biology

Ostromia

Ostromia 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 Ostromia rather than just read about it. In short: Ostromia (named after John Ostrom) is a genus of anchiornithid theropod dinosaur containing a single species, Ostromia crassipes. Recovered from the Late Jurassic Painten Formation of Germany, it was named by Christian Foth and Oliver Rauhut in 2017.

Key takeaways

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

Reference excerpt

Ostromia (named after John Ostrom) is a genus of anchiornithid theropod dinosaur containing a single species, Ostromia crassipes. Recovered from the Late Jurassic Painten Formation of Germany, it was named by Christian Foth and Oliver Rauhut in 2017.

Discovery and naming

The holotype was discovered near Riedenburg, Germany in 1855 and it was originally misidentified as a species of a pterodactyloid pterosaur and named Pterodactylus crassipes in 1857. In 1970 it was identified as an Archaeopteryx by paleontologist John Ostrom, who called it the "Haarlem specimen", since it was kept in the Teylers Museum in Haarlem. In 2017 Christian Foth and Oliver Rauhut concluded it was more closely related to the Chinese Anchiornis and introduced the generic name Ostromia, named after Ostrom. The only known specimen is fairly incomplete compared to most specimens of Archaeopteryx, as it only preserves limb bones, cervical vertebrae and ribs. Most bones are also incomplete, as a result of the poor preservation. A high-quality cast of the holotype (Teylers specimens TM 6928 and 6929) is in the collections of the Bayerische Staatssammlung für Paläontologie und Geologie under the specimen number SNSB-BSPG 1971 I 211.

Description

Differences from Archaeopteryx The Haarlem specimen has many features which contrast with those of Archaeopteryx. The length ratio between the third and the first metacarpal of the hand is larger in Ostromia than in any Archaeopteryx specimen. In addition, the ungual (claw) of the first digit of the hand is smaller than the corresponding first metacarpal, while in Archaeopteryx the claw is larger. The Haarlem specimen's metatarsals are also estimated to be proportionally longer than those of Archaeopteryx specimens.

In addition, the Haarlem specimen shares several features with Anchiornis. Most notably, they both have longitudinal furrows on the top and bottom sides of their manual phalanges (finger bones). While such structures can be a result of collapsed or broken bones (as is the case in several Archaeopteryx specimens), the straight, smooth edges of the furrows in Ostromia and Anchiornis indicate that they are legitimate biological features. The pubic shaft of the Haarlem specimen is also strongly flexed backwards and has a triangular pubic boot, similar to the pubis of Anchiornis but unlike that of Archaeopteryx.

Classification Foth and Rauhut (2017) recovered Ostromia within Anchiornithidae as the only known European member of this family. Agnolin et al. (2019) argued that the putative anchiornithid affinities of Ostromia are also seen in Unenlagiinae, and that it is best to consider this genus as an indeterminate paravian. In contrast, Foth et al. (2025) still recovered the same conclusion that Ostromia is an anchiornithid based on their phylogenetic analysis.

Illustrations

Worked examples

Example 1 — a first encounter with Ostromia

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

In research: Ostromia 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 Ostromia 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: Ostromia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anchiornithidae, Dinosaur genera, Dinosaurs of Germany, so understanding it makes those chapters shorter.
In everyday life: Look for Ostromia 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 Ostromia in 20 minutes

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

Frequently asked questions

What is Ostromia in simple terms?

Why does Ostromia 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 Ostromia?

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 Ostromia.