust morphology of the holotype dentary.

Classification

To determine the phylogenetic affinities of Obelignathus, Czepiński & Madzia (2025) used an updated version of the comprehensive phylogenetic dataset of Fonseca et al. (2024), who had independently recovered "Rhabdodon" septimanicus outside of the genus Rhabdodon and suggested it may represent a taxon distinct from Rhabdodon priscus. Czepiński & Madzia included the 'Quarante rhabdodontomorph' as a separate operational taxonomic unit (OTU); the specimens comprising this OTU were referred to cf. "R." septimanicus in a doctoral thesis but have not yet been formally described. Using implied weighting and K-values of 15 and 21, the authors recovered Obelignathus as the most basal member of the Rhabdodontomorpha. These results are displayed in the cladogram below:

References

Illustrations

Worked examples

Example 1 — a first encounter with Obelignathus

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

In research: Obelignathus 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 Obelignathus 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: Obelignathus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Campanian dinosaurs, Dinosaur genera, Dinosaurs of France, so understanding it makes those chapters shorter.
In everyday life: Look for Obelignathus 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 Obelignathus in 20 minutes

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

Frequently asked questions

What is Obelignathus in simple terms?

Why does Obelignathus 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 Obelignathus?

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 Obelignathus.