science

Stenopterygii

Stenopterygii is a science 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 Stenopterygii rather than just read about it. In short: Stenopterygii are a superorder of ray-finned fish in the infraclass Teleostei. Their validity is somewhat doubtful, as the group was established to separate, out of a large group of closely related Teleostei, a mere two rather peculiarly autapomorphic orders at best.

Key takeaways

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

Reference excerpt

Stenopterygii are a superorder of ray-finned fish in the infraclass Teleostei. Their validity is somewhat doubtful, as the group was established to separate, out of a large group of closely related Teleostei, a mere two rather peculiarly autapomorphic orders at best. In some treatments, it is even monotypic. As originally conceived, the "Stenopterygii" include the Ateleopodiformes and Stomiiformes. Sometimes, the former are removed to form a monotypic superorder Ateleopodomorpha. These lineages are moderately advanced teleosts, but each is uniquely adapted to a deep-water oceanic environment. Their plesiomorphies are similar to the Salmoniformes and other Protacanthopterygii, but plesiomorphic traits are no reliable indicator of a close relationship. Nonwithstanding, the "Stenopterygii" appear to be close relatives of the Protacanthopterygii. Some cladistic analyses find at least the Stomiiformes deep within the latter superorder. It thus cannot be ruled out that the "Stenopterygii" are better included in the Protacanthopterygii. An alternative approach is to consider the entire group – "Stenopterygii", Protacanthopterygii, the monotypic superorders "Cyclosquamata", and perhaps the monotypic superorders "Lampridiomorpha" and "Scopelomorpha" – an unranked clade named Euteleostei. But this would probably require splitting up the Protacanthopterygii, so that each euteleost superorder would at most contain 2 orders (though most would be monotypic), as the relative placement of all these groups is not very well resolved. Such a profusion of monotypic taxa is generally rejected by modern taxonomy, if it is not absolutely required to adequately reflect phylogeny. Moreover, owing to the uncertain relationships of the euteleosts to the less advanced Otocephala (which include the superorders Clupeomorpha and Ostariophysi) and the more advanced teleosts (e.g. Acanthopterygii), it may well be that the supposed "clade" is merely an evolutionary grade. Such a paraphyletic group would according to modern understanding not warrant a taxon name at all. In this case, a possible solution would be to expand the Protacanthopterygii to subsume all the small "superorders", and to treat the Euteleostei as including the Protacanthopterygii and their more "modern" relatives.

Footnotes

References Media related to Stenopterygii at Wikimedia Commons

Diogo, Rui (2008): On the cephalic and pectoral girdle muscles of the deep sea fish Alepocephalus rostratus, with comments on the functional morphology and phylogenetic relationships of the Alepocephaloidei (Teleostei). Anim. Biol. 58(1): 23-29. doi:10.1163/157075608X303636 Nelson, Joseph S. (2006): Fishes of the World (4th ed.). John Wiley & Sons, Inc. ISBN 0-471-25031-7

Illustrations

Worked examples

Example 1 — a first encounter with Stenopterygii

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

In research: Stenopterygii appears in science 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 Stenopterygii 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: Stenopterygii is common in secondary-school and first-year university syllabi. It links to neighbouring topics Euteleostei, Fish superorders, Polyphyletic groups, so understanding it makes those chapters shorter.
In everyday life: Look for Stenopterygii 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 Stenopterygii in 20 minutes

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

Frequently asked questions

What is Stenopterygii in simple terms?

Why does Stenopterygii matter?

Because it connects several science 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 Stenopterygii?

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 Stenopterygii.