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Gulf of Guinea Expeditions 

March 5, 2014

The Race: The Amphibians of Sâo Tomé and Príncipe, and the Eighth Expedition

The Biodiversity Education team has been hard at work on our product for GG VIII, of April, 2014.  The 2000 students we have been visiting since the 3rd grade are now in the 5th grade and will be moving on next year, so this is our last visit with them.  We have produced a slightly more technical biodiversity booklet (livreto) for each of them. This cohort represents slightly more than 35% of the island studentsin their age group.

bio reader small

NOSSAS PLANTAS E ANIMAIS ESPECIAIS.

 

2014 BioTeam

The Bio-education team in my Lab: Roberta Ayers (senior educator, and translation – on Skype), Velma Schnoll (Project Manager), Lindzy Bivings (education advisor),Jim Boyer (art work and layout), Tom Daniel (science text).Absent: Mike Murakami (graphics), me..

Just recently a great new book was published called The Monkey’s Journey, by Alan de Queiroz.  An entire chapter (6) is based on our hypothesis as to how amphibians and many of the other unexpected, endemic animals originally crossed over to the islands from the mainland.

alans book

One of us has made an exciting discovery recently (see below) which prompts me to reacquaint readers with the amazing amphibian fauna of Sâo Tomé and Príncipe.  As readers already know, there should not be any amphibians on these islands at all;  they are true oceanic islands which have never been attached to the African mainland, and amphibians have no tolerance for saltwater. There are no native amphibians on the Galapagos or the Hawaiian Islands for this reason. Yet, there are seven species on our islands, possibly eight – all unique and found nowhere else in the world!  The most unlikely of these is the famous “Cobra bobo” of Sâo Tomé.

Q hand shot

Cobra Bobo in the hands of Quintino Quade of Sao Tome. D. Lin phot – GG I

live bearing and collage

 Upper left, unknown phot, upper right, RCD GGI, lower, R. A. Nussbaum

The cobra bobo (Schistometopum thomense) is a caecilian, part of a group of amphibians only distantly related to frogs and salamanders. They are found almost exclusively in the Old and New World Tropics. About 25% of the 200 species lay eggs, the rest, including our cobra bobo give birth to living young (see above).

unique chars

Although they look very much like earthworms, caecilians have backbones, teeth and a vertebral columns. (above lef-UCL photot). Most are burrowers although some are aquatic, but all caecilians lack legs, tails and have reduced eyes, and they are the only amphibians that have sensory tentacles located on each side of the head, between the nostril and the eye (above right – different species-J. Measey phot.).  These are protruded to sense prey items and the environment.

The cobra bobo is widespread under moist leaf litter, old banana stems, etc from sea level to as high as 1400m, at Lagoa Amelia. Although they are totally harmless, they are widely feared by the islanders, which is the reason we use a cobra bobo cartoon for our expedition logo (see earlier posts). We are attempting to demystify it. One of the most interesting things about this endemic species is the distribution of its closest relative.

schisto dist.

Note that several thousand km separate the two known species; the red ? indicates a single old specimen in Brussels from the Ituri region of Zaire that might also be a member of the same genus.

A frog unique to Sâo Tomé is Newton’s rocket frog, Ptychadena newtoni. There are over 50 species recognized on the African mainland, but this endemic is by far the largest of the genus, with females attaining lengths of over 60mm. This qualifies Newton’s rocket frog as a true “island giant.”

adult Ptychs

Newton’s rocket frog. above phot RCD- GGI, below A. Stanbridge,-GGVI

Early records suggested it is a frog of streams and rivers in the northern lower elevations, but we have found its larvae as high as Java, at 600m, and in recent years, Hugualay Maya of ABS has discovered the species in river drainages farther south down the west coast. (pink markers).

P newtonii localities

Known localities for Newton’s rocket frog. RCD construct

Frog larvae (or tadpoles as they are often known in English) are used in identification of species by scientists, as well as the study of adults and are formally described.

newtoniX

Ptychadena newtoni.  above, whole larva; below are mouthparts] drawings -Dylan Kargas.

An extremely interesting fact about Newton’s rocket frog is the location of its closest relatives.  Like the cobra bobo, the species of Ptychadena genetically closest to our island frog are eastern species, not Central or West African.

ptcy dsit

This study included 108 rocket frog samples from all over sub-Saharan Africa, including the Nile drainage, Madagascar and the Seychelles.

Another endemic island giant is Príncipe’s giant treefrog, Leptopelis palmatus. In fact, the first specimen ever collected and described nearly 150 years ago was a female measuring 110mm from snout to between the legs. This is the largest ever recorded for the genus.  The largest specimen we have collected was a 108mm female, during GG I near Sundi.

large female

 Sundi female of 108mm. D. Lin phot-GG I

big lepto and male

Left:  same female, R Stoelting phot. GG I; right: Pico Papagaio male, just after calling.  Weckerphoto GG III

There are a number of strange things about this species; the females are usually always dark to dull green, while the males come in a great range of color patterns, some quite bright (polychromatic- see below). Moreover, the largest males are usually less than half the size of the females (above and below).  While we were the first to record its call, this is the one species on both islands for which we have no data for eggs or larvae. Most large females have been found in the lowlands of Príncipe, while males seem to be common up to 700m on the Pico.

polychromatism

Three males and a juvenile Principe giant tree frog.  J. Ledford phot- GG I

lepto nearest

Distribution of the Príncipe giant tree frog and its closest mainland relative, L. macrotis.  This may suggest that the ancestor of both rafted from the Niger River delta into the Gulf of Guinea.

Both islands have small species of puddle frog, Phrynobatrachus, that are widely distributed on both islands in leaf litter, and breed in temporary puddles of water. Both island forms were thought to be the same species (they are tiny and remarkably similar to the untrained eye) until we discovered that they were genetically quite distinct species with physical differences.

dispar principe

The Príncipe puddle frog, Phrynobatrachus dispar, can be found in wet areas from sea level to the top of Pico do Príncipe. While we have its larvae and eggs, we have not yet described them. D. Lin phots-GG II.

leveleve comp

The Sao Tome puddle frog, Phrynobatrachus leveleve  is very similar in appearance to the Príncipe species but there are great genetic differences and physical differences as well.  Like its relative on Príncipe, it is broadly distributed in wet areas from sea level to very high elevations. RCD phots, GG VI.

Its larval characteristics can be seen below.

leveleveX

Drawings: Dylan Kargas

Like the other amphibians, the distribution of the nearest relatives of our two island puddle frogs is intriguing.

phryno phylo

According to a recent study, Príncipe’s puddle frog, P. dispar is most closely related to a population in the Caprivi Strip of Namibia, and together their nearest relative is P. leveleve of Sâo Tomé. The interesting thing to notice is that all of the other members of this lineage, called a clade and defined by the purple box, are East African species.  This is reminiscent of the rocket frog and cobra bobo distributions.

Returning to island giants, we have the Sâo Tomé giant treefrog, Hyperolius thomensis. There are well over 200 species of this genus known from the African mainland, and females of this Sâo Tomé endemic are by far the largest at just under 50mm.

thom adult 2

D. Lin phot- GG I

thom adult1

D.Lin phot. GG – I

 thom amplexus

Breeding pair of Sao Tome giant treefrog. D. Lin phot, GG II

This large flamboyant tree frog appears to largely be a tree canopy dweller.  We have discovered that eggs are laid in water-filled holes in trees (phytotelmata). They can be heard calling from treetops but are extremely difficult to locate; in fact all of our specimens have come from a single locality at around 1100m; we monitor this locality every year and keep its exact location a secret.  We have described the larval characteristics, below.

Hyperolius thomensis tads

 Drawings by Dylan Kargas

Our last endemic species is closely related to the Sâo Tomé giant tree frog, although it is much smaller and not so brightly colored: Hyperolius molleri, the oceanic tree frog. Since our work began, it is the only remaining amphibian that has been thought to inhabit both Sâo Tomé and Príncipe.  In fact, years ago an early intern of mine, Katie Marshall, compared the two populations using mitochondrial genes and found no significant differences between them; they are certainly extremely similar morphologically ( see below).

2 molleris

Above, Weckerphoto GG III; below, RCD phot GG I

Recent work by Rayna Bell, our Cornell colleague (GG VI, VII) included a reanalysis of the two populations with more advanced technology, and indications are that the two populations may be quite distinct genetically. If this turns out to be the case, the Príncipe population will require much closer morphological examination and redescription, bringing the total number of endemic amphibians on our islands to eight!

While this small green tree frog appears to be a lower elevation dweller on Príncipe, on Sâo Tomé it reaches at least 1400m and can be heard calling at Lagoa Amelia. Like most other members of the genus, eggs are laid on leaves above water, the developing tadpoles ultimately wiggling out of the jelly mass and falling into the water for further development.  We have studied the larvae of the big island form (the original Hyperolius molleri- the species was described based on a specimen from that island) and the characteristics are below.

Hyperolius molleri ST

Drawings by Dylan Kargas

The team leaves for the islands in early April; our mission for GG VIII will largely be on biodiversity education as I mentioned in the beginning, but we will continue to post on our progress while there.

Until then, here is the parting shot:

b-b kingfisher Bronkhorst

The brilliant Blue-breasted kingfisher of Principe Island.  Photo by Michael “Bobby” Bronkhorst, 2014

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


May 3, 2013

The Race: GG VII—We Reunite and Part Again

After two hectic weeks of education activities on São Tomé, Rayna Bell (Cornell University) arrived and the four of us joined the botanists, Tom Daniel, Jim Shevock, Miko Nadel, Tamas Szuts (our spider guy) and Andrew Stanbridge (our photographer) on Príncipe.   I  have asked Andrew, a veteran of three Gulf of Guinea expeditions, to illustrate some of what transpired while the group was divided.

blog-1

Our botany team, day one on Principe: Jim Shevock, Tom Daniel and Miko Nadel.

blog-2

Botany team en route to climb the mesa. Back left in the yellow hat is our guide Baloo.

blog-3

Jim on the “trail” to the mesa.

blog-4

Male Leptopelis palmatus found on the trail to the mesa. The females are the largest tree frogs in Africa.

blog-5

Tom discovers Principina, a unique sedge.

 blog

Miko on top of the mesa

blog-6

Jim and Tom collecting specimens along the route to Roça Sundy.

blog-7

First Academy visit to the offshore island “Jockey’s Bonnet”.

blog-8

Bonnet seedeater, unique to the small island of “Jockey’s Bonnet”.

blog-9

Tom carrying specimens upriver.

blog-11

Tamas and “Bobby” Bronkhurst pooting spiders on Jockey’s Bonnet.

 

Here is the parting shot.

parting

 

All images by Andrew Stanbridge

PARTNERS:

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

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


January 4, 2013

The Race: Peregrinations of a Pinniped (Our Islands get Seal of Approval)

I have recently learned from my island friend Madalena Patacho of Bom Bom Island that a Cape fur seal (Arctocephalus pusillus) was seen and photographed on a beach at the north end of Príncipe Island and was also later seen by a number of islanders along the São Tomé coast.

The Cape (South African) fur seal, Arctocephalus pusillus at Praia Sundy, Principe Id. December 2012. photo by Jamili

Why is this noteworthy? It is special because although vagrant individuals of this large species have occasionally been seen as far north as the southern border of Angola, the nearest breeding colony of Cape (or South African) fur seals is just under 2,700 km south of Príncipe, at Cape Cross Namibia!  This is almost exactly the same distance as between Príncipe and Kampala, Uganda.

My colleague, Bastien Loloum works for MARAPA, an NGO on the islands heavily involved in marine life and conservation. Bastien is coordinator of a cetacean  monitoring program there. So far they have recorded ten species of cetaceans but he informs me that there are no formal records of the Cape fur seal in the islands waters.  However, he and his colleagues think that this is may be the second or third account of a vagrant fur seal there during the past decade.  This would be rare indeed, but for reasons given below, I am not too surprised.

Map from  IUCN Red list.

The Cape or South African fur seal is the largest of its kind (Otariidae= fur seals + sea lions; true seals lack external ears and belong to a different family, the Phocidae); males reach 2.27m in body length and 360kg in mass. Females are much smaller. As the map shows, this species lives and breeds along the South African and Namibian coast. There are about 23 major breeding colonies, and there are population estimates of over one million individuals. In 1992,  I was fortunate to explore the Skeleton Coast of Namibia by air from Capetown to about 16º south latitude, and the Cape fur seal colonies were impressive to say the least.

Above the Namib coast;  RCD photo 1992

Above the Namib coast;  RCD photo 1992

Later and somewhat farther north, we were able to approach a colony by land as there were intervening rocks disguising our presence.

On the Namib Coast.  RCD phot. 1992

On the Namib Coast. RCD phot. 1992

Note the conspicuous external ear which is one characteristic that differentiates these mammals from true seals. RCD phot. 1992

The key to understanding how these enormous populations of large pinnipeds are sustained, and how one individual might have arrived in the Gulf of Guinea 2700 km to the north lies in understanding the nature of the Benguela Current which flows up the west coast of southern Africa. The Benguela is a cold current and is thus highly oxygenated water. This supports vast amounts of plankton which in turn provide sustenance for a huge marine fauna “higher up the chain.” In fact, the Benguela Current is one of the richest fisheries in the world.

Notice the persistent, thick, slightly discolored foam on the shore which indicates high plankton content in the water. RCD phot. 1992

A major factor important to our seal story and indeed, perhaps to the early colonization of the Gulf of Guinea islands’ unique plants and animals, is the fact that the Benguela Current flows from South to North and has undoubtedly done so since the Atlantic Ocean opened up in the Cretaceous.

Dominant currents in  the Gulf of Guinea and South Africa.  CAS construct

As the map shows, the Benguela flows north past the Congo River Delta. At the same time, the Guinea Current flows West to East across the Niger Delta. These two currents converge in the Bight of Benin to form the South Equatorial Current, and this major current flows due West, directly through the Gulf of Guinea Islands and across the Atlantic.

Hypothesized raft. artwork by Richard E. Cook. insert photos D. Lin GG I and II

Because these two major currents cross the deltas of two of the mightiest rivers in Africa each with huge interior drainages, then change direction westward through São Tomé and Príncipe suggested to us that many of the endemic plants and animals on the two islands arrived there millions of years ago by rafting.  We suggested that the raft(s) would be large chunks of riverbank which broke off and floated to the sea. Our hypothesis that the rafts would have been very large is supported by the fact that a significant percentage of the unique reptiles (and one amphibian) of both islands are burrowing species (see inset, above), unlikely to cross ocean barriers on small floating objects.  We published this hypothesis in the Journal of Biogeography in 2007.

With respect to our Cape fur seal visitor, a closer look at the first image reveals that this animal ran afoul of a fishing operation of some sort; note the blue polyethylene rope or netting around its neck which may have come from a trawling operation to the south.  While it is highly unlikely that the poor creature was dragged 2700km, it IS possible that having been entangled, and then escaping, the seal became disoriented and probably very much weakened.  It seems likely that the “line of least resistance” would be to follow the Benguela Current until it converged with the South Equatorial Current, ultimately depositing the animal in the waters off São Tomé and Príncipe. This, in a sense, would be following part of the same dispersal pathway as the original plant and animal colonizers of the islands if our rafting hypothesis is correct.  It is impossible to know for sure, but this seems to me a possible scenario.

Here’s the parting shot:

Blue-breasted kingfisher. This one hangs out above 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, (GG I, II), the Société de Conservation et Développement (SCD) and Africa’s Eden for logistics, ground transportation and lodging (GG III-V), STePUP of Sao Tome http://www.stepup.st/, Arlindo de Ceita Carvalho, Director General, and Victor Bomfim, and Salvador Sousa Pontes of the Ministry of Environment, Republic of São Tomé and Príncipe for permission to collect and export specimens for study. Special thanks for the generosity of private individuals who made the GG III-V expeditions possible: George G. Breed, Gerry F. Ohrstrom, Timothy M. Muller, Mrs. W. H. V. Brooke, Mr. and Mrs. Michael Murakami, Hon. Richard C. Livermore, Prof. & Mrs. Evan C. Evans III, Mr. and Mrs. Robert M. Taylor, Velma and Michael Schnoll, and Sheila Farr Nielsen; GG VI supporters include HBD of Bom Bom and the Omali Lodge for logistics and lodging, The Herbst Foundation, The “Blackhawk Gang,” the Docent Council of the California Academy of Sciences in honor of Kathleen Lilienthal, Bernard S. Schulte, Corinne W. Abell, Prof. & Mrs. Evan C. Evans III, John and Judy Sears, John S. Livermore and Elton Welke.
Our expeditions can be supported by tax-deductable donations to “California Academy of Sciences Gulf of Guinea Fund”.



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