biology

Ichthyodectes

Ichthyodectes 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 Ichthyodectes rather than just read about it. In short: Ichthyodectes is an extinct genus of marine ichthyodectid ray-finned fish known from the Late Cretaceous of North America & Europe. Taxonomy The following definitive species are known: I. ctenodon Cope, 1870 - Cenomanian of Saskatchewan, Canada (Ashville Formation), Turonian of Northwest Territories (Lac des Bois) & Alberta (Kaskapau Formation), Canada and Kansas & South Dakota, US (Carlile Shale & Niobrara Formatio…

Key takeaways

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

Reference excerpt

Ichthyodectes is an extinct genus of marine ichthyodectid ray-finned fish known from the Late Cretaceous of North America & Europe.

Taxonomy The following definitive species are known:

I. ctenodon Cope, 1870 - Cenomanian of Saskatchewan, Canada (Ashville Formation), Turonian of Northwest Territories (Lac des Bois) & Alberta (Kaskapau Formation), Canada and Kansas & South Dakota, US (Carlile Shale & Niobrara Formation), Coniacian to mid-Campanian of Manitoba, Canada (Pierre Shale Formation), and late Santonian/early Campanian of Alabama, US (Mooreville Chalk). All other Ichthyodectes species from the Niobrara Formation are now considered synonymous with I. ctenodon. I. tenuidens Woodward, 1901 - Cenomanian of England (English Chalk) Another small indeterminate Ichthyodectes, previously assigned to the nomen dubium species I. minor (Egerton, 1850) is known from the Cenomanian to the Turonian of the English Chalk. Although a number of species have previously been placed in the genus, more recent analyses indicate that only two species can confidently be placed in the genus, with the rest being synonymous with this species or belonging to different genera.

Biology

Ichthyodectes ctenodon ("fish biter with comb teeth") was an ichthyodectid over 3 m (9.8 ft) in length. It lived in the Western Interior Seaway of North America during the late Cretaceous. It was closely related to the 4–6 m (13–20 ft) long Xiphactinus audax, and the 2 m (6 ft 7 in) long Gillicus arcuatus, and like other ichthyodectids, I. ctenodon is presumed to have been a swift predator of smaller fish. As its species name suggests, I. ctenodon had small, uniformly sized teeth, as did its smaller relative, G. arcuatus, and may have simply sucked suitably sized prey into its mouth. A notable specimen of I. ctenodon was collected by Charles H. Sternberg from the Smoky Hill Chalk prior to 1919 and officially described in 2010. This specimen comprises a complete individual with the skeleton of a smaller fish, most likely an Enchodus petrosus, within its stomach. This specimen is reminiscent of the famous "fish-within-a-fish" Xiphactinus specimen, and confirms that Ichthyodectes had a piscivorous diet.

References

Illustrations

Worked examples

Example 1 — a first encounter with Ichthyodectes

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

In research: Ichthyodectes 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 Ichthyodectes 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: Ichthyodectes is common in secondary-school and first-year university syllabi. It links to neighbouring topics Campanian genus extinctions, Cenomanian genus first appearances, Coniacian genera, so understanding it makes those chapters shorter.
In everyday life: Look for Ichthyodectes 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 Ichthyodectes in 20 minutes

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

Frequently asked questions

What is Ichthyodectes in simple terms?

Ichthyodectes is an extinct genus of marine ichthyodectid ray-finned fish known from the Late Cretaceous of North America & Europe. Taxonomy The following definitive species are known: I. ctenodon Cope, 1870 - Cenomanian of Saskatchewan, Canada (Ashville Formation), Turonian of Northwest Territorie…

Why does Ichthyodectes 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 Ichthyodectes?

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 Ichthyodectes.