Category Archives: gigantism

THE RACE: As the (Flat)worm Turns

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Dr. Tom Daniel, senior botanist, demonstrating impressive intrepidity in a Sao Tome river. GG VII A.  Stanbridge phot.

In the earliest blogs we discussed how islands are ideal for studying certain evolutionary processes and patterns; some of these phenomena like gigantism and dwarfism (below) are actually characteristic of islands. And, the results of these processes are much easier to see on islands because of their smaller size (versus, say, continents) and the smaller size of the plant and animal populations that inhabit them.

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Worlds largest (left, Sao Tome) and smallest (right, Principe) Begonia. (RCD construct).

Invasive species are organisms that somehow become accidentally established in areas where they did not exist before; they can be hugely damaging to ecosystems especially on islands, that are made up of plant and animal species that have co-evolved in isolation over perhaps millions of years. In the absence of natural predators (checks and balances), invader populations can become numerous and spread rapidly, and this can have a devastating effect by exhausting the resources these species utilize in the local environment. Invasive animal species populations can burgeon hugely, and then frequently die off; by then, the damage is usually done.

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(Phot. Miko Nadel, GG VII)

A few years ago, we received a photo of a brightly colored worm-like creature on São Tomé (above), taken by one of our graduate students, Miko Nadel, a lichenologist from San Francisco State University. This striped creature turned out to be a terrestrial flatworm, a member of a primitive phylum of invertebrates called the platyhelminthes. Those of us lucky enough to study biology backwhen students were given actual organisms to observe rather than plastic models or video clips will remember “planarians,” aquatic flatworms (below) noted for their amazing ability to regenerate.

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Planarian (Dugesia) . Stock photo, Google photos.

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Flatworm regeneration. (Univ. Heidelberg photo.

Terrestrial flatworms, also known as geoplanids have no anatomical or physiological mechanisms for retaining water and are thus very much tied to moist environments. They are voracious predators upon other soil invertebrates such as earthworms, slugs and, most importantly for us, snails. Geoplanids secrete a mucus that begins to digest and dissolve their prey externally (below), and all geoplanid species known feed using an extendable digestive tube or pharynx.

new geoattackGeoplanid attacking a snail. (R. Lima, phots)

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As above, at Macambrara, Sao Tome. [Phot S. Mikulane]

Once aware of these, we began to notice more of them as did our ecologist colleague, Dr. Ricardo Lima, and we all became rather concerned. Why? Readers may recall that about half to 60% of all of the species of terrestrial mollusks (snails) of both São Tomé and Príncipe are endemic; i.e., they are found nowhere else in the world.

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[RCD construct-multiple photographers]

In fact, these snails have been isolated on the island and evolving for such a long period that scientists currently recognize six different genera and a unique snail family there! Given what we know about invasive species, if these geoplanids are indeed a new arrival then the unique snail fauna of the islands may well be in significant danger.

 

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Another geoplanid [phot. F. Azevedo]

In 2012, we sent the original specimen to Dr. Ronald Sluys of Naturalis Biodiversity Centre in Leiden, Holland, one of the few specialists on flatworms. In the meantime, Dr. Ricardo Lima (below) has been conducting ecological research on the São Tomé forests for several years and has been able to collect many more geoplanids and send them to Dr. Sluys.

When the GG IX team visited Dr. Lima at Monte Café, São Tomé last year, he showed us pictures of a number of very different looking morphs of flatworms that he had collected and sent to Dr. Sluys. Were these different species or just variations on one or two species (morphs)?

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Various geoplanids from Sao Tome [phots R. Lima, F. Azevedo, M. Nadel, R. Rocha]

Ron Sluys has been supervising a graduate student from the University of Kassel, Germany who is doing his MSc degree based on this material. His name is Matthias Neumann and as I write, he is on the island of São Tomé with Dr. Lima, studying the flat worms in situ and collecting more! We were able to fund his expedition with the Academy’s Gulf of Guinea Fund (see “Partners”, below).

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Matthias Neumann and partner in the bush on Sao Tome. [R. Lima phot]

Matthias’ preliminary work suggests that there are indeed a number of species of geoplanids on the island: at least five new, undescribed species of the genus Othelosoma, and another previously known species, Bipalium kewense. B. kewense is an extremely widespread species, presumably carried about in the roots of plants; evidently it preys on earthworms rather than snails.

So far, little is known of these strange creatures. Neumann says that at least two of the undescribed species of Othelosoma are snail predators but even so, the presence of a number of species on the island rather than one dominant, rapidly spreading one might be taken as somewhat reassuring. If there are a number of closely related members of the same flatworm genus, it is more likely that the common ancestor of these species arrived a long time ago, speciated, and thus co-evolved with the endemic snail fauna. If this is so, than we would expect an ecological predator/prey balance in this system. If the flatworm fauna is in fact a radiation from a given colonizer, then it would mirror the status of the earthworm fauna as we understand it (below). So far, we are uncertain whether geoplanids are present on Príncipe.

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We are in the planning stages for GG XI; see the next blog.

The Parting Shot:

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A local teacher assists us in a binoculars demonstration on Sao Tome, GG IX. Dr. Luis Mendes in background.  [phot. A. Stanbridge]

Partners:

The research expeditions and the primary school education program are supported by tax-deductable donations to the “California Academy of Sciences Gulf of Guinea Fund”* We are grateful for ongoing governmental support, especially to Arlindo de Ceita Carvalho, Director General, Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for their continuing authorization to collect and export specimens for study, and to Ned Seligman, Roberta dos Santos and Quintino Quade of STePUP of Sao Tome http://www.stepup.st/, our “home away from home”. GG VIII, IX , X and upcoming GG XI have been funded by a generous grant from The William K. Bowes Jr. Foundation, and substantial donations from Mrs. W.H.V.“D.A.” Brooke, Thomas B. Livermore, Rod C. M. Hall, Timothy M. Muller, Prof. and Mrs. Evan C. Evans, Mr. and Mrs. John L. Sullivan Jr., Clarence G. Donahue, Mr. and Mrs. John Sears, and a heartening number of “Coolies”, and members of the Docent Council of the California Academy of Sciences. Once again we are deeply grateful for the support of the Omali Lodge (São Tomé) and Roça Belo Monte (Príncipe) for both logistics and lodging and for partially sponsoring our education efforts for GG VII and GG VIII.

*California Academy of Sciences
55 Music Concourse Dr.
San Francisco, CA 94118
USA

 

 

THE RACE: Homage to “The Prince”

The island of Príncipe is ancient… at 31 million years of age it is twice as old as São Tomé, yet biologically the two islands are unquestionably related. Along with documenting and describing hitherto unknown species of strange, endemic plants and animals that inhabit one or the other island (rarely, both), we attempt to understand the relationships of these species to each other and to their ancestral populations from the African mainland.

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For instance among the striking Príncipe uniques is Leptopelis palmatus, the Príncipe giant tree frog (above). Females of this species attain dimensions such that they are largest tree frog in Africa! Males, first described by us, are usually less than half their length. The original specimen upon which the species description was based over a century ago was a single female of 110mm body length (excluding legs). Like all female frogs, they do not have an advertisement call and despite their great size, very few have been found and reported in the scientific literature.

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(male)

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(female)

A few days ago, Dr. Rayna Bell found the large female pictured above, pressed to the surface of a small flat rock on the ground on a steep, dryish slope in the northwestern part of the island. Females tend to be dark compared to males, but this is the first all-black specimen reported. There are three other tree frog species on the islands, but they are all closely related to each other and belong to a different frog family from the Príncipe giant.

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Dr Bell has shown that these other three are most closely related to a species from the Ogooué and Congo River basins and thus likely of western Central African origin. Other work has shown that the nearest relative of Leptopelis palmatus of Príncipe is from west of the Niger River and thus the giant is  probably of northern (West African) origin, perhaps dispersing from the Niger River drainage..

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Dr. Luis Mendes and Maria Jeronimo have continued to collect butterflies to fill in knowledge gaps with species for Luis’s book. Luis has collected a number of specimens that he cannot readily identify; on these poorly-known islands, this is particularly exciting.

Maria has actually been doing a lot of everything: collecting butterflies with Luis, joining us in the classrooms and going out at night collecting with Dr. Rayna Bell, Lauren Scheinberg and our photographer, Andrew Stanbridge. Considering that this is a “break” from her PhD dissertation work, her energy level is truly impressive.

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Most geckos are nocturnal but the genus Lygodactylus is comprised of strictly daytime species in Africa and Madagascar. Readers may recall that the islands of Annobon, São Tomé and Príncipe are each inhabited by a single endemic species usually distinguishable by different black markings under the chin; other than these markings, the island species are usually a combination of grey and black. Luis Mendes captured an adult male on Príncipe that appears to be in breeding coloration of a sort I have not seen before in this genus. There is one species endemic to a small forest in Tanzania that is a beautiful blue, several others in East Africa that have yellow heads, and one species in Zambia that has a yellow belly. The male collected on Principe has a bright yellow head and the body that is a striking shade of light green. Not only is this the first time I have observed a green individual, I am also unaware of any literature describing temporary (usually hormonal) color intensities associated with breeding activities in this group of lizards.

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Many of the photos we post on social media might well suggest that our work is being carried out in some sort of paradise; in some ways it is exactly that but is by no means easy!

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The work we do here is only possible with the support of local entities; this is especially true on Príncipe. On our first two expeditions years ago we had difficulty finding suitable accommodations (reliable power for our equipment, etc) and logistics; there were not many available vehicles on the island, and we had little access to the really interesting higher elevation areas of the island or more remote southern areas. Since that time, our efficiency has increased hugely due to the generous support of several organizations on the old island. First and foremost is the Office of the Regional President (Tose Cassandra-he is also head of the recently created Principe World Biosphere Reserve, and also Daniel Ramos, head of the Príncipe Obo Natural Park.

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For a number of years, we have been able to stay at Bom Bom Island resort which has also helped with needed transportation, both vehicular and marine. This year we were invited to stay at the new Roça Belo Monte (Africa’s Eden) who also provided transportation and assistance. At one point we planned a boat trip to explore the remote southeastern part of the island but the skipper, Bobby Bronkhorst, of Makaira Lodge fell ill.

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Our work is now also in cooperation with the newly formed Príncipe Trust; the Trust played a major supporting role in the production of this year’s biodiversity bird field guide/coloring book and binoculars! Our biodiversity education efforts were concluded for Gulf of Guinea IX here on the old island with our return to the 3rd grade classes of the same schools we have been visiting since 2011. Usually after class visits, we see 3rd graders out in the bush peering through their new binoculars but frequently backwards! This may well be more fun for them.

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Parting Shot:
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PARTNERS:
We are most grateful to Arlindo de Ceita Carvalho, Director General, Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for their continuing authorization to collect and export specimens for study, and to Ned Seligman, Roberta dos Santos and Quintino Quade of STePUP of Sao Tomehttp://www.stepup.st/, our “home away from home”.We gratefully acknowledge the support of the G. Lindsay Field Research Fund, Hagey Research Venture Fund of the California Academy of Sciences for largely funding our initial two expeditions (GG I, II). The Société de Conservation et Développement (SCD) and Africa’s Eden provided logistics, ground transportation and lodging (GG III-V), and special thanks for the generosity of private individuals who made the GG III-VII expeditions possible: George G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke, Mr. and Mrs. Michael Murakami, Hon. Richard C. Livermore, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. Robert M. Taylor, Velma and Michael Schnoll, and Sheila Farr Nielsen; GG VI supporters include Bom Bom Island and the Omali Lodge for logistics and lodging, The Herbst Foundation, The “Blackhawk Gang,” the Docent Council of the California Academy of Sciences in honor of Kathleen Lilienthal, Bernard S. Schulte, Corinne W. Abel, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. John Sears, John S. Livermore and Elton Welke. GG VIII was funded by a very generous grant from The William K. Bowes Jr. Foundation, and substantial donations from Mrs. W.H.V.“D.A.” Brooke, Thomas B. Livermore, Rod C. M. Hall, Timothy M. Muller, Prof. and Mrs. Evan C. Evans, Mr. and Mrs. John L. Sullivan Jr., Clarence G. Donahue, Mr. and Mrs. John Sears, and a heartening number of “Coolies”, “Blackhawk Gang” returnees and members of the Academy Docent Council. Once again we are deeply grateful for the support of the Omali Lodge (São Tomé) and Roça Belo Monte (Príncipe) for both logistics and lodging and for partially sponsoring part our education efforts for GG VII and GG VIII.

Our expeditions can be supported by tax-deductable donations to “California Academy of Sciences Gulf of Guinea Fund

THE RACE: GG IX – RETURN TO THE BIG ISLAND

The seven members of GG IX all met up in the Lisbon airport on September 18 and arrived the next day in São Tomé. Two new collegues on this expedition are from Portugal. Dr. Luis Mendes, a butterfly expert from the Natural History Museum in Lisbon is finishing a major book on the butterflies of the islands and is checking certain localities for species that have not been seen for many years.

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Maria Adelina Jeronimo, a PhD candidate from the Gulbenkian Institute in Portugal, also studies butterflies but specifically the genetics of certain novel morphological characters. Maria is a matter of months from finishing her doctoral dissertation.

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Dr. Rayna Bell has returned for her third trip and is continuing her studies of the interesting hybridization phenomenon that seems to be occurring between the two endemic São Tomé tree frog species, reported in a major publication earlier this year. She has also discovered that the little green tree frogs of Principe, while seemingly nearly identical to those of São Tomé, are in fact a separate species. This does not surprise us really; see earlier blogs on geckos and snakes!

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Rayna is being assisted by our third new member,  Lauren Scheinberg of the Herpetology Department of the California Academy of Sciences.

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Our brilliant (and very tall) photographer, Andrew Stanbridge, has joined us for the fifth time (also as co-leader).

The education team is, as usual, Roberta Ayers and myself, plus our long-time São Toméan colleagues, Roberta dos Santos, Anita Rodriguez and Quintino Quade Cabral. Maria Jeronimo has been assisting. A new cycle begins this year, starting again with third grade.

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There have been several interesting discoveries already. A couple of years ago we published a study of the giant geckos of the islands, describing a new species from Príncipe (Miller, et al, 2012). We suggested that the large endemic species of São Tomé, Hemidactylus greefi, was only found in natural settings, having been out-competed in the towns by common, widespread recent colonizers. During our first week the group found an adult Greef’s gecko at sea level on a door in Angolares, the second largest town on the big island. I suspect that if competition with widespread common immigrants accounts for the absence of this gecko in the capitol city, there must be fewer of the former in Angolares. This is understandable as Angolares is still quite small and is not by any means a port city; that has always been São Tomé city.

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As in every year, we went to the Olea tree at Macambrara (1100 m) to check on the known population of the giant São Tomé tree frog, Hyperolius thomensis. Long-time readers will recall that two holes in this enormous tree are the only place we have consistently found this colorful species. While we have conjectured that the giant tree frog must be widespread in the higher elevation forests (we can hear it call from far above in the canopy), we have been unable to find another locality or tree with appropriate breeding holes… until now!

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With our colleague, Dr. Ricardo Lima of University of Lisbon, we were able to gain access to the primary forest above the huge southern oil palm plantation of Agripalma. At 350 m, above an abandoned roça called Monte Carmo, Bell, Scheinberg, Lima and Stanbridge found large numbers of the giant São Tomé tree frog breeding in pockets of water on fallen logs. This southern-most locality indicates, as we suspected, that this flamboyant frog is widespread in the relatively undisturbed forest and that while not restricted to high elevation (Macambrara), it does indeed seem to breed in pockets of water such as tree holes, rather than standing water like its close relative.

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Here, there appears to be no hybridization as the two tree frog species are separated by oil palm rather than less biologically hostile agricultural fields or plots. In fact, so far as I know, hardly any endemic vertebrates or native plants are able to survive in oil palm.

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This area is also the last bastion of a remarkable endemic bird, the Dwarf ibis, the smallest species of ibis in the world; it is severely threatened, both by hunting and by habitat destruction (oil palm). Notably, there are now two charismatic endemic species, a bird and a frog, endangered by human activities on this remote and fascinating island.

So far, this year’s activities have included working in a number of new localities including the central massif and in the far south. High in the mountains above Roça Agua Izé, one of the larger of the coastal colonial cacao plantations, we got our first decent view of a Giant weaver, Ploceus grandis. One of many endemic island giants on São Tomé and Príncipe, this colorful weaver is the largest in the world.

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As always, our educational efforts are aimed at raising the children’s awareness of the unique aspects of the island flora and fauna. We do not preach conservation per se. but rather try to show the young students how special their islands are and thus how special they are as owners.

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This year, each third-grader gets our coloring book about endemic bird species on both islands, a box of colored pencils and a pair of plastic binoculars (which work!!) These are not just handed out…. we present them personally to each student in each classroom, along with enthusiastic instructions for use, and the reasons  we come each year; we involve the students, the teachers, even school principals, and it is great fun. At the end, 10 of our stick-on logo patches are given to the teacher to reward good work. Each of us is involved at one time or another, as voices begin to suffer after 3 or 4 classroom visits.

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At this point, I must mention some wonderful folks who have been vital to the education effort this year: Alice and Wayne Settle conceived of and sponsored the acquisition of the small binoculars; Jim Boyer of the California Academy of Science once again produced a booklet that qualifies as a work of art, and help with producing the bird books is coming from the Príncipe Trust.

In the next blog, I will report on our progress on the smaller geologically ancient island of Príncipe.

Meantime, here’s the parting shot:

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All photos by Andrew Stanbridge

 

 PARTNERS:
We are most grateful to Arlindo de Ceita Carvalho, Director General, Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for their continuing authorization to collect and export specimens for study, and to Ned Seligman, Roberta dos Santos and Quintino Quade of STePUP of Sao Tomehttp://www.stepup.st/, our “home away from home”.We gratefully acknowledge the support of the G. Lindsay Field Research Fund, Hagey Research Venture Fund of the California Academy of Sciences for largely funding our initial two expeditions (GG I, II). The Société de Conservation et Développement (SCD) and Africa’s Eden provided logistics, ground transportation and lodging (GG III-V), and special thanks for the generosity of private individuals who made the GG III-VII expeditions possible: George G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke, Mr. and Mrs. Michael Murakami, Hon. Richard C. Livermore, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. Robert M. Taylor, Velma and Michael Schnoll, and Sheila Farr Nielsen; GG VI supporters include Bom Bom Island and the Omali Lodge for logistics and lodging, The Herbst Foundation, The “Blackhawk Gang,” the Docent Council of the California Academy of Sciences in honor of Kathleen Lilienthal, Bernard S. Schulte, Corinne W. Abel, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. John Sears, John S. Livermore and Elton Welke. GG VIII was funded by a very generous grant from The William K. Bowes Jr. Foundation, and substantial donations from Mrs. W.H.V.“D.A.” Brooke, Thomas B. Livermore, Rod C. M. Hall, Timothy M. Muller, Prof. and Mrs. Evan C. Evans, Mr. and Mrs. John L. Sullivan Jr., Clarence G. Donahue, Mr. and Mrs. John Sears, and a heartening number of “Coolies”, “Blackhawk Gang” returnees and members of the Academy Docent Council. Once again we are deeply grateful for the support of the Omali Lodge (São Tomé) and Roça Belo Monte (Príncipe) for both logistics and lodging and for partially sponsoring part our education efforts for GG VII and GG VIII.

Our expeditions can be supported by tax-deductable donations to “California Academy of Sciences Gulf of Guinea Fund

The Race: The Blog Returns with a Science Update

“The Race” has been silent for a while; a sabbatical accompanied by computer glitches at both sites (Wildlifedirect.org; calacademy.org) led to it, but this was not meant to signal a pause in our island work by any means! We will be returning to the islands for two more expeditions later this year.

During the past nine months or so, some important scientific papers have been published by expedition members; these continue to illustrate the unique nature of the island fauna and flora.

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Ricka Stoelting (D. Lin phot, GGI)

Ricka Stoelting was on the islands for a solid two months during GG I in 2001. The research she did on the unique Sâo Tomé caecilian was the basis for her MSc degree, and this has just been published; this paper is the first on the population genetics of a caecilian species,  and she has shed light on a number of issues involving this strange Sâo Tomé endemic.

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(left) Cobra bobo, Schistometopum thomense (A. Stanbridge phot. GG VII); (right) from Stoelting, et al., 2014, PLoS One.

Ricka discovered that there are four distinct populations of the cobra bobo that are genetically different from each other – not different enough to be considered separate species, but different enough to suggest that these populations were isolated from each other in the distant past (recall that evolution is genetic change accumulated in isolation over time). She also found that these different populations were probably separated from each other through major geological changes in the environment. Note (above right) that the western populations (green) and northern populations (red) are associated with volcanic landscapes less than 1 million years old, while the southern populations (blue) are associated with older volcanic soils of about 2.5 million years in age. This suggests that the formerly widespread caecilian species was wiped out to the north by volcanism about 1 million years ago, then later repopulated from the surviving southern population. The yellow population is very young, perhaps only about 36 thousand years. Currently Ricka is pursuing a PhD at the University of Wisconsin.

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Dr. Ricardo Lima with caecilian, Schistometopum thomense. (R. Ayres phot. GG. IV)

While on the subject of the endemic Sâo Tomé caecilian, I can report that our colleague, Dr. Ricardo Lima (above), just found three  caecilians while climbing the Pico de Sâo Tomé, and one of these establishes an altitude record for this strange worm-like amphibian species at 1504 meters (4,600+ feet).

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Dr. Rayna Bell on Sao Tome.  (A. Stanbridge phot, GG VI)

Last September, Rayna Bell, a participant on both GG VI and GG VII expeditions, completed her PhD degree at Cornell University; her doctorate was based on her work on the Hyperolius tree frogs of the islands, and the first part of it has just been published.

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(left) after Bell, R.C. et al. 2014. Journal of Biogeography. (right). Nearest mainland relative of island Hyperolius tree frogs. (RDC phot)

We knew from earlier work that the two tree frogs of Sâo Tomé were each other’s nearest relatives.  But where did they come from originally?  Dr. Bell’s research indicates that the nearest relative of both the endemic oceanic treefrog and the Sâo Tomé Giant treefrog is a member of a large group of species in West Africa, Hyperolius cinnamomeoventris (above right); in particular, a subset of this group she terms “clade A,” (indicated by green stars above left) appears to share joint ancestry with the island species.

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Hypothesized large “riverbank” raft.  (artwork by R.E.Cook)

Her research suggests that the common ancestor of the island treefrogs reached Sâo Tomé first, in a single colonization event, probably by rafting (above). This event likely occurred between 9 and 3.5 million years ago, and the original colonists probably originated from the Ogooué or Congo Rivers. On Sâo Tomé, these original “pioneers” differentiated into a giant highland form (now H. thomensis) and a smaller lowland species. Then, between 1.1 million and 270 thousand years ago, members of the lower elevation species, the oceanic treefrog, Hyperolius molleri dispersed to the much older island of Príncipe, where they again became isolated from the parent population on Sâo Tomé and began to accumulate genetic change (“speciation”). A second scientific paper by Dr. Bell on these species and their evolution on the Gulf of Guinea Islands is due out soon.

The status of the Sâo Tomé shrew (Crocidura thomensis) has been somewhat problematic, for scientists at least. Shrews are very poor overwater dispersers, and since it is possible for the shrew to have been transported from the mainland by man fairly recently, there have been questions about its validity as a true endemic species. Did it reach Sâo Tomé by natural means?  This strange insectivore was recorded only nine times after its original description in 1887 and until recently, it has also been considered quite rare. (Someone should have asked the locals!)

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The Sâo Tomé  shrew (phot. Dr. Mariana Carvalho).  (left) Dr. Ricardo F. de Lima.

In a recent publication, (below) our colleague, Dr. Ricardo Lima has added twenty-three new locality records for this fascinating creature, indicating that it is not rare. It has just been overlooked. An excellent ecologist, de Lima has assessed the conservation status of this important species.  Moreover, he and his colleagues have provided tissue so that we have been able to examine its DNA to determine whether or not it arrived on the island by natural means or was more recently brought by man. It appears to be a true endemic species (to be reported in a future publication), and as such it is the only non-flying endemic mammal species on the island of Sâo Tomé.

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From de Lima, R.F., et al]. 2015 Fauna & Flora International. Oryx. Grey dots denote localities known in 1996. Black dots are new localities.

During GG II (2006), we collected two shrew new-borns on the island of Príncipe which at the time we assumed were a mainland species, Crocidura poensis. Dr. Luis Ceriaco, who is now an adjunct member of our CAS faculty, subsequently obtained many more adult individuals on the island (it is much more common than C. thomensis) and surprisingly this species is also new and endemic.

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From Ceriaco, et al. 2015. Mammalia

Dr. Ceriaco has just formally described it as Crocidura fingui, its name in the local Creole. So the only non-flying endemic mammals in the Republic of Sâo Tomé and Príncipe are shrews! I do not think any biogeographer would have predicted this (see August 2010 blog: the “Magic of Molecules).

Here’s the parting shot:

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Rotula deciesdigitatus, one of the rarest sand dollars in the world; in the islands, known principally from Praia Morrao, west coast of Sao Tome. (Weckerphoto, GG III)
PARTNERS

We are most grateful to Arlindo de Ceita Carvalho, Director General, Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for their continuing authorization to collect and export specimens for study, and to Ned Seligman, Roberta dos Santos and Quintino Quade of STePUP of Sao Tomehttp://www.stepup.st/, our “home away from home”. We gratefully acknowledge the support of the G. Lindsay Field Research Fund, Hagey Research Venture Fund of the California Academy of Sciences for largely funding our initial two expeditions (GG I, II). The Société de Conservation et Développement (SCD) and Africa’s Eden provided logistics, ground transportation and lodging (GG III-V), and special thanks for the generosity of private individuals who made the GG III-VII expeditions possible: George G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke, Mr. and Mrs. Michael Murakami, Hon. Richard C. Livermore, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. Robert M. Taylor, Velma and Michael Schnoll, and Sheila Farr Nielsen; GG VI supporters include Bom Bom Island and the Omali Lodge for logistics and lodging, The Herbst Foundation, The “Blackhawk Gang,” the Docent Council of the California Academy of Sciences in honor of Kathleen Lilienthal, Bernard S. Schulte, Corinne W. Abel, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. John Sears, John S. Livermore and Elton Welke. GG VIII was funded by a very generous grant from The William K. Bowes Jr. Foundation, and substantial donations from Mrs. W.H.V.“D.A.” Brooke, Thomas B. Livermore, Rod C. M. Hall, Timothy M. Muller, Prof. and Mrs. Evan C. Evans, Mr. and Mrs. John L. Sullivan Jr., Clarence G. Donahue, Mr. and Mrs. John Sears, and a heartening number of “Coolies”, “Blackhawk Gang” returnees and members of the Academy Docent Council. Once again we are deeply grateful for the support of the Omali Lodge (São Tomé) and Bom Bom Island (Príncipe) for both logistics and lodging and for partially sponsoring part our education efforts for GG VII and GG VIII.

Our expeditions can be supported by tax-deductable donations to “California Academy of Sciences Gulf of Guinea Fund”

The Race: On Rocket Frogs and Millipedes

First, some great news on the academic front.  One of the graduate student participants on GGI back in 2001 just completed his PhD at the University of California, Berkeley. Meet Dr. Joel Ledford, newly-minted world authority on spiders and explorer of Gulf of Guinea biodiversity.  In the picture below, he is holding “bubba,” one of the three endemic tarantula species of São Tomé.

DR. Joel Ledford with Hysterocrates apostolicus.   D. Lin phot. GGI

Readers of this blog already know that when we talk about biodiversity, we are talking about everything living, not just the big fancy stuff like birds and giant begonias.  Many of the secrets of island evolution are to be unlocked through the study of small organisms.   I have just received some preliminary news from Dr. Didier Van den Speigel of the Royal Central African Museum in Belgium.  After Dr. Rowland Shelley of the North Carolina State Museum did a preliminary analysis of our GG IV millipede specimens, we sent them to Didier, a specialist on this group in the Old World.  Rowland had concluded that we had at least one new species of the genus Globanus from each island.

A millipede (not Globanus) phot.  from cephalopodiatrist.com

Didier has examined material from other museums and has concluded that, in fact, the genus Globanus itself is endemic, found nowhere else in the world but the islands of São Tomé and Príncipe.  We are still unsure of how many species our GG IV material represents, but what seems evident at this time is that they are all each other’s closest relatives.  Drs Van den Speigel and Shelley are in agreement that this turns out to be the case, it would represent a “species swarm,” much like the endemic earthworms of São Tomé (see July 2010 blog “Nightmares….”, for an explanation).  The work continues……

In my memorial to Abade last month, I described one of our early unsuccessful  searches for Newton’s rocket frog during GG I.

Newton’s rocket frog, Ptychadena newtoni.  D. Lin phot.  GGI

This widely distributed genus of about 50 species is found throughout sub-Saharan Africa and distinguished by a sharp snout, paired vocal sacs (lower arrow),  distinctive glandular ridges on the back (upper arrow) and very long legs.  In fact a member of this group from South Africa holds the world record frog jump of over 33 feet (10m)!  P. newtoni is one of São Tomé’s classic “island giants; at 76 mm (not including legs) a  São Tomé female is much larger than any specimens of mainland species on record.

After days of visiting known localities mostly in and near the town of São Tomé and finding them dry, heavily disturbed and frogless, one rainy evening two young boys led us to a vacant lot less than 200m from where we were living, and there were the frogs!   Ultimately, genetic analysis of these frogs established that they were, indeed, full endemic species, but also led John Measey, currently of South Africa, and a group of us to publish our rafting hypothesis in the Journal of Biogeography (2007 – see earlier blogs).

Our difficulty in finding this species in the northern lowlands of São Tomé (all of the known localities at the time) suggested to me that this may be the only endemic amphibian species on São Tomé that might be endangered due to human development.

Series of Ptychadena newtoni larvae from Java, Sao Tome.  RCD phot. GG II

However, during GG II we found a series of tadpoles at Java (elevation 595m) which we later determined belonged to this species (although no adults were seen).  Tadpoles are typically identified by various external characteristics, but especially by fine structures of the mouthparts. The drawings below are taken from a nearly completed manuscript that attempts to technically describe the tadpoles (larvae) of all the endemic island frog species; it has not been published because, even after all these years, we have still not found the larvae of the Príncipe giant treefrog, Leptopelis palmatus!

P. newtoni mouthparts from unpublished manuscript.

P. newtoni left lateral view from unpublished manuscript.

Our discovery of the Java larvae indicated that Newton’s rocket frog is not necessarily present only in the heavily developed northern lowlands.

Recently, a young biologist, Hugulay Maia, whom we first met during GG IV has found some new P. newtoni localities.

Hugulay Maia of ABS, doing tree work.  unknown photographer]

Hugulay is a member of Associação dos Biologos (ABS), a local group of biologists involved in biodiversity efforts on São Tomé. The group is led by Dr. Alzira Rodrigues of the Polytechnic Institute; other members you have met in this blog are Angus Gascoigne and Victor Bomfim.

Current P. newtoni localities: green = to 1992; pink = to date

Now, thanks to Hugulay’s observations (and photographs) we have a somewhat better idea of the distribution of Newton’s rocket frog.  Earlier known localities are in green and were published by a Swiss worker in 1992; our GG II Java locality and Hugulay’s new localities are in pink.  Hugulay’s data confirm that the species is not confined to the north.  He has observed it at Colonia Açoreana (labeled) and two more southerly spots, Angra Toldo Cavaleite and Roça Alinhança.

The data are still thin, but we can at least infer that Ptychadena newtoni is more widespread than originally thought.  Almost all of the mainland species breed in relatively still or slow-moving water, and it is reasonable to assume this is the case with Newton’s rocket frog.  All of the old localities (in green) are associated with lowland reaches of major water courses: the city localities are in the Agua Grande drainage; Hugulay Maia’s new records are all from the Ribeira Afonsa drainage, and the Diogo Vaz locality (green symbol in the NW) is from the small Agua Anambo, which parallels the larger, much faster Rio Maria Luiza to south.  Java our highest locality is on the Rio Abade, but the tadpoles were collected in a man-made pool in a roadside, partially dry creek bed, not in the river itself.   To assess the actual status of Newton’s rocket frog, I think we just need to look more closely in bodies of slow or still water along major rivers throughout the island.

The Parting Shot:

Dr. Joel Ledford: Spider hunters in repose. D. Lin phot.   GG I

PARTNERS

We gratefully acknowledge the support of the G. Lindsay Field Research Fund, Hagey Research Venture Fund of the California Academy of Sciences, the Société de Conservation et Développement (SCD) and Africa’s Eden for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, Salvador Sousa Pontes and Danilo Barbero of the Ministry of Environment, Republic of São Tomé and Príncipe for permission to export specimens for study, the continued support of Bastien Loloum of Zuntabawe  and Faustino Oliviera, Curator of the Herbarium at Bom Sucesso. Special thanks for the generosity of private individuals, George G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke, Mr. and Mrs. Michael Murakami, Hon. Richard C. Livermore, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. Robert M. Taylor, Velma and Michael Schnoll, and Sheila Farr Nielsen for helping make these expeditions possible.  Our expeditions can be supported by donations to “California Academy of Sciences Gulf of Guinea Fund”.

The Race: Within the House of Slytherin (I. Lizards)

Our race to discover and describe the unique fauna and flora of São Tomé and Príncipe continues, and the six members of Gulf of Guinea Expedition III (B) are diving in the ancient waters of Príncipe as I write; they return to the Academy next week.  As I wrote earlier, Marta is sampling the sea slug fauna (nudibranchs), Gary, Bob and Dana are looking at coral and barnacles, having found a new species of the latter in waters off São Tomé during GG II, and John and David are looking at small marine fish, with emphasis on eels.  The group has an added goal, and that is to bring back some freshwater prawns (Macrobrachium) that abound in the São Tomé rivers. These specimens are for a young high school student named Alex Kim.

  

 A freshwater Macrobrachium prawn from Guinea (www.)

Alex is a senior at Thomas Jefferson High School of Science and Technology in Virginia.  He is doing an ambitious biogeography project on these prawns, relatives of which are found on both sides of the Atlantic.  Alex contacted me through this blog—you can read his comments at the end the November posting.  During a brief visit to DC over the holidays, I brought some preserved specimens we collected in GG I and GG II which I handed over to one of his advisors, Dr. Patrick Gillevet of George Mason University, and now the GG III (B) group plans to bring him some fresh material for DNA studies.  This is really fun academic stuff, and we are delighted to have the involvement of a young colleague.

 

 A Macrobrachium prawn from Cameroon. (www) 

Except for documenting our exciting hunt for Príncipe Jita, (see first May posting), I have not written that much about the endemic reptiles of these islands; in fact, there are quite a few of them, some rather spectacular.  While reptiles, especially geckos and skinks, are much better dispersers over saltwater than amphibians, snakes are not particularly good at it; moreover, like the amphibian caecilian, cobra bobo, a number of these endemics are legless species.  There are also some island species that may be endemic, but we are not sure…. we just haven’t studied them closely enough yet. In this posting I will show you the unique lizard species.  One readily identifiable endemic species is Greeff’s gecko, or the Giant gecko, Hemidactylus greeffii.  

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Greeff’s Gecko, Hemidactylus greeffii . A Sao Tome specimen. RCD phot. GG I   

Greeff’s gecko is an island giant; it is evidently much larger than other African member of the genus (and there are over 55 African taxa of Hemidactylus with likely many more to be discovered). Our longest specimen is over 200 mm in total length (including original tail); but longer specimens are known.  This gecko is not only very large it also differs from all of its African relatives in lacking a claw on the first (inner) finger and first toe. Somehow, this feature has been lost during the thousands, perhaps millions of years of isolation on the Gulf of Guinea Islands. Greeff’s gecko also has greenish eyes, which also distinguishes it from other nocturnal geckos on the island which, so far as we know, are not endemics.

 

 H. greeffii.  Note absence of claw on first thumb. ST specimen. RCD phot. GGI

 

H. greeffii with  greenish eyes.  ST specimen. D. Lin phot. GG II.

Greeff’s gecko occurs on both São Tomé and Príncipe; at least we think it does. Here’s what I mean: specimens from both islands look very much the same but a couple of years ago, a group of researchers from the University of Madeira and Portugal looked at the DNA of specimens from both islands and found that data from mitochondrial DNA suggested the two populations were very different, and that they may well be two distinct species in spite of their apparent anatomical similarity. These results were not confirmed by study of nuclear DNA however, so scientifically the “jury” is still out, and we call both island forms, Greeff’s gecko. This critter is quite common in rock walls, culverts, rock crevices on both islands and is strictly nocturnal. 

 

Principe specimen of Greeff’s gecko. D. Lin phot. GG II.  

A similar situation exists with a small terrestrial skink called Panaspis africana, or Gulf Leaf-litter skink. A daytime forager, this small uniform-brown skink is very common in the lowlands; it can be easily heard and seen scuttling through dried cacao leaves and it is almost always found on the ground on both islands; one of our largest gravid (with eggs) female specimens from São Tomé is about 100 mm in total length, but most of our examples are smaller.  

Gulf Leaf-litter skink. Panaspis africana; D. Lin phot. GG II. 

The same group of researchers from the University of Madeira studied the DNA of leaf litter skinks of both islands, and also Annobón, the last island in the chain and part of Equatorial Guinea.  They used, in part, tissues and specimens collected by us during GG I in 2001.  In this case they found clear evidence for three separate species, one on each island (the one on Annobón is already called P. annobonensis); this was supported by both mitochondrial and nuclear DNA sequence.  However, in one of those tragic, fortunately rare, occurrences in science, the specimens from which the tissue samples were taken were either lost in transit or misplaced.  Without voucher samples the results cannot be duplicated or tested nor can we demonstrate the results.  So for now, although there was evidence that Panaspis is two different species on São Tomé and Príncipe we cannot confidently describe the populations of the different islands nor give them scientific names.  Until the study can be redone with new material, the Gulf leaf-litter skinks remain known as simply Panaspis africana

Author working on Principe.  Weckerphoto. GGIII  

The way we collect these specimens is not sophisticated – we use our hands. We turn over logs, rocks and branches on the ground or sift through leaf litter with rakes; we climb trees and cliffs; we go out at night with flashlights and headlamps. After capture, the specimens are put in separate plastic bags for later processing.  

 

Dr. Iwamoto in Sao Tome H. greeffii habitat on Sao Tome. RCD phot. GG I 

Jens Vindum searching leaf litter on Sao Tome. D. Lin phot. GG II 

 

Principe day gecko in plasic bag. RDC phot. GG III.

Every specimen we collect gets a unique field number, which is the same used for photographs of it, recordings or tissues samples taken. 

 

My grad student, Ricka Stoelting,  processing specimens on Principe. RCD phot. GG I 

Certainly one of the oddest endemic lizards is the legless skink, unique to Príncipe Island, Feylinia polylepis.  There are about six species known in this genus, the remaining five found broadly distributed on the African mainland.   

 

Principe legless skink, Feylinia polylepis. brown  phase. D. Lin phot. GG I. 

 They appear in two different color morphs, a brown one and a pale gray one, regardless of size or sex.  The locals call them, Ozhgah (or at least the name  sounds like that). 

 

Principe legless skin – grey phase.  D. Lin  phot. GG II 

 

Feylinia polylepis head shot. D. Lin phot. GG II 

They can be found under almost anything on the ground provided the earth is slightly moist. Once exposed, they are very quick and can rapidly disappear into holes in the ground. They are conspicuously common in the Príncipe lowlands, and in this regard are reminiscent of the caecilians of São Tomé Island; the high density of their numbers in suitable habitats suggests predation may be low in these areas. 

Not all geckos are nocturnal.  In the Old World there are two large groups that are secondarily diurnal, although they, like all geckos, lack eyelids.  The genus Phelsuma is a group of numerous species of velvety green geckos found on Madagascar and the Indian Ocean islands; the other group, Lygodactylus are also present in Madagascar but also distributed throughout the Afrotropical region as well.  They are not brightly colored, and taxonomically rather poorly known.  The group as a whole is being studied by Dr. David Vieites (and his students) of Madrid and Dr. Adam Leache, of the University of Washington.  I have been involved as well but largely in studying the relationships of day geckos of the Gulf of Guinea Islands.  

 Lygodactylus thomensis. Sao Tome.  D. Lin  phot. GGI 

The Gulf of Guinea Day geckos are sun-lovers and strictly climbers, being fairly common on tree trunks and scuttling up walls even in São Tomé town and Santo Antonio, Príncipe.  They are very small, at about 70-80 mm total length.  The day geckos of the Gulf of Guinea islands (excluding the continental island of Bioko) have long been recognized as a distinct, endemic species, Lygodactylus thomensis, first discovered on São Tomé Island.  The day geckos on Príncipe and Annobón have been described as subspecies (or races, if you will) of the São Tomé species..  As you can see from the illustration below, one of the characteristics used to define species of day geckos is the throat pattern. 

 

 Day geckos of the Gulf of Guinea Islands.  RCD prep.

The throat patterns of the lizards on each of the three islands are quite consistently distinct from one another, and work by us and the University of Madeira suggest that they have been isolated from each other for a long, long time, and that each is a full species unique to its island. Work is continuing on these lizards.

 

 L. delicatus of Príncipe Island. RCD phot. GG III

 There are other conspicuous lizards on both islands but these are not considered endemics; i.e., they occur elsewhere and are probably just good over-water dispersers. The large speckled-lipped skink, Mabuya maculilabris, is common and widespread in the lowlands of both São Tomé and Príncipe. It is a good climber and is seen in a variety of habitats especially along the coast lines.  This species also broadly distributed on the African mainland.

 

 Speckle-lipped skink (Mabuya maculilabris) of the Gulf of Guinea. Sao Tome. D. Lin phot. GG II] 

 

M. maculilabris detail. D. Lin phot. GGII 

There are also non-endemic, nocturnal geckos on both islands. Most appear to be the widespread house gecko, Hemidactylus mabouia, also occuring nearly throughout Africa. 

 

House gecko, Hemidactylus mabouia.  D. Lin. phot.  GG II\] 

Note that the eyes are not greenish and that this species does not lack claws on the inner toe and finger.  There is some confusion as to how many non-endemic species are present and what to call them. 

H. mabouia foot from beneath. note claws. Weckerphoto GG III.

Snakes are coming next. 

Here’s the parting shot:  

The thrill of discovery! Bom Bom Island, Principe.  Weckerphoto. GG III  

PARTNERS We gratefully acknowledge the support of the G. Lindsay Field Research Fund,  Hagey Research Venture Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero  of the Ministry of Environment, Republic of Sao Tome and Principe for permission to export specimens for study, and the continued support of Bastien Loloumb of Monte Pico and Faustino Oliviera, Director of the botanical garden at Bom Sucesso. Special thanks for the generosity of private individuals, George F. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke and Mr. and Mrs. Michael Murkami for helping make these expeditions possible.  

The Race: A Toad Less Traveled

 Sorry, I love titles like this… and I have more!  Actually, there are no toads (Bufonidae) on São Tomé and Príncipe; interesting in itself because seven other amphibian species of five different families have survived the ocean crossing during the many millions of years since the islands first emerged. Moreover, toads are common in almost every  conceivable terrestrial mainland habitat.  

My last two blogs have been a bit academic.  Having laid the biogeographical ground work, it is probably time to get back to the unique, endemic island critters.   The tiny, 31-million year old island of Príncipe is the only home of Africa’s largest treefrog, Leptopelis palmatus – the Príncipe Giant Treefrog.  It is one of the world’s rarest frogs, as well.

 

 L. palmatus – D. Lin phot. GG I 

Let me be quick to point out that the Príncipe critter is not Africa’s largest frog; that title belongs to Conraua goliath (below), which is found on the mainland in southern Cameroon and Gabon.  In fact, the goliath frog is the largest in the world but it is not related to any on São Tomé and Príncipe– no members of its family have made it across the saltwater gap to the islands, or if they ever did, they have not survived. 

  

Conraua goliath—J.-L. Perret phot. 

Leptopelis palmatus is the largest African treefrog (emphasis on “tree”) — frogs that are adapted for climbing with, among other features, enlarged finger and toepads.  As I have pointed out in earlier blogs, gigantism is a relative thing; the giant endemic plants, frogs, birds and lizards of São Tomé and Príncipe are bigger than all of their relatives but they are not necessarily so large you trip over them (like Galapagos or Aldabra tortoises); they are simply larger than all of their relatives.  The two images below put this frog in some perspective, and I think you will agree that this is one BIG treefrog. 

Me, with the first female. R. Stoelting phot. GG I 

 

The frog on Dong Lin, our photographer.  R. Stoelting phot GG I

This species was first described in 1868 on the basis of a single female specimen, housed in the Berlin Museum. At the time of GG I in 2001, the Príncipe giant treefrog was known only from this single type specimen and seven additional specimens, all females, collected by local Príncipeans for a Swiss colleague named Catherine Loumont.  The largest of Loumont’s specimens is 110 mm from snout to vent (we do not include legs when we measure frog sizes), and even after our years of work, this specimen remains the largest ever found – it is nearly 30 mm longer than the largest of its nearest mainland relative, Leptopelis macrotis, distributed from central Sierra Leone to Ghana. One of several differences between the two species is the striking deep-red eyes of our island endemic. 

The eye of the Príncipe giant treefrog. D. Lin phot. GG II 

This first specimen we found during GG I (first three treefrog images, above) was yet another female, 108 mm in length.  Our mammalogist, Doug Long, was led to the critter by some kids from the now-defunct plantation of Sundi in northwest Príncipe. Sundi may no longer function as a plantation but it is still inhabited by the descendents of former workers—lots of them, there is even a mayor. 

 

Doug Long and the Sundi kids. RCD phot. GG I 

The arrival of this frog was greeted with great enthusiasm by yours truly; here in my hands one of the rarest frogs in the world! And it was huge! I was not surprised to learn that it had been found on the ground, as it is hard to imagine something so bulky climbing around in bushes and trees. The male of this species was completely unknown, so far as we knew at the time,.  None had ever been collected, photographed nor described in the scientific literature.  So we also knew nothing about the species’ breeding biology, male advertisement call or tadpole.  At the time, we were unaware of a blog posted two years before our visit by Jonathan Bailey on the Gulf of Guinea Conservation Group website, entitled “One month in the Forest of  Príncipe.” Jonathan (now Dr.) Baillie described hearing the calls of male L. palmatus as “like a pop bottle being continuously opened.”  He heard them high up on Pico do Príncipe near a small stream at about 700 m and actually collected two of them which had been deposited in the Natural History Museum in London.  But during GG I, the male giant treefrog was terra incognita, so far as we were concerned.  

Second female from Rio Papagaio.  J. Ledford phot..  GG I 

During a second GG I visit to Príncipe a few weeks later, my then-graduate student,  Ricka Stoelting, collected another female along the Rio Papagaio, a large-ish river that flows through Príncipe’s only town, Santo Antonio.  It was also of a rather dull in color but with white spots. We have since learned that this is about as brightly colored as females get. 

Rio Papagaio in town, downstream. RCD phot. GG III

 

Ricka Stoelting, my graduate student on Sao Tome.  RCD phot. GG I.  

During this second visit, Ricka and Dr. Sarah Spaulding ascended Pico do Príncipe to the top and camped at nearly the same spot where Jonathan Baillie had been two years before.  There she found the males, lots of them, calling from bushes and branches at night near a very small creek.  

 

Tiny creek on the Pico.  J. Uyeda phot. GG II

 Ricka brought the series of males back down the mountain, and they were astounding.  Unlike the females they were very brightly colored and highly variable, in pattern, as well; this variability is rather unusual in frogs, although there are some species that are sexually dimorphic for color. And they were much, much smaller than the females, though we knew they were full-sized breeding adults. During later analysis we learned that the largest breeding males are only about 41% of the size of the largest females, a size disparity that is striking.

First series of live males (far right is a juvenile).  J. Ledford phot. GG I

  Ricka never heard them calling and anyway she had no way of recording them if they had.  One of the parameters we use in establishing relationships among frog species is analysis of the voice (or advertisement call.). Males call to attract females, and at the same time to advertise their presence and territory to other males.  The advertisement call is species- specific and obviously adaptive when there are other species utilizing the same water for breeding.   To really define Leptopelis palmatus, I needed a recording of the voice, and this was to become a priority in the future. Below is a preliminary analysis of the call of another Gulf of Guinea frog species which we think is present on both islands.  Here, we are comparing the advertisement calls of males from two different localities on both islands, and we can see that they are basically the same.

 

 Preliminary sonograms of Oceanic treefrog. Marshall/Drewes construct.  

 Back at the Academy, Ricka and I prepared the first formal description of male Príncipe giant treefrogs.  Now aware of Baillie’s blog, we read his word description of the advertisement call.  Although the Principeans insisted the frogs did call, it remained an open question, especially when I learned from anatomical study that the male frogs  lack vocal sacs and vocal sac openings, features that most calling frogs possess (including other members of the genus Leptopelis).   GG II in 2006 included Josef Uyeda as my student (now a PhD candidate at Oregon State University).  Josef was working on a different group of island endemics called puddlefrogs (see earlier blog: “We Find Jita”) but when we were on Príncipe, I sent him up the Pico with his friend Mac and the same guide, Manona, who had led Jonathan Baillie and Ricka years before. They were armed with my old Sony cassette recorder (my iPod had failed).  Bear in mind that the only known localities for males were at nearly 700 m, high on the Pico and while this made no biological sense, that’s where my stalwarts had to go. This is no small matter given the topography of the island, but graduate students are good at this sort of thing and anyway, they tend to be younger and more vigorous than their advisors!

Principe terrain. Pico do Príncipe is in the clouds to the left of the large Pico Papagaio. R. Wenk phot. GG III

 

 Josef Uyeda hunting for caecilians on São Tomé. D. Lin phot. GG II  

While in the same general area as earlier workers at about 700 m, Josef got a lot done but the party was caught in heavy rains.  He heard males and saw them calling but only managed some rather distant, poor-quality recordings (the conditions were miserable), but now at least we knew that the frogs did, indeed, call.  GG III, last spring, provided some answers, thanks in part to our friend Ramos of Bom Bom Island.  Ramos is assistant manager of the resort, a native Principean and a keen, observant naturalist.  See the photo of Ramos in the “We Find Jita” blog.  I described our past difficulties in trying to record the voice of the Príncipe giant treefrog to him, and he grinned and said, We will go to my roça (farm) on Pico Papagaio and at 5:30, we will get them!  I was highly skeptical…

Roça Papagaio, Ramos’s farm at 250 m. R. Wenk phot. GG III 

Ramos’s farm is in the forested area on the northern flanks of Pico Papagaio at about 250 m.  Just before you reach it on a dirt steep uphill road, you cross a tiny creek; this is where Ramos took us –  about 30 m up that small creek, thick with dense undergrowth, and there we sat, waiting for the forest cacophony of grey parrots, mona monkeys to subside.  Nothing much happened.  I had my iPod with recording head at the ready.  We waited in the gathering gloom for about 20, maybe 30 minutes, Ramos grinning throughout and occasionally exclaiming,  Just wait. We will get them! 

Me waiting, iPod in hand, for the giants to call.  T. Daniel phot GG III 

And sure enough, we began to hear frogs calling. I looked at my watch. It was 5:30. The call is certainly a strange one; it lacks resonance (remember males don’t have a vocal sac) and thus it is rather flat and unmelodius. Rather than my trying to describe it or arguing with earlier descriptions, you can listen to it yourself by clicking this link: 

Click here to listen

And here are a couple of photos of the male that was calling, taken by Wes. These are un-posed and taken before we collected it as a voucher specimen for the voice:

 Weckerphoto GG III

 Weckerphoto – GG III 

There are still great gaps in our knowledge of this most unique frog.  Obviously, the males are well-distributed in the lower elevations; we just have not been in right place at the right time.  We still cannot explain why females are dull and rather cryptic in coloration and usually found on the ground, while there appears to be no selection for color in males.  The dull color of females seems consistent, as a couple of months ago I found six additional females (no males) collected in 1988 at the Doñana Institute in Seville and they were clearly drab in life; my colleagues at Donana tell me they were collected on the ground in lowland localities at Rio Papagaio and Bela Vista.

Six female Seville specimens at Donana Institute.  RCD phot. 

We still have not observed breeding, nor have we ever seen tadpoles.  In this genus, Leptopelis, they are very distinctive, and I would predict the tadpole will look like this: 

 

A Leptopelis tadpole. Image courtesy of Dr. R. Altig 

Here’s the parting shot: 

 

Nezo, of Angolares, Sao Tome: artist, musician, restaurateur and worthy man – Weckerphoto GG III

PARTNERS We gratefully acknowledge the support of the G. Lindsay Field Research Fund,  Academy Research Venture Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero  of the Ministry of Environment, Republic of Sao Tome and Principe for permission to export specimens for study, and the continued support of Bastien Loloumb of Monte Pico and Faustino Oliviera, Director of the botanical garden at Bom Sucesso. Special thanks for the generosity of four private individuals, George F. Breed, Gerry F. Ohrstrom, Timothy M. Muller and Mrs. W. H. V. Brooke for making these expeditions possible.          

   

          

The Race: Strange Bedfellows (Part II)

First, I thought it would be useful to illustrate, in one place, how many scientists have been involved in the Gulf of Guinea expeditions since 2001 including the folks going in January 2009 (Gulf of Guinea III B). 

 

In Part I of this blog, I suggested that it is not just the high numbers of plants and animals that are endemic to these islands that is striking; it is also the fact that many of them are particularly poor dispersers over salt water and, according to dogma, they just shouldn’t be there! A scientist would never predict the presence critters like amphibians on oceanic islands. Don’t believe me? Even Darwin himself made the observation:

 

 Courtesy Dr. M. Vences, University of Braunschweig.

Amphibians and burrowing reptiles are among the most obvious of the unlikely inhabitants on the two islands but there are more subtle oddities as well.  The plant group Acanthaceae (shrimp plants), which are the specialty of Dr. Tom Daniel (GG III – see May 2, “News From the Flower People”) is another group whose presence is surprising.  

 

Dr. Tom Daniel. Lagoa Amelia, Sao Tome (RCD phot. GGIII) 

Heteradelphia  paulowilhelmina– an endemic genus? Weckerphoto GGIII  

The seeds of this group have no “wings” or other morphological adaptations allowing them to be blown by winds (wind dispersal is very common among plants – think of dandelions).  They do not float, they are too heavy, and anyway they are not salt-tolerant. If that were not enough, shrimp plant seeds do not have endosperm; i.e. they are not nutritious and thus are very unlikely to be routinely eaten by birds or mammals, then transported as stomach contents.  In fact, seed dispersal in this group is accomplished by the capsule that bears the seeds “exploding” and casting the seeds a matter of a few meters away from the parent plant.  Yet, there are 15 species native to the islands (non-introduced), two of which are endemic.  How did they get there across the water? 

I think the most likely answer to this question is that in the distant past these species crossed the marine barrier between Africa (the source) and the islands by floating on rafts.  My colleagues and I published this “rafting hypothesis” about a year and a half ago, largely based on the study of one group of frogs; however, the more I learn about the island endemic fauna, the more I am convinced that this is the most likely scenario.  

 

The first thing to remember is that two of the mightiest rivers on earth feed directly into the Gulf of Guinea – the Congo and the Niger. The Congo especially has an enormous drainage from deep within the African interior, and we know that the Niger flowed from current Lake Chad not so long ago; these might be considered amphibian freshwater highways from the interior to the coast.  It is not difficult to envision rafts of matted vegetation, tree trunks etc., floating downstream on one of these great rivers and being discharged into the Gulf of Guinea.  But we propose rafts composed of huge chunks of riverbank, chunks large and diverse enough to harbor burrowing forms and amphibians. 

 

Illustration by Richard E. Cook, San Francisco.

Such rafts might be many acres (hectares) in size such as in this drawing by my artist friend, Richard Cook. Rafts of this size might be expected to have rotten logs, trees, bushes rocks etc.  Does this actually happen? Yes, such huge rafts containing all manner of wildlife are fairly common breaking off and floating down the Amazon and the La Plata (they are called Camalotes); however, in the case of the Amazon, they are not often discharged into the Atlantic. Rather, they tend to accrete together at the delta, forming large masses. 

 

Satellite image, from World Wide Web.  

In the satellite image above, the red star indicates a large accretion island in the Amazon Delta called Marajó – it is about the size of Belgium! I can think of two possible explanations for why islands formed in the Amazon accumulate at the delta rather than float out to sea. 

 

RCD phot. 

First, notice above that the water remains relatively shallow for a great distance seaward from the Amazon Delta; this is because the continental shelf is about 200 miles wide before dropping off into great depths.  By contrast, the continental shelf off the Niger and Congo Rivers is much narrower (arrows on the right); moreover, just offshore from the Congo Delta is a deep abyss called the Congo Canyon.   Second, I think the water velocity in the Amazon is significantly lower in the Amazon than it is in the Congo, at least.  In fact the Congo is only navigable for about 80 miles inland.  The yellow star in the image below is the town of Matadi, which is as far inland as one can get by boat.

 

 

 Matadi, D.R.C., as far as you can go.  (RCD phot. 1984 

Upstream from Matadi are a series of rapids or cataracts formed as the river cuts though the African coastal uplift. 

 

Congo cataract. Google Earth image.

Rapids below Stanley Pool, D.R.C. –  Souljah phot.  WWW.

 These rapids increase the water velocity so that I suspect the river is much swifter overall than the Amazon, and it is far more likely that floating objects would be ejected out over deep water from the mouth.  How such floating objects would survive the cataracts themselves is an open question.  Given a large chunk of riverbank being ejected out into the Atlantic Ocean from the mouth of the Congo, what happens next?

Google Earth, RCD composite.

 The image above shows the mouths of the Congo and Niger (yellow stars) and the directions of the dominant ocean currents in the region.  Note that any floating object ejected from the Congo River will immediately encounter the Benquela Current and be carried north; such an object from the mouth of the Niger will be carried East by the Guinea Current.  It so happens that these two major currents converge to form the South Equatorial Current which flows due west, right through the central Gulf of Guinea Islands!  Conditions being perfect, we estimate that a floating object would take less than two weeks to reach São Tomé or Príncipe from the mouth of the Congo.     But, given our knowledge of the physiology of amphibians, what about the effects of the saltwater during the voyage.  Well, it seems that at predictable times of the year, the surface water of the Gulf of Guinea is not all that salty. 

From Measey, et. al. (2007). Journal of Biogeography

Notice that during the rainy season (around February) the surface salinity around the islands drops to around 31 parts per thousand of salt (technically it is brackish). Recall that because of differences in density, freshwater floats upon salt water. This sharp decrease in surface salinity is due to massive freshwater discharges of both the Congo and the Niger into the Gulf, plus the extremely high precipitation in the area as a whole.  And of course, with high flow rates and the two mighty rivers in spate, this would be the time of year when pieces of riverbank would be most likely to break off and flow downstream.  So a combination of factors, the locations of the rivers, the directions of the dominant ocean currents and periodic surface salinity changes, all point to rafting as the most likely way the amphibian ancestors of the current endemics actually arrived on the islands. We cannot prove this happened; we simply claim it is possible and likely.  Moreover, , one must bear in mind  that there has been a 13 million year period during which it might have in the case of São Tomé; as for Principe, it has been sitting out there “available for colonization for over 30 million years! 

Here is the parting shot: 

 

Angle of Repose on Principe. Weckerphoto, GG III.

PARTNERS We gratefully acknowledge the support of the G. Lindsay Field Research Fund,  Academy Research Venture Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero  of the Ministry of Environment, Republic of Sao Tome and Principe for permission to export specimens for study, and the continued support of Bastien Loloumb of Monte Pico and Faustino Oliviera, Director of the botanical garden at Bom Sucesso. Special thanks for the generosity of four private individuals, George F. Breed, Gerry F. Ohrstrom, Timothy M. Muller and Mrs. W. H. V. Brooke for making these expeditions possible.             

The Race: Glorious Ghost in the Forest

Scientists love islands because the processes of evolution on islands are simpler than they are on more complex, much larger continents and thus more easily studied. I have made the point that the islands of Sao Tome and Principe are very poorly known, but what we do know is very exciting. One evolutionary pattern that seems to consistently appear on islands is the phenomenon of gigantism; for some reason certain successful colonizers become very large on islands: for instance, think of the tortoises on the Galapagos Ids. or on Aladabra. There are a number of hypotheses that attempt to explain this phenomenon, but none is particularly compelling; nevertheless, the pattern exists and is very evident on the oceanic Gulf of Guinea Islands. The composite image below illustrates just a few of the giants on Sao Tome and Principe.

Some Island Giants

Think of potted plants for a moment… how large is a begonia? The central plant in this composite image is the largest species in the world, Begonia baccata. It is found only on the island of Sao Tome and reaches 10 meters in height! This particular specimen graces the southern shore of Lagoa Amelia at about 1480 m elevation – my head comes up to about flower level on this old friend (I am 6′ tall); these enormous plants are common at higher levels. The two birds figured are also giants: the yellow one on the right is the world’s largest weaver. Ploceus grandis,. and the one on the left is the world’s largest sunbird, Dreptes thomensis; both endemic to the larger island of Sao Tome. This is a good point at which to mention that island dwarfism is also an observable phenomenon  here as well, and the world’s smallest ibis, the Sao Tome Dwarf Ibis, Bostrychia bocagei is also an endemic.  The other critters in the collage, the frogs and the lizards, are all endemic giants but I will deal with them later. It is important to bear in mind that when we call a species a “giant”, we are describing its size compared to all of its other relatives only; such a species may not appear to be a giant at all, in our eyes.

The Sao Tome Giant Treefrog, Hyperolius thomensis, and I go back a long way; back to when I was writing my doctoral dissertation many years ago. This sapo (as all frogs are called on the islands) is endemic to Sao Tome only and is easily the largest member of its genus (Hyperolius)- females reach lengths of nearly 50 mm.from snout to vent!

Sao Tome Giant Treefrog, Hyperolius thomensis.GG I and GG II – D. Lin

Nearly all of the original material from which this species was described in 1886 was destroyed in the fire in Lisbon.  But I managed to find four remaining specimens, two in Vienna and two at the Natural History Museum in Vienna, allowing me to treat them in my dissertation.  In 1988 and again 1990 more specimens were reported by a Swiss worker, but her published locality data are very general, if not vague, and it turns out that most of the material she worked on was collected by locals at her request prior to her arrival.  During GG I, we visited most of her reported localities, finding nothing until we finally got lucky. Now, I can state that this most flamboyant of treefrogs is currently known for certain from only a single locality!  Our work in GG I, II and III has confirmed that this marvelous critter is known only from higher elevations (above 1000 m), inhabiting the canopy of old secondary or primary growth trees on steep slopes.  And it appears to breed only in the water-filled holes in trees with fluted bark or buttresses.  This is a rarity – in Africa, only 9 other frog species are known to breed in phytotelmata (scientific word for treehole). But it makes sense.  Most frogs lay eggs, which develop into free-swimming, gilled tadpoles, which then metamorphose.  Although there are many fast moving rivers on the steep slopes of Sao Tome, these are far to swift for breeding; still bodies of water simply do not exist. So, H. thomensis has adapted to breeding in ephemeral, rain-filled holes in the trunks of very large trees! All of the other frogs native to the islands utilize slow moving or still water for reproduction.

The tree – J. Clara, GG III

This is the only tree in which we have collected the Sao Tome Giant treefrog.  It is at about 1100 m on a high ridge, and we return each expedition to check its status. Adults are usually present but there are always eggs and tadpoles at different stages of development in the holes.  Tom and Rebecca, our botanists, could not identify this tree – it is simply too tall its see its canopy, and moreover it is festooned with epiphytes.

Frogs and eggs in treeholes –  WE, GG III

Wes Eckerman, our photographer tried to climb it, and then tried to climb an adjacent tree to see if there were more holes, but the tree is just too big in girth to handle; with our friend Jose Clara, we tried to erect a crude ladder to examine a hole farther up the trunk but to no avail.

RCD, GG III

I do not mean to imply that this species is restricted to this tree.  We have heard the species calling at night from high up in the canopy and reasonably certain that it is pretty widespread, at least in the high elevation forests we have visited – I suspect it is present on Sao Tome anywhere the trees are large enough and that. of course.  means upslope above the former Portuguese plantations.  What is different about this single documented tree is that it is the only one whose rain-filled holes are within our reach – there are undoubtedly more holes in many more trees that are too high for us to access.  I am left with the notion that given its restricted range and peculiar breeding biology, the Sao Tome Giant Treefrog is a classic indicator species; its presence means healthy mature forest.  If I were to choose an icon to symbolize the dogged persistence of pockets of nature in the face of man’s depredations and at the same time the attitude, beauty and whimsy of the citizens of Sao Tome and Principe, it would be this gorgeous island giant. Josef, my former student, informs me that he has already seen the name of this species on a price list in the pet trade in Europe.  If you  wonder why I have not described the location of this tree is in more detail, now you know. 

In the last posting, I promised you a picture of the cobra jita of Sao Tome. Here are shots of both island forms, which are currently considered to be the same species.

Sao Tome Jita – RCD, GG I

Principe Jita – WE, GG III

Not only do these critters look different from those on Sao Tome (stripes vs. patterned blotches), they act differently as well. On Sao Tome, cobra jita appears to be strictly nocturnal; during GG I and GG II we easily found them at night by first listening for the loud choruses of oceanic treefrogs (more about them later). So far as we know, the Sao Tome jita largely feeds on these frogs while they are breeding and is strictly nocturnal; to see at least ten of these snakes in a single night under the right conditions is not uncommon.

 

R. Stoelting, my grad student, with her first Jita – GG I, RCD phot. After our week on Principe, however, I am prepared to say that that jita is diurnal and although we will not know until we check stomachs, I think it feeds on lizards and small rodents. We even located a chorus of treefrogs behind Bombom but failed find a jita, nor did we ever find one during our night hunts. Only time and careful study of morphology nd DNA will tell us how closely related these two island snakes really are.Thanks to Caitlin D. for her generous donation. We are doing what we can!

PARTNERS We gratefully acknowledge the support of the Research Investment Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/ and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making GG III possible.

A biodiversity Goldmine?

What We Are Doing.

Surprisingly, São Tom? and Príncipe have remained largely unstudied since the early 19th Century work of Portuguese biologists Fea, Greef and Newton. In spite of the wonderful but preliminary stuff discovered by these early biologists, São Tom? and Príncipe have remained “off the scientific beaten path”. Historically, the islands were used as major slave entrepots by the Portuguese and were of world importance in the production of sugar, coffee and then cacao. Lying 200 to 250 km off the coast of West African coast, the islands have always been rather remote, and even to this day, there is but one flight per week from Europe to São Tom? (via Lisbon) and only a couple from Libreville, Gabon. In spite of several hundred years of agricultural efforts, fairly large amounts of original forest remain in higher elevations that were simply too steep to be cultivated by the colonials. While the birds have been studied and a preliminary flora has been published, huge portions of the biodiversity of these unique islands remain completely unknown.

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Drs. Iwamoto and Drewes sampling fish. Principe GG I (D. Lin phot)

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Periopthalmus A Principe mudskipper GG I (D. Lin phot)

So what we are doing is the most basic work in science; we are hiking into these remaining natural areas and surveying them to find out what species live there, what their evolutionary relationships are and where they came from. Depending upon our different specialties, we work both by day and by night, collecting, sampling, photographing, recording, etc. Most of our material is brought back to the California Academy of Sciences for study, but much also goes out to specialists around the world. As systematists, our job is to explore and sample all of the elements of the fauna and flora. When new species are discovered, we must analyze and describe them. Systematics is the fundamental discipline upon which all other biological work depends, especially including conservation efforts. You cannot save what you do not know.

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Grad student R. Stoelting. Night work on Sao Tome GG I (RCD phot)

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Giant gecko (H. greefii) Principe GG II (D. Lin phot)

WHY A “RACE”?

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Exclusive Economic Zone, Rep. Sao Tome and Principe.
As the title “Island Biodiversity Race” implies, there is a significant element of urgency in our work. The islands of the are about to undergo profound change, and the reason is oil. The exclusive economic zone of the Republic includes areas in the Gulf of Guinea where oil has been discovered. This means that at the very least, there will be a huge influx of revenue into this tiny republic of less than 300,000 people, and along with this revenue will come enormous pressure to expand infrastructure and a consequent burgeoning of the human population. History repeatedly shows us that such a phenomenon almost always affects natural wild areas negatively. Thus, It is our purpose to learn as much about the flora and fauna of the islands as quickly as we can, before the changes come. We hope to demonstrate to the citizens of the Republic of São Tom? and Príncipe the unique biological nature of their islands and enable them to make informed decisions down the road. We hope to show what they, and for(and for that matter, the rest of the world) stand to lose without adequate stewardship.

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Kids at Santa Catarina, Sao Tome GG II (D. Lin phot)

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Sao Tome GG II (D. Lin phot)

In this blog, I will describe the Third California Academy of Sciences Gulf of Guinea Expedition (GGIII) as it unfolds. Each expedition is made up of scientists chosen because their specialties are poorly known on the islands. The following URL describes our goals, the participants in the first two expeditions, and our scientific progress since the first expedition in 2001 (GGI).

PARTNERS We gratefully acknowledge the support of the Research Investment Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/ and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making GG III possible. http://research.calacademy.org/research/herpetology/bdrewes/