Scientists Describe The World's Smallest, Lightest
Rare, tiny specimen in Scripps fish collection
the smallest animal with a backbone on the planet
By Mario Aguilera
San Diego have described the earth's smallest, lightest animal
with a backbone. H.J. Walker of Scripps Institution of Oceanography
at the University of California, San Diego, and William Watson
of the Southwest Fisheries Science Center, National Marine Fisheries
Service, in La Jolla have identified the miniscule "stout
infantfish," a new species no longer than the width of
in the vicinity of Australia's Great Barrier Reef and the Coral
Sea, only six specimens are known to exist.
The largest specimen-and
only female-measures approximately a third of an inch (8.4 millimeters)
while the males measure just over a quarter of an inch (7 millimeters).
Roughly 500,000 of these fish weighed together would barely
tip the scales at one pound. A full scientific description of
the animal was published in the latest issue of Records of the
The first stout infantfish
was captured in 1979 by the Australian Museum's Jeff Leis during
fieldwork in the Lizard Island / Carter Reef area of the Great
Barrier Reef. After it was left unstudied for years, Watson
and Walker recently analyzed the animal in detail for the first
time. They spent roughly six months studying the creature but
instantly recognized it as something special.
"It was a really
good day when I first looked under the microscope and recognized
something that I knew was a new species. I said to myself, 'Wow,
this is really great,'" said Walker, a senior museum scientist
in the Scripps Marine Vertebrates Collection. "But at the
time I didn't realize that I was looking at the world's smallest
The stout infantfish
supplants the dwarf goby as the new record holder of the world's
smallest vertebrate (animal with a backbone). The scientists
developed the animal's name (scientific name Schindleria brevipinguis)
to characterize its thick, or "stout," structure as
compared with other infantfishes. "Infant" describes
the uncommon early-stage features of the animal. It is transparent
without pigmentation, except for its eyes, and lacks teeth,
scales and certain characteristics typical of other fishes.
Scientists note that
the stout infantfish's unusual appearance corresponds with its
extremely short lifespan, which is believed to be approximately
two months. Many features characteristic of a larval stage of
development appear even though it is fully mature.
that these animals experience several generations each year,"
said Watson, a fishery biologist. "This suggests that they
could evolve quite quickly as well. They live in a specialized
habitat that could be threatened by global warming or human
development, but they may have the ability to evolve as fast
as their environment changes."
Philip Hastings, the
curator of the Scripps Marine Vertebrates Collection, says the
identification of the stout infantfish is another demonstration
that scientists do not yet possess a complete inventory of marine
animals, even for relatively well-studied groups like fishes,
and in fact many important species remain undiscovered.
"Anytime a scientist
identifies an 'extreme' in the world it's important," said
Hastings. "Think about the whole envelope of life. Most
of us systematists describe things that fill in the dots in
the middle of the envelope. This new discovery is pushing the
edge, increasing the size of the envelope. It's important because
it demonstrates that we're still expanding our knowledge of
the limits of the diversity that's present on this planet and
there are still significant new discoveries to be made. We need
to continue doing what we can to explore and describe the diversity
before it's gone, in addition to focusing our efforts on protecting
Other recent examples
of discoveries of new fish species by Scripps scientists include
the description of the "saddled prickleback," a species
that lives on the sea bottom, discovered off San Diego's coastline,
and the "orangeflag blenny," a species found on reefs
off Belize. New discoveries continue to unfold near and far.
The recent findings
also underscore the importance of scientific resources such
as Scripps's invaluable Marine Vertebrates Collection. This
collection of more than two million fish specimens is used by
researchers at Scripps and around the world to uncover new information
about the animal world.
as these provide an enormous library of materials that allow
us to make comparisons for new discoveries," said Hastings.
"Unless you know what's already known, you don't know what's
Media Contacts: Mario Aguilera or Cindy Clark