science

Solenogastres

Solenogastres 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 Solenogastres rather than just read about it. In short: The Solenogastres (less often referred to as Neomeniomorpha), commonly known as solenogasters, are a class of small, worm-like, shell-less molluscs (Aplacophora), the other class being the Caudofoveata (Chaetodermomorpha). Some recent literature and recent molecular evidence, indicates that the Aplacophora may be polyphyletic, and therefore some taxonomists may divide Solenogastres and Caudofoveata into separate cla…

Key takeaways

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

Reference excerpt

The Solenogastres (less often referred to as Neomeniomorpha), commonly known as solenogasters, are a class of small, worm-like, shell-less molluscs (Aplacophora), the other class being the Caudofoveata (Chaetodermomorpha). Some recent literature and recent molecular evidence, indicates that the Aplacophora may be polyphyletic, and therefore some taxonomists may divide Solenogastres and Caudofoveata into separate classes.

Morphology In contrast to many other mollusc classes, aplacophorans have no shell, and are instead covered by aragonitic sclerites (calcareous spicules), which can be solid or hollow. These spicules can be arranged perpendicular to one another within the cuticle to form a skeleton, stick up to form a palisade, or can lie flat against the cuticle. 80% of solenogaster species have a radula, while in others it is secondarily lost. The radula may bear one or more teeth per row; where there is more than one tooth, there is no central radular tooth. The radula grows by dividing existing teeth in two, or by adding a new tooth at the center of the radular row. The salivary glands are very elaborate, and are an important characteristic for taxonomy. Next to the mouth they have a unique sense organ, the vestibulum. Solenogastres do not have true ctenidia, though their gill-like structures may resemble them.

Development During development, many Solenogastres are covered by a spiny scleritome comprising spines or scale-like plates. This has been likened to the halwaxiid scleritome. Sclerites of Epimenia start out solid before developing a hollow stem that subsequently solidifies. Solenogastres can be found in a diverse range of habitats across the world, from the coast to the deep ocean.

Ecology

Diet Solenogastres feed on cnidaria and ctenophores, either sucking their bodily fluids or eating their tissue. They do not use their radulae to rasp prey, as some other molluscs do.

Phylogeny There is some uncertainty regarding the phylogenetic position of the Solenogastres. Traditionally considered to be the most basal molluscan group and the sister group to the Caudofoveata, alternatives to both of these statements have been proposed. Some molecular datasets plot Solenogastres as an outgroup to Mollusca. However, there are cryptic species which are hard to delineate due to there being a lack of multiple morphological characteristics.

Families Acanthomeniidae Salvini-Plawen, 1978 Amphimeniidae Salvini-Plawen, 1972 Apodomeniidae Kocot, Todt, N. T. Mikkelsen & Halanych, 2019 Dondersiidae Simroth, 1893 Drepanomeniidae Salvini-Plawen, 1978 Epimeniidae Salvini-Plawen, 1978 Gymnomeniidae Odhner, 1920 Hemimeniidae Salvini-Plawen, 1978 Heteroherpiidae Salvini-Plawen, 1978 Imeroherpiidae Salvini-Plawen, 1978 Lepidomeniidae Pruvot, 1902 Macellomeniidae Salvini-Plawen, 1978 Meiomeniidae Salvini-Plawen, 1985 Neomeniidae Ihering, 1876 Notomeniidae Salvini-Plawen, 2004 Phyllomeniidae Salvini-Plawen, 1978 Proneomeniidae Mitchell, 1892 Pruvotinidae Heath, 1911 Rhipidoherpiidae Salvini-Plawen, 1978 Rhopalomeniidae Salvini-Plawen, 1978 Sandalomeniidae Salvini-Plawen, 1978 Simrothiellidae Salvini-Plawen, 1978 Strophomeniidae Salvini-Plawen, 1978 Syngenoherpiidae Salvini-Plawen, 1978 Unassigned in Solenogastres Pholidoherpia Salvini-Plawen, 1978 Rhabdoherpia Salvini-Plawen, 1978 Synonyms

Superorder Aplotegmentaria (not monophyletic) Myzomeniidae Thiele, 1894: synonym of Dondersiidae Simroth, 1893 Superorder Pachytegmentaria (not monophyletic) Parameniidae Simroth, 1893: synonym of Pruvotinidae Heath, 1911 (invalid: type genus a junior homonym) Pararrhopaliidae Salvini-Plawen, 1972: synonym of Pruvotinidae Heath, 1911 Perimeniidae Nierstrasz, 1908: synonym of Pruvotinidae Heath, 1911 Proneomenidae Mitchell, 1892: synonym of Proneomeniidae Mitchell, 1892 Pruvotiniidae Heath, 1911: synonym of Pruvotinidae Heath, 1911 (incorrect original spelling) Solenopodidae Koren & Danielssen, 1877: synonym of Neomeniidae Ihering, 1876 Wireniidae Salvini-Plawen, 1978: synonym of Gymnomeniidae Odhner, 1920

Images

References

Illustrations

Worked examples

Example 1 — a first encounter with Solenogastres

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

In research: Solenogastres 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 Solenogastres 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: Solenogastres is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mollusc classes, Solenogastres, so understanding it makes those chapters shorter.
In everyday life: Look for Solenogastres 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 Solenogastres in 20 minutes

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

Frequently asked questions

What is Solenogastres in simple terms?

Why does Solenogastres 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 Solenogastres?

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 Solenogastres.