Brachypterygius
Name:
Brachypterygius
(Short wing).
Phonetic: Brak-ip-teh-re-ge-us.
Named By: Friedrich von Huene - 1922.
Synonyms: Brachypterygius zhuralevi,
Grendelius mordax, Ichthyosaurus extremus, Otschevia
pseudoscythius, Brachypterygius mordax.
Classification: Chordata, Reptilia,
Ichthyosauria, Ophthalmosauridae, Platypterygiinae.
Species: B. extremus (type),
B.
alekseevi, B. cantabrigiensis, B.
pseudoscythius.
Diet: Piscivore.
Size: Depending upon the species, between 2.5
and 5 meters long.
Known locations: England - Kimmeridge Clay
Formation, Madagascar?, Norway, Spitsbergen - Agardhfjellet
Formation, and Russia.
Time period: Kimmeridgian to Tithonian of the
Jurassic.
Fossil representation: Several individuals, though
often of partial remains.
Brachypterygius
initially started out as a species of Ichthyosaurus,
I. extremus,
but in 1922 palaeontologist Friedrich von Huene renamed the
species as a distinct genus. This is actually a reflection of how the
Ichthyosaurus genus was once used as a wastebasket
taxon with almost
any ichthyosaur remains being referred to it upon the basis of just
being remotely similar.
The
classification of Brachypterygius is still a
little tricky to get
your head around with the genera Grendelius and Otschevia
also being
attributed to the genus as synonyms. There is also speculation that
the species B. mordax may actually be synonymous
with the type
species B. extremus. So far most
Brachypterygius remains are known
from locations across northern Europe including England, Russia and
Spitsbergen, though the partial remains of a limb paddle from
Madagascar have also been attributed to the genus.
Brachypterygius
is noted for having short and wide paddles, features that may suggest
that Brachypterygius were not as fast swimming as
some other
ichthyosaur genera. This is because the front paddles (which were
analogous to the pectoral fins of a fish) act as hydroplanes to
counteract the downward pitching effect of being pushed through the
water by the tail. Shorter fins meant a smaller surface area, and a
reduced counteracting ability when compared to some ichthyosaurs which
had much larger paddles.
Brachypterygius
is classed within the Platypterygiinae which is a sub group of the
Ophthalmosauridae, a larger group that contains many big eyed
ichthyosaurs
such as the type genus of the group Ophthalmosaurus.
Brachypterygius however differs from these other
genera in having eyes
that were proportionately much smaller. This may infer that
Brachypterygius inhabited waters that were nearer
the surface and well
lit, and therefore did not require the larger and more light
sensitive eyes of some of its relatives which were required for hunting
in deeper waters where very little sunlight penetrated. It’s possible
that the smaller eyes and paddles of Brachypterygius
are features of a
genus that hunted in sunlit waters for slower prey such as fish moving
in shoals that would rely more upon numbers rather than speed to evade
predators.
Compared
to other platypterygiine ichthyosuars, the genera Platypterygius
and
Caypullisaurus
seem to be particularly close relatives to
Brachypterygius.
Further reading
- On a new species of ichthyosaur from Bath. - Proceedings of the
Zoological Society of London, 1904, 424–426. - G. A.
Boulenger - 1904.
- Die Ichthyosaurier des Lias und ihre Zusammenh�nge. - Verlag
von Gebr�der Borntraeger, Berlin, 114 pp., 22 pls. -
Friedrisch von Huene - 1922.
- The description and phenetic relationships of a new ichthyosaur
genus from the Upper Jurassic of England - Canadian Journal of
Earth Sciences 13(5):668-683 - C. McGowan - 1976.
- On the paleogeographic distribution of Callovian and Late Jurassic
ichthyosaurs. - Journal of - Vertebrate Paleontology
17(4):752-754 - M. F. Fernandez - 1997.
- The taxonomic status of Grendelius mordax: a
preliminary report.
- Journal of Vertebrate Paleontology, 17, 428–430. - C.
McGowan - 1997.
- An Ichthyosaur, Otschevia pseudoscythica
gen. et sp. nov.
from the Upper Jurassic Strata of the Ulyanovsk Region (Volga
Region). - Paleontologicheskii Zhurnal 32 (2): 187-191.
- V. M Efimov - 1998.
- On the ichthyosaurian fossils from the Volgian Stage of the Saratov
Basin. - Palaeontological Journal (2)87-91 - M. S.
Arkhangelsky. 1998.
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