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Gulf of Guinea Expeditions 

August 16, 2011

The Race: In Defense of the Road Less Traveled

In Memory of Rebecca C. Wenk: 1979-2011

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Bom Successo Botanical Gardens, Sao Tome. (Weckerphoto. GG III)

When asked what one does for a living, many can easily respond with but one of three simple words: “medicine, law, or business.”  The societal value of these career paths is constantly reinforced and requires no embellishment nor further explanation.  Since our dads and moms (or grandparents) came home from WWII, these professions and their variations have been the tried and true paths to property, prestige and power: the “American Dream.”

But there are some among us for whom the goals of the American Dream are simply irrelevant.  While I doubt there is a single biologist anywhere who would not love to have the freedom of economic security, in truth this is simply not as important to us as doing what we love – that which fascinates us and keeps us in a constant state of active curiosity and quest.  I firmly believe that for most of us, this obsession is innate; we are born with it, and our profession chooses us, not the other way around.

So our response to the question is frequently troublesome, especially when it gets to the inevitable: “Why?”  “Why do you spend your life studying weird plants? or African frogs? or spiders? or diatoms?”  An honest response to this would be, “because I love it,” but we don’t say this because as Americans, it would make us seem selfish, immature and even an impediment to mainstream progress.  And, of course, the unspoken question is really:  “What good is it? What does it do for ME?”

Describing our values and feelings to others who lack our passion is nearly impossible–there is simply no emotional shared frame of reference, but I can at least say this: based on my own life experience, there is simply no joy on earth that can compare with the thrill of academic discovery… I don’t just mean finding a new species (exciting, yes, but a pain to describe scientifically!);  I also mean discovering a new relationship, or a new connection, or arriving at a new concept.  This “Aha!” moment transcends all other emotions I have ever experienced.  In 2008 during the Gulf of Guinea III expedition, I learned that watching the thrill of discovery happen to a young student for the first time is just as wonderful as experiencing it myself.

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Rebecca among the world’s largest Begonia, Lagoa Amelia.  (T Daniel phot. GG III)

Rebecca Wenk was a curatorial assistant in the Academy’s Botany Department and also the graduate student of Dr. Tom Daniel, curator of Botany, my colleague and companion on a number of Gulf of Guinea island expeditions.  Rebecca’s Master’s project at San Francisco State University was a study of a group of plants, one rare species of which was found on Sao Tome and Principe, and so her advisor Tom brought her along with us on the GG III expedition.   Rebecca REALLY needed this plant!

She was a real character.  The fact that she was the only female among the seven of us did not inhibit her in the least.  As a member of an academic family, she was not at all shy about challenging each and every of us at one time or another and usually in a voice that commanded attention – a quite memorable voice, at that.  She was a fine boonie rat, tirelessly collecting and pressing plants but also joining in the various activities of the rest of us.

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Rebecca visits the mycologists, Drs. Perry and Desjardin as they prepare mushroom collections,  Principe  RCD phot. GG III]

Our first week and half on the larger island of São Tomé was full of adventure and highly successful for all us; we collected up and down the central mountain, the west and east coasts, but Rebecca could not find her plant.  Later the group flew to the smaller, much older island of Príncipe. During GG I and II, we had no transport on Príncipe, and thus had not been able to sample this fascinating island in any detail.  GG III was the first year we were offered the logistical support of Africa’s Eden, an ecotourism company that owns two fine lodges, the Omali on São Tomé and Bom Bom on Príncipe. The company also has fishing boats and vehicles on both islands allowing us access to remote areas otherwise inaccessible.

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The Red Truck; Ramos, Dr. Perry and Wes Eckerman.  (R. Wenk phot. GG III)

Bom Bom resort drove us around in an open red truck with benches in back, on roads and trails we had not known existed.  They also furnished us with Ramos, a guide who soon became a good friend and supporter on all of our subsequent expeditions.  On our first full day, Ramos drove us up a very steep, rather scary road to his roça (plantation), high on Pico Papagaio (Parrot Peak).

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Pico Papagaio in background, south of Principe Airport.  (R. Wenk photo GG III)

As we were slowly proceeding up the track, at about the 300 m level, Rebecca let out a series of shrieks, leapt out of the truck and prostrated herself on the steep, downhill side of the road!  She had found her plant, Elytraria marginata! It is important to note here that Rebecca saw and found it herself; no one brought it to her, and none of us probably would have noticed it, even Dr. Daniel!   This little population of Elytraria was the only one we found during all of GG III.  To this day, there is no consensus among those of us witnesses as to what words Rebecca was actually screaming, but we are all agreed that it was in sheer joy.

I have a series of pictures of Rebecca racing around at the discovery site, hooting and hollering, but the best image of all is this one, taken by Wes Eckerman, our photographer:

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Rebecca with her “questing beast,” Elytraria marginata!  (Weckerphoto GG III)

Shortly after the discovery, we reached Ramos’ plantation and had lunch; the glow of Rebecca’s “aha” moment is still obvious on her face (and also on the face of her adviser, Dr. Tom Daniel!)

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Post discovery lunch at Roca Papagaio. (Weckerphoto GG III)

Two years later, Rebecca C. Wenk was awarded her MSc degree in Botany from San Francisco State University, and in the next year, her dissertation was formally published:

Rebecca C. Wenk and Thomas F. Daniel. 2009. Molecular Phylogeny of Nelsonioideae (Acanthaceae) and Phylogeography of Elytraria. Proc. C. A.S. 60:53-68.
This paper is considered an important contribution to our understanding of this group of shrimp plants and according to Tom Daniel, it has stimulated additional work by others; this is one of our goals as scientists.

Rebecca was a fine botanist with a good and inquiring mind and a bright future; a career in academia was certainly one of her options should she have chosen it.  But only a couple of weeks ago Rebecca Wenk died of cancer, suddenly and tragically, at the age of 32.  All of us at the Academy feel her loss deeply; the Department of Botany where she worked is especially bereft.  Those of us who were with her during her special moment on the remote island of Príncipe in 2006 feel particularly blessed to have been witness to it.

The parting shot.

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Loss.  Praia Mutamba (Shipwreck Cove), Sao Tome.  (J. Ledford 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, (GG I, II), the Société de Conservation et Développement (SCD) and Africa’s Eden for logistics, ground transportation and lodging (GG III-V), STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for permission to export specimens for study.  Special thanks for the generosity of private individuals who have made the last three 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. Our expeditions can be supported by tax-free donations to “California Academy of Sciences Gulf of Guinea Fund”.


June 30, 2011

The Race: A New Species, Birds and Special People

Readers will recall our bryophyte expert, Jim Shevock, tireless companion on GG IV in 2010.  He is certainly one of the best field men I have met, and as I reported earlier, he collected around 700 specimens of mosses, hornworts and liverworts on São Tomé and Prìncipe.  The first fruit of his labors has just been published in the journal, Tropical Bryology; the description a new endemic species of moss from the island of São Tomé, a new species record for the island, and three new records for the country as a whole.

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Jim Shevock with type of Porotrichum saotomense Enroth & Shevock- RCD phot.

The new species (of the Family Neckeraceae) is just the beginning.   Shevock and colleagues have another paper in press on the hornworts and liverworts (moss relatives) of the islands,  and the rest of the mosses are still being analyzed.  Jim expects many new species and records among this latter group, and all of this continues to show how rich and unique the biota of the islands is and at the same time, how poorly known.

Early readers of the blog will know that I only include experts on poorly-known groups of plants and animals on these expeditions. Thanks to the excellent doctoral work of Dr. Martim Melo, who employed molecular as well as morphological analysis, we know more about the birds of São Tomé and Prìncipe than any other vertebrate group and for that reason, we have never been accompanied by an ornithologist nor have I written much about them in this blog. That said, I must confess to being an unabashed birder of many years, a passionate bird “freak” with a life list that I keep on Facebook.

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Birding on Principe – note puddle.  Desjardin phot.  GG III

The birds (avifauna) of these two islands are remarkable.  One of the commonest birds on São Tomé, even in the densely populated capital, is the endemic warbler, the São Tomé Prinia.  You cannot miss them and yet, I have never been able to photograph one– they just don’t stop moving!  So early in GG V I challenged my two colleagues, photographer Andrew Stanbridge and Poster Project Head, Velma Schnoll to take just one photograph of the critter.  Here are the results (bear in mind these were taken on the grounds of the Omali Lodge, the upscale hotel of our supporters, Africa’s Eden)—decide for yourselves who won:

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São Tomé Prinia,  Prinia molleri . A. Stanbridge phot GGV

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Prinia molleri – V. Schnoll phot  GG V

Martim Melo and his colleagues have suggested that, taken together, the islands of São Tomé and Prìncipe have, per unit area, the highest concentration of endemic (unique) species in the world!  Below is a simple comparison between the heavily studied Galapagos Islands with a surface area of 8,000 km2 and our islands with only 1/8th the size.

bird comparison

The comparison above only tells part of the story; the  twenty two species of endemic Galapagos birds are basically descended from but three lineages: the mockingbirds, the flightless cormorant and the famous Galapagos finches; this is not surprising, given the great distance between the archipelago and South America.  On the other hand, the endemic birds of São Tomé and Prìncipe are from all over the phylogenetic map: flycatchers, pigeons, weavers, sunbirds, warblers, etc. etc.  Moreover, some workers recognize up to seven endemic genera here.  Here are just a few:

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São Tomé forest weaver, Ploceus sanctithomae. Weckerphoto GG III

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(l) Sao Tome Speirops, Zosterops lugubris; (r) Principe Speirops, Zosterops leucophaeus. RCD and J. Uyeda phots. GG III

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Newton’s sunbird, Anabathmis newtoni. Weckerphoto – GG III

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Sao Tome thrush, Turdus olivaceofuscus.  J. Uyeda phot- GG II

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Principe golden weaver,  Ploceus princeps. Weckerphoto  GG III

There are many other spectacular endemics on both islands; I have mentioned the island phenomena of gigantism and dwarfism in earlier blogs.  São Tomé Island is also home to the world’s largest weaver (Ploceus grandis), the world’s largest sunbird (Dreptes thomensis) and the world’s smallest ibis (Bostrychia bocagei)!

Many people support our work in the islands, and as you know I acknowledge financial help at the end of each blog.  Still others are old friends who live on the islands through whom we work and who welcome and assist us on each expedition. These too have appeared many times in the blog and they include the people of the organization STeP UP, where it all started (Ned Seligman, Quintino Quade and Roberta dos Santos), and our friend, Sr. Arlindo Carvalho, Director General in the Ministry of the Environment.

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Arlindo Carvalho, Ministry of the Environment.  A Stanbridge phot GG V

Dr. Carvalho told me that during the past year, he has  shown this blog to delegates at a number of international meetings on Climate Change he has attended representing the Republic… a great honor for us.

GG V was unique in that it was dedicated to biodiversity awareness not pure science; because we were less in the bush and more in the inhabited areas, it led to our meeting some remarkable people who actually joined our efforts simply out curiosity about and interest in our activities.

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Velma Schnoll, Eddie Herbst and me at Angolares. A. Stanbridge phot. GG V

I first met Eddie Herbst at the Omali Lodge during GG IV where I gave one of my slide shows on island biodiversity.  Eddie was seriously interested in what we were doing at the time, and during GG V he actually joined us while we distributed our posters down the east coast of São Tomé (above).

But Eddie’s real job is senior pilot for Africa’s Connections, the small airlines that serves both islands and various mainland cities around the Gulf (he is also an ordained minister, but that is another story), and he is usually in the cockpit when we travel between the two islands.

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Eddie Herbst’s day job.   RCD phot GG V

During GG V, I asked Eddie if he could fly over a large mesa in the remote southwest corner of Príncipe, as I have always wanted to study the top and wondered about access routes.  I should mention that this is definitely not the usual approach route to the Prìncipe landing strip! To give you an idea of how rugged and difficult the southern part of the island is, below is a topographic image of this part of the island.

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Topo map of SW Principe. red and yellow dots on mesa.

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The mesa from the air.  RCD phot. GG V

And here is the view we got from Eddie’s flyover which, I might add, was an experience the other passengers will probably never forget!

On that same plane was a remarkable Portuguese couple, Frank and Ana. They were both fluent in English, warm and friendly, and we became friends almost immediately.

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Ana and Frank on Principe.  RCD phot. GG V

Bear in mind that these two were full-paying guests at Bom Bom which is by far the most upscale and expensive venue on Prìncipe; yet rather than lying on the beach, or fishing or whatever,  Frank and Ana joined us each day as translators as we drove from school to school distributing our posters.  Through sheer good will and friendliness, they added greatly to the effectiveness of our small team.

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Anna and Frank translating. A. Stanbridge phot.  GG V.

Believe it or not, also on Eddie’s plane was a fabulous lady named Marnie Saidi, also bound for Bom Bom Lodge  but not as a tourist.  Marnie is the new Project Manager for the Africa’s Eden Belo Monte project (which I will perhaps describe in another blog).  Like Frank and Ana, Marnie joined us for fun and acted as translator on our various daily tasks, including our meeting with the Regional President of Prìncipe, Toze Cassandra and the subsequent local television interview.

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Marnie Saidi translating during TV interview.  A. Stanbridge phot. GG V.

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Marnie Saidi and Velma Schnoll, Principe primary school. A. Stanbridge phot. GG V.

These serendipitous meetings were not limited to Prìncipe; during our final week on the big island we met a young Portuguese business man named Antonio Fernandes.  Just like Marnie, Frank and Ana, Fernando joined us on some of our longest poster trips during our last week… and I should mention he also had a functioning vehicle!. This is part of GG V I have not yet described.

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Antonio, me and Quintino before ISP conference on Sao Tome.  A. Stanbridge phot. GG V.

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Antonio translating at Sao Tome secondary school. A. Stanbridge phot. GG V.

Finally, individual personalities are very important on expeditions; a little friction now and then is to be expected but on a research expedition which is mostly out in the bush,  this matters somewhat less than on an expedition such as GG V.  We were in daily contact with the citizens, teachers, ministers and other government officials and each of us had to be goodwill ambassadors every hour of every day.

My colleagues on this trip, Velma Schnoll, who took over the poster project here in the States and brought it to completion, and Andrew Stanbridge, the world’s largest and sneakiest photographer were both exactly that and much  more.  They will be more than welcome back on the islands at any time.

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Andrew Stanbridge at Monte Café, Sao Tome.   RCD phot. GG V

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Velma Schnoll and me at Principe primary school.  A. Stanbridge phot. GG V

Here’s the parting shot:

parting shot

“Education is an act of love and courage.”  Principe Secondary School, A. Stanbridge phot.  GG V.

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”.


April 22, 2011

The Race: The Sharing Begins

This is our seventh day, and we have been to all the schools, ministries, health centers and public places we can find, giving our biodiversity posters to head masters, principals, ministers. etc.. We started at the southern end of Sao Tome on one side, the town of Santa Catarina and worked north; then Porto Alegre on the east coast, working toward the city. This morning we delivered posters to a number of the bigger town schools but then spent the afternoon hunting spiders in the garden of Henrique da Costa, former Minister of Agriculture and a dear friend and wise counselor. As to our main mission, how have our posters been received? I thought I would just post a number of images of our poster adventures, and you can decide for yourself!

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And of course we had to jump back in the bush:

The Parting Shot:

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PARTNERS
We gratefully acknowledge the support of the G. Lindsay Field Research Fund (GG I), Hagey Research Venture Fund (GG II) of the California Academy of Sciences, the Société de Conservation et Développement (SCD) and Africa’s Eden for logistics, ground transportation and lodging (GG III-V), STePUP of Sao Tome http://www.stepup.st/., Arlindo de Ceita Carvalho, Director General, and Victor Bonfim, 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 Loloumb of Zuntabawe and Faustino Oliviera, Director of the botanical garden 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, and Mrs. Sheila Farr Nielsen for helping make these expeditions possible. Tax-deductable donations in support of this work can be made to “CAS-Gulf of Guinea Fund.”


February 18, 2011

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”.


December 7, 2010

The Race: Really Weird Island Snakes

A wormsnake from Kenya (Leptotyphlops drewesi).   Phot. D. Lin, CAS

In these accounts, I have written a fair amount about the two species of island house snakes (Lamprophis-cobra jita) that Lisette is still analyzing and a bit on the supposedly introduced cobra on São Tomé (Naja melanoleuca – “cobra preta”);  I have also mentioned the fact that each island also has a diurnal green snake, endemic  but unrelated to each other (Hapsidophrys principis, Philothamnus thomensis –“cobra sua sua”.   However, there are three additional snakes that I have not mentioned much: these are the so-called blind- or worm snakes.  Collectively, their technical name is the Scolecophidia, and the group is considered primitive relative to other snakes.  As their common names imply, all have reduced or no vision, virtually all of them are burrowers; they are small as snakes go and blunt at both ends, and there are about 300 species in three families found world-wide in tropical and many subtropical regions.

The fact that they are burrowers (fossorial), like the endemic São Tomé caecilian, Schistometopum thomense –“ cobra bobo”, lends credence to our 2007 hypothesis that some of the Gulf of Guinea endemics were carried to the islands from mainland Africa on very large floating chunks of riverbank from either the Niger or the Congo.  Burrowing legless vertebrates are unlikely to be found floating on logs or being carried by high winds!

Proposed riverbank raft (Measey, et al., 2007). Illustration: Richard E. Cook

There are three endemic blindsnakes on the oceanic Gulf of Guinea Islands: The beatiful golden blindsnake, Typhlops elegans is endemic to Príncipe island.  It is often confused by locals with the São Tomé burrowing caecilian, as its Kreo name implies: “cobra bobo do Príncipe.

Typlops elegans, the “cobra bobo do Principe.”  Weckerphoto GG III

Typlops elegans. D. Lin phot. GG II

Two endemic blindsnakes inhabit São Tomé exclusively, and as you can see they are extremely similar in appearance.

Fea’s wormsnake, Rhinotyphlops feae. D. Lin phot. GG II

Newton’s wormsnake, Rhinotyphlops newtoni. RCD phot. GG I

The reason I have not written much about them is that they are rather poorly known. Most species are small and difficult to work with, in that the characteristics that might serve to distinguish them are also very small and nearly impossible to discern without magnification.  My colleague, Dr. Van Wallach, of Harvard University is probably the current world authority on these wormlike snakes, and it has taken much of his career to understand them; many of the characteristics he has studied are internal.

Colleagues of mine have just published a major work on one of the families, the Typhlopidae,  in Biology Letters, a distinguished international journal.  Prof. Blair Hedges kindly gave me permission to reproduce the figure below, and I am discussing it here relative to our island work in order to show how the work of others can add to, support or even falsify one’s own– it is how science proceeds.

from Vidal, Marin, Morini, Donnellan, Branch, Thomas, Vences, Wynn, Cruaud & Hedges. 2010 Biology Letters 6:558-561

This is not as complicated as it may seem although it will be difficult to read at low resolution.  As with other cladograms, each of the names on the far right column  represents a single species clustered with its nearest relative(s); thus it is a “picture” of proposed evolutionary relationships.  This figure also contains estimates of when each lineage and its nearest relative split from their common ancestor (time divergence)—the common ancestor is indicated by a black dot (node) and the length of each branch linking two species is an indication of time.  Actual time in millions of years is given on the very bottom, along with the names of the geologic periods in vertical colored bars (blue= Jurassic; light green = early and late Cretaceous (K); orange  = Paleogene, and yellow, the most recent =  Neogene).  The authors have also provided diagrams (upper left) of the relative positions of the continents during the breakup of Gondwanaland.  The major points of this study are (1) that the common ancestor of all scolecophidians dates back 150 million years to the Jurassic Period (before the breakup of Gondwanaland), (2) that the ancestor of the modern Typhlopidae originally existed on an early landmass the authors call Indigascar (Madagacar + India) back in the Late Cretaceous, and (3) that the presence of their modern relatives in South America, Australia and the West Indies is most likely the result of a number of overwater dispersal events (like rafting), including a major western transatlantic one.

Vidal and the other authors included samples of the Gulf of Guinea Islands endemics which we collected during GG I and GG II, and their results are of great interest to us as we try to understand the origins of the Gulf of Guinea Islands biodiversity.

Expanded view of African clade from Vidal et al. Principe species in blue; Sao Tome species in red.

Distribution of the two Sao Tome wormsnakes and nearest relatives.

Here is the disjunct pattern that has frequently appeared when we look at the evolutionary relationships between Gulf of Guinea island endemics and their African mainland relatives; first, note that Rhinotyphlops newtoni and R. feae appear to have diverged from their common ancestor only a few million years ago.  Since, the minimum age of São Tomé is regarded as about 13 million years, it seems likely that this split occurred on the island, possibly as a result of volcanic events which isolated two populations of the ancestor from each other.  This is a more likely scenario than separate colonization events from the mainland.  However, the nearest relatives of the island species are a clade (sister-group) comprising R. unitaeniatus of East Africa and R. lalandei of southern Africa, and a look at the branch lengths of this sister-relationship suggests that, if the time divergence estimates  in this publication are correct, the common ancestor of both groups existed on the mainland over 50 million years ago.

Distribution of Principe wormsnake and its nearest relatives.

The situation with the beautiful Príncipe endemic, Typlops elegans is somewhat unclear, since the true distribution of its nearest relative, T. angolensis, is not known with certainty; the latter is said to occur from coastal Cameroon, south to Gabon and Angola and west to western Kenya, but these specimens have never been systematically examined.  Moreover, African distributions as broad as this one frequently turn out to be made up of the distributions a number of similar “cryptic” species.  But assuming that T. angolensis does have this distribution, that the tree is accurate, and the time divergences therein are reasonable estimates, one would naturally conclude that the ancestor of “cobra bobo do Príncipe“ reached that island and diverged from mainland T. angolensis during the past few million years.  If branch lengths are accurate it would appear this happened at roughly the same time as the two São Tomé endemics were diverging from their common ancestor.  Even though Príncipe, at 31 million years, is more than twice as old as São Tomé is geologically, this is not an unreasonable hypothesis.

This cladogram also suggests that these two blindsnakes share common ancestry with an unidentified species (specimen) collected at Lwiro, Democratic Republic of the Congo.  This interests us because this locality is close to the Itombwe Highlands, which are, geologically, very, very old, dating back to the Mesozoic.

On a different tangent, our island biodiversity posters are nearing completion, and that will be my next topic.

The parting shot:

Our work in Paradise.  Sao Tome, 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) 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 and Velma and Michael Schnoll for helping make these expeditions possible.  Our expeditions can be supported by donations to “California Academy of Sciences Gulf of Guinea Fund”.


Filed under: Biodiversity,biogeography,Gulf of Guinea,snakes — bob @ 4:47 pm
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