The Race: New Fish Excitement
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, fish, principe | Date: Jul 09 2009 | By: islandbiodiversityrace
Our colleague, Ricardo Lima, currently working on São Tomé has sent us another exciting photo; not of another São Tomé shrew this time, but of a large fish that we somehow missed during the island river surveys of GG I and GG II.
Led by Dr. Tomio Iwamoto, we surveyed all of the major rivers on both São Tomé and Príncipe in 2001 and 2006. As a result, Drs. Iwamoto and Petzold published a paper on the freshwater gobies of the islands, and later Dr. Iwamoto was one of the authors of the updated Checklist of Coastal Fishes of São Tomé and Príncipe Islands. This checklist is based on a great deal of our expedition material. Regardless, the fish that Ricardo has photographed was not included in either work and at the moment we have no idea to which species it belongs.
“Charroco“ R. Lima phot. 2009.
Quintino Quade and Dr. Iwamoto on Sao Tome. D. Lin phot. GG I
It is a fairly large fish and well-known by the local Sao Tomeans as “charroco ” Ricardo tells us, “I was told by an old man that lives in S. Jose (Binda), that he used to fish these upstream. But this photo is from the other [east] side of the island, near EMOLVE, the big oil palm plantation! I’m not sure where they got the animal, but I think it’s widespread, and according to the people who fish them, it lives in holes under the rocks. The specimen I photographed is not very big for the species. According to them, it can get much bigger, but they eat even the small ones, deep fried!”
Tomio and Drewes on Principe. D. Lin phot. GGI
Dr. Iwamoto has sent Ricardo’s photo to two other experts, Dr. Lynne Parenti of the US National Museum and Dr. David Greenfield of Monterey, California, and both agree that this is probably a member of the Family Eleotridae, or “sleeper gobies”. During our surveys, we caught other species of this family, one of which is pictured below; but at the moment, we seem to have another unidentified species from the Gulf of Guinea and will have to work to obtain more material and identify it.
A Sao Tome eleotrid fish. RCD phot. GG I
The Parting Shot:
A beach on north Principe. R. Wenk phot. 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.
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.
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: A Toad Less Traveled
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, frogs, gigantism, principe | Date: Dec 15 2008 | By: islandbiodiversityrace
Sorry, I love titles like this… and I have more! Actually, there are no toads (Bufonidae) on São Tomé and Príncipe; interesting in itself because seven other amphibian species of five different families have survived the ocean crossing during the many millions of years since the islands first emerged. Moreover, toads are common in almost every conceivable terrestrial mainland habitat.
My last two blogs have been a bit academic. Having laid the biogeographical ground work, it is probably time to get back to the unique, endemic island critters. The tiny, 31-million year old island of Príncipe is the only home of Africa’s largest treefrog, Leptopelis palmatus – the Príncipe Giant Treefrog. It is one of the world’s rarest frogs, as well.
L. palmatus – D. Lin phot. GG I
Let me be quick to point out that the Príncipe critter is not Africa’s largest frog; that title belongs to Conraua goliath (below), which is found on the mainland in southern Cameroon and Gabon. In fact, the goliath frog is the largest in the world but it is not related to any on São Tomé and Príncipe– no members of its family have made it across the saltwater gap to the islands, or if they ever did, they have not survived.
Conraua goliath—J.-L. Perret phot.
Leptopelis palmatus is the largest African treefrog (emphasis on “tree”) — frogs that are adapted for climbing with, among other features, enlarged finger and toepads. As I have pointed out in earlier blogs, gigantism is a relative thing; the giant endemic plants, frogs, birds and lizards of São Tomé and Príncipe are bigger than all of their relatives but they are not necessarily so large you trip over them (like Galapagos or Aldabra tortoises); they are simply larger than all of their relatives. The two images below put this frog in some perspective, and I think you will agree that this is one BIG treefrog.
Me, with the first female. R. Stoelting phot. GG I
The frog on Dong Lin, our photographer. R. Stoelting phot GG I
This species was first described in 1868 on the basis of a single female specimen, housed in the Berlin Museum. At the time of GG I in 2001, the Príncipe giant treefrog was known only from this single type specimen and seven additional specimens, all females, collected by local Príncipeans for a Swiss colleague named Catherine Loumont. The largest of Loumont’s specimens is 110 mm from snout to vent (we do not include legs when we measure frog sizes), and even after our years of work, this specimen remains the largest ever found – it is nearly 30 mm longer than the largest of its nearest mainland relative, Leptopelis macrotis, distributed from central Sierra Leone to Ghana. One of several differences between the two species is the striking deep-red eyes of our island endemic.
The eye of the Príncipe giant treefrog. D. Lin phot. GG II
This first specimen we found during GG I (first three treefrog images, above) was yet another female, 108 mm in length. Our mammalogist, Doug Long, was led to the critter by some kids from the now-defunct plantation of Sundi in northwest Príncipe. Sundi may no longer function as a plantation but it is still inhabited by the descendents of former workers—lots of them, there is even a mayor.
Doug Long and the Sundi kids. RCD phot. GG I
The arrival of this frog was greeted with great enthusiasm by yours truly; here in my hands one of the rarest frogs in the world! And it was huge! I was not surprised to learn that it had been found on the ground, as it is hard to imagine something so bulky climbing around in bushes and trees. The male of this species was completely unknown, so far as we knew at the time,. None had ever been collected, photographed nor described in the scientific literature. So we also knew nothing about the species’ breeding biology, male advertisement call or tadpole. At the time, we were unaware of a blog posted two years before our visit by Jonathan Bailey on the Gulf of Guinea Conservation Group website, entitled “One month in the Forest of Príncipe.” Jonathan (now Dr.) Baillie described hearing the calls of male L. palmatus as “like a pop bottle being continuously opened.” He heard them high up on Pico do Príncipe near a small stream at about 700 m and actually collected two of them which had been deposited in the Natural History Museum in London. But during GG I, the male giant treefrog was terra incognita, so far as we were concerned.
Second female from Rio Papagaio. J. Ledford phot.. GG I
During a second GG I visit to Príncipe a few weeks later, my then-graduate student, Ricka Stoelting, collected another female along the Rio Papagaio, a large-ish river that flows through Príncipe’s only town, Santo Antonio. It was also of a rather dull in color but with white spots. We have since learned that this is about as brightly colored as females get.
Rio Papagaio in town, downstream. RCD phot. GG III
Ricka Stoelting, my graduate student on Sao Tome. RCD phot. GG I.
During this second visit, Ricka and Dr. Sarah Spaulding ascended Pico do Príncipe to the top and camped at nearly the same spot where Jonathan Baillie had been two years before. There she found the males, lots of them, calling from bushes and branches at night near a very small creek.
Tiny creek on the Pico. J. Uyeda phot. GG II
Ricka brought the series of males back down the mountain, and they were astounding. Unlike the females they were very brightly colored and highly variable, in pattern, as well; this variability is rather unusual in frogs, although there are some species that are sexually dimorphic for color. And they were much, much smaller than the females, though we knew they were full-sized breeding adults. During later analysis we learned that the largest breeding males are only about 41% of the size of the largest females, a size disparity that is striking.
First series of live males (far right is a juvenile). J. Ledford phot. GG I
Ricka never heard them calling and anyway she had no way of recording them if they had. One of the parameters we use in establishing relationships among frog species is analysis of the voice (or advertisement call.). Males call to attract females, and at the same time to advertise their presence and territory to other males. The advertisement call is species- specific and obviously adaptive when there are other species utilizing the same water for breeding. To really define Leptopelis palmatus, I needed a recording of the voice, and this was to become a priority in the future. Below is a preliminary analysis of the call of another Gulf of Guinea frog species which we think is present on both islands. Here, we are comparing the advertisement calls of males from two different localities on both islands, and we can see that they are basically the same.
Preliminary sonograms of Oceanic treefrog. Marshall/Drewes construct.
Back at the Academy, Ricka and I prepared the first formal description of male Príncipe giant treefrogs. Now aware of Baillie’s blog, we read his word description of the advertisement call. Although the Principeans insisted the frogs did call, it remained an open question, especially when I learned from anatomical study that the male frogs lack vocal sacs and vocal sac openings, features that most calling frogs possess (including other members of the genus Leptopelis). GG II in 2006 included Josef Uyeda as my student (now a PhD candidate at Oregon State University). Josef was working on a different group of island endemics called puddlefrogs (see earlier blog: “We Find Jita”) but when we were on Príncipe, I sent him up the Pico with his friend Mac and the same guide, Manona, who had led Jonathan Baillie and Ricka years before. They were armed with my old Sony cassette recorder (my iPod had failed). Bear in mind that the only known localities for males were at nearly 700 m, high on the Pico and while this made no biological sense, that’s where my stalwarts had to go. This is no small matter given the topography of the island, but graduate students are good at this sort of thing and anyway, they tend to be younger and more vigorous than their advisors!
Principe terrain. Pico do Príncipe is in the clouds to the left of the large Pico Papagaio. R. Wenk phot. GG III
Josef Uyeda hunting for caecilians on São Tomé. D. Lin phot. GG II
While in the same general area as earlier workers at about 700 m, Josef got a lot done but the party was caught in heavy rains. He heard males and saw them calling but only managed some rather distant, poor-quality recordings (the conditions were miserable), but now at least we knew that the frogs did, indeed, call. GG III, last spring, provided some answers, thanks in part to our friend Ramos of Bom Bom Island. Ramos is assistant manager of the resort, a native Principean and a keen, observant naturalist. See the photo of Ramos in the “We Find Jita” blog. I described our past difficulties in trying to record the voice of the Príncipe giant treefrog to him, and he grinned and said, We will go to my roça (farm) on Pico Papagaio and at 5:30, we will get them! I was highly skeptical…
Roça Papagaio, Ramos’s farm at 250 m. R. Wenk phot. GG III
Ramos’s farm is in the forested area on the northern flanks of Pico Papagaio at about 250 m. Just before you reach it on a dirt steep uphill road, you cross a tiny creek; this is where Ramos took us – about 30 m up that small creek, thick with dense undergrowth, and there we sat, waiting for the forest cacophony of grey parrots, mona monkeys to subside. Nothing much happened. I had my iPod with recording head at the ready. We waited in the gathering gloom for about 20, maybe 30 minutes, Ramos grinning throughout and occasionally exclaiming, Just wait. We will get them!
Me waiting, iPod in hand, for the giants to call. T. Daniel phot GG III
And sure enough, we began to hear frogs calling. I looked at my watch. It was 5:30. The call is certainly a strange one; it lacks resonance (remember males don’t have a vocal sac) and thus it is rather flat and unmelodius. Rather than my trying to describe it or arguing with earlier descriptions, you can listen to it yourself by clicking this link:
And here are a couple of photos of the male that was calling, taken by Wes. These are un-posed and taken before we collected it as a voucher specimen for the voice:
Weckerphoto GG III
Weckerphoto - GG III
There are still great gaps in our knowledge of this most unique frog. Obviously, the males are well-distributed in the lower elevations; we just have not been in right place at the right time. We still cannot explain why females are dull and rather cryptic in coloration and usually found on the ground, while there appears to be no selection for color in males. The dull color of females seems consistent, as a couple of months ago I found six additional females (no males) collected in 1988 at the Doñana Institute in Seville and they were clearly drab in life; my colleagues at Donana tell me they were collected on the ground in lowland localities at Rio Papagaio and Bela Vista.
Six female Seville specimens at Donana Institute. RCD phot.
We still have not observed breeding, nor have we ever seen tadpoles. In this genus, Leptopelis, they are very distinctive, and I would predict the tadpole will look like this:
A Leptopelis tadpole. Image courtesy of Dr. R. Altig
Here’s the parting shot:
Nezo, of Angolares, Sao Tome: artist, musician, restaurateur and worthy man - Weckerphoto GG III
PARTNERS We gratefully acknowledge the support of the G. Lindsay Field Research Fund, Academy Research Venture Fund of the California Academy of Sciences, the Société de Conservation et Développement (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, Salvador Sousa Pontes and Danilo Bardero of the Ministry of Environment, Republic of Sao Tome and Principe for permission to export specimens for study, and the continued support of Bastien Loloumb of Monte Pico and Faustino Oliviera, Director of the botanical garden at Bom Sucesso. Special thanks for the generosity of four private individuals, George F. Breed, Gerry F. Ohrstrom, Timothy M. Muller and Mrs. W. H. V. Brooke for making these expeditions possible.
The Race: Strange Bedfellows (Part II)
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: Matters of Currency
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, invertebrates, principe | Date: Jun 30 2008 | By: islandbiodiversityrace
Yes, the title is a play on words, and given the great threat posed to the unexplored natural environments of these two little unique islands by future oil revenues, I suppose a more appropriate title would be “Matters of Urgency,” but I couldn’t help myself. In this posting I want to talk about the work of Dr. Richard Mooi, who was with us on GG II. 
Rich stalks an unsuspecting sea urchin on São Tomé. D. Lin phot. GG II.
Dr.Rich Mooi is a Curator in our Department of Invertebrate Zoology, but more importantly to us (and to the blog title!), he is one of the world’s authorities on echinoderms, a large phylum that includes sea urchins, seas stars and what we Americans call “sand dollars,” the flat, disk-like tests (endoskeletons) of which we find commonly on our beaches. One of the most fascinating, yet poorest known sand dollars in the world is Rotula deciesdigitata, known only from the Gulf of Guinea. This species is probably not really rare but the places it occurs are remote and not frequently visited by scientists. Hence, they are super-scarce in the world’s natural history collections; even more so in North America.
Technical photo. Rotula deciesdigitata.
The unit of currency in the Republic of São Tomé and Prìncipe is the Dobra; there are about 15,000 of ‘em to the US dollar. Here is a photo of a bunch of dobras drying on my bed at Bom Bom Island on Principe. Why? Well, the wonderful folks at Bombom Island and SCD allowed us to attempt to survey by boat the otherwise inaccessible southwest shore of Prìncipe; at a critical point, too many of us climbed into a small red dinghy and flipped in the surf. Along with the dobras went a lot of equipment including cameras, my cell phone, ipod, etc.—more on this in another posting.
Drying dobras RCD GGIII
The offending boat, post-flipping. Weckerphoto GG III
Anyway, once we finally found specimens of Rich’s Rotula, it was only natural that they become “sand dobras,” and the only beach we have found them on the west side of Sao Tome became Sand Dobra Beach– its real name is Praia Morrão.
Rotula deciesdigitata on Sand Dobra Beach. D. Lin phot. GG II
During GG II, Rich and I swam out beyond the surf line to try to secure a live specimen for DNA analysis (remember, the test you find on the beach is not the living animal, but rather its endoskeleton). The undertow was so powerful that we both nearly drowned, but we did find one specimen that retained a greenish color, suggesting that there might be some remaining tissue to analyze; the jury is still out on this. The sand dobras present a rather interesting mystery, in that they appear to be wholly unrelated to those of the New World, while such might not be the case with other echinoderms. In his own words, Rich says “this strange pattern is further underscored by the fact that as I looked at all the other echinoderms around Sao Tome, the faunas were nearly perfectly Caribbean in nature. There were times that I felt as though I was snorkeling around in Florida or Belize — at least as far as the sea urchins were concerned. The rotulids were a glaring exception to that.”
Rich working. D. Lin phot. GG II.
Interestingly, there are many species with holes and notches in them throughout the Caribbean. These are almost all members of a sand dollar family known as the Mellitidae. However, there are absolutely no mellitids on the west coast of Africa. In fact, there are no “true” sand dollars at all. The truth is that the Gulf of Guinea sand dobras are not even closely related to the Caribbean sand dollars, but belong not only to a different family (Rotulidae), but to a completely different major clade (suborder). This is perplexing.
Rotula deciesdigitata on Sand Dobra Beach. Weckerphoto GG III
Dr. Rich Mooi is still working on the many fascinating echinoderms he collected on the beaches and tidepools of São Tomé and Prìncipe in 2006, and I will report his discoveries as they appear.
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: Glorious Ghost in the Forest
Category: Biodiversity, Gulf of Guinea, Island endemics, Sao Tome, frogs, gigantism, principe, snakes | Date: May 27 2008 | By: islandbiodiversityrace
Scientists love islands because the processes of evolution on islands are simpler than they are on more complex, much larger continents and thus more easily studied. I have made the point that the islands of Sao Tome and Principe are very poorly known, but what we do know is very exciting. One evolutionary pattern that seems to consistently appear on islands is the phenomenon of gigantism; for some reason certain successful colonizers become very large on islands: for instance, think of the tortoises on the Galapagos Ids. or on Aladabra. There are a number of hypotheses that attempt to explain this phenomenon, but none is particularly compelling; nevertheless, the pattern exists and is very evident on the oceanic Gulf of Guinea Islands. The composite image below illustrates just a few of the giants on Sao Tome and Principe.
Some Island Giants
Think of potted plants for a moment… how large is a begonia? The central plant in this composite image is the largest species in the world, Begonia baccata. It is found only on the island of Sao Tome and reaches 10 meters in height! This particular specimen graces the southern shore of Lagoa Amelia at about 1480 m elevation - my head comes up to about flower level on this old friend (I am 6′ tall); these enormous plants are common at higher levels. The two birds figured are also giants: the yellow one on the right is the world’s largest weaver. Ploceus grandis,. and the one on the left is the world’s largest sunbird, Dreptes thomensis; both endemic to the larger island of Sao Tome. This is a good point at which to mention that island dwarfism is also an observable phenomenon here as well, and the world’s smallest ibis, the Sao Tome Dwarf Ibis, Bostrychia bocagei is also an endemic. The other critters in the collage, the frogs and the lizards, are all endemic giants but I will deal with them later. It is important to bear in mind that when we call a species a “giant”, we are describing its size compared to all of its other relatives only; such a species may not appear to be a giant at all, in our eyes.
The Sao Tome Giant Treefrog, Hyperolius thomensis, and I go back a long way; back to when I was writing my doctoral dissertation many years ago. This sapo (as all frogs are called on the islands) is endemic to Sao Tome only and is easily the largest member of its genus (Hyperolius)- females reach lengths of nearly 50 mm.from snout to vent!
Sao Tome Giant Treefrog, Hyperolius thomensis.GG I and GG II - D. Lin
Nearly all of the original material from which this species was described in 1886 was destroyed in the fire in Lisbon. But I managed to find four remaining specimens, two in Vienna and two at the Natural History Museum in Vienna, allowing me to treat them in my dissertation. In 1988 and again 1990 more specimens were reported by a Swiss worker, but her published locality data are very general, if not vague, and it turns out that most of the material she worked on was collected by locals at her request prior to her arrival. During GG I, we visited most of her reported localities, finding nothing until we finally got lucky. Now, I can state that this most flamboyant of treefrogs is currently known for certain from only a single locality! Our work in GG I, II and III has confirmed that this marvelous critter is known only from higher elevations (above 1000 m), inhabiting the canopy of old secondary or primary growth trees on steep slopes. And it appears to breed only in the water-filled holes in trees with fluted bark or buttresses. This is a rarity – in Africa, only 9 other frog species are known to breed in phytotelmata (scientific word for treehole). But it makes sense. Most frogs lay eggs, which develop into free-swimming, gilled tadpoles, which then metamorphose. Although there are many fast moving rivers on the steep slopes of Sao Tome, these are far to swift for breeding; still bodies of water simply do not exist. So, H. thomensis has adapted to breeding in ephemeral, rain-filled holes in the trunks of very large trees! All of the other frogs native to the islands utilize slow moving or still water for reproduction.
The tree - J. Clara, GG III
This is the only tree in which we have collected the Sao Tome Giant treefrog. It is at about 1100 m on a high ridge, and we return each expedition to check its status. Adults are usually present but there are always eggs and tadpoles at different stages of development in the holes. Tom and Rebecca, our botanists, could not identify this tree – it is simply too tall its see its canopy, and moreover it is festooned with epiphytes.
Frogs and eggs in treeholes - WE, GG III
Wes Eckerman, our photographer tried to climb it, and then tried to climb an adjacent tree to see if there were more holes, but the tree is just too big in girth to handle; with our friend Jose Clara, we tried to erect a crude ladder to examine a hole farther up the trunk but to no avail.
RCD, GG III
I do not mean to imply that this species is restricted to this tree. We have heard the species calling at night from high up in the canopy and reasonably certain that it is pretty widespread, at least in the high elevation forests we have visited – I suspect it is present on Sao Tome anywhere the trees are large enough and that. of course. means upslope above the former Portuguese plantations. What is different about this single documented tree is that it is the only one whose rain-filled holes are within our reach – there are undoubtedly more holes in many more trees that are too high for us to access. I am left with the notion that given its restricted range and peculiar breeding biology, the Sao Tome Giant Treefrog is a classic indicator species; its presence means healthy mature forest. If I were to choose an icon to symbolize the dogged persistence of pockets of nature in the face of man’s depredations and at the same time the attitude, beauty and whimsy of the citizens of Sao Tome and Principe, it would be this gorgeous island giant. Josef, my former student, informs me that he has already seen the name of this species on a price list in the pet trade in Europe. If you wonder why I have not described the location of this tree is in more detail, now you know.
In the last posting, I promised you a picture of the cobra jita of Sao Tome. Here are shots of both island forms, which are currently considered to be the same species.
Sao Tome Jita - RCD, GG I
Principe Jita - WE, GG III
Not only do these critters look different from those on Sao Tome (stripes vs. patterned blotches), they act differently as well. On Sao Tome, cobra jita appears to be strictly nocturnal; during GG I and GG II we easily found them at night by first listening for the loud choruses of oceanic treefrogs (more about them later). So far as we know, the Sao Tome jita largely feeds on these frogs while they are breeding and is strictly nocturnal; to see at least ten of these snakes in a single night under the right conditions is not uncommon.
R. Stoelting, my grad student, with her first Jita - GG I, RCD phot. After our week on Principe, however, I am prepared to say that that jita is diurnal and although we will not know until we check stomachs, I think it feeds on lizards and small rodents. We even located a chorus of treefrogs behind Bombom but failed find a jita, nor did we ever find one during our night hunts. Only time and careful study of morphology nd DNA will tell us how closely related these two island snakes really are.Thanks to Caitlin D. for her generous donation. We are doing what we can!
PARTNERS We gratefully acknowledge the support of the Research Investment Fund of the California Academy of Sciences, the Société de Conservation et Développement (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/ and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making GG III possible.
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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)