Brachypterygius

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Brachypterygius
Temporal range: Late Jurassic, Kimmeridgian–Tithonian
Brachypterygius NT small.jpg
Restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order:† Ichthyosauria
Family:† Ophthalmosauridae
Subfamily:† Platypterygiinae
Genus:† Brachypterygius
von Huene, 1922
Species

Brachypterygius (meaning ″short wing/paddle″ in Greek) is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur known from the Late Jurassic of England. [1] The type species was originally described and named as Ichthyosaurus extremus by Boulenger in 1904. [2] Brachypterygius was named by Huene in 1922 for the width and shortness of the forepaddle, and the type species is therefore Brachypterygius extremus. [3] The holotype of B. extremus was originally thought to be from the Lias Group of Bath, United Kingdom, but other specimens suggest it more likely came from the Kimmeridgian Kimmeridge Clay (Late Jurassic) of Kimmeridge Bay, Dorset, UK.

Description

Brachypterygius is a medium-sized ichthyosaur, with a skull length of 0.5–1.2 metres (1.6–3.9 ft) and a body length up to 4 metres (13 ft). [4] [5] [6] The snout is long, as is characteristic for ichthyosaurs, with larger and more robust teeth, and a relatively smaller eye than Ophthalmosaurus . [5] The basioccipital has a very narrow extracondylar area. [5] The forepaddle may have five or six digits, with the maximum phalangeal count being between 8 and 16. [2] [5] 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. [2]

Taxonomy

The holotype of Brachypterygius extremus is a single right forepaddle, clearly different from other Late Jurassic ichthyosaurs (e.g. Ophthalmosaurus). [2] Brachypterygius is closely related to Platypterygius and Caypullisaurus . [7]

Species previously assigned to Brachypterygius

Owen (1840) erected Ichthyosaurus trigonus based upon a single dorsal vertebra (ANSP 10124) from the Kimmeridge Clay of Westbrook, Wiltshire, UK. [8] The holotype was long thought to be lost until it was rediscovered in 1988. [9] Many specimens were referred to Ichthyosaurus trigonus; Bauer (1898) suggested that – what are now – Ophthalmosaurus, Brachypterygius and Nannopterygius should be synonymised into Ichthyosaurus trigonus. [10] I. trigonus was included in the new genus Macropterygius by Huene (1922), [11] who later (1923) made it the type species of the genus. [12] Nowadays, I. trigonus (and hence Macropterygius) is a nomen dubium because its holotype is indistinguishable from other ophthalmosaurids. [13] (Christopher McGowan and Ryosuke Motani mistakenly stated that I. trigonus may be synonymous with Ophthalmosaurus icenicus [1] )

Richard Lydekker erected the species Ophthalmosaurus cantabridgiensis from the Cambridge Greensand (Albian, Early Cretaceous) of Cambridge, UK, on the basis of a humerus (NHMUK PV OR 43989). [14] McGowan and Motani (2003) considered it to be a species of Brachypterygius, [1] but a 2014 re-assessment of Cambridge Greensand ichthyosaurs found it to be a nomen dubium indeterminate beyond Ophthalmosaurinae. [15] In 2020, Nikolay Zverkov and Dmitry Grigoriev reassigned this species to Maiaspondylus . [16]

A large skull was discovered in the Kimmeridge Clay of Stowbridge, Norfolk, UK and named as a new genus and species, Grendelius mordax, by McGowan in 1976. [4] More complete material from the Kimmeridge Clay of Kimmeridge Bay indicated that these two species were quite similar, so the two genera were synonymised. [5] 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. [1] 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. [17]

Phylogeny

The following cladogram shows a possible phylogenetic position of Brachypterygius in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020). [18]

Ophthalmosauria
Ophthalmosaurinae
Platypterygiinae

See also

Related Research Articles

<i>Ophthalmosaurus</i> Extinct genus of reptiles

Ophthalmosaurus is a genus of ichthyosaur known from the Middle-Late Jurassic. Possible remains from the earliest Cretaceous, around 145 million years ago, are also known. It was a relatively medium-sized ichthyosaur, measuring 4 m (13 ft) long and weighing 940 kg (2,070 lb). Named for its extremely large eyes, it had a jaw containing many small but robust teeth. Major fossil finds of this genus have been recorded in Europe with a second species possibly being found in North America.

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 or species level, or represent distinct genera, even being argued as invalid. While fossils referred to Platypterygius have been found throughout different continents, the holotype specimen was found in Germany.

<i>Aegirosaurus</i> Extinct genus of reptiles

Aegirosaurus is an extinct genus of platypterygiine ophthalmosaurid ichthyosaurs known from the late Jurassic and early Cretaceous of Europe. It was originally named as a species of Ichthyosaurus.

Macropterygius is a genus of ichthyosaurs known from the Late Jurassic of England. Though many specimens have been referred to this genus from all over Europe, the type specimen of the only recognized species, M. trigonus, consists of just a single vertebra. Because this cannot be used to distinguish ichthyosaurs from one another, the genus and species are currently considered nomina dubia.

Plutoniosaurus is an extinct genus of ophthalmosaurid ichthyosaur of uncertain validity from the Early Cretaceous of the vicinity of Ulyanovsk, European Russia.

<i>Caypullisaurus</i> Extinct genus of reptiles

Caypullisaurus is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic to the Early Cretaceous of Argentina. Its holotype was collected from the Vaca Muerta Formation of Cerro Lotena, Neuquen, dating to the early Tithonian stage of the Late Jurassic, about 150 million years ago. Caypullisaurus was first named by Marta Fernández in 1997 and the type species is Caypullisaurus bonapartei. It was a large ichthyosaur, measuring about 7 m (23 ft) long.

<span class="mw-page-title-main">Ophthalmosauridae</span> Extinct family of reptiles

Ophthalmosauridae is an extinct family of thunnosaur ichthyosaurs from the Middle Jurassic to the early Late Cretaceous worldwide. Almost all ichthyosaurs from the Middle Jurassic onwards belong to the family, until the extinction of ichthyosaurs in the early Late Cretaceous. Ophthalmosaurids appeared worldwide during early Bajocian, subsequent to the disappearance of most other ichthyosaur lineages after the end of the Toarcian. Currently, the oldest known ophthalmosaurids is Mollesaurus from the early Bajocian of Argentina, as well as indeterminate remains of the same age from Luxembourg and Canada. Named by George H. Baur, in 1887, the family contains the basal taxa like Ophthalmosaurus. Appleby (1956) named the taxon Ophthalmosauria which was followed by some authors, but these two names are often treated as synonyms; Ophthalmosauridae has the priority over Ophthalmosauria. However, some researchers argue that Ophthalmosauridae should be restricted to the group typically referred to as Ophthalmosaurinae, with classic Platypterygiinae instead being referred to as Undorosauridae or Brachypterygiidae and Ophthalmosauria being used to unite these two groups.

<i>Undorosaurus</i> Extinct genus of reptiles

Undorosaurus is an extinct genus of ophthalmosaurid ichthyosaur known from western Russia, Svalbard, and Poland. It was a large ichthyosaur, with the type species measuring 4–6 metres (13–20 ft) long.

Mollesaurus is an extinct genus of large ophthalmosaurine ophthalmosaurid ichthyosaur known from northwestern Patagonia of Argentina.

<i>Nannopterygius</i> Extinct genus of reptiles

Nannopterygius is an extinct genus of ophthalmosaurid ichthyosaur that lived during the Middle Jurassic to the Early Cretaceous. Fossils are known from England, Kazakhstan, Russia, and Norway and six species are currently assigned to the genus.

<i>Chacaicosaurus</i> Extinct genus of reptiles

Chacaicosaurus is a genus of neoichthyosaurian ichthyosaur known from the Middle Jurassic of Argentina. The single known specimen of this genus was excavated from the Los Molles Formation in Neuquén Province, and is housed at the Museo Olsacher under the specimen number MOZ 5803. This specimen consists of a skull, forelimb, some vertebrae, and some additional postcranial elements. The genus was named by Marta Fernández in 1994, and contains a single species, Chacaicosaurus cayi, making it the first named distinctive ichthyosaur from the Bajocian stage. It is a medium-sized ichthyosaur with a very long snout, which bears a ridge running along each side. The forelimbs of Chacaicosaurus are small and contain four main digits.

<i>Grendelius</i> Extinct genus of reptiles

Grendelius is a genus of platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic (Kimmeridgian-Tithonian) of the UK and European Russia. It was a medium-sized ichthyosaur measuring about 4 metres (13 ft) long.

<i>Arthropterygius</i> Extinct genus of reptiles

Arthropterygius is a widespread genus of ophthalmosaurid ichthyosaur which existed in Canada, Norway, Russia, and Argentina from the late Jurassic period and possibly to the earliest Cretaceous.

Mixosauridae was an early group of ichthyosaurs, living between 247.2 and 235 million years ago, during the Triassic period. Fossils of mixosaurs have been found all over the world: China, Timor, Indonesia, Italy, Germany, Spitsbergen, Switzerland, Svalbard, Canada, Alaska, and Nevada.

Sveltonectes is an extinct genus of platypterygiine ophthalmosaurid ichthyosaurs known from Ul’yanovsk region, western Russia.

<i>Acamptonectes</i> Extinct genus of ophthalmosaurid ichthyosaur known from England and Germany

Acamptonectes is a genus of ophthalmosaurid ichthyosaurs, a type of dolphin-like marine reptiles, that lived during the Early Cretaceous around 130 million years ago. The first specimen, a partial adult skeleton, was discovered in Speeton, England, in 1958, but was not formally described until 2012 by Valentin Fischer and colleagues. They also recognised a partial subadult skeleton belonging to the genus from Cremlingen, Germany, and specimens from other localities in England. The genus contains the single species Acamptonectes densus; the generic name means "rigid swimmer" and the specific name means "compact" or "tightly packed".

<span class="mw-page-title-main">Platypterygiinae</span> Extinct subfamily of reptiles

Platypterygiinae is an extinct subfamily of ophthalmosaurid thunnosaur ichthyosaurs from the early Late Jurassic to the early Late Cretaceous of Asia, Australia, Europe, North America and South America. Currently, the oldest known platypterygiine is Brachypterygius. Platypterygiines were characterized by square tooth roots in cross-section, an extremely reduced extracondylar area of the basioccipital, prominent dorsal and ventral trochanters on humerus and ischiopubis lacking an obturator foramen.

<span class="mw-page-title-main">Timeline of ichthyosaur research</span>

This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, sharks, or swordfish. Scientists have documented ichthyosaur fossils at least as far back as the late 17th century. At that time, a scholar named Edward Lhuyd published a book on British fossils that misattributed some ichthyosaur vertebrae to actual fishes; their true nature was not recognized until the 19th century. In 1811, a boy named Joseph Anning discovered the first ichthyosaur fossils that would come to be scientifically recognized as such. His sister Mary would later find the rest of its skeleton and would go on to become a respected fossil collector and paleontologist in her own right.

<i>Keilhauia</i> Extinct genus of reptiles

Keilhauia is a genus of ophthalmosaurid ichthyosaur, a type of dolphin-like, large-eyed marine reptile, from the Early Cretaceous shallow marine Slottsmøya Member of the Agardhfjellet Formation in Svalbard, Norway. The genus contains a single species, K. nui, known from a single specimen discovered in 2010 and described by Delsett et al. in 2017. In life, Keilhauia probably measured approximately 4 metres (13 ft) in length; it can be distinguished by other ophthalmosaurids by the wide top end of its ilium and the relatively short ischiopubis compared to the femur. Although it was placed in a basal position within the Ophthalmosauridae by phylogenetic analysis, this placement is probably incorrect.

Myobradypterygius is an extinct genus of ophthalmosaurid ichthyosaur from the Early Cretaceous (Barremian-Hauterivian) of Argentina and possibly also Chile. One species is known, M. hauthali, which was once believed to have been a species of Platypterygius.

References

  1. 1 2 3 4 McGowan, C. & Motani, R. Ichthyopterygia. In Sues, H.-D. (ed.) Handbook of Paleoherpetology, vol. 8. Verlag Dr. Friedrich Pfeil, Munich, 175 pp., 19 pls.
  2. 1 2 3 4 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.
  3. ↑ Huene, F. F. von 1922. Die Ichthyosaurier des Lias und ihre Zusammenhänge. Verlag von Gebrüder Borntraeger, Berlin, 114 pp., 22 pls.
  4. 1 2 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/e76-070
  5. 1 2 3 4 5 McGowan, C. 1997. The taxonomic status of Grendelius mordax: a preliminary report. Journal of Vertebrate Paleontology, 17, 428–430. doi:10.1080/02724634.1997.10010986
  6. ↑ Zverkov, N. G.; Arkhangelsky, M. S.; Stenshin, I. M. (2015). "A review of Russian Upper Jurassic ichthyosaurs with an intermedium/humeral contact. Reassessing Grendelius McGowan, 1976". Proceedings of the Zoological Institute. 318 (4): 558–588. doi:10.31610/trudyzin/2015.319.4.558.
  7. ↑ Fernández M. 2007. Redescription and phylogenetic position of Caypullisaurus (Ichthyosauria: Ophthalmosauridae). Journal of Paleontology81 (2): 368-375.
  8. ↑ Owen, R. 1840. Report on British Fossil Reptiles. Part I. Report of the British Association for the Advancement of Science, 9, 43–126.
  9. ↑ Spamer, E.E., Bogan, A.E. & Torrens, H.S. 1989. Recovery of the Etheldred Benett collection offossils mostly from Jurassic-Cretaceous strata of Wiltshire, England, analysis of the taxonomic nomenclature of Benett (1831), and notes and figures of type specimens contained in the collection. Proceedings of the Academy of Natural Sciences of Philadelphia, 141:115-180.
  10. ↑ Bauer, F. 1898. Die Ichthyosaurier des oberen weissen Jura. Palaeontographica, 44, 283–328.
  11. ↑ Huene, F. von. 1922. Die Ichthyosaurier des Lias und ihre Zusammenhange. Monographien zur Geologic and Palaeontologie, 1: 1-114.
  12. ↑ Huene, F. von. 1923. Lines of phyletic and biological development of the Ichthyopterygia. Bulletin of the Geological Society of America, 34: 463-468.
  13. ↑ Bardet N, Fernández M. 2000. A new ichthyosaur from the Upper Jurassic lithographic limestones of Bavaria.Journal of Paleontology74 (3): 503-511.
  14. ↑ Lydekker, R. (1888). "Note on the classification of the Ichthyopterygia (with a notice of two new species)". Geological Magazine. 5 (7): 309–313. Bibcode:1888GeoM....5..309L. doi:10.1017/S0016756800181968. S2CID   130015670.
  15. ↑ Fischer, V.; Bardet, N.; Guiomar, M.; Godefroit, P. (2014). "High diversity in Cretaceous ichthyosaurs from Europe prior to their extinction". PLOS ONE. 9 (1): e84709. Bibcode:2014PLoSO...984709F. doi: 10.1371/journal.pone.0084709 . PMC   3897400 . PMID   24465427.
  16. ↑ Zverkov, N. G.; Grigoriev, D. V. (2020). "An unrevealed lineage of platypterygiines (Ichthyosauria) with peculiar forefin structure and semiglobal distribution in the mid-Cretaceous (Albian–Cenomanian)". Cretaceous Research. 115: 104550. doi:10.1016/j.cretres.2020.104550. S2CID   225721312.
  17. ↑ Zverkov, N. G.; Arkhangelsky, M. S.; Stenshin, I. M. (2015). "A review of Russian Upper Jurassic ichthyosaurs with an intermedium/humeral contact. Reassessing Grendelius McGowan, 1976" (PDF). Proceedings of the Zoological Institute RAS. 319 (4): 558–588. doi:10.31610/trudyzin/2015.319.4.558. S2CID   56362895.
  18. ↑ Nikolay G. Zverkov & Megan L. Jacobs (2021) [2020]. "Revision of Nannopterygius (Ichthyosauria: Ophthalmosauridae): reappraisal of the 'inaccessible' holotype resolves a taxonomic tangle and reveals an obscure ophthalmosaurid lineage with a wide distribution". Zoological Journal of the Linnean Society. 191 (1): 228–275. doi:10.1093/zoolinnean/zlaa028.
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