biology

Leyvachelys

Leyvachelys 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 Leyvachelys rather than just read about it. In short: Leyvachelys is an extinct genus of turtles in the family Sandownidae from the Early Cretaceous (Late Aptian to Early Albian) of the present-day Altiplano Cundiboyacense, Eastern Ranges, Colombian Andes. The genus is known only from its type species, Leyvachelys cipadi, described in 2015 by Colombian paleontologist Edwin Cadena.

Key takeaways

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

Reference excerpt

Leyvachelys is an extinct genus of turtles in the family Sandownidae from the Early Cretaceous (Late Aptian to Early Albian) of the present-day Altiplano Cundiboyacense, Eastern Ranges, Colombian Andes. The genus is known only from its type species, Leyvachelys cipadi, described in 2015 by Colombian paleontologist Edwin Cadena. Fossils of Leyvachelys have been found in the fossiliferous Paja Formation, close to Villa de Leyva, Boyacá, after which the genus is named. The holotype specimen is the oldest and most complete sandownid turtle found to date. Fossils of a turtle found in the dinosaur-rich Glen Rose Formation of Texas, informally named Glenrosechelys brooksi, have been assigned to the same genus and type species.

Etymology The genus name is derived from Villa de Leyva and chelys means "turtle" in Greek. The species epithet cipadi refers to the CIP; the Centro de Investigaciones Paleontológicas, the paleontological research centre outside Villa de Leyva.

Description The holotype was found on the Loma La Catalina, west of Villa de Leyva, Colombia in 2009. The fossil was discovered in a layer of calcareous claystone with abundant occurrences of ferruginous-calcareous nodules and concretions. The section belongs to the middle segment of the Paja Formation called "Arcillolitas abigarradas Member" and has been dated on the basis of ammonites to be Late Barremian to Early Aptian in age. The turtle is the earliest recorded sandownid turtle in the world and the first of this family discovered in South America. The fossil find consists of a fairly complete skull, a well-preserved lower jaw and postcrania with an almost complete carapace, three cervical vertebrae, right humerus and coracoid, both femora, tibiae, and pelvic girdle. The length of the skull is estimated at 15.6 centimetres (6.1 in) and the maximum size of the carapace has been reported as 88 by 108 centimetres (35 by 43 in). The carapace of L. cipadi is the first complete ever found for a sandownid.

Habitat

The Hauterivian to Late Aptian Paja Formation is one of the richest fossiliferous stratigraphic units of Colombia, where other marine reptiles are found too. Pliosaurs as Kronosaurus and Stenorhynchosaurus, ichthyosaurs as Muiscasaurus and Platypterygius and a plesiosaurs known as Callawayasaurus represent the known marine reptile fauna assemblage of the formation. From the Paja Formation in the same year as Leyvachelys, the oldest sea turtle known in the world, Desmatochelys padillai, has been reported. The habitat of Leyvachelys is described as littoral, not open marine as is the case for Desmatochelys. Additionally, many different ammonites and crustaceans are described from the formation. The morphology of the shell of L. cipadi, allows the support of previously hypothesized habitat adaptations for sandownids; in particular, that they inhabited littoral to near-shore shallow marine environments, and that their general body-plan was not designed for leading an open marine lifestyle. They nevertheless potentially shared niches with open marine turtles, as evidenced by the occurrence of protostegids as Desmatochelys, from the same stratigraphical horizons. The abundant occurrence of molluscs, principally ammonites, some of them preserved associated with the carapace of L. cipadi, suppose a potential source of food for its durophagous diet adaptation which could have also included arthropods, as for example crabs. Fossil turtle fragments, initially and informally described as Glenrosechelys brooksi, found in the contemporaneous to slightly younger Glen Rose Formation of Texas have been assigned to the same genus Leyvachelys. Both occurrences in Texas (paleocoordinates 30.0° N, 55.5° W), and Colombia (paleocoordinates 3.6° N, 42.2° W) represent the northern and southern paleocoastline of the Early Cretaceous proto-Caribbean Sea.

Illustrations

Worked examples

Example 1 — a first encounter with Leyvachelys

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

In research: Leyvachelys 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 Leyvachelys 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: Leyvachelys is common in secondary-school and first-year university syllabi. It links to neighbouring topics Altiplano Cundiboyacense, Cretaceous Colombia, Early Cretaceous reptiles of South America, so understanding it makes those chapters shorter.
In everyday life: Look for Leyvachelys 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 Leyvachelys in 20 minutes

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

Frequently asked questions

What is Leyvachelys in simple terms?

Why does Leyvachelys 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 Leyvachelys?

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 Leyvachelys.