science

Oneirodidae

Oneirodidae 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 Oneirodidae rather than just read about it. In short: Oneirodidae, the dreamers are a family of marine ray-finned fishes belonging to the order Lophiiformes, the anglerfishes. These fishes are deepwater fishes found in the Atlantic, Indian and Pacific Oceans, and it is the most diverse family of fishes in the bathypelagic zone.

Key takeaways

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

Reference excerpt

Oneirodidae, the dreamers are a family of marine ray-finned fishes belonging to the order Lophiiformes, the anglerfishes. These fishes are deepwater fishes found in the Atlantic, Indian and Pacific Oceans, and it is the most diverse family of fishes in the bathypelagic zone.

Taxonomy Oneirodidae was first proposed as a family in 1879 by the American biologist Theodore Gill with Oneirodes as its only genus. Oneirodes had been proposed as a monospecific genus in 1871 by the Danish zoologist Christian Frederik Lütken when he described O. eschrichtii, giving its type locality as off the western coast of Greenland. The 5th edition of Fishes of the World classifies this family in the suborder Ceratioidei of the anglerfish order Lophiiformes.

Genera Oneirodidae has the following genera classified within it:

With over 60 species classified within this family, it is the most species diverse family of fishes in the bathypelagic zone.

Etymology Oneirodidae is derived from Oneirodes, its type genus, which means "dream-like". Lütken did not explain this choice of name, David Starr Jordan and Barton Warren Evermann suggested in 1898 that the name referred to the small, skin-covered eyes. Alternatively, in 2009 Theodore Wells Pietsch III proposed that the name was given because a "fish so strange and marvelous that it could only be imagined in the dark of the night during a state of unconsciousness".

Characteristics Oneirodidae are sexually dimorphic like other anglerfishes; the largest females are up to 37 cm (15 in) in length contrasting with the longest males being 2.85 cm (1.12 in) in length. The metamorphosed females are very variable in body shape, with most having short, deep, globe-like or slightly compressed bodies, though some taxa have elongate, streamlined bodies. These fishes typically have naked skin, although some taxa have short dermal spines. They have between 4 and 8 soft rays in the dorsal fin and between 4 and 7 soft rays in the anal fin. They also have forwardly directed, thin, flattened process that reaches over the sphenotic, a bone in the posterior part of the orbit. The jaws are of similar length with neither protruding beyond the other. These fishes also have a bioluminescent bulb (the esca) at the tip on the illicium, lack any fleshy growths along the centre of the back, do not have upward pointing mouths, there are teeth on the upper denticular bone, the esca lacks denticles, they have large eyes and large olfactory organs with forward opening nostrils located at the end of the snout. The males, like those of other ceratioids, are considerably smaller than the metamorphosed females, do not have an esca or an illicium extending beyond the dermis, their eyes and olfactory organs are much larger than those of the females and they have pincer-like jaws armed with hooked denticular teeth, thought to be utilised in grabbing on to the female. They also have naked skin and the front end of the pterygophore is distant from the rear end of the denticular bone. The males in this family are typically not sexual parasites of the females.

Distribution and habitat Oneirodidae are found in all the world's oceans in the mesopelagic and bathypelagic zones at depths between 300 and 3,000 m (980 and 9,840 ft).

Biology Fish of this family are predatory, feeding on other fish and on crustaceans. They are oviparous with pelagic eggs and larvae.

References

Illustrations

Worked examples

Example 1 — a first encounter with Oneirodidae

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

In research: Oneirodidae 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 Oneirodidae 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: Oneirodidae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ceratioidei, Deep sea fish, Oneirodidae, so understanding it makes those chapters shorter.
In everyday life: Look for Oneirodidae 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Oneirodidae in 20 minutes

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

Frequently asked questions

What is Oneirodidae in simple terms?

Why does Oneirodidae 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 Oneirodidae?

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 Oneirodidae.