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Opisthoteuthis californiana

Opisthoteuthis californiana is a earth 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 Opisthoteuthis californiana rather than just read about it. In short: Opisthoteuthis californiana, also known as the flapjack octopus or flapjack devilfish, is a species of umbrella octopus. Description O. californiana is one of 14 species in the genus Opisthoteuthis, these species are also collectively known as the flapjack devilfishes (due to the anterior-posterior compression of their bodies, which makes them flatter when laying on the seafloor).

Opisthoteuthis californiana — main illustration
Opisthoteuthis californiana — illustration

Key takeaways

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

Reference excerpt

Opisthoteuthis californiana, also known as the flapjack octopus or flapjack devilfish, is a species of umbrella octopus.

Description O. californiana is one of 14 species in the genus Opisthoteuthis, these species are also collectively known as the flapjack devilfishes (due to the anterior-posterior compression of their bodies, which makes them flatter when laying on the seafloor). O. californiana is morphologically very similar to Opisthoteuthis albatrossi, and they may be the same species, but the two have never been critically compared (due to the latter being historically placed in the genus Stauroteuthis). If they are conspecific, O. californiana would be a synonym of O. albatrossi (as the latter was described first in 1920, the former in 1949). Flapjack octopuses usually appear pinkish, possessing a gelatinous body. They have fins above their eyes, similar to those found on some species of squid. Their maximum size is 20 cm (7.9 in) mantle length. They have eight arms (like any other octopus), but these are joined together by a membrane or "webbing", forming an umbrella-like shape; these webbed arms are spread into a parachute-like shape when maneuvering through dimly lit water. Unlike commonly known octopus which live in shallower waters, they are unable to camouflage by changing skin color and texture. They swim by moving their fins, pulsing their webbed arms, pushing water through their funnel for jet propulsion, or all three at once. What was thought to be an undescribed Opisthoteuthis species from off California, overlapping the distribution of O. californiana, was dubbed 'Opisthoteuthis adorabilis' in the media. This name is a nomen nudum (invalid name), due to a lack of a published description. The late F.G. Eric Hochberg was also planning on describing this species. Recent work using molecular data, ROV observations, and Hochberg's unpublished descriptions indicate that this second Californian species, is actually the northern range extension of Opisthoteuthis bruuni (previously known from off Peru and Chile).

Distribution O. californiana is distributed in the northern and northeastern Pacific Ocean, ranging in the west from off central Honshū (Japan) and the Sea of Okhotsk, its northernmost range being the Bering Sea, and its eastern range is along the western coast of North America as far south as Eureka Bar, California (the type locality, at 350 metres (1,150 ft) depth). The depth at which the species occurs typically ranges from 124 to 823 metres (407 to 2,700 ft), but more recent records indicate that they may occur down to 1,500 metres (4,900 ft). This species lives on the "muddy" seafloor (pelagic sediment ).

Biology The stomach contents of eight members of O. californiana were found to contain small benthic/epibenthic crustaceans, including copepods, isopods, mysids, and small shrimp (crangonid or hippolytid). From observations of other Opisthoteuthis species, the extensive arm webbing is possibly used to trap small crustaceans, with the cirri and suckers moving small prey items towards the mouth (a fairly low-energy feeding strategy compared to shallow-water octopus).

Reproduction

Opisthoteuthis species (like other cirrate octopuses) use continuous spawning, where the female lays one or two large eggs at a time over several years (rather than a large batch near the end of her lifespan). These eggs have a hard, protective outer shell (unlike the eggs of incirrate octopus) and are not brooded or protected by the mother, with the hatched young undergo direct development (lacking the paralarvae stage of incirrate octopus) and are likely benthic. Mature O. californiana females carry about 1400–2380 eggs in their ovary, with the individually spawned mature eggs measuring 11 millimetres (0.43 in) long. Estimations of egg hatching time (using water temperature and egg size) for O. californiana are up to 1.4 years at 4 degrees Celsius (39 °F). Mating has never been observed in O. californiana; the males lack the hectocotylus of typical octopus, instead having a series of enlarged suckers that presumably have a role in mating or competition. Males move seasonally, and occur in shallower waters during the summer.

Relation to humans Members of O. californiana from the Monterey Canyon were researched ex situ in 2015 by scientists from the Monterey Bay Aquarium Research Institute, with several Opisthoteuthis sp. specimens (including a fertile female) that resemble O. californiana (in media these were given the informal name Opisthoteuthis 'adorabilis'). Due to the challenges of mimicking their deep sea environment in captivity, some of the octopuses lived only for a few months, but some of the laid eggs incubated for a year in the laboratory. In the Finding Nemo franchise, one of Nemo's classmates, Pearl, is a flapjack octopus. Flapjack octopuses appear in Abzû along the sea floor in levels depicing the deep sea.

References

External links "CephBase: Opisthoteuthis californiana". Archived from the original on 2005-08-17. Photo of a Flapjack Octopus taken at 400 m depth.

Illustrations

Opisthoteuthis californiana illustration
Opisthoteuthis californiana illustration

Worked examples

Example 1 — a first encounter with Opisthoteuthis californiana

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

In research
Opisthoteuthis californiana appears in earth 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 Opisthoteuthis californiana 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
Opisthoteuthis californiana is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cephalopods described in 1949, Cephalopods of North America, Cephalopods of Oceania, so understanding it makes those chapters shorter.
In everyday life
Look for Opisthoteuthis californiana 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 Opisthoteuthis californiana in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Opisthoteuthis californiana means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Opisthoteuthis californiana out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Opisthoteuthis californiana in simple terms?

Opisthoteuthis californiana, also known as the flapjack octopus or flapjack devilfish, is a species of umbrella octopus. Description O. californiana is one of 14 species in the genus Opisthoteuthis, these species are also collectively known as the flapjack devilfishes (due to the anterior-posterior…

Why does Opisthoteuthis californiana matter?

Because it connects several earth 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 Opisthoteuthis californiana?

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 Opisthoteuthis californiana.

Tags

  • Cephalopods described in 1949
  • Cephalopods of North America
  • Cephalopods of Oceania
  • Fauna of California
  • IUCN Red List data deficient species
  • Marine molluscs of Asia
  • Molluscs of Japan
  • Molluscs of the Pacific Ocean
  • Western North American coastal fauna

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