science

Stolephorus astrum

Stolephorus astrum 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 Stolephorus astrum rather than just read about it. In short: Stolephorus astrum, the astral anchovy, is a species of anchovy in the family Engraulidae. It is currently known only from estuarine habitats around Babeldaob Island, Palau.

Key takeaways

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

Reference excerpt

Stolephorus astrum, the astral anchovy, is a species of anchovy in the family Engraulidae. It is currently known only from estuarine habitats around Babeldaob Island, Palau. The species was formally described in 2024 by Harutaka Hata and Hiroyuki Motomura based on 17 specimens collected from mangrove‑influenced coastal waters.

Taxonomy Stolephorus astrum was described in the Raffles Bulletin of Zoology in 2024. The holotype (CAS 230413) and paratypes were collected from shallow, turbid estuaries in Karamado Bay and Kamiyangaru Bay on Babeldaob Island. The species name astrum ("star") refers to the distinctive star‑like melanophore pattern on the pectoral fin rays.

Description Stolephorus astrum is a slender, laterally compressed anchovy reaching at least 54.8 mm standard length. Key diagnostic characters include: Short maxilla reaching to or slightly beyond the anterior margin of the preopercle, 1–4 prepelvic scutes and no predorsal or postpelvic scutes, Dorsal fin with 3 unbranched and 12–14 branched rays, Anal fin with 3 unbranched and 18–19 branched rays, High gill‑raker counts, especially on the first arch (50–56 total), Melanophores on the 2nd–8th uppermost pectoral‑fin rays, forming the "astral" pattern, Slender body (16.8–19.0% SL) and relatively long caudal peduncle. Preserved specimens are pale with a faint longitudinal band and paired dark patches on the parietal and occipital regions. Fresh coloration is unknown.

Distribution and habitat The species is known only from Babeldaob Island, Palau, where all specimens were collected in shallow, muddy estuarine waters influenced by mangroves and river outflow. Depths ranged from approximately 0.6 to 15 m.

Comparisons Stolephorus astrum belongs to a group of congeners with short maxillae and high gill‑raker counts, including Stolephorus leopardus, Stolephorus pacificus, and Stolephorus teguhi. It differs from these species in combinations of: Lower total gill‑raker counts, Narrower body proportions, Shorter predorsal‑fin length, Longer caudal peduncle, Presence of melanophores on pectoral‑fin rays (vs. absent in StolephorusS. pacificus), Absence of dark dorsal lines (present in Stolephorus leopardus and Stolephorus teguhi). These distinctions are supported by meristic and morphometric analyses presented in the original description.

Etymology The specific epithet astrum (Latin: "star") refers to the star‑like pattern of black melanophores on the upper pectoral‑fin rays.

References

Worked examples

Example 1 — a first encounter with Stolephorus astrum

Start with the simplest possible case. Write down what Stolephorus astrum 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 Stolephorus astrum 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 Stolephorus astrum 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 Stolephorus astrum

In research: Stolephorus astrum 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 Stolephorus astrum 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: Stolephorus astrum is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fish, Fish described in 2024, Stolephorus, so understanding it makes those chapters shorter.
In everyday life: Look for Stolephorus astrum 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 Stolephorus astrum in 20 minutes

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

Frequently asked questions

What is Stolephorus astrum in simple terms?

Stolephorus astrum, the astral anchovy, is a species of anchovy in the family Engraulidae. It is currently known only from estuarine habitats around Babeldaob Island, Palau.

Why does Stolephorus astrum 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 Stolephorus astrum?

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 Stolephorus astrum.