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.
