biology

Metanephrocerus

Metanephrocerus 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 Metanephrocerus rather than just read about it. In short: Metanephrocerus is an extinct genus of big-headed flies in the dipteran subfamily Protonephrocerinae, for which it is one of only two genera. The genus contains four described species, Metanephrocerus belgardeae, M. collini, M. groehni, and M. hoffeinsorum.

Key takeaways

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

Reference excerpt

Metanephrocerus is an extinct genus of big-headed flies in the dipteran subfamily Protonephrocerinae, for which it is one of only two genera. The genus contains four described species, Metanephrocerus belgardeae, M. collini, M. groehni, and M. hoffeinsorum. Metanephrocerus is known from a group of Middle Eocene fossils which were found in Europe and a single early Eocene fossil from North America.

History and classification When first described, Metanephrocerus was known only from two separate fossils, the holotype female, and the female paratype were fossilized as inclusions in transparent chunks of Baltic amber. Baltic amber is approximately forty-six million years old, having been deposited during the Lutetian stage of the Middle Eocene. There is debate on what plant family produced the amber, with evidence supporting relatives of either an Agathis or a Pseudolarix relative. Fossils of the type species, M. collini, were first studied by American entomologist Frank M. Carpenter and F. M. Hull who placed the new species in the genus Protonephrocerus. Carpenter and Hull's 1939 type description of the new species was published in the monograph series Bernstein-Forschungens. The species was moved to the new genus Metanephrocerus in a 1948 paper by Martin L Aczél, and since that time both the type specimens have been lost and are considered possibly destroyed. After the M. collini description, 75 years passed before an additional three related species were described. Two of those, M. groehni and M. hoffeinsorum. were described from solitary fossil inclusions in Baltic amber. The 2014 descriptions were made by Christian Kehlmaier, Manuel Dierick and Jeffrey H. Skevington, based on detailed CT scans of the specimens. They chose the species name "groehni" is a patronym honoring Carsten Gröhn, who supported the research of the authors, and who was the owner of the specimen before description. The fossil was to be deposited into the collections of the Geologisch-Paläontologisches Institut und Museum der Universität Hamburg. Similarly, the epithet of the second species "hoffeinsorum" is a patronym for Christel and Hans-Werner Hoffeins for the donation of the type fossil to the Senckenberg Deutsches Entomologisches Institut and for their support of the authors research. The third related species, M. belgardeae, bringing the total to four, was described from a compression fossil found in the early Eocene, Ypresian Klondike Mountain Formation lagerstätten, its discovery expanding both the temporal range and geographic range. M. belgardeae was described by S. Bruce Archibald, Christian Kehlmaier, and Rolf Mathewes from a single partial female. The specific epithet is a matronym of Azure Rain Belgarde, who collected the type specimen, SR 08-06-02, and donated it to the Stonerose Interpretive Center. Placement of the group has changed several times, with Metanephrocerus and Protonephrocerus being placed in the pipunculid subfamily Nephrocerinae as tribe Protonephrocerini from 1948 until 2014. The placement of the tribe was challenged in 2014 by Kehlmaier, Dierick and Skevington who suggested inclusion of the genera made Nephrocerinae paraphyletic. As such they elevated the tribe Protonephrocerini to the subfamily rank as Protonephrocerinae, leaving only Nephrocerus and Priabona in Nephrocerinae.

Description Metanephrocerus belgardeae is a large species, with a wing length of 9.2 millimetres (0.36 in), and a hyaline wing coloration, broken by a smokey tone to the pterostigma and basal area of the wing. The wing has a long third section of the costal vein and the median vein that is long and straight. The female's abdomen is approximately 4.4 millimetres (0.17 in) long, with short setae on the tergites, which grade to longer tergites on the first and second tergites. The short abdominal setae are distinct for the genus and exclude the species from other pipnculid genera. M. collini was known from 2 female specimens, which had hyaline wings with colored pterostigma. M. groehni is a nearly complete male fly with a total body length of 5.7 millimetres (0.22 in), and is only missing the tip of the left hind leg. The hind legs show a distinct chaetotaxy to the setae, with front sides having setae that are longer than the femur is wide. The eyes connect for three times the length of the frons. The wings are 6.0 millimetres (0.24 in), though the wings are folded slightly and difficult to fully assess. The halters are darkened at the base and on the knob. M. hoffeinsorum is a whole male, though large portions of it are enclosed in white mold and the specimen has a total length of 6.6 millimetres (0.26 in). The wings show a length of 6.7 millimetres (0.26 in) and have a covering of microtrichia. As with M. groehni the halters have darkened knobs and bases and the pteropleuron has 6 hairs on it. Tergite three of the abdomen is 1.3 times as long as tergite two.

References

Illustrations

Worked examples

Example 1 — a first encounter with Metanephrocerus

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

In research: Metanephrocerus 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 Metanephrocerus 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: Metanephrocerus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Baltic amber, Eocene insects of Europe, Eocene insects of North America, so understanding it makes those chapters shorter.
In everyday life: Look for Metanephrocerus 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 Metanephrocerus in 20 minutes

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

Frequently asked questions

What is Metanephrocerus in simple terms?

Why does Metanephrocerus 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 Metanephrocerus?

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 Metanephrocerus.