DO YOU KNOW YOU HAVE FOUND A NEW SPECIES?
by Whit Gibbons
January 21, 2007
How do scientists know when they have found a new species, one not already
known to science? I thought we were losing species worldwide, but lately
I seem to be reading a lot about one scientist or another discovering
a new bird, bat, or tree.
A. We are
indeed losing species worldwide, at a much faster rate than we discover
new ones. That's not the focus of this column, but it is a truth we should
not lose sight of.
step in discovering a new species is knowing which species have already
been discovered. When ecologists travel to regions where they are not
familiar with the plants and animals, they read field guides about the
flora and fauna. Many of these guides have photographs, keys to species
recognition, and descriptions of size, color, and general appearance.
Ideally, the books also have information about geographic ranges and the
ecology of species. Examining museum specimens to learn about variations
among species in a taxonomic group is important, too.
To recognize that a species is new to science, you must be an expert in
a particular taxonomic group. The most likely areas for new species discoveries
are exotic, unpopulated regions, especially in the tropics. For example,
within recent months a new species of bat was found in Madagascar, a new
monkey in Tanzania, and a new plant (in the violet family) in Cameroon.
The scientists describing the new species had to be familiar with the
particular taxonomic group and know the characteristics of every known
species in the world.
particularly insects, continue to be discovered even in North America,
but the numbers pale in comparison to tropical regions. Because most of
the United States and western Europe have been surveyed extensively, truly
new species of vertebrates are less likely to be discovered. However,
the use of DNA and other genetic analyses has brought greater definition
to the relationships among species, so a plant or animal once thought
to be a single species may be redefined as two or more.
a map in a U.S. field guide from the 1970s will show a single species
of the slimy salamander (Plethodon glutinosus) occupying most of the eastern
United States. Today, slimy salamanders are partitioned into 16 different
species, with different ones occupying different parts of the former range,
based on a gene identification technique known as electrophoresis. Although
most of the "new" species cannot be distinguished from each
other visually, they are genetically distinctive. These kinds of species
descriptions, however, do not count as discoveries never before seen by
use of genetic analyses "to discover a new species" can be found
in the 2003 description of Chamberlain's dwarf salamander from the Carolinas.
These tiny brownish creatures are distinguishable from most other salamanders
by their small size and by having four toes on each hind foot instead
of five. Since at least the 1980s, the dwarf salamander has been known
by herpetologists to represent two distinct species, because one form
has a bright yellow belly. However, no one had formally described them
in a scientific journal using the "International Code of Zoological
Nomenclature." The 2003 description used genetic evidence along with
morphological traits to distinguish two species that were already known
to be distinct.
analyses were also used this past year to confirm the discovery of a new
species of lizard in the rainforests of Borneo. In this case, the scientists
were not splitting an assumed single species into separate genetic units
or giving official recognition to a species already recognized as having
two distinct forms. This was a species of lizard never before seen by
scientists. They used DNA analyses to determine who its closest lizard
relative is, which turns out to be a distantly related lizard from the
new to science will continue to be found as long as scientists look for
them. But we must guard against the misconception that such species are
new to the world. They are not. They have been here for millions of years.
And it is up to us to ensure that both "old" and "new"
species remain a part of our environment.
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