''Brachypterygius'' (meaning ″short wing/paddle″ in Greek) is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of platypterygiine ophthalmosaurid ichthyosaur known from the

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

.McGowan, C. & Motani, R. ''Ichthyopterygia''. In Sues, H.-D. (ed.) Handbook of Paleoherpetology, vol. 8. Verlag Dr. Friedrich Pfeil, Munich, 175 pp., 19 pls. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

was originally described and named as ''

Ichthyosaurus ''Ichthyosaurus'' (derived from Greek ' () meaning 'fish' and ' () meaning 'lizard') is a genus of ichthyosaurs from the Early Jurassic (Hettangian - Pliensbachian), with possible Late Triassic record, from Europe ( Belgium, England, Germany, ...

extremus'' by Boulenger in 1904.Boulenger, G. A. 1904. Exhibition of, and remarks upon, a paddle of a new species of ichthyosaur. ''Proceedings of the Zoological Society of London'', 1904, 424–426. ''Brachypterygius'' was named by Huene in

1922 Events January * January 7 – Dáil Éireann, the parliament of the Irish Republic, ratifies the Anglo-Irish Treaty by 64–57 votes. * January 10 – Arthur Griffith is elected President of Dáil Éireann, the day after Éamon de Valera ...

for the width and shortness of the forepaddle, and the type species is therefore ''Brachypterygius extremus''.Huene, F. F. von 1922. ''Die Ichthyosaurier des Lias und ihre Zusammenhänge''. Verlag von Gebrüder Borntraeger, Berlin, 114 pp., 22 pls. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

of ''B. extremus'' was originally thought to be from the

Lias Group The Lias Group or Lias is a lithostratigraphic unit (a sequence of rock strata) found in a large area of western Europe, including the British Isles, the North Sea, the Low Countries and the north of Germany. It consists of marine limestones, sh ...

of Bath,

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

, but other specimens suggest it more likely came from the

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...

Kimmeridge Clay The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation is the major source rock for Nor ...

(Late Jurassic) of

Kimmeridge Bay Kimmeridge Bay () is a bay on the Isle of Purbeck, a peninsula on the English Channel coast in Dorset, England, close to and southeast of the village of Kimmeridge, on the Smedmore Estate. The area is renowned for its fossils, with The Etches ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of , ...

, UK.

Description

''Brachypterygius'' is a medium-sized ichthyosaur, with a skull length of and a body length up to .McGowan, C. 1976. The description and phenetic relationships of a new ichthyosaur genus from the Upper Jurassic of England. ''Canadian Journal of Earth Sciences'', 13, 668–683. doi:10.1139/e76-070McGowan, C. 1997. The taxonomic status of ''Grendelius mordax'': a preliminary report. ''Journal of Vertebrate Paleontology'', 17, 428–430. doi:10.1080/02724634.1997.10010986 The snout is long, as is characteristic for ichthyosaurs, with larger and more robust teeth, and a relatively smaller eye than ''

Ophthalmosaurus ''Ophthalmosaurus'' (meaning "eye lizard" in Greek) is an ichthyosaur of the Jurassic period (165–150 million years ago). Possible remains from the Cretaceous, around 145 million years ago, are also known. It was a relatively medium-sized ich ...

''. The

basioccipital The basilar part of the occipital bone (also basioccipital) extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. In the young skull this area is rough and uneven, and is joined t ...

has a very narrow extracondylar area. The forepaddle may have five or six digits, with the maximum phalangeal count being between 8 and 16. A key feature is the three facets at the distal end of the humerus; the middle is the smallest and articulates with the intermedium, which clearly separates ''Brachypterygius'' from ''Ophthalmosaurus'', the most common Late Jurassic ichthyosaur.

Taxonomy

The holotype of ''Brachypterygius extremus'' is a single right forepaddle, clearly different from other Late Jurassic ichthyosaurs (e.g. ''Ophthalmosaurus''). ''Brachypterygius'' is closely related to ''

Platypterygius ''Platypterygius'' is a historically paraphyletic genus of platypterygiine ichthyosaur from the Cretaceous period. It was historically used as a wastebasket taxon, and most species within ''Platypterygius'' likely are undiagnostic at the genus ...

'' and ''

Caypullisaurus ''Caypullisaurus'' is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic to the Early Cretaceous ( Tithonian and Berriasian stages) of Argentina. Its holotype was collected from the Vaca Muerta Formation ...

''.Fernández M. 2007. Redescription and phylogenetic position of ''Caypullisaurus'' (Ichthyosauria: Ophthalmosauridae). ''Journal of Paleontology'' 81 (2): 368-375.

Species previously assigned to ''Brachypterygius''

Owen Owen may refer to: Origin: The name Owen is of Irish and Welsh origin. Its meanings range from noble, youthful, and well-born. Gender: Owen is historically the masculine form of the name. Popular feminine variations include Eowyn and Owena. ...

(1840) erected ''Ichthyosaurus trigonus'' based upon a single dorsal vertebra (ANSP 10124) from the Kimmeridge Clay of Westbrook,

Wiltshire Wiltshire (; abbreviated Wilts) is a historic and ceremonial county in South West England with an area of . It is landlocked and borders the counties of Dorset to the southwest, Somerset to the west, Hampshire to the southeast, Gloucestershire ...

, UK.Owen, R. 1840. Report on British Fossil Reptiles. Part I. ''Report of the British Association for the Advancement of Science'', 9, 43–126. The holotype was long thought to be lost until it was rediscovered in 1988. Many specimens were referred to ''Ichthyosaurus trigonus''; Bauer (1898) suggested that – what are now – ''Ophthalmosaurus'', ''Brachypterygius'' and ''

Nannopterygius ''Nannopterygius'' (meaning "small wing/flipper" in Greek) is an extinct genus of ophthalmosaurid ichthyosaur that lived during the Middle Jurassic to the Early Cretaceous (Callovian to Berriasian stages). Fossils are known from England, Kazakhsta ...

'' should be synonymised into ''Ichthyosaurus trigonus''.Bauer, F. 1898. Die Ichthyosaurier des oberen weissen Jura. ''Palaeontographica'', 44, 283–328. ''I. trigonus'' was included in the new genus ''Macropterygius'' by Huene (1922), who later (1923) made it the type species of the genus. Nowadays, ''I. trigonus'' (and hence ''Macropterygius'') is a nomen dubium because its holotype is indistinguishable from other ophthalmosaurids. (Christopher McGowan and Ryosuke Motani mistakenly stated that ''I. trigonus'' may be synonymous with ''Ophthalmosaurus icenicus'')

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

erected the species ''Ophthalmosaurus cantabridgiensis'' from the

Cambridge Greensand The Cambridge Greensand is a geological unit in England whose strata are earliest Cenomanian in age. It lies above the erosive contact between the Gault Formation and the Chalk Group in the vicinity of Cambridgeshire, and technically forms the lo ...

(

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0 ...

, Early Cretaceous) of

Cambridge Cambridge ( ) is a College town, university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cam ...

, UK, on the basis of a humerus (NHMUK 43989). McGowan and Motani (2003) considered it to be a species of ''Brachypterygius'', but a 2014 re-assessment of Cambridge Greensand ichthyosaurs found it to be a nomen dubium indeterminate beyond Ophthalmosaurinae. In 2020, Nikolay Zverkov and Dmitry Grigoriev reassigned this species to '' Maiaspondylus''. A large skull was discovered in the Kimmeridge Clay of Stowbridge,

Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...

, UK and named as a new genus and species, '' Grendelius mordax'', by McGowan in 1976. More complete material from the Kimmeridge Clay of Kimmeridge Bay indicated that these two species were quite similar, so the two genera were synonymised. In 2003, McGowan & Motani synonymised the two species ''B. extremus'' and ''B. mordax'' into ''B. extremus'', considering differences in the forepaddle to be of insufficient taxonomic value. However, a 2015 publication by Zverkov and colleagues instead found ''Grendelius mordax'' to be sufficiently different from ''Brachypterygius extremus'' to be considered both a separate genus and species.

Phylogeny

The following cladogram shows a possible phylogenetic position of ''Brachypterygius'' in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020).

References

{{Taxonbar, from=Q1028288 Fossil taxa described in 1922 Late Jurassic ichthyosaurs Late Jurassic reptiles of Europe Ophthalmosauridae Ichthyosauromorph genera

Description

Taxonomy

Species previously assigned to ''Brachypterygius''

Phylogeny

See also

References