Orbulina
photo
credit: © Prof. Howard J. Spero, Dept. of Geology,
University of California Davis
Fossil
foraminifera are crucial indicators in biostratigraphy,
palaeoecology, palaeobiogeography, and oil exploration.
Fossils of these single-celled organisms (protists) are
widely used for dating purposes and as zonal markers, indicating
the potential oil-bearing nature of the sediments in borehole
cores. Such is the stratigraphic precision of these fossils
that they are even used to direct sideways drilling within
an oil-bearing horizon to increase well productivity. The
Commission has ruled on such key genera as Alveolina, Anomalina, Borelis, Discocyclina, Endothyra, Globigerina, Nummulites, Orbulina, Pseudoschwagerina and Sorites,
in many cases defining these genera by determining their
type species. [1945-1998]
Ammonites are important indices for stratigraphical
investigations. A recent application proposes the stabilisation
of the usage of names of Jurassic ammonites and that 34 names
of important species or subspecies, being either type species
of genera or indices of standard chronostratigraphic Zones
and Subzones, be placed on the Official List of Specific
Names in Zoology. Important zonal or subzonal index fossils
included in this case are: Ammonites
biplex bifurcatus,
index of Bifurcatus Zone, Middle Oxfordian, and Ammonites
polymorphus, index of Polymorphites
polymorphus Subzone, Jamesoni Zone, Pliensbachian.
[2004]
Trilobite
photo
credit: © Natural History Museum, London
Trilobites
are the single most diverse group of extinct organisms.
These Palaeozoic marine arthropods exhibited an immense
diversity of size and form and thus are of great stratigraphic
and palaeoecological importance. An application for the
conservation of the name Cryphops, for a genus
of Late Devonian trilobites, was a benchmark case for the
Commission: it was the first case to be placed, in its
entirety, on the World Wide Web, stimulating comments from
the academic community concerned with the taxonomy and
stratigraphic importance of these organisms. [2002]
Iguanodon Mantell,
1825, a gigantic herbivorous terrestrial reptile of Cretaceous
age, was one of three early fossil discoveries made in
England that led to the term Dinosaur (from the Greek ‘deinos’
meaning fearfully great, and ‘sauros’ meaning
lizard) being coined by Owen in 1842. Fossils of Iguanodon
(meaning
‘iguana tooth’) have been found in Europe (England,
Belgium and Germany), northern Africa and North America.
The Commission defined the genus Iguanodon by designating
its type species, Iguanodon bernissartensis. [2000]
Ichthyosaurus
photo
credit: © Natural History Museum, London
Ichthyosaurus species
(meaning ‘fish lizard’), ichthyosaurs, were
marine reptiles, contemporary with dinosaurs, living
from the Middle Triassic until the early Cretaceous age. Ichthyosaurus species
were about 2 metres long and may have weighed up to 90
kg. They had a tall dorsal fin, a half-moon-shaped tail,
paddle-like flippers, and smooth skin. Ichthyosaurus fossils
have been found in England, Germany, Greenland, and Canada.
The Commission has defined the ichthyosaur species Ichthyosaurus
trigonus Owen, 1840, and Ichthyosaurus cornalianus Bassani,
1886 by determining their type specimens. [1993 &
2001]
Tyrannosaurus
rex
photo
credit: © Natural History Museum, London
Tyrannosaurus vs. Manospondylus and Apatosaurus vs. Brontosaurus:
not battles of the dinosaurs but arguments about dinosaur
names. A recent amendment in the Commission’s International
Code of Zoological Nomenclature (1999), allows names fixed
in popular usage to be validated even if older designations
have technical priority. The name Tyrannosaurus rex (meaning ‘tyrant
lizard king’) Osborn 1905 has been used for about
a hundred years, nearly as long as its synonym Manospondylus
gigas had been forgotten. In this case by judicious
application of The Code the reign of T. rex can
continue. However, in contrast, the name of the giant herbivore, Brontosaurus (‘thunder
lizard’) Marsh, 1879, has been sunk, with the older
name Apatosaurus (‘deceptive lizard’)
Marsh, 1877, replacing it. Both names were widely used
for a long time but the consensus among palaeontologists
here was that a name change would not be too upsetting.
Stephen Jay Gould wrote that Brontosaurus was ‘everyone’s
typical sourwood, indeed the canonical herbivorous dinosaur
of popular consciousness from the Sin clair logo to Walt
Disney’s Fantasia’, yet this name has been
abandoned.
