''Lanarkopterus'' is a genus of prehistoric

eurypterid Eurypterids, often informally called sea scorpions, are a group of extinct marine arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period, 467.3 Myr, mil ...

with one recognised species, ''Lanarkopterus dolichoschelus''. ''Lanarkopterus'' was long seen as a species of the closely related ''

Mixopterus ''Mixopterus'' is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of ''Mixopterus'' have been discovered in deposits from Late Silurian age, and have been referred to several different species. Fossils have been recovered f ...

'', though more complete specimens discovered in the 1960s determined that it differed in several aspects, enough to warrant a separate genus. Specimens of the genus have been recovered from deposits of Late

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

age in

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

Description

''Lanarkopterus'' was a small to moderately large (ranging in size from less than 10 centimeters to over 30 centimeters) mixopterid eurypterid that like its close relative ''

'' appeared almost scorpion-like with a broad and trilobed preabdomen, a narrow and tapering postabdomen and a sharped and curved telsonic spine.

History of discovery

Specimens of ''Lanarkopterus'' were first noted by Peach and Horne (1899) in the Ludlowian fish beds of the

Lesmahagow Lesmahagow ( ; or ''Lesmahagae'', ) is a small town in the historic county of Lanarkshire on the edge of moorland, near Lanark in the central belt of Scotland. Lesmahagow was also a civil parish. It lies west of the M74 motorway, M74, and sout ...

and Hagshaw Hills

inliers in

Ayrshire Ayrshire (, ) is a Counties of Scotland, historic county and registration county, in south-west Scotland, located on the shores of the Firth of Clyde. The lieutenancy areas of Scotland, lieutenancy area of Ayrshire and Arran covers the entirety ...

and

Lanarkshire Lanarkshire, also called the County of Lanark (; ), is a Counties of Scotland, historic county, Lieutenancy areas of Scotland, lieutenancy area and registration county in the Central Lowlands and Southern Uplands of Scotland. The county is no l ...

. Fragments of the genus, then referred to ''

Eurypterus ''Eurypterus'' ( ) is an extinct genus of eurypterid, a group of organisms commonly called "sea scorpions". The genus lived during the Silurian period, from around 432 to 418 million years ago. ''Eurypterus'' is by far the most well-studied and ...

'', were recovered from many localities that also yielded Silurian vertebrates such as ''

Birkenia ''Birkenia'' is a genus of extinct Anaspida, anaspid fish from Middle Silurian strata of Northern Europe, and Middle Silurian to possibly Earliest Devonian strata of Arctic Canada.Blom, Henning, T. Märss, and C. G. Miller. "Silurian and earlies ...

'', ''

Lasanius ''Lasanius'' is a genus of basal jawless fish from the Early Silurian, around 443.8 million years ago, known from fossils found near Lesmahagow, Scotland. Specimens range from 13.3 to 74.5 mm in length. ''Lasianus'' has a pair of eyes, and a ...

'', ''

Thelodus ''Thelodus'' (from , 'nipple' and , 'tooth') is an extinct genus of thelodont agnathan that lived during the Silurian period. Fossils have been found in Europe, Asia and North America.

'', ''

Lanarkia ''Lanarkia'' is a genus of extinct thelodont agnathan which existed in what is now Scotland and Canada during the upper Silurian period.

'' and '' Atleleaspis''. Størmer (1936)Størmer, L. (1936). ''Mixopterus dolichoschelus'' (Laurie MS), a Downtonian eurypterid from Scotland.''S umm. Prog. geol. Surv. for 1934'', 41-46. described several specimens of ''Mixopterus'' from Ludlowian deposits of Ringerike,

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

. The specimens referred to ''Eurypterus dolichoschelus'' were described in further detail and referred to ''Mixopterus''. An almost complete, but weathered specimen (T. 3357) from the collection of the Geological Survey of Scotland, in

Edinburgh Edinburgh is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. The city is located in southeast Scotland and is bounded to the north by the Firth of Forth and to the south by the Pentland Hills. Edinburgh ...

, was taken as the holotype of ''Mixopterus dolichoschelus''. Further specimens discovered during the second half of the twentieth century and ones discovered in several national and university museum collections allowed a full description of the morphology and a more accurate assessment of the taxonomic position of the species. Ritchie (1968) presented evidence that suggested that ''M. dolichoschelus'' was not as closely related to the other species of ''Mixopterus'' as previously thought and placed it in its own genus within the

Mixopteridae The Mixopteridae are a family of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". The family is one of two families contained in the superfamily Carcinosomatoidea (along with Carcinosomatidae), which in ...

, ''Lanarkopterus''.

References

Carcinosomatoidea Silurian eurypterids Eurypterids of Europe {{eurypterid-stub

Description

History of discovery

See also

References