The Race: Taming of the Shrew (and updates)
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, flowers, mushrooms, principe, shrews | Date: Jun 24 2009 | By: islandbiodiversityrace
Things have been very busy.
Our flower people, Dr. Tom Daniel and Rebecca Wenk have been very active. Rebecca successfully completed her M.Sc . degree at San Francisco State University, based in part on plants she collected in the islands during GG III (A). She then published her research, with Tom, in the latest Proceedings of the California Academy of Sciences; the publication includes a special treatment of the genus Elytraria – E. mariginata is the little flower that Rebecca finally found high up on Pico Papagaio on Príncipe that was so exciting and which we reported last May. (See “News from the Flower people”).
Rebecca among the giant Begonias. Lagoa Amelia. Wenk camera: GG III.
Tom is nearing completion of his monograph on the acanthus (shrimp) flowers of São Tomé and Pr<!–[if gte msEquation 12]>í<![endif]–>
ncipe. He is now collaborating with Estrela Figueiredo, a Portuguese botanist who has been on the islands many times and has added much to our knowledge of the botany of the Gulf of Guinea as a whole There are several species of the Acanthaceae found only on São Tomé and Príncipe and one (Heteradelphia paulowilhelmia) which may be endemic at the genus-level. We found this beautiful flower in the middle of Lagoa Amelia at 1400 m. during GG III.
Heteradelphia paulowilhelmia. Lagoa Amelia. Weckerphoto: GG III
Wes Eckerman (photographer) Rebecca and Tom at Lagoa Amelia. RCD phot: GGIII
Another species in Tom’s group that is of particular interest to me personally is an acanth called Justicia thomeensis. This flower is known only from São Tomé and has not been collected since the late 19th Century – the original collector did not provide detailed locality data, and we have not found it on the islands yet. We hope it is not extinct, or that it was not actually collected somewhere else. Tom has examined the original dried specimens in Coimbra; it is perfectly valid, and he is re-describing the species. Another botanist named Hedrén examined this material, and in a 1989 study found that J. thomeensis is more closely related to a group of species in East Africa than to any in nearby West Africa. I am finding the same strange disparate distribution patterns among my island frogs.
Justicia relationships. RCD
On the crustacean front, Alex Kim, our freshwater shrimp colleague (see January and March blogs) has decided to attend Harvard for his undergraduate studies, and this summer he is doing fieldwork on prawns in Puerto Rico. He tells us that the São Tomé specimens collected for him earlier this year by the marine group “..represent at least two species which, based on morphology, have clear affinities with New World forms. DNA analysis is still ongoing, but the geological youth of these prawns leads me to suspect that we will soon have genetic evidence of trans-Atlantic larval dispersal.” Pretty impressive stuff for an incoming freshman.
A New World prawn. Alex Kim phot.
A few months ago I had an opportunity to lecture on some of the scientific results of our Gulf of Guinea Island expeditions to a group of biologists at international meetings in Sardinia; afterward in Spain, I met one of the foremost experts on bats, Javier Juste, of Institute Doñana in Seville who has also worked on the islands and has discovered some of the same strange evolutionary relationships that we have. We are about to send him bat tissues from our GGI collection for DNA extraction.
7th Congresso Nazionale, Societas Herpetologica Italica. Sardinia. C. Corti phot.
In earlier blogs, we discussed the fact that mammals make poor dispersers over saltwater barriers; except for some bats, mammals simply cannot survive long enough to colonize oceanic islands. This is because we mammals have to eat regularly in order to maintain constant body temperatures –without “stoking the furnace” by eating regularly, mammals quickly die of exposure. This is specially the case with shrews; because of the ratio of their tiny body masses to their surface area, shrews lose heat faster than any other mammal, and a shrew has eat almost constantly, or it dies of hypothermia. It is perhaps a testimony to the great geological age of São Tomé and Príncipe that shrews appear to have, nevertheless, successfully colonized both islands! If the two species are indeed valid and occur naturally (not brought to the islands accidentally through human agency), then these may be the only oceanic island shrews in the world.
The Sao Tome shrew (Crocidura thomensis). R. Lima phot. 2009
To our knowledge, the photographs above and below are the first ever published of the supposedly endemic São Tomé shrew, Crocidura thomensis. The photographs were taken by Ricardo Lima, a doctoral candidate at the University of Lancaster who is studying the environmental effects of various agro-forestry techniques on São Tomé. Ricardo tells us that the shrews are not at all rare; in spite of this, we don’t know much about this little critter, nor the one on Príncipe. The São Tomé species was first discovered in 1886 by the great Portuguese explorer, Francisco Newton and described in 1887.
C. thomensis. R. Lima phot. 2009.
The relationships of these small island insectivores were not assessed until nearly 100 years later by Heim de Balsac and Hutterer in 1982. These authors concluded (on morphological evidence) that the São Tomé shrew was a full endemic species, and that the Príncipe form was an endemic subspecies of Fraser’s musk shrew (C. poensis) which is widespread on mainland Africa.
Ricardo Lima and friends, crossing the Rio Lemba, Sao Tome. 2009.
Now, we are in the exciting position of being able to test these assumptions using modern genetic techniques; just how closely related are the two shrews, based on DNA sequence? Did these mammals arrive naturally by rafting, as we suggest for the amphibians? Perhaps millions of years ago? Or were they hitchhikers on an old Portuguese galleon a couple of hundred of years ago? We hope to find out.
Aspergillus dykowskii and Sarophorum palmicola on monkey pod cacao; Lagoa Amelia. D Lin phot. GG II
Finally, our mycologists have a huge job. As you know before our expeditions began back in 2001, there were only four species of mushrooms known from São Tomé, and Príncipe had never been sampled. Now, after Dr. Dennis Desjardin’s work on GG II (2006) and his subsequent return with Dr. Brian Perry during GG III last year, we now have 225 species (including 75 listed for the first time on Príncipe). Many of these are probably new to science and it will be a major effort to fully analyze the entire collection. But Dennis and Brian took the opportunity to describe one of the new species separately. It has just been formally published in the journal Mycologia, and they have named it after me! It is a weird looking thing, and I will describe the whole process (including the humor sometimes involved) in the next blog.
Here’s the parting shot:
“After the Race.” 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, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero of the Ministry of Environment, Republic of São Tomé and Príncipe 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 G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke and Mr. and Mrs. Michael Murakami for helping make these expeditions possible.
Within the House of Slytherin (II. some snakes)
Category: Biodiversity, Sao Tome, biogeography, snakes | Date: May 05 2009 | By: islandbiodiversityrace
Snakes are not great over-ocean dispersers; they are certainly better than frogs or freshwater fish but not as successful as spiders, geckos and skinks. For instance there are no native snakes in the Hawaiian Islands although they do occur in the Galapagos, but these are much closer to a source continent. In spite of their small size and isolated nature, São Tomé and Príncipe have a rather surprising snake fauna; there are at least seven species, five of which we know to be endemic - they are found nowhere else. This group includes three species of “lower snakes” or scolecophidians; these are small, blind burrowing forms, two of which are endemic to São Tomé and one to Príncipe.
Rhinotyphlops newtonii, a burrowing scolecophidian from Sao Tome. (D. Lin phot. GG I)
The more advanced snakes (caenophidians) are represented by one endemic, diurnal (daytime) species on each island (belonging to two unrelated genera) and a nocturnal subspecies which is currently thought to be the same on both islands.
Hapsidophrys principis- (cobra sua sua:“snake fast”)- the endemic diurnal species of Principe (D. Lin phot. GGI).
The nocturnal snakes are known as cobra jita (“snake slow”). I have mentioned these in earlier blogs, and my suspicions are that the two island populations are distinct endemics—we are beginning a molecular study this summer to test this hypothesis.
Cobra jita (”snake slow”), the nocturnal species from both islands? (Weckerphoto. GG III)
But here I want to talk about the remaining snake found on São Tomé which the islanders call cobra preta (“snake black”); this is the only dangerous species on the islands, and it is a bit of a mystery to me.
The black and white, or Forest cobra - Naja melanoleuca. Ethnobiomed phot.
Widely distributed on the African mainland, this species is known as the forest cobra, or black and white cobra (Naja melanoleuca), and it is quite a venomous and formidable animal. In some parts of its range it can exceed 3 meters in length (10’).
Forest cobra distribution. map by Nils Boyson
Head of Forest or Black and White cobra, Naja melanoleuca.
This snake, like most true cobras, displays a hood as part of its defense system, essentially making itself look larger in order to warn of its presence. Like all members of family Elapidae, cobra preta has erect front fangs that are hollow and syringe-like, and it injects prey animals with venom that attacks the nervous system (neurotoxin).
[l.] C. melanoleuca fang showing aperture (Bruce Young) [r.] direction of venom injection (E. Jose)
All of the São Toméans know of cobra preta and fear it, although I have no idea how frequently citizens are bitten. Based on a dead-on the-road specimen at nearly sea level in the south of the island, we know it occurs in lowlands, but I suspect it is more common in the mid-level forests; during GG I, we purchased a number of skins from farmers at Bombaim, which is at middle elevation.
Dead on the road, south Sao Tome. (RCD phot. GG recon 2000)
Joel Ledford with Bom Sucesso specimen. (J. Ledford phot. GG I)
The 2- meter specimen above was killed by locals near the Botanic Gardens and Herbarium of Bom Sucesso at about 1000 m, and we were able collect it during the GG I expedition.
During GG II in 2006, we encountered a very large specimen while collecting along an aquaduct in the Contador Valley on the west side of the island at 700 m; in fact, several of us nearly stepped on it before we were aware of its presence.
On our most recent foray, GG III A, we were again on the Contador Aquaduct when a middle-sized snake was killed by locals around a bend in the road, less than 100 m from where we were working.
Contador Valley specimen (Weckerphoto GG III)
Regrettably, they had beheaded the specimen, and so it was of no value as a voucher specimen; however, we were able to photo-document the animal and I removed some liver tissue for future analysis.
Liver tissue removal. (Weckerphoto. GG III)
The presence of the cobra on São Tomé Island is widely considered to be the result of human introduction, most likely accidental (it is hard to imagine an individual bringing a deadly snake on purpose!). Physically it appears to be identical to the widespread Naja melanoleuca of the mainland. Accidental introduction makes ecological sense to me as well because the species does not really fit into this old ecosystem as we are beginning to understand it. We know that the other higher snakes feed on endemic prey species such as frogs and lizards. But aside from some birds, there do not seem to be endemic prey species that are of sufficient size to sustain a large, heavy-bodied snake like cobra preta; on the other hand, plenty of rats, chickens, etc. have been brought over by humans since the 15th Century.
Two of the top African cobra experts are Drs Wolfang Wuster of the University of Wales and Donald Broadley of Zimbabwe. They are currently working on this species, and we have been sending them our tissue samples for DNA analysis. Soon, we should know whether or not this large cobra drifted out to the islands on its own and has since been genetically diverging, or whether it was brought to the island through human agency. Wuster and Broadley are currently describing a new species from Ghana that was long thought to be the species Naja melanoleuca.
Our parting shot:
Roadside enterprise on Principe(Weckerphoto GGIII)
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, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero of the Ministry of Environment, Republic of São Tomé and Príncipe 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 Murakami for helping make these expeditions possible.
The Race: Return of the Marines Redux!
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, Uncategorized, barnacles, biogeography, coral, invertebrates, principe | Date: Feb 20 2009 | By: islandbiodiversityrace
I have just heard that Alex Kim, the student at Thomas Jefferson High School of Science and Technology in Virginia has received the new freshwater prawns GG III (B) collected for him and is in the process of extracting DNA from the fresh tissues. As I mentioned in the last couple of blogs, Alex is a finalist in the Intel Science Talent Search, and we are very interested in his progress. His results will add to our understanding of our own work and the biodiversity of these islands. When Alex first contacted me, I had some concern that we might have neglected to bring prawns back with us from GG I and II. We had, of course, and Alex has been studying some of the preserved specimens er brought to him in December. Just yesterday I found an image of Dr. Tomio Iwamoto carefully processing these some of these same prawn specimens in 2006 on São Tomé (during GG II). This will give you an idea of the size of the critters Alex is studying (although there are two species on the islands – I am not sure which one this is!)
Tomio Iwamoto on Sao Tome. RCD phot. GG II
The marine biologists of GG III (B) are busily sorting through their material, and I thought an early update was in order. In the last blog I mentioned that the Dr. Williams had done very well with his octocorals (also known as gorgonians or sea fans), and so had Dr. Van Syoc and Dana Carrison with their barnacles. Dana is Bob Van Syoc’s graduate student at San Francisco State University.
Dana Carrison during a more northerly field trip. NOAA photo
Bob Van Syoc found an undescribed barnacle species on São Tomé during GG II, and it appears that Dana has now confirmed this for Príncipe as well. And there may well be other new barnacle species; it is just too soon to tell. Dana is studying the relationship between these barnacles and Dr. Williams’ sea fans. This is an obligate relationship – some species of sea fans are always found in association with certain species of barnacles.
The barnacle Conopea calceola on a gorgonian. D. Carrison phot. GG III
Note that the barnacle settles on the gorgonian, and the gorgonian’s tissue (red, in this case) grows up around it. Along with describing new species and adding to our island biodiversity list, Dana is testing the hypothesis that the different species of barnacles have a preference for certain species of gorgonian upon which to settle. Dana got about 30 different Príncipe barnacles but has not yet begun identifying them or comparing them to the GG II barnacles collected in São Tomé. Also included in her collections are at least three different gorgonians and their associated barnacles that were not collected previously by the Academy expeditions.
Undescribed species of Conopea on a different species of gorgonian. D. Carrison phot. GG III
New barnacle species or the relationships of freshwater prawns may not sound exciting to you. In our biodiversity race, we are studying everything we can, as biodiversity is the sum of all living species in a given area; thus, everything is important as a measure of the uniqueness and past history of these ancient islands. Think of our mushroom work: before we started, there were only four species known from São Tomé and none from Príncipe; now the people of the islands know that there are at least 220 species, many of them undescribed and unexpected. The same is true for the ant lions I have documented earlier, and I fully expect similar results when analysis of our collections of diatoms and spiders are completed. The story of biodiversity can never be told by the study of furred and feathers critters alone.
Here’s the parting shot:
Incipient Dr. Uyeda with collecting party, Nova Cuba, 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, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero of the Ministry of Environment, Republic of São Tomé and Príncipe 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: Within the House of Slytherin (I. Lizards)
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, gigantism, invertebrates, lizards, principe | Date: Jan 26 2009 | By: islandbiodiversityrace
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: Strange Bedfellows (Part II)
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, gigantism, principe | Date: Nov 18 2008 | By: islandbiodiversityrace
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: Strange Bedfellows (Part I)
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, principe | Date: Oct 23 2008 | By: islandbiodiversityrace
Our research on the unique flora and fauna of São Tomé and Príncipe Islands is allowing us to document the different kinds of critters that are endemic; i.e., found there and only there. And there are many of all kinds. It is important for us to do this so that the citizens of the islands are aware of how different these islands are from the rest of the world so they can make informed decisions in the future. I have already stressed how poorly known the biota of these islands is, and a good example lies in our mushroom work which you can read about in “May Day Mushroom Madness“, below. Prior to our work, only four species had been listed from São Tomé and no one had ever looked at Príncipe. Now, as a result of our most recent expedition (GG III (A), we have 225 species, 75 of which are listed for the first time from Príncipe—and our mycologists Dennis Desjardin and Brian Perry tell me many of these are new to science.
Cross-section of G of G Islands and mainland highlands (RCD compiled image)
As I established in the first blog below, “Islands at the Center of the World,” São Tomé and Príncipe, and also tiny Annobón are classic oceanic islands; they have never been attached to mainland Africa. This is obvious from the island cross-section above – you can see that the first island, Bioko, is separated from the mainland by very shallow water (arrow), and it was clearly connected to the mainland perhaps numerous times during the Holocene as sea levels rose and fell. However our oceanic islands are surrounded by water depths of up to 4,000 meters and could never have been connected to the mainland. This means that everything living on the islands had to get there from the mainland (or somewhere else?) across several hundred kilometers of deep salt water. As described in the first blog, this happens by random chance and we call it dispersal. In the case of the Gulf of Guinea, there has been a lot of time for this to happen: São Tomé and Príncipe are very old as islands go (the Seychelles are a special case).
Island ages. (RCD combined image)
Once established, colonist species begin to accumulate genetic changes and ultimately become endemic, that is physically and genetically isolated from their ancestors on the distant source continent. We are able to predict the sorts of plants and animals we are most likely to find present and established on oceanic islands. Distance from the source is a limiting factor and, of course, so is island area— the larger and more diverse the island the greater the array of suitable niches for colonizers. But for an individual species the most important parameter has to do with behavior, morphology and physiology in determining “who gets there successfully.” It is a fact that some species are better able survive crossing broad saltwater barriers than others; these, we call good dispersers. Good dispersers include many plant species with either resistant seeds (e.g. palms) or seeds that are wind-dispersed. Spiders, notably species that disperse by “ballooning,” are also good dispersers; as tiny juveniles, they spin a single long strand of silk that is caught by air currents, enabling them to be carried great distances. Some lizards such as geckos and skinks commonly make good dispersers and successful colonizers of oceanic islands.
A salticid spider of the genus Eris. (B. Marlin phot. on www)
Plants like dandelions have wind-dispersed seeds and are good colonizers. (C. Higgins phot. www)
Hemidactylus greefi, a gecko endemic to both islands (D. Lin phot. GG II)
Conversely, there are poor dispersers, species we would never expect to cross expanses of salt water; a classic example is primary freshwater fish (species that evolved in freshwater, as opposed to some groups that are anadromous, spending part of their life cycle in both) There are groups that evolved in saltwater but have members that readily adapt to freshwater; these are called secondary freshwater fish. All of the fish we have found in the many streams on Sao Tome and Principe are secondary freshwater fish, most gobis.
Sicydium bustamanei, a secondary freshwater fish from Rio Micondo, Sao Tome. (RCD phot. GG I)
São Tomé and Príncipe are remarkable for the large number of endemic species that live there, but it is the nature of some of these species that is even more fascinating to me. Some of these endemics fall into the category of “poor dispersers”; I mean really lousy dispersers. Amphibians, because of the structure of their skin, freshwater aquatic larvae and unshelled eggs, are second only to primary freshwater fish in their lack of tolerance to saltwater. They are never predicted as successful colonizers of oceanic islands. Think of it: there are no native amphibians whatsoever on either the Hawaiian or the Galapagos Islands. Prior to our work in the Gulf of Guinea, the only other frog group shown to have crossed saltwater barriers are populations of rocket frogs (Ptychadena) on Madagascar; this was not dicovered until genetic work was completed in 2004. But São Tomé and Príncipe are not limited to just one amphibian endemic colonizer; there are fully seven species there belonging to five families, each of which must have somehow crossed the broad expanse of saltwater separating these islands from Africa.
The Amphibians of Sao Tome and Principe. (RCD compliled photos of D. Lin (GG I, II, Weckerphoto, GG III; light green=Sao Tome only; light blue=Principe only; white=both islands)
The fact that there are any amphibians at all on these islands is surprising enough, but that such a diverse fauna exists there which also includes a legless burrowing caecilian, the cobra bobo (found only on São Tomé), is truly mind-boggling. How does such a creature get across the ocean?
“Cobra bobo,” Schistometopum thomense. Sao Tome. (Weckerphoto - GG III).
Before we try to answer this question, there are some other endemic species on the islands whose presence we would not predict. Except for bats (especially of the Family Vespertilionidae), mammals are considered very poor dispersers, largely for physiological reasons. We mammals have to continually eat (stoke the fire, so to speak) in order to maintain our constant body temperatures; for this reason, mammals cannot tolerate long periods of exposure and are unlikely to survive long ocean passages before succumbing to hypothermia (unless, of course, there is food available). And among mammals, the critters that have the largest heat loss problems are the shrews; these tiny creatures have such a large surface area relative to their mass that they lose heat constantly and rapidly, to the point that an individual shrew has to eat continuously just to avoid dying by hypothermia. These would be the very last sorts of mammals we would predict to successfully colonize an oceanic island; yet there is an endemic shrew on São Tomé, Crocidura thomensis (we have not yet seen it, although I am informed there are scientists currently looking for it), and an species assumed to be from the mainland, the White-toothed shrew (C. poensis) inhabits Príncipe. We have to consider the possibility that this latter species was brought in by man, but if not and if C. thomensis is a naturally occurring endemic, how on earth do such fragile creatures survive an ocean crossing?
Crocidura suaveolens, an Old World Shrew.
Crocidura poensis (?). A dead-on the road shrew on Principe Id. (J. Uyeda phot. GG III)
Newborns found on Principe, near Santo Antonio. (D. Lin phot. GG II)
There are a number of ways species can be naturally dispersed across saltwater barriers: some can fly (bats, birds, many insects), they can be carried by winds and storms (seeds, insects, birds); some salt-tolerant species can float or swim (palm seeds, tortoises to Galapagos and Aldabra, the ancestors of the marine and land iguanas of the Galapagos). Darwin postulated that amphibian eggs might be dispersed on the feet of wading birds, but to my knowledge this has never been demonstrated. A mechanism of dispersal that is frequently invoked by biogeographers is rafting. I remember as a student that it was not difficult to imagine a gecko or its eggs, being carried out to sea on a floating palm tree or chunk of riverbank and then ultimately washing up on an island shore. This no doubt has occurred many times throughout history, but it of course requires that the hitchhiker have certain tolerances to exposure, potential starvation, etc. My colleagues and I suggest that rafting is the most likely scenario for the colonization of the Gulf of Guinea Islands by the amphibians and reptiles, but on a much grander scale than a few pieces of floating matter over time. I say “much grander” because along with the caecilian, Schistometopum thomense, nearly half of the endemic reptiles on the islands are also fossorial, legless, burrowing species. Their continental relatives are all fossorial as well, so we know that loss of limbs has not occurred since these species arrived. It is extremely difficult to imagine a mechanism by which burrowing species can cross a saltwater barrier unless they are floating on and carried by really large rafts.
Legless endemic Reptiles of Sao Tome and Principe. (D. Lin phots. GG I, II)
The celebrated endemic “Cobra bobo”, a legless burrowing amphibian found only on Sao Tome Island (Weckerphoto - GG III)
I will explain our hypothesis in more detail in Strange Bedfellows, Part II.
Here’s the parting shot:
Willing helpers at Sao Nicolau, Sao Tome Id. (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/ the staff of the Ministry of Environment, Republic os Sao Tome and Principe and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making these expeditions possible.
THE RACE: How Little We Know About Lions!! (antlions, that is)
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, insects, principe | Date: Jul 30 2008 | By: islandbiodiversityrace
A recurrent theme in our work in the Republic of São Tomé and Príncipe is the continuous reminder of how little we and the 160,000 citizens of these fragile little islands know about the unique biology found here. I have already told you that when we first arrived, there were but four species of mushrooms listed from São Tomé and none from Príncipe; we now have at least 180, and the first ever recorded from Príncipe (75), the older of the two islands. Many of these are species new to science and are being described for the first time; this is a huge jump in the island biodiversity list and there is much more to come.
During our first expedition in 2001 (GG I), we were interviewed twice by the local television station in São Tomé. In the second interview two weeks after our arrival, I had the whole gang prepared to show some of the specimens we had collected. When we showed him the scorpions, the reporter, Gui Gui, went nuts! Neither he nor any other citizen we have spoken to since, has ever seen nor heard of a scorpion. And yet they are quite common at night (along with numerous geckos and crabs) on the basalt cliffs of the northwestern shore of the island near Laguna Azul.
Isometrus, widespread tropical. Sao Tome (D. Lin phot) GG I
Basalt Cliffs near Laguna Azul, Sao Tome. GG I (J.Ledyard phot)
Jens Vindum confronts crab on basalt cliffs. Sao Tome. GG I (RCD phot)
I am told that if the new hotel project at Laguna Azul becomes a reality, the coastal area will become inaccessible to local traffic, and the road will be re-routed higher, some 3 km through the dry, north end of the island from Laguna Azul to Neves. What we call “Shipwreck Cove” (Praia Mutamba), one of our favorite study sites and the location of some remnant dry forest will become the marina for the new hotel.
Praia Mutamba, Sao Tome. note basalt cliffs in background. GG III (weckerphoto)
Dr. Tomio Iwamoto negotiates old dry forest. Praia Mutambo, Sao Tome GG I (RCD phot)
Yet another example of how little we know about these islands can be found in the insect order Neuroptera. Neuropterans are world-wide and include the lacewings, mantis flies and antlions. As kids, we western North Americans know antlion larvae as “doodlebugs”, the little critters that form funnels in the ground. One of the world’s leading experts on the Neuroptera is the Academy’s Dr. Norm Penny,who was with us on both GG I in 2001 and GG II in 2006.
Dr. Norm Penny with a malaise trap, Principe. GG II (D. Lin phot)
Prior to GG I, there were only four species of neuropterans known from São Tomé and Príncipe from as many specimens. All were lacewings; antlions had never been recorded from either island. At the end of GG I, Norm had about 370 specimens, representing 14 species in three families!
Apochrysa leptalea Sao Tome. GG I (D. Lin phot)
Borniochrysa squamosa Sao Tome. GG I (D. Lin phot)
Ceratochrysa sp. Sao Tome. GG I (D. Lin phot)
Glenochrysa sp. Sao Tome. GG I (D. Lin phot)
The distribution of these critters throughout the Gulf of Guinea archipelago refelects an old island biogeographic principe: the number of species supportable on an oceanic island can be predicted by the island area and its distance from the mainland. As you can see below, island area seems more important in this case. One might predict that because Príncipe is closer to the mainland, it should support more species than São Tomé. But, put simply, the larger, more variable an island’s topography, the greater number of niches (read “jobs”) are available to be filled by colonizers.
As I mentioned above, antlions (Myrmeleon) are close relatives of lacewings and had not been recorded on either island prior to GG I. Antlion larvae dig funnel-shaped pits and hide at the bottom, partially buried in sand and waiting for an unsuspecting ant or other arthropod to slide into the pit, whereupon the larva or “doodlebug” kills and eats it. We first noticed these pits across the road from where we were staying in São Tomé in 2001.
Antlion (doodlebug) pits. Sao Tome GG I (D. Lin phot)
antlion larva (doodlebug) exposed (J. Robinson phot)
A doodlebug lies in wait at the bottom of his pit. (WWW phot)
Now, the curious thing is that one does not have to capture the winged adults in order to study antlions. It turns out that the larvae are very hardy, and you only need to winkle them out of the pits, put them in a small vial of sand, and they become quiescent, surviving for long periods of time. Norm can then raise them to adulthood later in his doodlebug lab.
Dr. Penny in his antlion lab (note cups) (RCD phot.)
First adult Sao Tome antlion raised in lab. New record for Sao Tome. (D. Lin phot)
Norm puts the newly arrived larvae in styrfoam cups, they revive, feed on tiny crickets he provides, and then pupate. He then covers the cup, because, obviously, the adult will be winged. We have been quite excited because we brought back the first ever Príncipe antlion larvae and one pupated in Dr. Penny’s lab.
First Principe antlion locality. Bombom Island. GG III (weckerphoto)
Note the doodlebug has pupated. (RCD phot)
The hatching! Note hole in the old pupa ball. (RCD photo)
First Principe antlion hatched in our lab and a new record for Principe (RCD phot)
Very exciting. Norm says both are species of Myrmeleon but whether they are the same species or different species has yet to be determined… This baseline work we do takes time. But again, our job is to discover, analyze (understand) and describe. We cannot preserve what we do not know.
Dr. Norm Penny on Praia Agulhas, Principe. GG I (RCD phot)
Here is our usual “parting shot”:
The “race” on Sao Tome
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.
The Race Continues: We Find Jita!
Category: Biodiversity, Gulf of Guinea, Sao Tome, biogeography, frogs, principe, snakes | Date: May 03 2008 | By: islandbiodiversityrace
We are still on Principe and down to the hard corps: me, Wes and Josef. The mushroom and plant folks, Dennis, Brian, Tom and Rebecca are home in San Francisco by now. So it is time to tell you a little about my own research interests. Cobra Jita is a snake and we have been looking for it all week; in order to explain why, I need to tell you a frog story.
Josef Uyeda on Principe. Weckerphoto GGIII
As I have said, the fact that there are amphibians here at all is astounding; amphibians, along with primary freshwater fish, are among the poorest dispersers across saltwater barriers known. They are the last kinds of critters one would expect to find on an oceanic island…. Think of the Hawaiian Islands and the Galapagos, perhaps the two most intensely studied oceanic archipelagos in the world… no frogs or other amphibians, right? But here on Sao Tome and Principe we have seven amphibian species, one of which is the famous caecilian, Schistometopum thomense. How can this be? How did they get here? More on this later, but one of the keys is time: remember that Sao Tome is at least 15 million years old, and Principe is more than double that, perhaps 31 million years. Hawaii and the Galapagos are but 5 million years max.
During GG I, we collected series of little brown frogs of the genus Phrynobatrachus from various locations on both islands; at the time all of them were considered the same species, P. dispar, originally described from Principe over 100 years ago. In 2005, a bright young intern from Willamette University named Josef Uyeda, spent the summer in my lab studying these preserved specimens and concluded that the frogs were quite different. Josef joined GG II and did a lot of collecting on both islands, recorded calls, did dissections and comparisons of DNA from the critters on both islands. The results are that the two island frogs are VERY different; in fact, there is nearly 21% DNA sequence difference between the two; indicating that they have not interbred in many millions of years, possibly predating the existence of Sao Tome (yet they still look virtually identical!). Moreover the two together appear to be more closely related to East African species than to more nearby West African species, but more on that later. In 2007, Josef, I and Breda Zimkus of Harvard described the Sao Tome brown frogs as a new species, Phrynobatrachus leveleve.
Phrynobatrachus leveleve. Sao Tome. Weckerphoto GGIII
Phrynobatrachus dispar Principe. Weckerphoto GGIII
from Uyeda et al. 2007. Proc. Calif. Acad. Sci. 58
This brings me to cobra jita (pronounced “zheetah” – it means snake slow, as opposed to the other Principe snake, cobra sua sua, which means snake fast!). Here we have the same situation as we had with the small brown frogs, Phrynobatrachus. Jita (more properly known as Lamprophis lineatus bedriagae, or lined house snake) has always been considered to be the same species on both islands. After our frog studies, I am not so sure! They look different – regrettably I will have to post a picture of the Sao Tome form later… didn’t bring one in my zip drive—the Principe form is much more obviously patterned than the Sao Tome snake. During GG I and GG II we got very good samples of the Sao Tome population, but for some reason, only one specimen from Principe.
Lamprophis from Bombom Id, Principe. Weckerphoto GGIII
Lamprophis from Sao Tome. D. Lin photo. GGII
Josef is now a PhD candidate at Oregon State University and joined us a couple of weeks ago in our search for Jita (among other things I will describe later). Snakes, as you probably know, are where you find them… as primary predators, they are never very common but always around, and such has been the case here on Principe. It has taken us six days of trekking around in the forest, turning over logs, etc. to find six snakes. But I am delighted. This is certainly enough now to estimate the genetic distance between the two populations, and given the age of these islands, I will not be surprised at all to learn that they are distinct at the species level.
Josef and I looking for Jita on Bombom Id. Weckerphoto. GGIII
We have learned a lot about this critter. On Sao Tome, Jita is primarily nocturnal while the daylight hours on that island seem to be dominated by the endemic Sao Tome green bush snake, Philothamnus thomensis. This is the situation we would predict using island biogeographic theory—no niche overlap – they both seem to eat frogs and skinks, but at different times. But here on Principe, all of the jitas we have caught have been during the daylight hours, as was the single individual caught during GG II in 2006. Moreover, the green snake of Principe (yes there is a green sua sua here as well, but not related to the Sao Tome species) also seems to be diurnal! They are incredibly fast; we have seen two of them and missed both. So until we can look at stomach contents, we seem to have an ecological mystery.
Me, Josef and Ramos on Bombom Id. Weckerphoto GGIII
Our search has been greatly aided by an amazingly bright local naturalist; Jose Ramos Maria Vital Pires, or Ramos for short. Ramos has led us around this island searching for the elusive jita we have been blown away by his keen perception and observations of the local flora and fauna, and his delightful smile and sense of humor. The thing is everyone knows about this snake, most of the locals are to say the least, not exactly fond of snakes and one referred to as a “house snake” frequently comes a little too close for comfort, as you might imagine. But finding a snake when you are looking for it is entirely different matter. Our first success occurred on Bom Bom Island (not really and island, but sort of). I had just commented that the area Ramos was leading us through was too steep to find a snake, when he began excitedly shouting “snake!” only meters away. Within moments we had bagged our first jita.
There have been some rather ignominious moments for me personally. My two young compadres, Wes and Josef are willing to give me credit for catching but one jita, a dead one. The specimen had, in fact, been killed two hours earlier by a local woman who was delighted to have us remove it from along the road. This morning was the last straw. We had been combing Bom Bom Island again; Josef and Wes had taken a lower route than I and about an hour in, I heard Josef yell that they had caught a snake in the act of ripping a tail off a skink. Well and good, I thought, but where’s mine? So I am walking along, seeing snake food like skinks all over the place, when Wes and Josef come down the trail towards me. We stopped, admired the snake Josef had already bagged and the photos Wes took of it eating its skink tail, all three of us turned around…Josef stooped over and grabbed our largest jita of the expedition, about a foot behind me. I must have stepped right over it a moment beforehand. Perhaps it is not necessary to tell you that there has been much snickering among the younger members of this outfit ever since… Argh.
Josef collecting a jita on Bombom. Weckerphoto GGIII
Nova Cuba, near Santo Antonio, Principe. Weckerphoto GGIII
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. More anon.
A biodiversity Goldmine?
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, biogeography, gigantism, principe | Date: Apr 29 2008 | By: islandbiodiversityrace
What We Are Doing.
Surprisingly, São Tomė 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 Tomė 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 Tomė (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.
Drs. Iwamoto and Drewes sampling fish. Principe GG I (D. Lin phot)
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.
Grad student R. Stoelting. Night work on Sao Tome GG I (RCD phot)
Giant gecko (H. greefii) Principe GG II (D. Lin phot)
WHY A “RACE”?
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 Tomė 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.
Kids at Santa Catarina, Sao Tome GG II (D. Lin phot)
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/
ISLAND BIODIVERSITY RACE
Category: Biodiversity, Gulf of Guinea, Sao Tome, biogeography | Date: Apr 22 2008 | By: islandbiodiversityrace
ISLANDS AT THE CENTER OF THE WORLD.
My name is Bob Drewes; I am a research biologist, and I have worked in Africa’s wild places with considerable pleasure for over 35 years. I am Curator of Herpetology at the California Academy of Sciences, the western United States’ oldest academic research institution.
Very shortly, I will be leading the Academy’s third biodiversity expedition to the remote islands of São Tomé and Príncipe which lie off the west coast of Africa in the Gulf of Guinea,. These two mountainous islands together form the world’s second smallest republic (after the Seychelles Islands). São Tomé and Príncipe are biologically unique; they are the two middle members of a four-island chain (sometimes known as the Gulf of Guinea Islands) that is the only archipelago on earth comprised of both continental and oceanic islands.
Continental vs Oceanic Islands
Unlike the northernmost island, Bioko (formerly Fernando Pó) which is a continental island separated from the Cameroon coast by only 20 miles of relatively shallow water, São Tomé and Príncipe arose some 2 to 4000m up from the ocean floor and thus have never been attached to mainland Africa; this means that the ancestors of all the plants and animals that are found on the islands today must have crossed hundreds of km of deep salt water to get there (dispersal) - this only occurs over time and is successful only by random chance. The colonizers that make it and survive are then separated from their mainland founder populations and over time begin to accumulate genetic changes, a process we all know as evolution.
The forest at 1400 m. Sao Tome GG II (D. Lin phot)
In the case of São Tomė and Príncipe, there’s been plenty of time for this to occur as São Tomé and Príncipe are very old islands. It is fact that the Hawaiian Islands and the Galapagos are only about 5 million years at the oldest; compared with the Gulf of Guinea islands, these two famous and well-studied archipelagos are relative infants! Solid geological evidence tells us that São Tomé is at least 15 million years old, and Principe is more than twice that, at over 30 million years. This is a very long time for successful dispersal, long-term isolation and evolution to take place, and it has — in spades! The evidence can be found in the high numbers of endemic plant and animal species that still inhabit the higher elevations on the two islands – species that are found nowhere else in the world.
Endemic Newtons sunbird Sao Tome GG II (J. Uyeda phot)
Sao Tome, view SW from 1400 m. GG I (RCD phot)
Sao Tome fruit bat GG II (D. Lin phot)
Among the vertebrates, more than half of the 49 species and subspecies of land birds breeding on São Tomė and Príncipe are endemic, and they include the world’s largest sunbird, the world’s largest weaver and the world’s smallest ibis. Mammals make poor over-water dispersers (high metabolic rates) so as we would predict, endemic mammals are limited to a couple of bats and two shrews that have not been well studied. There are no endemic freshwater fish on the islands, but our first two expeditions yielded many more species in the rivers and streams than previously recorded. About half of the reptile species on the islands are unique to them; one of them is the largest lizard in its genus, Greef’s gecko (Hemidactylus greeffi). But most surprising of all is the presence of an amphibian fauna, especially because due to the nature of their permeable skin, amphibians almost never cross saltwater barriers; they are considered among the poorest dispersers, along with freshwater fish. Not only are six unique frog species present (we just described a new one), there is also a legless amphibian known as a caecilian that is found only on São Tomė; its nearest relative is found only in East Africa, thousands of miles away.
Sao Tome endemic caecilian “cobra bobo) GG I (D. Lin phot)
Principe giant treefrog GG I (D. Lin phot)
The invertebrate species and flora are also remarkable; so far as is known, about 14% of the flowering plants are endemic, including the world’s largest Begonia at 2 meters ! More than half of the ladybugs and spiders, 80% of the stag beetles and 2/3rds of the terrestrial snails are found nowhere else in the world; but these data are based on very limited sampling much of which was done in the late 19th Century, this is one of the reasons we are here. [Begonia ebaccata]. [bubba]
Begonia baccata Sao Tome.. world’s largest GG I (D. Lin phot)
J. Ledford with Sao Tome tarantula. GG I (D. Lin phot)
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.
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I am Dr. Robert (Bob) Drewes. I am Curator of Herpetology at the California Academy of Sciences and specialize on the evolutionary biology and natural history of African reptiles and amphibians. During my entire career, spanning over three decades, I have conducted virtually all of my field work in Africa. Since 2001, I have been leading multidisciplinary research expeditions to the Gulf of Guinea, and our progress and activities are described in this blog.
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Island Biodiversity Race- The Race: New Species or What’s in a Name?
- The Race: New Fish Excitement
- The Race: Taming of the Shrew (and updates)
- Within the House of Slytherin (II. some snakes)
- The Race: Bad News/Good News
- The Race: Return of the Marines Redux!
- The Race: Return of the Marines!
- The Race: Within the House of Slytherin (I. Lizards)
- The Race: A Toad Less Traveled
- The Race: Strange Bedfellows (Part II)