biology

Martharaptor

Martharaptor 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 Martharaptor rather than just read about it. In short: Martharaptor is a genus of therizinosauroid theropod dinosaurs from the Early Cretaceous of the Cedar Mountain Formation in Utah. They can be distinguished from other therizinosauroids by means of several features of the skeleton (particularly the hands and feet) which were intermediate between early therizinosaurs such as Falcarius and Beipiaosaurus, and more "advanced" members of the group like therizinosaurids.

Key takeaways

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

Reference excerpt

Martharaptor is a genus of therizinosauroid theropod dinosaurs from the Early Cretaceous of the Cedar Mountain Formation in Utah. They can be distinguished from other therizinosauroids by means of several features of the skeleton (particularly the hands and feet) which were intermediate between early therizinosaurs such as Falcarius and Beipiaosaurus, and more "advanced" members of the group like therizinosaurids. The deep and homogeneous hand claws clearly differ from the case in early therizinosauroids, but the foot has not yet acquired the robust morphology of therizinosaurids.

Discovery and naming The holotype specimen, UMNH VP 21400, hails from the Hayden-Corbett site of the Cedar Mountain Formation of Utah, approximately eight miles southeast from the city of Green River. The specimen was unearthed from a higher stratigraphic level (upper Yellow Cat Member) than Falcarius. The generic name, Martharaptor, is in honor to the paleontologist assistant Martha C. Hayden who helped in the discovery of the site, and the specific name, greenriverensis, is a reference to the Green River. The specimen includes fragments of vertebrae, a scapula, forelimb and hindlimb bones, and an ischium. It also includes well-preserved manual unguals. Manual and pedal morphology show that the specimen is distinct from other theropods from the Cedar Mountain Formation and from other previously described therizinosauroids.

Description

Forelimbs

A pair of fragmentary elongated bones preserved next to each other may represent the radius and ulna of the antebrachium. Hand and finger bones are more well-preserved, with strongly ginglymoidal (pulley-shaped) joint surfaces. The manual unguals (hand claws) are very distinctive. Their height is greater than their length, and they are strongly curved. One of the preserved unguals is larger than the others, and it may represent the claw of the first finger. Other unguals are as large as each other, indicating that the second and third fingers had claws of equal size. The deep unguals of similar shape differs from the condition in other early therizinosauroids, which have longer unguals which differ in shape between different fingers.

Hindlimbs

Several bones of the left foot are preserved. The first metatarsal thins towards the ankle, similar to most theropods but unlike therizinosaurids, indicating that the first toe did not contact the ground. In conjunction with this, the claw of the first toe is smaller than those of the other toes. On the other hand, the toe claws are all deep and curved, as in other therizinosauroids. The fourth metatarsal is beveled (slightly slopes to the side) compared to the rest of the foot. This is intermediate between Falcarius, which has no slope, and therizinosaurids, which have a fourth metatarsal angled at 90 degrees to the rest of the foot. None of the metatarsals are ginglymoidal, but the toe bones are.

Other bones

The only preserved bone of the pectoral girdle is the left scapula (shoulder blade). This bone has a hatchet-like shape, expanded near the shoulder as in other therizinosauroids which preserve a scapula and measures about 15 cm (150 mm) long. The pelvis (hip) preserves fragments of the pubis and part of the ischium, which is very flattened (from the side) near the hip socket. Three vertebral fragments are preserved. These include a strip of bone from the upper portion of a cervical (neck) vertebra, the centrum (main body) of a dorsal (back) vertebra, and the lower portion of a vertebra believed to be a distal caudal (i.e. from the tip of the tail). The cervical fragment shows that the prezygapophysis (front joint plate) is not flexed, indicating that the specimen was not a dromaeosaurid. Each side of the dorsal vertebra possessed a hypapophysis (rib facet) at its lower front corner and a pit located at the center of the side.

Classification Phylogenetic analysis placed Martharaptor within Therizinosauroidea as the sister taxon to the Alxasaurus + Therizinosauridae group, although support for this placement is weak. Nevertheless, Hartman et al. (2019) performed a phylogenetic analysis for the Therizinosauria corroborating the initial placement of Martharaptor.

Left cladogram shows the probable placement of Martharaptor within Therizinosauroidea performed in the original description.

Illustrations

Worked examples

Example 1 — a first encounter with Martharaptor

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

In research: Martharaptor 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 Martharaptor 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: Martharaptor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cedar Mountain Formation, Dinosaur genera, Dinosaurs of the United States, so understanding it makes those chapters shorter.
In everyday life: Look for Martharaptor 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 Martharaptor in 20 minutes

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

Frequently asked questions

What is Martharaptor in simple terms?

Why does Martharaptor 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 Martharaptor?

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 Martharaptor.