biology

Olenellus

Olenellus 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 Olenellus rather than just read about it. In short: Olenellus is an extinct genus of redlichiid trilobites, with species of average size (about 5 centimetres or 2.0 inches long). It lived during the Botomian and Toyonian stages of the Lower Cambrian (Olenellus-zone), 522 to 510 million years ago, in what is currently North America, part of the palaeocontinent Laurentia.

Key takeaways

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

Reference excerpt

Olenellus is an extinct genus of redlichiid trilobites, with species of average size (about 5 centimetres or 2.0 inches long). It lived during the Botomian and Toyonian stages of the Lower Cambrian (Olenellus-zone), 522 to 510 million years ago, in what is currently North America, part of the palaeocontinent Laurentia.

Etymology Olenellus means small Olenus, after a genus belonging to the Ptychopariida, to which the type species O. thompsoni was originally assigned. The name Olenus refers to a mythological figure who was turned to stone by the gods. The names of the species have the following derivations. agellus comes from the Latin word for field or hamlet. chiefensis refers to the Chief Range, which includes the Ruin Wash section, that holds the last of the Olenellina. fowleri was named in honor of Ed Fowler, whose quarrying skills exposed the type locality of this species. getzi is called after Noah L. Getz, on whose Lancaster estate several Olenellus species were first collected. nevadensis refers to the state of Nevada, where this species is found. parvofrontatus means ‘small front’ from the Latin words parvus and frontatus, indicating the short distance between the anterior border and the glabella in this species. roddyi was named in honor of Dr. H. Justin Roddy (1856-1943), an internationally known naturalist, curator and professor of geology. romensis refers to the Rome Formation. terminatus is from the Latin terminus, meaning final, indicating the demise of the Olenellus lineage.

Taxonomy

Relationship within the Olenellidae Olenellus is the only genus currently recognised in the subfamily Olenellinae. The sister group called the Mesonacinae consists of the genera Mesonacis and Mesolenellus.

Status of the clade "Paedeumias" "Paedeumias" was previously regarded as a genus related to Olenellus or a subgenus being part of Olenellus. Recent analysis shows that there is a group of species formerly assigned to Olenellus (Paedeumias) nested within Olenellus (O. clarki, O. nevadensis, O. parvofrontatus, O. roddyi and O. transitans). However, this group is more closely related to the majority of the remainder of Olenellus species than to O. agellus and O. romensis. This implies that either two new monophyletic subgenera need to be erected, or Olenellus (Paedeumias) and Olenellus (Olenellus) need to be dropped as subgenera, the latter being proposed by Lieberman.

Reassigned species

Distribution

O. thompsoni is found in the middle Upper Olenellus-zone of Vermont (Franklin County, Parker Slate, Georgia). O. agellus is present in the middle Upper Olenellus-zone of Vermont (Parker Slate, Georgia). O. chiefensis has been collected from the final layer of the Upper Olenellus-zone of Nevada (Pioche Formation). O. clarki is found in Upper Olenellus-zone of California (Bristol Mountain, near Cadiz, on the Santa Fé Railroad, 100 miles (160 km) east of Barstow, Mohave Desert, probably Latham Shale; Latham Shale – treated as the Bristolia-zonule – Marble Mountains, 1⁄2 mile (0.80 km) east of Cadiz, and at the southern end of the Marble Mountains, near Chambless in the Mohave Desert portion of San Bernardino County, as well as from the Latham Shale, near Summit Springs on the west side of the Providence Mountains, San Bernardino County. In California also from the Carrara Formation, Funeral Mountains, Resting Spring Range, Eagle mountain, Grapevine Mountains, Salt Spring Hills); and in Nevada (Nevada Test Site, Desert Range). O. crassimarginatus has been collected in the middle Upper Olenellus-zone of Vermont (Parkers Quarry, Parker Slate, Georgia); and 1⁄2 mile (0.80 km) south of East Petersburg; 2 miles (3.2 km) north of York and Fruitville, 3 miles (4.8 km) north of Lancaster (all in the Kinzers Shale). O. fowleri has been collected from the final layer of the Upper Olenellus-zone of Nevada (Pioche Formation). O. getzi is found in Upper Olenellus-zone of Pennsylvania (2 miles (3.2 km) north of York, and Noah Getz Farm, 1 mile north of Rohrerstown, Kinzers Shale). O. howelli occurs in the final layer of the Upper Olenellus-zone of Nevada (Pioche Formation). O. nevadensis has been collected in the Upper Olenellus-zone, Bristolia-zonule of California (Carrara Formation, Funeral Mountains and Grapevine Mountains); and from the Latham Shale – treated as the Bristolia-zonule – at the south end of the Marble Mountains, near Chambless in the Mohave Desert portion of San Bernardino County. It also occurs in the Bristolia-zonule, Upper Olenellus-zone of Nevada (Carrara Formation, Desert Range, Locality M-5). O. parvifrontatus has been collected in the Olenellus-zone of the Yukon Territory, Canada (Unit 6 of the Upper Illtyd Formation, Wernecke Mountains). O. puertoblancoensis was found in the Botonian/Toyonian Olenellus-zone of the Caborca Region, Mexico (Buelna Formation, Cerro Rajon) O. robsonensis occurs in the ?Middle Olenellus-zone of British Columbia, Canada (?Upper Mahto Formation, drift block on the slope of the Mural Glacier below Mumm Peak, Near Mount Robson). O. roddyi occurs in the Olenellus-zone of Pennsylvania (2 miles (3.2 km) north of York, Fruitville; 3 miles (4.8 km) north of Lancaster; Getz Quarry; 1 mile north of Rohrerstown; 1⁄2 mile (0.80 km) south of East Petersburg; all in the Kinzers Shale). O. romensis occurs in the middle Upper Olenellus-zone of Virginia (Rome Formation, Mason Creek, Salem; northeast of Roanoke, near Webster; 2 miles (3.2 km) southwest of Blue Ridge Springs, 2 miles (3.2 km) south of Max Meadows; Mason Creek, 1 mile (1.6 km) east of Salem; 1⁄2 mile (0.80 km) southeast of Indian Rock; 1 mile (1.6 km) east of Cleveland, Alabama; 1+1⁄2 miles (2.4 km) north of Montevallo; 1+1⁄2 miles (2.4 km) west of Montevallo). O. terminatus has been collected from the final layer of the Upper Olenellus-zone of Nevada (Pioche Formation). O. transitans has been collected from the middle Upper Olenellus-zone of Vermont (Parker Slate, Georgia).

Description

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Olenellus

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

In research: Olenellus 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 Olenellus 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: Olenellus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cambrian genus extinctions, Cambrian trilobites, Fossils of Canada, so understanding it makes those chapters shorter.
In everyday life: Look for Olenellus 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 Olenellus in 20 minutes

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

Frequently asked questions

What is Olenellus in simple terms?

Why does Olenellus 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 Olenellus?

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 Olenellus.