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Endangered
Rhinoderms
Is
the Chile Darwin's Frog (Rhinoderma
rufum) still alive?
By
Klaus Busse. The
frogs of the genus Rhinoderma live in the temperate humid forests of the southern part
of Southamerica. So they do not inhabit tropical
latitudes but regions with a moist
climate of moderate temperatures especialliy in the western slope of the Andes,
This corresponds to south
central Chile and to a small extent Argentina. There they dwell in forests
of southern beeches (Nothofagus), some Lauraceae,
Proteaceae, Myrtaceae and others. They became popular or even famous by the special way
they reproduce. Their parental care is unique in refinement among frogs. Rhinoderma is the only
batrachian genus which broods the tadpoles inside the vocal pouch.
An
equally sophisticated brood care can be found only in the Australian genus Rheobatrachus.
This frogs even rear their offsping
in the stomach (Tyler 1983, 1984; reproductive biology in frogs in general see
Duellmann & Trueb 1986, Crump 1994).
I
have a breeding stock of Rhinoderma
darwinii since many years in Bonn. They are held in terraria at outdoor conditions. They reoproduce every
year. In consequence of
this I was invited to a
congress in Santiago de Chile in
December 2001, together with REPTILIA-editor
Heiko Werning . The subject of the
meeting was
„ A seminar on breeding of Chilean
fauna in captivity“. Since I have
held only this one species, in the sence of own experience I could report only
on R.
darwinii . In my presentarion
I refered to my aim of keeping also the second species of
the genus, R. rufum which is much more rare and much less known in its habits.
As I wanted to make compartative studies of the behaviour, I complained that I
have not been able to get it in the wild, although I had done
considerable effort in search of it. In
the following discussion some of the Chilean collegues argued
that, R. rufum is considered as
already extinct. But just this sholdn't be true! Having in mind this alarming
backgound Heiko Werning and me
discussed the problem already during the congress and aslo we consulted some of
the Chilean colleagues, in order to start a
project with the goal of clarifiing
if some natural populations of R. rufum may
have subsisted, and if yes, to try to promote the protection of its natural
environment. Furthermore one could start a breeding program with some
induividuals. At the same time we want to clarify the actual status of the
species R. darwinii, which in Chile is
equally considered as „endangered“ , and to improve the efforts of
captivity breeding. In any case, the situation of
rhinoderms is very serious: In the worst of all cases one of both known
species of theese singular frogs could be already beextinct, while the second
one is severely threatended. Hopefuly there may be a chance for both species, if
we do something for their survival! On Systematics and Nomenclature of Rhinoderms
The
species Rhinoderma darwinii was
described by Duméril & Bibron (1841) (see also Bell 1943). It was done on
the base of specimens collected by
Charles Darwin during his voyage
around the World on the Beagle. The name of this species stood the same from the
beginning until now and is also inquestionable. The second species Rhinoderma rufum
has caused some more confusion among taxonomists.
In 1902 the director of the Natural
History Museum in Santiago de
Chile, R. A. Philippi, described a frog, which he called Heminectes
rufus. As locality he mentioned „the
surroundings of Lago Vichuquén“.
This is a lake placed in a coastal
district westward to Curicó. There has been payed little attention to this
species in litterature, wich
probably may be due to the reason, tha it has passed quite unobserved,
because it is very similar
in appearance to the first and it ever has been the more rare of both species. Mainly
Barros (1918) dealt more in detail with this frog, although he thought
them belonging to the more common species R.
darwinii. Even Cei (1962) considered the species described by Philippi as a
local form of R. darwinii. Lastly basing on studies by Jorquera et al. (1972, 1974) it could be finally followed,
that this view could no longer be sustained. Theese authors, primarily
interested in embryology and the elaboration of a developmental table, really
did find fundamental differences in egg- and
larval development, when they compared individuals from Valdivia whit those
from Concepción. While the first ones stay in the vocal pouch of the
father until the end of metamorphosis, the second ones after a short stay in the
vocal pouch pass through a long lasting free living tadpole stage, before they
change into froglets (details see
below).
At last it was Formas et al. (1975) ( see also Formas, 1981) who draw the
conclusion that they dealt with two different species. Basing on the
developmental differences this conclusion is more than justified.
Additionally both species are, or at least were living in simpatry near
Concepción. As in systematics often occurs, furtherly there could be
established some differences also visible in the adults when observed with
detention. The toes in R. rufum are more
conspicuously webbed, the colour pattern of the under surface of feet is not as
contrastfully coloured as in R. darwinii.
This one having a more pronounced heel appendage, in contrast has a less
developped metatarsal tubercle. The nomenclaorial consecuence of the finding
that two species are involved, is that for the second one
the generic name Heminectes
given by Philippi could not be
kept, because doubtless both belong to Rhinoderma.
The species name rufus changes into
rufum, because Rhinoderma
(grammatically) is a neutrum.
In Englisch for R.
darwinii the vernacular name of „Darwin's-frog“
has established, in Spanisch
„sapito de Darwin“ or „ranita de Darwin“. For R.
rufum in Spanish there is no vernacular name of common use, one should look
for a ..(griffig=handy?)....name. But in this language there is a good
candidate, it is „sapito vaquero“ already used by
Barros (1918). Although he confused it with R.
darwini, ignoring the existance of the second species, on geographical
reasons, he must have dealt with R. rufum.
He probably used a local popular name (see Kilian , 1965: 187) , which also
according to my information is not
in use for the more southern Rhinoderma
darwinii, so it should be restricted to the species R.
rufum. In German (see the German version of this article in REPTILIA....ggfs
formal richtig zitieren????).. apart from the name in honour of Charles Darwin
there is a name referring to the nose „Nasenfrosch“. As
this name refers to the whole genus there was no harm to translate
part of the original name of the second described species
„Heminectes“ as „Halbschwimmer-Nasenfrosch“
which means something like „semi-swimming rhinoderm“ this could be interpreted in a double meaning: One refering
to the toes, that contrary to the unwebbed ones of R. darwinii
are partially webbed. The other is a coincidence making sence with
the larva which lives as a free swimming tadpole during
part of its development. Anyway it is related to the name given by
Philippi (1902), which by the way this year has its centenary babtism
aniversary. A problem is the
english name: „Chile Darwin's-frog“ proposed by Frank & Ramus 1995: 114.
It is quite misleading, because the name „Darwin's-frog“ is pre-occupied for
and should be restricted to R. darwinii, which
like R. rufum equally is a
Chilean inhabitant. Some on Reproductive
Biology
In the first species of Rhinoderma being
desccribed - R. darwinii -, it was
early noticed that some individuals carried tadpoles inside their body.
Accordingly they were thought to be feemales, until the Spanisch scientist
Jimenez de la Espada (1872) recognized that the „pregnant“ individuals were
males which reared their tadpoles inside the vocal sac. So details of the
reproducve biology were complemented piece by piece until novadays (for further
details see Busse 1989, 1991,
2002). In the second Rhinoderma
species it was quite different: In this case finally it was the knowledge on
reproducition which allowed to
confirm its distinctness at species level. A comparison should help to
demonstrate it: Rhinoderma darwinii
lays large eggs with abundant yolk (approx. 5-15 eggs with a diameter of about
3,6 mm). first they develop 20 days
long outside the water, and hidden in te moist Vegetation on the ground. When
the tadpoles hach they are taken by the male, after which they are brooded
during 34 - 60 days in the
vocal pouch of the father who
releases them as already metamorohosed froglets. The main part of the larval
development and metamorohosis take place inside the vocal sac, they lack a free
living water dwelling tadpole. Rhinoderma rufum
lays considerably smaller eggs with
less yolk , but in a more numerous cluch (12-25 with a diameter of
2,5 mm, what means around 1/3 of the
volume). They develop only during 7 days on a terrestrial environment. Than the
fry is taken by the male inside his vocal sac, but he carries his offspring only
for two weeks, after which they
are released to the warter in a relatively early tadpole stage. A
considerable part of the larval development and growth as well as the
metamorphosis take place in the
water like in most other anurans. This takes about three months
(approx. 120 days). Considering
that, apart from the long lasting time the tadpole lives free in the water, but
also a short developmental span inside the father's pouch exists, here we have
an intermediate brood care mode. Just this intermediate brood biology model
makes R. rufum outstandingly
interesting. Studied more in detail
it may help to understand how oral brood care in rhinoderms has evolved. And
just this pecies would be extinct?.... No, it ought not be allowed to! Prospective search
of historical and present
occurence
It is an urgent need to clarify the case. To proceed efficiently, before
going in search in the field, we
are researching at different levels, trying to get as much as possible hints on
where there may be some places whith actual occurence of
R.. rufum or at least they have
occured in the past: literature research, vouchers from
collections in museums, interviews
with some persons etc. Prt of this has ben already done or is still being
undertaken. In literature naturaly there
are some data. Unambiguous proofs were provided by Formas et al. (1975).
Anotherone is the locality given by
Philippi (1902) in his original description. It is quite sure that
the R.
darwinii mentioned by Barros (1908) really are R.
rufum. Penna & Veloso (1990) published sonanagrams
of the call of diverse Chilean frogs. Their tape recordings of
R. rufum were done in October
1980 near to Concepción, accordingly this pecies at least at that time still
must have existed in that place. Additionally to data from literature in a second approach level, collecting
localities of museum specimens may help. The collections I could reach until
now, were rumaged through in search of R.
rufum.. The search Natural History Museum in Santiago de Chile had a
negative result. Although this taxon was described in this museum, already
Formas et al. (1975) could not find the types of Philippi there. For this reason
they, designated a specimen furtherly collected by them in the type locality
Vichuquén as a neotype. This was deposited at the Zoological Institute
in Valdivia, where Formas has
several more specimens from differen localities. In the meantime I have been in
Berlin at the Natural History Museum,
where also no R. rufum could be
found. In our institute (Museum
Koenig , Bonn) among about 70
Exemplars of R. darwinii six R. rufum were
found, who would have thougt so, because originally they had been catalogued as
R. darwinii. One must be aware
that such misidentifiings may occur in all herpetological collections,
especially when they date from
before the revalidation by Formas et al. (1975), therefore they should be examined
carefully. Our specimens in Bonn
are catalogued with the surely wrong collecting place Santiago de Chile. By
cahnce I knew the collector. The far childhood reminders I had of the late E.
Timmermann dating from the time I lived in Chile, scarcely
have been of use. His
decendants, not much interested in natural history, couldn't report anything to
correct the finding locality. This leads us to the third level of approach, the personal questioning: I
already have asked some Chilean colleqagues. Also the „guardaparques“ -
theese are the rangers of the
Chilean natural reserves and
national parks, which are dependant of the
CONAF (= Corporación Nacional Forestal) are a source of information.They
are fairly good instructed about the fauna in their areas. At this level there
still must be done more work on ahead. A stroke of luck was that the
airplain I took for a domestic flight during
my last stay in Chile choose its route
over Concepción to Santiago just
over the ridge of the Coastal Andes. So, I could have a short glance at the
small valleys draining in their short westward course to the Pacific. I was
somewhat concerned, how dry all was
looking and how widely the areas if even forested were artificially reforested
mainly with pine Pinus
radiata or eucalyptus Eucalyptus
globulus. But at least I saw some smaller gallery foerests along the
streams, which presumably are composed of native trees, and in which there may
exist some probability to find some live rhinoderms. It was striking how
impassable the western slope of the coastal range looked.
It seems hard to reach and, if at all, only with a good (...Geländefahrzeug....). Search in the
Field
As the fourth and most
important action level all the possible vouchers of litterature and collection
records should be visited from
North to South. This shold take
place during October and November, the presumable main activitiy season of
rhinoderms. Also the little streams of the small fluvial systems mentioned will
be included. The same for the natural reserves of
CONAF. In at least one of them there were put under protection rare
species of southern beeches like the „ruil“
(Nothofagus alessandrii), which had
been thought to be extinct , but fortunatedly there were found some relict
stocks. For R. darwinii in
the field it had prooved to to go in search either
by sight as well as akoustically. This procedure should also be applied
to R.
rufum. We plan to provoque the frogs to respond by playing back their calls.
The coordinates of searching places
and finding places should be recorded by GPS and registered. The Chilean Ministery of Acriculture gave me a permitssion to export six
individuals of each species. I could proceed accordingly only for
R. darwinii. The frogs were
brouht to Bonn and joined to our breeding population in order to prevent
possible inbreeding disadventages. If we find R.
rufum we will act very carefully. Anyway we give the first prioryty to the
protection of the natural habitat of an endangered species, and a second one to
the effort to beed it in captivity. On the other hand a better knowlewdge of the
breeding biology of this species in
a mediate way can be of great
importance also for its protection. This reason justifies to take some
individuals from the wild in order to breed them in terraria. Call for Donnations and
Financial Support
The Chilean Ministery of Agriculture, Section Renewable Natural Ressources,
showed much interest in the project
for which we thank Mr. Horacio Merlet and Mr. Agustín Iriarte. Also
Chilean zoologists as well as the Metropolitan Zoo
Santiago showed to be interested. They have assured their assistance.
Nevertheless the impassability of the landscape remains a problem. One will need
to rent or to buy a .... Geländewagen.... In some cases we probably will need
to use the logistics of the places of the forestal reserves, what means a tight
colaboration with CONAF. In Germany
the ZGAP (Gemeinnützige Zoologische Gesellschaft für Arten- und
Populationsschutz ) Zoological Society for Protecion of
Species and Populations) spontaneously
agreed to support the project. First they provided an account for financial
donations and furthermore they
promised to acompany the project with their help. Donations for the project
are......steuerlich absetzbar ....tax. For the performance of such an expedition and for its management a financial
effort is nessesary which cannot be
achieved by an individual initiative. Therefore REPTILIA adopted this
project and we ask you for
your help. The project has good chances of success, and additionaly it would be
a prtoof that terraria keepers are not simply consumers of animals, but most of
all they are active protectors of the fauna. Plese help us by means of your
donnation . Even a very small sum helps! Literature
Dr. Klaus
Busse, Zoologisches Forschungsinstitut und Museum Alexander Koenig;
Captions
1. Save the
Rhinoderms
Save the ............ 2. Extinct? Rhinoderma
rufum we can show only preserved specimens of the collection
of Museum Koenig in Bonn. 3.Comparison
of the plantar surface of Rhinoderma
darwinii (l) und Rhinoderma rufum
(r) (the
photograph should be turned upside down, then l and r
fit again) 4. Collecting
localities of Rhinoderma,
predominantly from the literature: R.
.rufum after Philippi (1902), Barros (1918) and Formas (1979), of R.
darwinii especially after Cei (1962)
and Formas (1979) (also
tanslate the legend forming part of the picture) 5. Pair of Rhinoderma darwinii in amplexus 6. Portrait of
a Darwin's frog Rhinoderma darwinii 7. Male Rhinoderma
darwinii with a tadpole
precocially removed from the vocal pouch 8. Preserved
Rhinoderma darwinii. Obviously
it cannot be a Rhinoderma rufum,
because tadpoles in such an advanced developmental stage in this species already
have abandoned the vocal pouch
9. Colour
phase of Rhinoderma
darwinii, occasionally they can change their colour completely whithin some
months. 10. Such
picrtures like this of Rhinoderma darwinii,
approaching his haching tadpoles to take them up do not exist for
Rhinoderma rufum because
observations are still lacking 11. Spawning
biotope of Rhinoderma darwinii on an enclearing of the forest. 12. Egg cluch
of Rhinoderma darwinii in an advancend
stage of embryonic development a few days before haching 13. Viev from
the suburb Angelmó to the port of Puerto Monrtt: in the middle background one
can see the a hill of wood tansformed into chips waiting to be exported for .....Pressspan....... Zusäzliche
Bilder von Heiko Werning 22. 05. 02 angefordert:
Für
Editorial-Artikel von Heiko Werning A)
Blick vom Vorort Angelmó auf den Hafen von Puerto Montt: Im Hintergrund wartet
die Halde von geschreddertem Holz auf ihren Export zur Herstellung von
Pressspan. Für
Nasenfrosch-Artikel von Klaus Busse B)
Ablaichbiotop von Rhinoderma darwinii in
einer Waldlichtung. C
und D) Weitere Farbphasen von Rhinoderma
darwinii Einzelne Tiere färben sich gelegentlich im Verlaufe von Monaten
total um. E)
Der Kehlsack des Männchens wird nicht
nur als Bruttasche verwendet, sondern spielt beim Balzruf durchaus noch eine
Rolle in seiner ursprüngliche Funktion als Schallblase. F)
Das Klammern führt bei Rhinoderma
darwinii nur dann zur Eiablage, wenn es innerhalb des Versteckes geschieht.
Hier dient es der Einspielung des Paares. G)
Frisches Gelege von Rhinoderma darwinii H)
Gelege von Rhinoderma darwinii in fortgeschrittenem Entwicklungszustand nur
wenige Tage vor der Aufnahme durch das Männchen. I)
Männchen von Rhinoderma
darwinii
mit vorzeitig aus dem Kehlsack geholter Kaulquappe.
REPTILIA-Projekt
zur Rettung der Nasenfrösche - das muss passieren Durch die
Zerstörung der chilenischen Urwälder sind viele Tier- und Pflanzenarten von
der Ausrottung bedroht. Besonders hart hat es die Nasenfrösche (Rhinoderma)
getroffen, eine Froschgattung aus zwei Arten mit einer einzigartigen und
spektakulären Fortpflanzungsbiologie: Die Männchen dieser hübschen Frösche
nehmen den Laich in ihren Kehlsack auf, wo die Kaulquappen sich entwickeln! Während
die südliche Art Rhinoderma darwinii als
von der Ausrottung bedroht gilt, jedoch noch von mehreren Fundorten bekannt ist,
wurde R. rufum, dessen Verbreitungsgebiet im land- und
forstwirtschaftlich intensiv genutzten zentralchilenischen Kernland liegt, seit
vielen Jahren nicht mehr gesehen und
gilt in Chile bereits als ausgerottet. Eine gezielte Nachsuche ist bisher aber
noch nicht erfolgt. Sie ist dringend erforderlich, um möglicherweise doch noch
Restpopulationen dieser bezaubernden Fröschchen zu finden und für ihre
sofortige Unterschutzstellung zu sorgen, ehe auch diese Amphibien-Art für immer
verloren ist! Der deutsch-chilenische Zoologe Dr. Klaus Busse vom Museum Koenig
in Bonn wird das Projekt betreuen und durchführen. Seine zahlreichen Kontakte
nach Chile ermöglichen die intensive Zusammenarbeit mit Wissenschaftlern, Behörden
und Naturschützern vor Ort. Busse beschäftigt sich zudem seit jeher mit
chilenischen Fröschen und besonders intensiv mit Rhinoderma
darwinii, über dessen Fortpflanzungsbiologie er ausführlich geforscht hat
und dessen Terrarienhaltung und -vermehrung ihm seit 15 Jahren in vielen
Generationen gelingt. Unterstützt wird er bei diesem Projekt vom
Naturschutzkampagnen- und Chile-erfahrenen REPTILIA-Redakteur Heiko Werning. Wir werden in
mehreren Stufen vorgehen: 1.
Hintergrundrecherche:
Dr. Busse hat bereits alle Informationen zu den Nasenfröschen aus der Literatur
zusammengetragen. Begleitend durchsuchte
er verschiedene zoologische Sammlungen auf Nasenfrösche und die Fundorte der
dort konservierten Tiere . Diese Arbeit wird in Deutschland bereits weiter
fortgesetzt und soll später auch in Chile fortgeführt werden. Auf diese Weise
wird ein möglichst vollständiges Bild über die ehemalige Verbreitung beider
Nasenfrosch-Arten und ihre Biologie gewonnen. 2.
Expedition in Chile: Evtl.
schon 2002, sonst 2003 soll im chilenischen Frühjahr (Oktober/November) eine
Expedition in das Verbreitungsgebiet der Nasenfrösche durchgeführt werden. Dr.
Busse wird hierfür vom Museum Koenig freigestellt. Die benötigten Gelder
(Reisekosten, geländegängiges Fahrzeug, Unterkunft) müssen vom Projekt
aufgebracht werden. Während dieser Expedition sollen potenzielle Vorkommen von R.
rufum aufgesucht werden, um diese Art nach Möglichkeit wiederzufinden.
Zudem sollen auch Vorkommen der ebenfalls gefährdeten Art R. darwinii erfasst und
untersucht werden. Bei Erfolg sollen einige Exemplare für Zuchtprogramme
entnommen werden. 3.
Bemühungen zur Unterschutzstellung der Habitate: Sollte
die Wiederentdeckung von R. rufum glücken,
soll nach Kräften die Unterschutzstellung der Vorkommen in Chile
angestrebt werden. Die kooperative Haltung der chilenischen Behörden lässt
hier auf Erfolg hoffen, behördliche Genehmigungen zur Naturentnahme stehen in
Aussicht. Mit dem wiederentdeckten Halbschwimmer-Nasenfrosch als
„Flaggschiff-Art“ sollte es auch möglich sein, Natur- und
Artenschutzorganisationen dafür zu gewinnen. 4.
Zuchtprogramme: Als
flankierende Maßnahme sollen zur Aufklärung biologischer Fragen und als
potenzielle Erhaltungszucht Zuchtprogramme in Chile und Europa eingerichtet bzw.
fortgeführt werden. Dr. Busse vermehrt R.
darwinii am Museum Koenig in Bonn sehr erfolgreich seit 15 Jahren. Dank
seiner umfassenden Erfahrung können wir davon ausgehen, dass auch die
Vermehrung von R. rufum unter Terrarienbedingungen gelingen wird, würde diese Art
wiederentdeckt. Gleichzeitig soll zunächst R.
darwinii, dessen Haltungsansprüche ja bereits geklärt sind, an ausgewählte
Zoos, die sich an dem Schutzprojekt beteiligen, weitergegeben werden. Wenn das
Zuchtprogramm für R. rufum erfolgreich
verläuft, soll auch diese Art auf Zoos in Chile und Europa ausgedehnt werden. 5.
Öffentlichkeitsarbeit: Obwohl
kaum im öffentlichen Bewusstsein präsent, ist Chile ein nicht-tropisches Land
mit einer ungeheuren Biodiversität, das mit erheblichen Umweltproblemen zu kämpfen
hat. Insbesondere die Lebensraumzerstörung durch Abholzen der Urwälder der gemäßigten
Breiten, aber auch die Landwirtschaft und die Umweltverschmutzung gefährden
viele Tier- und Pflanzenarten, unter ihnen die Nasenfrösche. Mit dem Projekt
soll - auch durch die Einbeziehung der Zoos - ein größeres öffentliches
Bewusstsein für diese Problematik erzielt, Aufklärungsarbeit geleistet und in
der Folge hoffentlich weiteres Geld für Schutzprogramme zur Verfügung gestellt
werden. Die REPTILIA wird alle Phasen des Projekts publizistisch begleiten.
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