''Lejopyge laevigata'' is a species of

agnostid Agnostidae is a family of Agnostida trilobites. Like all Agnostina, they were eyeless and bore only two thoracic segments. They ranged in benthic waters across the globe from 508 to 461 million years ago, containing the following genera, among o ...

trilobite belonging to the genus '' Lejopyge''. It existed during the Guzhangian to the Paibian Age (around to million years ago) of the

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

. It has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

and is an important index fossil in biostratigraphy.

Description

''Lejopyge laevigata'' exhibits a

cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont Company. Baldino s ...

and pygidium that are smooth and almost featureless ( effaced). Both possess axial furrows that gradually become shallower until they disappear distally. They surround the rear edges of the glabella (reaching about as far or a little past the basal glabellar lobes) and the anterior end of the central lobe of the pygidium. Basal furrows are also present. The

genae This glossary of entomology describes terms used in the formal study of insect species by entomologists. A–C A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though i ...

("cheeks") are usually smooth, but in extremely rare cases they may possess small pits (scrobicules) of moderate depth. The border around the pygidium is uniform in width at the back and narrows towards the front. Like all members of the suborder Agnostina, ''Lejopyge laevigata'' is completely blind.

Distribution

''Lejopyge laevigata'' has a

, making it an ideal intercontinental correlation tool in biostratigraphy. It has been described from Argentina,

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

(including Tasmania),

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, Denmark (including Greenland), Germany, India, Kazakhstan, Norway, Poland, Turkestan, Uzbekistan, Russia,

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

, the United Kingdom, and the United States (including rare finds in Alaska).

Taxonomy

''Lejopyge laevigata'' is classified under the genus '' Lejopyge'' of the family Ptychagnostidae. It was originally described in 1828 by the

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

naturalist

Johan Wilhelm Dalman Johan Wilhelm Dalman (November 4, 1787 in Hinseberg, Västmanland – July 11, 1828 in Stockholm) was a Swedish physician and a naturalist. He first studied at Christiansfeld in Schleswig-Holstein then at the University of Lund and the ...

as ''Battus laevigatus''. In a

monograph A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject. In library cataloging, ''monograph ...

Bohemia Bohemia ( ; cs, Čechy ; ; hsb, Čěska; szl, Czechy) is the westernmost and largest historical region of the Czech Republic. Bohemia can also refer to a wider area consisting of the historical Lands of the Bohemian Crown ruled by the Bohem ...

n trilobites, ''Prodrom einer Monographie der böhmischen Trilobiten'' (1847), the Czech

fossil collector Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many stil ...

Ignaz Hawle Ignaz is a male given name, related to the name Ignatius. Notable people with this name include: * Franz Ignaz Beck (1734–1807), German musician * Heinrich Ignaz Franz Biber (1644–1704), Bohemian-Austrian musician * Ignaz Brüll (1846–1907) ...

and

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

August Carl Joseph Corda established the genus ''Lejopyge'' using ''B. laevigatus'' as the type species. '' Lejopyge armata'' was formerly classified as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of ''Lejopyge laevigata''. The former differs from the latter in having spines on both the

and the pygidium, a characteristic unique to the entire genus. They are sometimes found together, but most collections are uniformly composed of either of them, which rules out sexual dimorphism as an explanation for the differences. Due to this, the American paleontologist Richard A. Robison separated ''Lejopyge armata'' from ''Lejopyge laevigata'' in 1984.

Biostratigraphy

''Lejopyge laevigata'' is used in biostratigraphy as an index fossil. Its first appearance at the GSSP section of the Huaqiao Formation in Hunan,

is defined as the beginning of the Guzhangian Age (around million years ago) of the Miaolingian ( Middle Cambrian). It has also been used as a zonal guide in various fossil localities around the world.

References

{{Taxonbar, from=Q6520530 Agnostoidea Cambrian trilobites Animals described in 1828 Index fossils Fossil taxa described in 1828 Guzhangian Paibian Trilobites of South America Miaolingian first appearances Furongian extinctions Cambrian genus extinctions