The Rubiaceae of São Tomé e Príncipe (Gulf of Guinea): taxonomy and conservation

A synoptic treatment of the Rubiaceae of São Tomé e Príncipe (Gulf of Guinea) is presented based on herbarium collections kept at BM, COI, K and LISC. There are 36 genera and 64 species of Rubiaceae represented in the flora of São Tomé e Príncipe. Identification keys are provided for genera, species and infraspecific taxa. A new combination is made in Chassalia . Twenty-nine taxa are endemic to these islands, two of which are also endemic to Annobon. The conservation status of the endemic taxa is assessed and IUCN categories of threat are proposed for ten taxa. Nineteen taxa of Rubiaceae are considered under threat in São Tomé e Príncipe and ten are considered nearly threatened.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 85–114.     

Habitat preferences of the forest birds on the island of Príncipe, Gulf of Guinea

The forests of southwest Príncipe are recognized as important for biodiversity conservation. Here, we study the distribution and density of fifteen of the island's endemic bird species (including three Globally Threatened and one Near-Threatened) within the National Park. The endemic subspecies of the Near-Threatened Gulf of Guinea thrush occurred at a density of 0.08 birds ha⁻¹, which is far lower than its sister subspecies on the neighbouring island of São Tomé. We also present evidence that the effects of access routes around the protected area exert an influence on bird species within the National Park. The grey parrot, which still suffers from illegal hunting, was more likely to be encountered further away from roads, with 25% of variation in its occurrence explained by distance to the nearest road. In addition, the occurrence of all four threatened species was more likely further from access routes. Careful consideration must therefore be given to the potential impacts within the National Park of developments outside the currently protected area.     

Checklist of Commelinaceae of Equatorial Guinea (Annobón,Bioko and Río Muni)

A checklist of Commelinaceae of Equatorial Guinea, comprising 46 taxa in 12 genera, is presented. The best represented genus is Palisota, with 11 species. Bibliographical references for Commelinaceae from Equatorial Guinea have been gathered and checked. Eleven species of Commelinaceae are recorded for the first time in the country. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 106–122.     

Screening for leaf-associated endophytes in the genus Psychotria (Rubiaceae)

Burkholderia endophytes were identified within the leaves of non-nodulated members of the genus Psychotria. In contrast to leaf-nodulated Psychotria species, which are known to accommodate their endosymbionts into specialized endosymbiont-housing structures, non-nodulated species lack bacterial leaf nodules and harbor endosymbionts intercellularly between mesophyll cells. Based on molecular data (rps16, trnG, and trnLF), the phylogenetic reconstruction of the host plants revealed a separate origin of leaf-nodulated and non-nodulated Psychotria species. Despite a distinct phylogenetic position of the two host clades, the endophytes of the non-nodulated plants were not placed into a single monophyletic group but were found to be closely related to the leaf-nodulated endosymbionts. The observation of genetically similar endophytes in both nodulated and non-nodulated Psychotria lineages suggests that the host plant is playing a crucial role in the induction of leaf nodule formation. Moreover, the concentration of endosymbionts into specialized leaf nodules may be considered as a more derived evolutionary adaptation of the host plant, serving as an interface structure to facilitate metabolic exchange between plant and endosymbiont.     

The Rubiaceae of Cabinda (Angola)

A treatment of the Rubiaceae of Cabinda (Angola) is presented based on various herbarium collections. There are 67 genera and 169 species of Rubiaceae represented in the flora of Cabinda. Eight entities are unnamed and could represent new taxa. Identification keys are provided for species and infraspecific taxa. A new combination is made in Rothmannia and two are made in Psychotria. A new name is provided in Psychotria . Eighteen taxa are endemic to Cabinda, two of which are also endemic to Angola. The conservation status of the endemic taxa is unknown due to the lack of collections over the last 40 years. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 455–495.     

A revision of the marine algae of São Tomé and Principe (Gulf of Guinea)

In all 101 species and varieties of marine algae are mentioned for S. Tomé and Príncipe. These records arise from examination of the material in the herbarium of the Botanical Institute of the University of Coimbra, together with material collected in 1956 by Dr C. A. Thorold. From the latter material there are 17 new records for the island of S. Tomé.
No new species have been described, but Acantkophora ramulosa Kütz. is emended, and Bryopsis densa Pilger and Struvea multipartita Pilger are reduced to the synonymy of Bryopsis pennata var. secunda and Struvea anastomosans respectively.
Information on the climate and tides of the islands is given, and a series of 'seasonal coincidences' likely to influence coastal marine conditions is described for the Gulf of Guinea.     

Population genetics of four PKLR intragenic polymorphisms in Portugal and S?o Tomé e Príncipe (Gulf of Guinea).

Four intragenic PKLR polymorphisms [1705A/C, 1738C/T. T10/19, and (ATT)n microsatellite] were studied in normal population samples of Central Portugal and S?o Tomé e Príncipe, a small archipelago located in the Gulf of Guinea, West Africa. For all loci, the observed genotype distributions do not deviate from Hardy-Weinberg equilibrium. The allele frequencies found in the Portuguese population are similar to those previously described in Caucasian populations. Mother-child pair analysis for the (ATT)n microsatellite does not show deviations to the Mendelian rules. In S?o Tomé e Príncipe the biallelic polymorphisms 1705A/C, 1738C/T, and T10/19 presented inverse allelic frequencies when compared with the Portuguese population. Two new alleles were found at the (ATT)n microsatellite. Significant statistical differences were found between both populations. The results showed that S?o Tomeans had higher haplotype diversity and lower linkage disequilibrium among the polymorphic sites. The PKLR intragenic polymorphisms, commonly used in haplotype analysis with the gene mutations in PK-deficient patients, can thus be successfully employed in anthropological genetics.     

Checklist of the Caesalpinioideae (Leguminosae) of Equatorial Guinea (Annobón, Bioko and Río Muni)

This study provides a checklist of the Caesalpinioideae (Leguminosae) present in Equatorial Guinea, comprising 52 genera and 124 taxa. Seven species are known from Annobón, 33 from Bioko and 109 from Río Muni. The best represented genus is Senna with eight species. In addition, bibliographic references for Caesalpinioideae (Leguminosae) from Equatorial Guinea have been gathered and checked. Fourteen species are included based on literature records, because their distribution ranges suggest they may occur in Equatorial Guinea, 11 introduced species could be naturalized, and 45 taxa are recorded for the first time from the country. This represents an increase of over 35% in the floristic knowledge of Caesalpinioideae from Equatorial Guinea. A statistical summary is presented at the end of the checklist.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 541–562.     

The role of zoological parks in biodiversity conservation in the Gulf of Guinea islands

Modern zoological institutions are devoting more of their resources to research, education and conservation than they have in the past. Many zoos recently have become increasingly involved in external or field (in situ) projects, with a view to conserving species and their habitats where they occur naturally. An opportunity to practice in situ conservation exists on Bioko, the largest and biologically the most diverse of the Gulf of Guinea islands. Although urgent political and economic problems confront Equatorial Guinea, of which Bioko is part, external aid will be needed if the infrastructure is to be developed to protect and maintain two important nature reserves on the island. Several initiatives are suggested for the involvement of zoos in this process.     

Breakdown of distyly and pin‐monomorphism in Psychotria carthagenensis Jacq. (Rubiaceae)

Rubiaceae contains the largest number of distylous species in the Angiosperms, but the evolution and control of distyly is poorly understood in this group. Atypical distylous populations and species have been described in this family and associated with disturbance, pollination failure and impaired reproductive success. Some of these atypical taxa belong to Psychotria, the largest genus in the family. In the present study, we investigate the pollination and breeding biology of Psychotria carthagenensis Jacq., a widely distributed species that has been described as typically distylous. Fieldwork was carried out mainly at the Panga Ecological Station, in Uberlândia, MG, Brazil. We carried out phenological observations, floral biology studies and hand pollination experiments within the Panga Ecological Station population. We complemented these data with herbarium and field surveys from elsewhere in Brazil. The studied population bloomed at the beginning of the rains (September–December). The main pollinators were Bombus and small Halictidae bees. The Panga Ecological Station population presented pin‐monomorphism with only two thrum individuals in more than 100 flowering individuals surveyed. Hand pollinations at the Panga Ecological Station showed self‐compatibility and intramorph compatibility. Typical distyly and isoplethy were found in other areas and both morphs appeared in herbarium material. However, pin‐monomorphism was also observed elsewhere in Brazil. Typical distyly, pin‐monomorphism and homostyly observed concurrently in Brazilian populations of P. carthagenensis indicate that alternative reproductive strategies, probably favoring selfing, appear to have developed independently in this species.     

Development and Structure of Bacterial Leaf Nodules in Psychotria bacteriophila Val. (Rubiaceae)

The development and mature structure of bacterial leaf nodules in Psychotria bacteriophila were studied by using light and electron microscopy. Bacteria in mucilage surrounding the shoot apex pass through certain stomates in leaf primordia into the substomatal chamber. These chambers enlarge and become nodules as the yound leaves grow out of the apical region. Surrounding mesophyll cells grow into each nodule and form a cellular reticulum whose interstices are occupied by bacteria. Each intrusive mesophyll cell wall is unusually thick and continually supplemented by vesicles originating from dictyosomes. The gram-negative bacteria are often surrounded by capsules. Nodule bacteria contain several crystal-like dense bodies. A population of normal, dividing, and degenerating bacteria is found in each nodule. Extensive membranes occur between the bacteria. A hypothesis is proposed to explain certain aspects of this obligate symbiotic relationship.     

Biodiversity conservation in the Gulf of Guinea islands: taking stock and preparing action

This paper introduces an Action Statement on biodiversity conservation in the four Gulf of Guinea islands arising from a workshop held in Jersey in 1993. The current state of the main habitats on all the islands, pressures acting upon them, existing institutions and actions taken so far are reviewed. The 24-point Action Statement was produced as a framework for future international initiatives in biodiversity research and conservation in this part of Africa. Attention is drawn to the progress made by the governments of the region in legislation and institutional support. The workshop recommended the establishment of a regional programme of research and conservation in conjunction with the Governments of Equatorial Guinea and of São Tomé and Príncipe.     

First record of Mugil capurrii (Mugilidae, Perciformes) in the Gulf of Guinea

Leaping African mullet Mugil capurrii was caught along the Togolese coast in the Gulf of Guinea. This is the first record of this species which usually occurs from Morocco to Guinea Bissau and the southernmost point of its known distribution.     

Terpenoids and a coumarin from aerial parts of Psychotria vellosiana Benth. (Rubiaceae)

The phytochemical investigation of Psychotria vellosiana aerial parts yielded five compounds, including two triterpenes (squalene and lupeol), two steroids (stigmasterol and sitosterol), and one coumarin (scopoletin). The structures of the isolates were established based on analysis of their spectroscopic data and comparison with literature. All metabolites isolated were previously detected in Psychotria, excepting squalene that is being described for the first time from this genus. This study adds a new species to a number of reports showing the absence of alkaloid in Psychotria.     

An extraordinary new rheophyte in the genus Leptactina (Rubiaceae, Pavetteae) from Rio Muni (Equatorial Guinea)

A distinctive new species of Rubiaceae from Rio Muni, Equatorial Guinea, is described and illustrated. Leptactina rheophytica is the only rheophyte known in the genus. Its diagnostic characters are elucidated, its taxonomic affinities are discussed, and notes on its conservation status are provided.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 109–113.     

Evolution and Conservation of Central African Biodiversity: Priorities for Future Research and Education in the Congo Basin and Gulf of Guinea

The tropical forests of the Congo Basin and Gulf of Guinea harbor some of the greatest terrestrial and aquatic biological diversity in the world. However, our knowledge of the rich biological diversity of this region and the evolutionary processes that have shaped it remains limited, as is our understanding of the capacity for species to adapt or otherwise respond to current and projected environmental change. In this regard, research efforts are needed to increase current scientific knowledge of this region's biodiversity, identify the drivers of past diversification, evaluate the potential for species to adapt to environmental change and identify key populations for future conservation. Moreover, when evolutionary research is combined with ongoing environmental monitoring efforts, it can also provide an important set of tools for assessing and mitigating the impacts of development activities. Building on a set of recommendations developed at an international workshop held in Gabon in 2011, we highlight major areas for future evolutionary research that could be directly tied to conservation priorities for the region. These research priorities are centered around five disciplinary themes: (1) documenting and discovering biodiversity; (2) identifying drivers of evolutionary diversification; (3) monitoring environmental change; (4) understanding community and ecosystem level processes; (5) investigating the ecology and epidemiology of disease from an evolutionary perspective (evolutionary epidemiology). Furthermore, we also provide an overview of the needs and priorities for biodiversity education and training in Central Africa.     

Biodiversity in the Gulf of Guinea: an overview

Patterns of species-richness and endemism in the Gulf of Guinea reflect the region's biogeographic history. Bioko is a continental-shelf island that was recently connected to the African mainland, whereas Príncipe, São Tomé and Annobón are truly oceanic and have never been connected with each other or with the mainland. As a result, Bioko supports a much more diverse flora and fauna but with relatively low levels of endemism at the species level, whereas the oceanic islands are relatively depauperate because of their isolation but rich in endemic taxa. Species endemism is 0–3% on Bioko for angiosperms, bats, birds, reptiles and amphibians, compared with much higher values on Principe for these same taxa of 8% (plants) to 100% (amphibians), on São Tomé between 14% (plants) and 100% (amphibians), and on Annobón 0% (bats) to 71% (reptiles). On a global scale, for their size both Príncipe and São Tomé support unusually high numbers of single-island endemic species of birds, reptiles and amphibia. For its tiny size, Annobón is also notable for its endemic birds and reptiles. Among terrestrial molluscs the rates of endemism are in general higher than for plants and vertebrates, from ca 50% on Bioko to ca 80% on the oceanic islands. In contrast and as might be expected, only Bioko supports a rich freshwater fish fauna and it contains many endemic taxa, whereas the oceanic islands support only a few salt-tolerant species. The Gulf of Guinea islands are also important for their marine organisms, amongst which coral reef fish and marginellid molluscs show high levels of endemism, though they are not especially species-rich. The Gulf of Guinea islands are of great interest to conservationists and evolutionary biologists. Each island, of greatly differing size and degree of isolation, has acquired its unique sub-set of plants and animals separately from the neighbouring mainland, followed by adaptive radiations in situ. For this reason the conservation value of the archipelago as a whole is greater than the sum of the biodiversity contained in its individual islands. Conservation initiatives in the Gulf of Guinea should therefore ensure that representative terrestrial, freshwater and marine habitats and groups of organisms are targeted in a co-ordinated manner among the islands.