biology

Meristodonoides

Meristodonoides 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 Meristodonoides rather than just read about it. In short: Meristodonoides is an extinct genus of hybodont known from the mid-late Cretaceous, with potential records dating back to the Jurassic. It is one of a number of hybodont genera composed of species formerly assigned to Hybodus.

Key takeaways

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

Reference excerpt

Meristodonoides is an extinct genus of hybodont known from the mid-late Cretaceous, with potential records dating back to the Jurassic. It is one of a number of hybodont genera composed of species formerly assigned to Hybodus. The genus is primarily known from remains from the Cretaceous of North America and Europe, spanning from the Aptian/Albian to Maastrichtian, making it one of the last surviving hybodont genera, though records of the genus likely extend as far back as the Late Jurassic, based on an undescribed skeleton from the Tithonian of England, and fragmentary teeth from the Kimmeridgian of Poland, England and Switzerland.

Taxonomy The type species is M. rajkovichi, which was originally a species in the genus Hybodus. The species, along with other Hybodus species such as H. butleri and H. montanensis, was reassigned to Meristodonoides by Charlie J. Underwood and Stephen L. Cumbaa in 2010.

Species M. butleri (Thurmond, 1971) - Aptian/Albian of Texas M. montanensis (Case, 1978) - Campanian of Montana and Wyoming, with similar remains from the Santonian of New Mexico M. novojerseyensis (Case & Cappetta, 2004) - Campanian of North Carolina, Maastrichtian of New Jersey M. rajkovichi (Case, 2001) (type species) - Cenomanian of Minnesota M. multiplicatus Cicimurri et al., 2014 - Santonian-Campanian of Mississippi Other remains of the genus are known from the Coniacian of England, the Aptian-Albian of France, and the Campanian of British Columbia, Canada, European Russia and France.

Ecology The morphology of the teeth suggests an adaptation to tearing prey, with a specialization for restraining fast-swimming prey such as small fish and squid, as well as weakly armored prey. Fossils from the Western Interior Seaway suggest that it preferred nearshore marine environments, being absent from deeper-water areas, with it likely also being able to tolerate brackish and freshwater conditions. In the Gulf Coastal Plain, Meristodonoides teeth are largely found in estuarine deposits. The restriction of Meristodonoides to nearshore habitats, combined with its late occurrence, fits the overall decline in niches occupied by hybodonts throughout the Cretaceous, likely due to them being outcompeted by lamniform sharks in open marine habitats. However, some Meristonoides teeth have also been recovered from deep-water deposits representing open marine environments, such as the Northumberland Formation in Canada.

References

Illustrations

Worked examples

Example 1 — a first encounter with Meristodonoides

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

In research: Meristodonoides 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 Meristodonoides 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: Meristodonoides is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cretaceous cartilaginous fish, Fossil taxa described in 2010, Fossils of Canada, so understanding it makes those chapters shorter.
In everyday life: Look for Meristodonoides 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 Meristodonoides in 20 minutes

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

Frequently asked questions

What is Meristodonoides in simple terms?

Why does Meristodonoides 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 Meristodonoides?

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 Meristodonoides.