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Interview
of
Pr Alan Kohn
Professor
Emeritus, Zoology
Adjunct Professor, Quaternary Research Center
Adjunct Curator, Burke Museum
Co-Author
of "Manual
Of The Living Conidae"
Principal Investigator Of "The
Conus Biodiversity Website"
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First of all, I extracted from the Washington
University (Biology Department) website this text from Alan, as
it is very helpful for the ones that might not know him :
"The general aim of my research is to increase understanding
of the evolutionary processes that have led to high biotic diversity
in tropical marine environments. Its more specific goal is to elucidate
important evolutionary trends in diversity, morphology, distribution,
and ecology of one of the largest families of marine molluscs, the
Conidae, from its early Cenozoic origin through the Tertiary and Quaternary
periods. The focal genus Conus is particularly important because of
its immense size (about 500 extant and at least as many extinct species),
its extensive range of variation in diversity, geographic distribution,
ecology, and development, and its highly neurotoxic venoms. Current
research efforts emphasize the evolution of taxonomic diversity, Tertiary
marine paleoecology, and relationships between larval developmental
mode and biogeographic patterns.
Prior to my retirement, some of my graduate students addressed similar
questions in their research, but most developed independent studies
in diverse areas of functional morphology, ecology and distribution
of a variety of local as well as tropical marine invertebrates. Currently,
a postdoctoral researcher is using molecular genetic methods to generate
hypotheses of the phylogenetic relationships of Conus species. Undergraduates
in the lab are studying shell and radular tooth morphometrics. These
data will be used to better understand the feeding process in Conus
and to test phylogenetic hypotheses resulting from the gene sequences."
The Conus Biodiversity Website
http://biology.burke.washington.edu/conus/index.php
"This web site is part of a National Science Foundation-sponsored
project aimed at expanding knowledge of systematics of the unusually
diverse marine gastropod genus Conus. The project goals are to integrate
species-level revisionary systematics of the major regional faunas,
contribute to molecular-based phylogenetic hypotheses, expand predictive
classifications, and promulgate the results in both electronic and
print media"
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Interview
I would like to thank several cone shell lovers that helped me with
this interview :
Giancarlo Paganelli, Paul
Kersten, Marco Bettocchi and
Carlie White for english correction.
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Hello Alan,
It is my honor to interview such a major specialist in Malacolgy,
as well as, the co-author of "Manual of the living Conidae";
which is one of the best cone shells related books that I have ever
read. I would like to thank you and your co-authors, in the name of
all cone shell lovers, for this spectacular revision of Indo-Pacific
Cone Shells. Thanks, Alan ! |
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| Would you tell us
more about your actual activity and main projects concerning the Conidae
family? |
| Almost all of my research
over the years has focused on molluscs, and most on Conus.
Of course it is only one of thousands of molluscan genera, but I argue
that it is the biggest and the best. With more than 500 species, Conus
is the most diverse genus of animals in the sea. Another way to say
that is evolutionarily, Conus is the most successful genus
at producing new species, and it has diversified more rapidly than
any other genus of shelled molluscs, as Steven Stanley demonstrated
many years ago from study of both fossil and recent species diversity.
Most of my research has
been in the Indo-Pacific region and has focused on how Conus
species make their living, how such large numbers of species can
coexist in the same environment without competing with each other
for the resources they need (food and space for example), and why
some habitats support more species, that is have higher biodiversity,
than others. Along the way I have had to study Conus taxonomy,
because one must determine the correct species names in order to
communicate the results of biological research. More recently I
have focused more on the systematics and phylogeny of Conus,
and how its adaptive radiation over evolutionary time can help us
understand the evolution of high biodiversity in the tropics more
generally.
I've also studied development
and life history of Conus, and shell and radular tooth morphology
and morphometry, mostly in the Indo-Pacific region, in order to
better understand the biology of the animals in nature.
As a university professor,
I taught mainly courses about the biology of marine invertebrates,
a much broader area. And some of my research has been on other carnvorous
gastropods such as mitrids, buccinids, and the parasitic taenioglossan
Trichotropis, as well as a few studies of polychaetes, sipunculans,
and tropical invertebrate communities. I also supervised the doctoral
studies of 22 graduate students. Most of them did their research
on marine molluscs (only one on Conus), but others studied
the biology of other invertebrates, including crustaceans, polychaetes,
nemerteans, and tunicates.
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| A question that comes
to mind, after reading the famous "Manual of the living Conidae"
vol.1 (also know as "RKK" for Röckel, Kohn, Korn) which
is one of the best and most recent publication about the Conidae family
is : Do you have plans for a vol.2 ? |
| There will be no Volume 2 of The
Manual of Living Conidae. Neither Dieter Röckel, who started
and led the project, and is even older than I, nor Werner Korn, who
became a museum director, wished to continue. I think we did quite
well in that book despite the "RKK" methodology (pronounce
it "RKiK" = archaic). We used primarily 19th Century methods.
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| Are you currently
working on a revision of this Family? |
| It is more rational to revise
the various biogeographic regions separately, because there are so
many species and there is so little overlap of species among regions. |
| Are you working on
a Caribbean project? We all know this area is a real treasure-trove
concerning classification. |
| My current major project
is a revisionary systematic study of the Western Atlantic Conus
species. This formidable project progresses slowly-at the proverbial
but appropriate "snail's pace," for several reasons.
First, the very complex
geologic history of the Caribbean has profoundly affected the evolution
and ecology of marine life in that region today, in ways that differ
markedly from the Indo-Pacific region to which I devoted most of
my career. Second, I have very little personal experience with the
animals in nature there, in contrast with the Indo-Pacific. I studied
the biology of Indo-Pacific Conus over a period of 50 years,
and obviously I don't have another 50 to devote to the Atlantic
fauna. Third, I don't have the benefit of working with my co-authors
of the Indo-Pacific Manual.
In addition to the Western
Atlantic revisionary study, in collaboration with my former postdoctoral
research associates, Tom Duda and Chris Meyer, as well as others,
I continue to try to understand how the species of Conus
are related genealogically or phylogenetically to each other. We
published a couple of papers on this aspect in 2008; the citations
are on the Conus Biodiversity Website, which of course is
itself another ongoing project.
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Shell lovers can also
thank you and your team (Trevor Anderson & Al.) for the excellent
website :
The
Conus Biodiversity Website. How did you get the idea for such
a database? |
| Actually it was not my idea.
The U.S. National Science Foundation supported the study for four
years (2003-07). It requested that grantees of revisionary systematics
projects on all groups of organisms develop web sites on their taxa,
so we complied. It turned out to be an excellent way to manage databases
as well as to make information available and easily accessible to
the world . The site has become more popular than I expected. It has
been averaging over 60 visits per day, and in January, 2009, for example
they came from people in 75 different countries.
However, a web site is
like a collection; without continued attention it deteriorates.
And now that the NSF support has expired, Trevor Anderson's position
has disappeared, and it has therefore become much more difficult
to continue the site. Serious users of the site undoubtedly realize
that it is no longer regularly updated. The NSF does not fund websites
that it initiated after the grants expire. Fortunately the Burke
Museum at the University of Washington continues to host the site,
but unfortunately we lack funding to maintain and update the site.
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| Are you, yourself,
collecting shells? Would you tell us what are your ten favorite cone
shells and why ? |
| I did collect shells, from
the time I was a child growing up near Long Island Sound in Connecticut
until I joined the University of Washington faculty in 1961. At that
time I also became associated with the Burke Museum, to which I donated
my collection, of about 2,500 lots. It is not appropriate for a person
affiliated with a museum to also maintain a private collection, because
it establishes a conflict-of-interest situation.
I will only name my one
favorite Conus species: C. ebraeus, mainly because
it is the most successful of all. The criteria for biological success
vary with the category. At the genus level, Conus is of course
the most successful in the sea, because it has the most species
and occupies a correspondingly broad array of habitats and areas.
For a species, criteria for success include how widespread it is,
how abundant it is, and how many types of environment it can exploit.
(This is why our species, Homo sapiens, is so successful
on land.) C. ebraeus has the widest geographic range of any
Conus species. It occurs throughout the Indo-Pacific region
(1/4 of the world's ocean area), and it has also crossed the East
Pacific Barrier to colonize the coast of Costa Rica. It has a planktonic
larva that stays afloat feeding and growing for at least several
weeks and can thus be transported widely by currents. Tom Duda and
Haris Lessios have shown that its populations in widely separated
regions have almost identical DNA sequences, indicating that they
continue to interbreed. In several habitats it is also the most
abundant species. And it occurs both intertidally and subtidally,
on a variety of different substrate types, although usually associated
with coral reefs or other habitats of reef origin.
Another reason why it is
my favorite is that I have been studying it off and on for about
55 years, and for most of that time it concealed a deep secret from
us. C. ebraeus has a cryptic sister species whose shells
we cannot distinguish from it. Tom Duda discovered this a few years
ago (by demonstrating from its DNA sequences that it does not interbreed
with C. ebraeus). We hope to finish a report on this situation
later this year.
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| What about your work
on DNA tissues of cone shells species ? |
| I am not a molecular biologist,
so I work with others who are. I did require my last several graduate
students to learn molecular methods, because they have become so useful
in answering so many different kinds of biological questions that
we just could not approach before the "molecular revolution."
In this project Tom Duda and Chris Meyer did most of the molecular
genetic work, and both continue research in this direction. We now
have sequences of four genes for perhaps 40% of all Conus species
(about 250). Not all of these results, as well as those of C. ebraeus's
cryptic sister just mentioned, have been published yet. It is heartening,
however, that in about 98% of cases in the Indo-Pacific, the DNA results
agree with our species-level, shell-based taxonomic decisions in RKK.
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| Do you regularly have
big surprises concerning actual nomenclature ? |
| Nomenclatural surprises do seem
rampant in Conus, but maybe they should not be so surprising.
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| Since the publication
of the "Manual", there have been many new Conus species
uncovered. In your opinion, isn't there an inflation of n. sp.? Can
your DNA investigation help you with correct identification? |
| Yes, many Conus species
have been described several times, but previously undescribed species
also continue to be discovered and described. A too common problem
is inadequate descriptions that do not distinguish (and sometimes
seem not to try to distinguish) intraspecific variation from interspecific
differences. Despite the increases in knowledge and technology, published
descriptions have improved disappointingly little from Linnaeus's
time to ours! I've tried over the years to help give guidance about
how to describe species. One such account is on the CBW, and I tried
to make my only new species description (C. kahiko) a model.
But a small fraction of people who have described new species since
then (1981) have paid any attention. One doesn't need to be a professional
biologist or a Ph.D. to properly describe a new species. One does
need a high school-level understanding of how evolution works, and
access to and evaluation of all the previous descriptions of species
in the genus. I know some non-professionals who have published quite
adequate descriptions of new Conus species in the last 10-15
years. I think one problem is that somewhere some people who describe
new species got the idea that some honor is attached to doing so.
But there is no honor; there is only responsibility---the responsibility
to defend the hypothesis that the new nominal species is really distinct.
The late very distinguished Danish marine biologist Anton Fr. Bruun,
whom I had the pleasure of knowing back in the 1950's, attributed
this stuation to the decision that the species name should be followed
by the author's name. This started when it was decided that zoological
nomenclature should begin in 1758 with Linnaeus's species. In a letter
to the editor of Science in 1950, Bruun called this "widespread
mental disease among systematists" the "Mihilisme"
and describers who think some honor accrues to the describer, "Mihilists."
It would help greatly if
all descriptions were published in peer-reviewed scientific journals.
Then, referees of manuscripts would help less experienced authors
to prepare adequate descriptions. But the International Commission
on Zoological Nomenclature permits the names of species published
anywhere to be available.
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Since Linnaeus many
Authors attempted to subdivide the Family Conidae in Genera and Subgenera,
but in spite of the great interspecific variation, the current trend
is to gather all the species in the unique Genus Conus. But
is this the right way ? Isn't there a complicated taxonomic problem
to solve? |
| If there is, we have
not solved it yet. Many attempts have been made to subdivide the genus,
starting with Linnaeus, as you said. In 1758, he divided Conus
into four subgenera on the basis of quantitative characters of shell
shape, or morphometry. A problem is that the schemes of different
authors have been based mainly on single character sets: shell shape,
shell sculpture, shell color pattern, radular teeth, or DNA sequences.
Each basis gives rise to different logical but conflicting schemes.
Because the generic/infrageneric classification is not yet resolved,
it seems most rational to continue to consider all the species in
a single genus. Of course these data also show that some species are
more closely related than others, and some day a bright student may
show that one scheme for subdividing the genus should be accepted
because it explains most of the data on diversity and leaves out the
fewest. This is of course how theories become accepted in all of science,
and systematics is no exception. |
| If someone wanted
to help you by collecting tissue samples from live specimens, how
would one proceed, and to whom should they contact? |
| The simplest method is to place
small tissue samples (we use a slice of fresh foot tissue of a few
cubic millimeters) in 95% (190 proof) ethyl alcohol. The volume of
alcohol should be at least several times that of the specimen, and
the container should be tightly stoppered because alcohol evaporates.
Samples can be sent to me or to Chris Meyer at the Smithsonian Institution.
They should be accompanied by a photograph of the animal's shell and
the usual collection data. Chris keeps a database of images of shells
of Conus specimens whose genes we have sequenced that is accessible
from the Florida Museum of Natural History website. Ideally the shell
itself and the rest of the preserved animal should go to a public
museum as a voucher specimen where it will be accessible to future
generations. |
| What about the mystery
of the presence of Conus pennaceus in Hawaii? I noticed you
were in Hawaii in the end of 2008, with Chris Meyer DNA analyst, did
you learn more about this local interesting specie/subspecie? Do you
have records of C. pennaceus from other places in the Pacific
area? |
| C. pennaeus remains a mystery
as you correctly say. What we call C. pennaceus is almost certainly
a flock of related species. We know that egg size and reproductive
mode, as well as shell form and pattern, differ in different geographic
areas. In RKK, we separated Indian Ocean populations as C. madagascariensis.
Even within Hawaii, where C. pennaceus lacks a planktonic larva,
shells differ markedly from place to place. Some populations have
reddish brown markings on the shells, in other places the shells are
yellow and white. Some have long, narrow shells, while others are
short and squat, etc. The extent of variation within the Hawaiian
Islands is reminiscent of that among some Western Atlantic species
that also lack planktonic larvae. But of course we lack adequate samples
from all of these for detailed molecular genetic analyses. |
| The operculum seems
to be a rudiment. What is your opinion for the real function for this
part of the animal? |
| The operculum does seem rudimentary,
and some species have been reported to have lost it entirely. I don't
know that anyone has demonstrated that it functions in any way. If
someone has, we would all like to hear about it. |
| What causes color
changes in the pattern. Conus regius with half of the whole
in citrinus pattern and the other half the normal pattern? |
| You are what you eat, and at least
some individuals can be induced to change color pattern in captivity
by changing their diet. I've done that with C. striatus in
the laboratory in Seattle. C. regius seems to change patterns
commonly during its life in nature. This likely is due to a change
in diet, but we don't know this for sure. C. regius eats polychaetes
of the family Amphinomidae ("fireworms") and different species
in that family themselves have different skin pigments. |
| What could be the
reason for the nice pattern of conus as it cannot be seen normaly,
because of the periostracum? |
| The pigments of Conus shells
are nitrogenous waste products of metabolism. Just as our kidneys
secrete urea as our main nitrogeous excretory product, Conus kidneys
probably produce the pigmented compounds. One can only speculate why
they are sequestered in the shells. The patterns likely result from
the rhythms of excretion and shell secretion, but little is really
known about this also. As you say, the color patterns probably don't
have any visual significance. Some are obscured by periostracum as
you noted. Conus species that have a thin, translucent periostracum
are those that tend to stay buried in sand during the day, coming
out to forage at night when the patterns aren't visible. And those
that are out in the open all the time typically have the periostracum
covered with algae that obscure the shell color pattern. |
| Does cannibalism appear
in cone species ( ex. adults eating juveniles )? |
| I don't know of any cases. Of
course some Conus eat mainly other Conus. C. marmoreus
and C. bandanus are good examples, at least in some regions.
Members of some species do eat very similar species: I found radular
teeth of a C. canonicus in the gut of a C. textile once.
Also I once (only once) did an experiment in Hawaii keeping a large
number of C. pennaceus in an aquarium for a long time. No cannibalism
occurred. |
| Are cones immune from
their own poison? |
| No, as the previous answer indicates.
But remember that the venom must be injected to be effective. If a
person or another predator eats a Conus, the venom molecules
will be digested as food in the predator's gut. Other snails (e.g.
Cymatium, naticids), some fishes, crabs and mantis shrimps,
and people in several parts of Asia don't hesitate to eat Conus
and are none the worse for the experience. I once taught a short
course on the biology of Conus to marine biologists in Vietnam.
Bad weather prevented much collecting, but the local market provided
enough specimens and species for study. |
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