biology

Sthenoteuthis pteropus

Sthenoteuthis pteropus 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 Sthenoteuthis pteropus rather than just read about it. In short: Sthenoteuthis pteropus, also known as the orangeback flying squid or orangeback squid, is a species of cephalopod in the family Ommastrephidae. It is native to tropical parts of the Atlantic Ocean where it is found to depths of about 200 m (656 ft).

Key takeaways

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

Reference excerpt

Sthenoteuthis pteropus, also known as the orangeback flying squid or orangeback squid, is a species of cephalopod in the family Ommastrephidae. It is native to tropical parts of the Atlantic Ocean where it is found to depths of about 200 m (656 ft).

Description Like other squid, Sthenoteuthis pteropus is bilaterally symmetrical and has a head with a pair of eyes, eight arms and two tentacles and a fleshy, muscular body known as the mantle. The head is not retractable, the arms have blunt tips and there is a marked crest on the outer surface of the third pair. The tentacles are slender and the terminal sections are armed with a transverse row of large toothed suckers and other smaller suckers for capturing prey, and the column with a fixing apparatus of knobs and small suckers. The mantle is cylindrical, narrowing slightly towards the posterior end where there is a wide, roughly diamond-shaped fin. There are a number of bioluminescent photophores on the head, mantle and fourth arms, with a concentrated patch on the anterior dorsal surface of the mantle forming a luminous orange oval shape. Sthenoteuthis pteropus grows to a mantle length of about 65 cm (26 in) with a fin width about three quarters of this.

Distribution and habitat Sthenoteuthis pteropus is native to the tropical Atlantic Ocean with a range between about 35°N and 36°S and a rather more restricted breeding range that extends to about 22° on either side of the equator. It is a common epipelagic species and is found in the upper surface layers of the sea to a depth of 200 m (656 ft).

Biology

Squid can move fast through the water by jet propulsion, expelling a jet of water through a flexible siphon located on the ventral surface just behind the head. Some species can even launch themselves out of the water and move rapidly through air, remaining airborne for several metres. The phenomenon has been little studied because it happens so rarely and so unexpectedly, but it has been photographed on a small number of occasions, and Sthenoteuthis pteropus has sometimes tentatively been identified. The squid seems to be engaging in an active flying process rather than a passive glide as the fin is spread widely and the arms are held in such a position as might help provide lift. The squid were found to travel five times as fast in air as in water and it is thought that the behaviour may occur during long distance migrations in order to conserve energy. Female Sthenoteuthis pteropus mature in two different size ranges, at mantle lengths of 23 to 27 cm (9 to 11 in) and 38 to 45 cm (15 to 18 in). In mature individuals, spawning takes place intermittently, up to a million ripe eggs with a diameter of about 0.8 mm (0.03 in) being present in the ovaries at any one time as well as a large number of immature oocytes. This seems consistent with a reproductive strategy consisting of producing large numbers of very small eggs, a long period of sporadic spawning and a continuation of feeding and growth by the female while breeding. This is a fast-growing species of squid. Juveniles reach a length of about 10 cm (4 in) in one hundred days. The life expectancy of females is under a year while males live for one or two months less than this.

References

Illustrations

Worked examples

Example 1 — a first encounter with Sthenoteuthis pteropus

Start with the simplest possible case. Write down what Sthenoteuthis pteropus 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 Sthenoteuthis pteropus 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 Sthenoteuthis pteropus 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 Sthenoteuthis pteropus

In research: Sthenoteuthis pteropus 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 Sthenoteuthis pteropus 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: Sthenoteuthis pteropus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cephalopods described in 1855, Cephalopods of South America, Gliding animals, so understanding it makes those chapters shorter.
In everyday life: Look for Sthenoteuthis pteropus 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 Sthenoteuthis pteropus in 20 minutes

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

Frequently asked questions

What is Sthenoteuthis pteropus in simple terms?

Why does Sthenoteuthis pteropus 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 Sthenoteuthis pteropus?

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 Sthenoteuthis pteropus.