Keywords

Introduction

From the beginning, humans have tried to understand, classify, and master the biodiversity that surrounds them. Through time, and across different civilizations and cultural groups, different approaches and classification schemes have been proposed to try to classify the natural world. Despite many attempts, the creation of a natural, objective, and replicable system to classify nature was only achieved in the mid-eighteenth century, with the seminal works of the Swedish naturalist Carl Linnaeus (1707–1778). The works of Linnaeus are universally recognized as marking the birth of modern natural history and all its resulting subdisciplines (biology, ecology, etc.). As supporting evidence for its foundational importance in the current international zoological and botanical codes of nomenclature, valid scientific names are those starting in the 1750s, following the works of Linnaeus. For zoological nomenclature, the fixed starting point is 1758 (ICZN 1999), which corresponds to the publication of the tenth edition of Linnaeus’ Systema Naturae (Linnaeus 1758). For botanical nomenclature, this point is only five years before, in 1753 (Turland et al. 2018), corresponding to the publication of the first edition of Linnaeus’ Species Plantarum (Linnaeus 1753). Although this renders all the previous works invalid, from the narrow point of view of biological nomenclature, this does not mean that earlier work does not provide important information and insights regarding the natural world. In addition, many important contributions to scientific knowledge throughout history (and today) are made outside of the formal scientific literature. For the oceanic islands of the Gulf of Guinea, the reports made by some of the earliest Portuguese navigators in the late fifteenth and early sixteenth centuries are teeming with information about the nature of these islands and the surrounding sea. This is the case of the report produced by the Portuguese navigator Gonçalo Pires (dates of birth and death unknown), transcribed by Valentim Fernandes (ca. 1450–1519) and subsequently published by Baião (1940), in which the author describes the geography, fauna, and flora of the three oceanic islands in considerable detail.

This chapter aims to provide a general overview of more than two centuries of scientific research on the biodiversity of the oceanic islands of the Gulf of Guinea. Due to the impossibility of providing a fully detailed account on the life and work of every naturalist or explorer that worked on the biodiversity of these islands, some of which would be sufficiently rich and detailed to write an entire chapter or book about, this text intends to be mostly a commented guide to the available publications. In a way, it is an updated and commented version of the important bibliographic compilations provided by Exell et al. (1952), Fernandes (1982) and Figueiredo (1994a) for plants and by Gascoigne (1993, 1996) for animals, but it also aims to present the major research trends regarding biodiversity of the oceanic islands of the Gulf of Guinea across time. Despite the historical importance of older records, such as those of Gonçalo Pires, we do not include them here and focus solely on works published after the Linnean revolution, as the latter ones are those more readily accessible to the present-day researcher and student.

Eighteenth Century to Mid-Nineteenth Century

Formal zoological research in the Gulf of Guinea did not begin until the latter half of the nineteenth century, although in the late eighteenth century and earlier decades of the nineteenth century small collections made their way into Europe. Naturalists like the Danish zoologist Otto Friedrich Müller (1730–1784), the Dutch merchant and entomologist Pieter Cramer (1721–1776), and the French zoologist Jean Guillaume Bruguiére (1749–1798) studied them and described the first known species of insects and molluscs from the islands (Müller 1774; Cramer 1775/76; Bruguière 1792). Most notably, the French Naval officer Sander Rang (1793–1844) docked the naval brig La Champenoise in Príncipe for a month, where he collected terrestrial molluscs, which he later described (Rang 1831). During these early days of the modern era, much of the collecting and research was conducted in a framework of private collections and a dilettante approach to science, but these first records can be seen as the beginning of taxonomic research in the region.

The oldest record of plants collected from the Gulf of Guinea Islands dates from 1787 and was collected by the French naturalist Ambroise Marie François Joseph Palisot de Beauvois (1752–1820), during his stay in Príncipe Island while he was ill (Exell 1944). Out of the four species he collected, Asplenium emarginatum, Aeschynomene indica, Tristemma hirtum, and Agrostis tropica, the last has never been collected again on Príncipe and no other specimen is known (Figueiredo et al. 2011). After Beauvois’ initial study, botanical specimens were only collected again in the Gulf of Guinea during the nineteenth century. The Scotsman George Don (1798–1856) spent three weeks collecting plants in São Tomé (15 May to 11 June 1822). All the sailors who accompanied him ashore died from a tropical disease after leaving the island (Exell 1944). It was a good collection for the time, with about twenty species new to science, some of which have not been found again in São Tomé (Figueiredo et al. 2011). These “missing” species may in part be because some of them, such as Cichorium intybus and Pluchea sagittalis (Epaltes brasiliensis), were alien weeds (from Europe and South America, respectively) that did not become established (Exell 1944) or were, perhaps, misidentified.

Later, Andrew Beveridge Curror (1811–1844), a British naval surgeon and naturalist, visited Annobón between 1839 and 1843, where he reportedly collected two species of plants, Begonia annobonensis and Vernonia amygdalina (Exell 1944). Figueiredo and Smith (2020a) cite the holotype of Begonia annobonensis [Curror 9 (K000242508), Annobón 1841]. At Herb. K there is also a herbarium sheet with several specimens of Vernonia amygdalina from Annobón, two of which were collected by Burton (Oct. 1863) and one by Curror (Curror 8, 1841). It is likely that Curror made more collections in Annobón. Curror died of “remittent fever”, during his last expedition (in 1844), off the coast of Gabon (Figueiredo and Smith 2020a). Curror also travelled to the island of Príncipe on four different occasions during 1839 (Figueiredo and Smith 2020a). Even though none of Curror’s collections at Herb. K are labelled as originating from Príncipe, one of his collections is, without a doubt, from that island, consisting of the fern Alsophila camerooniana var. currorii, which is endemic to Príncipe (Figueiredo and Smith 2020a).

Near the end of this period, Désiré Edélestan Stanislas Aimé Jardin (1822–1896), a clerk in the service to the French Navy, collected plants in Tropical West Africa between 1845 and 1848 and visited Príncipe. Amongst the plants (about 50 species) he mentioned from this island (Jardin 1850/51), he refers one Combretum without the specific name. Exell (1944), who did not see the collection, referred to it as Combretum platypterum, which has not been found again in Príncipe. This information was given to him by Georges Le Testu (Exell 1944), who, at Exell’s request, had searched the Jardin collection, then held at Herb. CN and later transferred to the Herb. P. The only species of Combretum recorded in Príncipe is Combretum paniculatum (Figueiredo et al. 2011).

Mid-Nineteenth Century to Early Twentieth Century

From the mid-nineteenth century forward, a wave of interest in African territories prompted several European institutions into commissioning naturalist expeditions to the continent. The need to catalogue the colonial possessions, together with the broader interest to uncover the planet’s biodiversity, led to the flourishing of taxonomy. Most of the publications and research outputs of this time came in the form of species descriptions, checklists, and catalogues.

The first publication was that of the Swedish mycologist Elias M. Fries (1794–1878), who was the first naturalist to report fungi from São Tomé (Fries 1851), namely six Agaricomycetes species collected by Krebs (no additional collector information). This publication is of special relevance not only as the first published account of fungi of the oceanic islands of the Gulf of Guinea, but also as the first major bibliographical record to feature a report on the biodiversity of the region following the investment boom in the continent.

In 1853, while en route to a botanical expedition to Angola, the Austrian botanist Friedrich Welwitsch (1806–1872) collected specimens on the islands of São Tomé and Príncipe, doing the same seven years later upon returning from the trip (Figueiredo and Smith 2020b). He visited Príncipe between 15 and 22 September 1853. Almost all the species he collected were new records for the island, except the fern Alsophila camerooniana var. currorii found years before by Curror in 1839 and those species collected by Jardin. On 23 September of the same year, he paid a short visit to São Tomé. In December 1860, on the return trip from Angola to Lisbon, Welwitsch stayed in São Tomé for some days and amassed a very good collection of plants, with interesting new records and new species, some of which he described (Exell 1944). The mollusc specimens collected by Welwitsch on the islands were studied and published by Morelet (1868), and later mentioned in Crosse’s (1868) compilation of known land molluscs from São Tomé. Pierre Marie Arthur Morelet (1809–1892) was a renowned French naturalist specializing in molluscs, whereas Joseph Charles Hippolyte Crosse was a French conchologist, co-editor of the publication Journal de Conchyliologie. Additional malacological fauna collections resulting from expeditions into the area undertaken by various naturalists were studied by Morelet (1848, 1858, 1860, 1873).

During the seven years between Welwitsch’s two visits to these islands (i.e. between 1853 and 1860) only the Scottish gardener Charles Barter (1821–1859), collector on William Baikie’s second Niger Expedition (1857–1863), visited Príncipe. In 1858, he made a small but important botanical collection, primarily comprised of orchids (Exell 1944; Figueiredo and Smith 2020b). He caught dysentery and died on 15 July 1859 at Rabba, Nigeria. Barter was replaced on this expedition by Gustav Mann (1835–1916), a German botanist, who collected a great number of plants during the three years he participated in the expedition (1859–1862). In August 1861, Mann collected across a large area of São Tomé and reached Pico de São Tomé, discovering several new species and various interesting plants that would be studied by Hooker (1863, 1864). Later, Mann collected on Príncipe (22 September–26 October 1861), again uncovering new species and novelties for the flora of the island (Exell 1944). A few years later, Richard Francis Burton (1821–1890), who served as the British Consul in Bioko from 1861 to 1864, visited Annobón (October 1863) on his way back to Bioko from the Niger–Congo rivers expedition (August–October 1863) and made a small collection, currently held at Herb. K (Burton 1876).

In 1865, the German explorer Heinrich Wolfgang Ludwig Dohrn (1838–1913) spent six months in Príncipe, where he collected birds, reptiles, and snails. The results were later published by him and by other specialists (Dohrn 1866a, b, c; Keulemans 1866; Heynemann 1868; Peters 1868). Subsequently, the German zoologist Richard Greeff visited São Tomé and Rolas Islet between 1879 and 1880, where he collected extensively and obtained important specimens that contributed to the description of a considerable number of new species by him and others (Peters 1881; Greeff 1882a, b, c, d, 1884, 1886; Bocage 1886a; Koch 1886; Krauss 1890).

In 1871, the Portuguese naturalist Félix António Brito Capello (1828–1879) published the first list of fishes from the Portuguese islands of Madeira and Azores, with the inclusion of fishes from its overseas possessions Angola, Cabo Verde, Mozambique, and São Tomé and Príncipe (Brito Capello 1871). After his death, António Roberto Pereira Guimarães continued Capello’s analysis of the material extant in the Lisbon Museum and published two additional papers on the topic (Guimarães 1882, 1884).

In 1885, Adolfo Frederico Moller (1842–1920; Fig. 5.1), chief gardener of the Botanical Garden of the University of Coimbra, was sent by the institution to collect natural history specimens in São Tomé. Despite it being a short four-month exploratory stint (23 May–25 September), Moller found time to teach Francisco Quintas (dates of birth and death unknown), the son of a Portuguese owner of coffee and cocoa plantations, how to continue his botanical collection (Gouveia 2014; Figueiredo and Smith 2019). Quintas travelled and made remarkable collections in the west and south of São Tomé between 1885 and 1889 and also in Príncipe between January and March 1889 (Figueiredo and Smith 2019). Bedriaga (amphibians and reptiles: Bedriaga 1892, 1893a, b), Bocage (amphibians and reptiles: Bocage 1893b), Moller (sponges: Moller 1894, studied by Weltner in Berlin), Nobre (land molluscs: Nobre 1886b, 1894), Osório (fish: Osório 1891a), Verhoeff (Chilopoda and Diplopoda: 1892, 1893), and Vieira (insects, spiders, and birds: Vieira 1886, 1887a, b, 1894) published the majority of the zoological results from the expedition. The botanical material was deposited at the Herb. COI and studied by the botanist Júlio Augusto Henriques (1838–1928; Fig. 5.1) for his publications on the flora of São Tomé and Príncipe.

Fig. 5.1
Two photographs. A. An old photograph of Adolfo Moller standing in the woods, he carries a shotgun on his shoulder. B. A photograph of Julio Henriques looking through the microscope.

Portraits of Adolfo Moller (left) and Júlio Henriques (right). Moller’s portrait from Henrique Eusébio Moller private family álbum, adapted from Gouveia (2014). Henriques’ portrait reproduced with the permission of the Botanical Archive—Department of Life Sciences, University of Coimbra, Portugal (PT-UC-FCT-DCV-ABUC-S2.13)

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Francisco Newton (1864–1909; Fig. 5.2), working for the Natural History Museum of Lisbon, fruitfully explored the Gulf of Guinea for a decade between 1885 and 1895 (Santos and Ceríaco 2021). The collections amassed by Newton during that period proved crucial in the first extensive faunal catalogues and the description of new species from the region, resulting in numerous works. Of special importance were those published by José Vicente Barbosa du Bocage (1823–1907), director of the zoological section of the Natural History Museum of Lisbon. Bocage provided the first comprehensive checklists of the islands’ vertebrate fauna, as well as the description of several species new to science, including amphibians, reptiles, birds, and mammals (Bocage 1886a, b, c, 1887a, b, c, 1888a, b, c, d, 1889a, b, c, 1891a, b, c, 1893a, b, c, 1895a, b, c, d, e, 1896, 1903, 1905). The butterflies collected by Newton were studied and published by Emily Mary Sharpe (1893), while the land molluscs were studied by Arruda Furtado (Furtado 1888), Girard (1893a, b, 1894, 1895), and Augusto Nobre (Nobre 1886a, 1887, 1909). Balthazar Osório studied both crustaceans and fishes (Osório 1887, 1888, 1889 1890, 1891a, b, 1892a, b, 1893, 1895a, b, c, d, e), Júlio Bettencourt Ferreira was responsible for the reptiles (Ferreira 1897, 1902), and the birds were studied by David Armitage Bannerman (1931), José Augusto de Sousa (1887, 1888) and Richard Bowdler Sharpe (1892). While Newton’s zoological collections were sent to Lisbon, his botanical specimens were sent to the University of Coimbra where they were studied by Júlio Henriques. An extensive collection of letters from Newton to Bocage and Osório is still extant in the collections of the Museu Nacional de História Natural e da Ciência, Lisbon, and are being processed for a future publication (Ceríaco and Santos, in prep.).

Fig. 5.2
Two photographs. The first photograph is of Francisco Newton holding a hat in his hand. The second is a watercolor painting of a frog from Principe Island by Francisco Newton.

Portrait of Francisco Newton and a watercolour he painted of a Leptopelis palmatus from Príncipe Island. Source: Arquivo Histórico do Museu Bocage

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Despite the few publications on the islands’ botany published in the previous decades, the research programme established by Henriques can be considered the birth of systematic botanical studies in the islands. The first contact Henriques had with the flora of São Tomé was through a few specimens collected by Newton in 1881 (Henriques 1884a; Figueiredo et al. 2019a). After the return of Moller from São Tomé, Henriques highlighted future plans for the study of the collections from the island (Henriques 1895). For the first instalment of what Henriques would call “Flora de S. Thomé” (Henriques 1886), he invited other specialists to identify and describe the collections in his possession (i.e. those from Newton, Moller, and Quintas). Henriques (1886) had the contributions of Charles Fuller Baker (ferns: in Henriques 1886, pp. 149–158 + 2 plates), Carl Muller (mosses: in Henriques 1886, pp. 159–169), Franz Stephani (liverworts: in Henriques 1886, pp. 170–184 + 3 plates), Heinrich Georg Winter (fungi: in Henriques 1886, pp. 185–204 + 3 plates), William Nylander (lichens: in Henriques 1886, pp. 205–217), and C. Agardh, O. Nordstedt, F. Hauck, and Charles Flahault (algae: in Henriques 1886, pp. 217–221).

This series of publications continued in the following years. In 1887, Henriques coordinated two additional papers, one based on Newton’s collections (among other collectors that were active in the African mainland; Henriques 1887a), and another based on the collections of Welwitsch, Moller, and Quintas (Henriques 1887b). For the latter, Henriques collaborated with foreign botanists such as Ernst Haeckel (grasses), Henry N. Ridley (sedges and orchids), the Count Solms-Laubach (Pandanus), and Cornelis A. Backer who made general reviews and corrections to the manuscript. For the paper on Newton’s collections, Henriques (1887a) had once again contributions of Franz Stephani (liverworts: in Henriques 1887a, pp. 224–225) and William Nylander (lichens: in Henriques 1887a, pp. 221–222).

Other contributions were published in 1889 by Henriques (1889a, b). Following the strategy used in the 1886 instalment, besides his own contributions and identifications, Henriques sent material to other European botanists, who subsequently provided the results of their observations. Henriques (1889b) had the collaboration of Karl August Otto Hoffmann (Capparidaceae: in Henriques 1889b, p. 224; Lithrarieae in Henriques 1889b, p. 229), Célestin A. Cogniaux (Melastomataceae: in Henriques 1889a, p. 226; Cucurbitaceae: in Henriques 1889b, p. 227), and Robert Allen Rolfe (Orchideae: in Henriques 1889b, pp. 236–238). In the same year, Augusto Nobre was able to study some fresh material of Afrocarpus mannii collected by Moller in Lagoa Amélia and sent to him by Henriques (Nobre 1889). This was the second study on this endemic and enigmatic conifer. Roumeguère (1889), Saccardo and Berlese (1889), Bresadola and Roumeguère (1889), and Bresadola (1890, 1891) studied and described several species of fungi from the collections sent to them by Henriques. The bryophytes collected by Quintas were studied, described, and published by Brotherus (1890).

Based on new material sent to Henriques by Quintas, Henriques (1891) published a further article with the contributions of Hoffmann (Crassulaceae: in Henriques 1891, p. 135) and Rolfe (Orchideae: in Henriques 1891, pp. 137–143). Henriques’ last contribution to the flora of São Tomé in the nineteenth century (Henriques 1892) stretched for about 160 pages and covered several families of plants. It included several contributions: Cogniaux (Melastomataceae: in Henriques 1892, pp. 118–119; Cucurbitaceae: in Henriques 1892, pp. 119–122), Casimir de Candolle (Begoniaceae: in Henriques 1892, pp. 122–124); Piperaceae: in Henriques 1892, pp. 152–155), Adolf Engler (Anacardiaceae: in Henriques 1892, p. 110), Gustav Lindau (Acanthaceae: in Henriques 1892, pp. 145–148), Ferdinand A. Pax (Euphorbiaceae: in Henriques 1892, pp. 156–161), Jules E. Planchon (Ampelideae: in Henriques 1892, pp. 108–109), and Karl M. Schumann (Rubiaceae: in Henriques 1892, pp. 126–134).

Sobrinho (1953a) refers some plants from Príncipe Island collected by Jacinto Augusto de Souza Junior in February 1880. These collections were not included in the revisions of Henriques. Efforts to identify this collector have yielded no results besides his name and herbaria where his collections are deposited: Herb. COI and LISU (Exell 1962, Liberato 1994). One of the most enigmatic results of Souza Junior works in São Tomé and Principe is the description of the species Justicia thomensis by Landau (Holotype at COI: COI00005706), a species of Acanthaceae that has never been collected again since its original description, raising questions if the specimens were in fact collected in the islands, or if the species may have become extinct (Figueiredo et al. 2011). Portuguese museums also received several small collections of zoological specimens from the Gulf of Guinea, mostly collected and offered by Portuguese military personnel deployed in the area, studied by various specialists (Bocage 1880a, b, 1887d; Nobre 1891, 1894, 1901; Osório 1887; Santos 1882).

The English diatomist John Rattray (1858–1900) participated in the Buccaneer steamship 1885–1888 expedition that combined plans to conduct sound operations and lay a telegraph line along the West African coast (Bencker 1930; Figueiredo et al. 2019b) with the collection of biological specimens. A brief stop during early 1886 in the Gulf of Guinea resulted in a small zoological collection, the results of which were later published by Hoyle (1887), Scott (1893), and Stebbing (1895), and botanical collections.

Leonardo Fea (1852–1903), an experienced Italian naturalist, explored the Gulf of Guinea from 1901 to 1902 under the sponsorship of the Museo Civico di Storia Naturale of Genoa (Fea 1902). This was his last expedition before passing away in 1903. His results were studied in the following years by Boulenger (reptiles: 1905, 1906), Breuning (insects: 1955, 1956), Germain (molluscs: 1912a, b, 1915, 1916), Griffini (Orthoptera: 1905), Kerremans (Buprestidae: 1905), Lewis (Histeridae: 1905), Lesne (1905), Martin (Odonata: 1908), Salvadori (birds: 1903a, b, c), Silvestri (Thysanura: 1908), and Simon (Arachnids: 1907).

During the second half of the nineteenth century, besides the taxonomically oriented works, several authors focused on the agricultural capacities and potential of São Tomé (Castro 1867; Henriques 1884, 1898; Nogueira 1885; Moller 1899). This resulted in the publication of several works related to coffee (Almeida 1858; Carvalho 1858; Castro 1857–1858), cinchona (Henriques 1876, 1878, 1880a, b, 1882), fruits (Almeida 1865), and timbers (Castro 1894). These topics, especially those related to coffee, would be explored in much more detail in the following decades. Plant uses and vernacular names were addressed by Almada Negreiros (1895, 1901) in publications that are arguably the first on ethnography of São Tomé.

Early Twentieth Century to the Independence of Equatorial Guinea (1968) and São Tomé and Príncipe (1975)

The taxonomic cataloguing efforts of the nineteenth century carried on into the first decades of the twentieth century. Some new research trends started to emerge, becoming quite prevalent in the mid-twentieth century and until the independence of the two colonies. These trends were mostly dedicated to what was known as “colonial sciences”—research dedicated to the improvement of the colonial enterprise in its different activities (but especially agriculture), as well the well-being of the colonists and native populations. Therefore, studies dedicated to economic entomology, fisheries, and parasites became the dominant focus. Traditional taxonomic work also continued on several groups.

The botanical collections amassed during the mid-nineteenth century contributed to increased botanical interest in the islands of the Gulf of Guinea. To continue his studies of the flora of São Tomé, Júlio Henriques in 1903 at the age of 65, fulfilled his dream of travelling to São Tomé. Henriques travelled through a large part of the island, but the weather conditions prevented him from ascending to the Pico. From his trip to São Tomé and the consolidation of his already vast knowledge of the island he published one of his most iconic monographs entitled “A ilha de S. Tomé sob o ponto de vista histórico-natural e agrícola” [The Island of S. Tomé from the historical-natural and agricultural point of view] (Henriques 1900, 1917). The study of the material collected in the previous century continued (e.g. Hariot 1908, with a revision of the algae collected by Moller and Quintas).

Exell (1944) gave a comprehensive account of botanical collecting in São Tomé, Príncipe, and Annobón, naming all collectors recorded up to that date. In the account he mentioned a “valuable collection” made by the Portuguese engineer “I. Campos” in 1907 on São Tomé, mostly deposited at Herb. COI. It included specimens of Adinandra manni re-collected on Pico de São Tomé, and three specimens which were described in Exell (1944) as three species new to science: Urophyllum camposii, Lachnopylis thomensis, and Peddiea thomensis. According to the data on the label of the specimens the collector is E. Campos. This is likely Ezequiel de Campos (1874–1965), an engineer who worked in São Tomé and Príncipe from 1899 (Campos 1920). He was later a professor and a member of Parliament in Lisbon. Much later, in 1954, Campos became the chief of Missão Científica de São Tomé (see below).

Among the most relevant collections referred by Exell (1962) is the one made by Auguste Chevalier (1873–1956), a French explorer and botanist who visited São Tomé and made collections from August to October 1905. Chevalier made over 700 collections (Chevalier 1914) in São Tomé that are deposited in the Herb. P, COI, K, and LY (Exell 1962, Liberato 1994). In 1909, the agronomist José Joaquim de Almeida (1862–1933), the first director of the Colonial Garden in Lisbon, made a study visit to São Tomé, collecting some plants that he later deposited in Herb. COI and LISJC (meanwhile integrated into LISC) (Exell et al. 1952, Liberato 1994).

An extensive botanical collection from Annobón was made by the German botanist Johannes Gottfried Wilhelm Mildbraed (1879–1954) under the auspices of the Deutsche Zentral Afrika-Expedition (1910–1911) in 1911, including 32 pteridophyte species. Mildbraed spent over a month on the island of Annobón from 5 September to 13 October 1911 collecting almost everything that was in flower or in fruit at the time. His collection was mainly kept at Berlin (Herb. B) but unfortunately, it was almost completely destroyed during the allied bombings of Berlin in World War II. Nevertheless, there are duplicates of Mildbraed’s collections at Herb. HBG, K, and BM. Mildbraed published his results (Mildbraed 1922) which were later reviewed by Exell (1944, 1963).

A new array of zoologists visited the islands in the following years. French zoologist Charles Gravier (1865–1938) was entrusted to lead a scientific mission to São Tomé (C.C.A.M. 1938), with several papers resulting from his collections (Polychaeta: Billard 1907; molluscs: Germain 1908; corals: Gravier 1906, 1907a, b, 1909, 1910; bivalves: Lamy 1907). The British Lieutenant of the Rifle Brigade, Boyd Alexander (1873–1910), was a renowned explorer and ornithologist who journeyed through the Gulf of Guinea in 1909 accompanied by his faithful Portuguese colleague José Lopes (Bannerman 1914). Alexander’s bird collections were subsequently studied and published by Bannerman (1914, 1915a, b). Additionally, mollusc specimens were sent to the British Museum around the same time, collected by amateurs working in the Gulf of Guinea and later studied by Tomlin and Shackleford (1912, 1913a, b, 1914/15, 1915), and Tomlin (1923). Seabra (1922) studied the insects collected by Sousa da Câmara (1871–1955) in São Tomé, on behalf of the Instituto Superior de Agronomia in Lisbon, and sent some material to be studied in the Imperial Bureau of Entomology. This material was reviewed a year later by Herbert Campion (1923). While on leave in Europe, the Trinidadian entomologist Frederick William Urich (1870–1937) carried out a short expedition to São Tomé in 1920, in which he rediscovered a parasitic dipteran species in its original bat host (Urich et al. 1922). The English explorer Thomas Alexander Barns (1881–1930) collected on behalf of the amateur entomologist James John Joicey (1870–1932) in the region of the Gulf of Guinea during the end of 1925 and 1926, on what was his third and last expedition (Talbot 1932). The results of this expedition were published by Joicey and Talbot (1926, 1927), Prout (1927a, b) and Riley (1928). José Correia (1881–1954; Fig. 5.3) and Virginia Correia (1900–1987), a husband-and-wife team of collectors, explored the Gulf of Guinea during 1928 and 1929 on a trip funded by S. Brinckerhoff Thorne, trustee of the American Museum of Natural History. Amadon (1953) published the ornithological results of their expedition.

Fig. 5.3
A photograph of Jose Correia standing in the woods, wearing hunting clothes, during his bird-collecting mission. He has a shotgun in his hands.

The Portuguese naturalist José Correia, during his bird-collecting mission to the Gulf of Guinea (1928–1929). Courtesy of the Ornithological Archives of the American Museum of Natural History

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From October 1932 to March 1933, the entomologist Willie Horace Thomas Tams (1891–1980) and the acclaimed botanist Arthur Wallis Exell (1901–1993) conducted a scientific mission to the Gulf of Guinea on behalf of the British Museum, sponsored by the Percy Sladen Memorial Fund and Godman Trusts Fund (Tams 1934). The zoological specimens collected in this expedition were examined and published by several authors (Diptera: Edwards 1934; Collembola: Maldwyn-Davis 1935; Microlepidoptera: Meyrick 1934; Odonata: Longfield 1936). During the four-month long British Museum expedition, Exell made extensive botanical collections in São Tomé (mostly in the mountains), Príncipe, Bioko (Moka region), and Annobón. Exell deposited his specimens at Herb. BM and sent duplicates to Herb. COI and BR (Exell 1962); his collections include bryophytes, algae, lichenes, and fungi (Exell 1944). Resulting from this collecting trip, Exell published a catalogue of the vascular plants of the three islands (Exell 1944), in which 75 new names were published (36 being for new species) and several new records noted (Figueiredo et al. 2011). In the following years, Exell published a supplement to the catalogue (Exell 1956), and a checklist of the angiosperms for the four islands in the Gulf of Guinea (Exell 1973a). Although he visited and collected on the four islands, Exell made use of earlier collections when compiling the plant catalogues of these islands, namely from Herb. COI where he spent some time in 1934 (Figueiredo et al. 2018; Fig. 5.4). In addition to having intensively and extensively collected and studied the botany of the islands of the Gulf of Guinea, while using the existing collections in comparative studies with his own specimens, Exell was responsible for reviewing and re-organizing many of the pre-existing collections, such as that of Herb. COI (Exell 1944, 1962; Figueiredo and Smith 2019). For the supplement of the catalogue, Exell (1956) studied some old collections that had not been examined previously or that he reassessed, and some recent ones. A substantial collection made by Newton in 1893 in Annobón is included in this supplement. The recent material consists mostly of the collections made by Espírito Santo (see below) in São Tomé. A few specimens collected by the agronomist Branquinho de Oliveira (1904–1983) and E. Noronha in 1951 in São Tomé (listed by Sobrinho 1953b), likely en route, were also included, consisting mostly of weeds and aliens.

Fig. 5.4
A photograph depicts a group of botanists outside the Botanical Garden of Coimbra in 1960.

From left to the right (including background), the botanists Luis Grandvaux Barbosa, Maria Leonor Gonçalves, Arthur Exell, Mildred Exell, Abílio Fernandes, Rosette Fernandes, and A. V. Bogdan in the Botanical Garden of Coimbra, September 1960

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Exell was one of the most prolific figures when it came to the cataloguing of the flora of the islands of the Gulf of Guinea. From 1944 to 1973, he produced a dozen publications, some of which became classic references (Exell 1944, 1952, 1956, 1958, 1959, 1962, 1963, 1968, 1973a, b; Exell et al. 1952; Exell and Rozeira 1958). Like Henriques, Exell also received the contributions of numerous botanists who identified the collections: 16 botanists were acknowledged in Exell (1944) and 21 botanists in Exell (1973b). Arthur Hugh Garfit Alston (1902–1958) who authored the treatment of the pteridophytes (Alston 1944) in Exell’s Catalogue (1944) also contributed with the pteridophytes for the Supplement (Alston 1956) and for two additional articles (Alston 1958, 1959).

The algae of São Tomé and Príncipe, that had not been revised since 1908, were finally treated by Rodrigues (1960).

Other plant collectors in the first half of the twentieth century were the Swiss botanist John Gossweiler (1873–1952), who collected in Príncipe during stopovers of his numerous trips between Angola and Portugal, in 1913, 1914, and 1938 (Liberato 1994), and the American botanist David H. Linder (1899–1846) on an expedition by Harvard University from 1926 to 1927, the specimens of which are deposited in Herb. GH (Exell 1944, Liberato 1994). On the zoological side, an ornithological team from Oxford University went on a short visit to São Tomé and Príncipe between September and October of 1949, providing additional notes about several species, in the first major contribution on the subject since the works of José Correia (Snow 1950).

In the second half of the twentieth century, the 1959 Peris-Álvarez Expedition to Annobón (Alvarado and Álvarez 1964), headed by entomologist Salvador V. Peris (1922–2007) and Julio Álvarez Sanchez, although short in duration, was fruitful in advancing knowledge regarding the fauna of the area (Anthribidae: Hoffman 1959; Nematoda: Gadea 1960a, b; Gastropoda: Ortiz de Zárate and Álvarez 1960; Collembola: Selga 1960, 1962; fishes: Lozano Cabo 1961; Rodentia: Peris SJ 1991; Muscidae: Peris SV 1961, 1963; Odonata: Sart 1962; Orthoptera: Llorente 1968; Oribatida: Pérez-Iñigo 1969, 1982, 1983, 1984). Commissioned by the Institute of Marine Science at the University of Miami, a team of scientists lead by Gilbert L. Voss (1918–1989), Frederick M. Bayer (1921–2007), and C. Richard Robins (1928–2020) conducted a deep-sea biological investigation to the Gulf of Guinea aboard the R/V Pillsbury between 1964 and 1965 (Voss 1966). In subsequent years, despite difficulties caused by the loss of manuscripts to a fire in December 1967, the results were eventually published (Echinoidea: Chesher 1966; shrimp: Holthuis 1966; Opisthobranchia: Marcus and Marcus 1966; birds: Robins 1966b, 1970; fishes: Courtenay 1970, Gibbs and Staiger 1970, Robins 1966a, 1970, Robins and Nielsen 1970, Emery 1970, Fraser and Robins 1970, Iwamoto 1970; Decapoda: Holthuis and Manning 1970; Foraminifera: Adegoke et al. 1971; Brachiopoda: Cooper 1975; Stomatopoda: Manning 1970).

The French research vessel “Calypso” undertook a short exploratory stint to the Gulf of Guinea in 1956, with a multitude of new publications resulting from the material collected (Pycnogonida: Fage 1959; Polychaeta: Fauvel and Rullier 1959; molluscs: Franc 1959; Chaetognatha: Furnestin 1959; Porifera: Levi 1959; Annelida: Wesenburg-Lund 1959; Foraminifera: Mangin 1959; Crustacea: Forest 1959, 1966, Stubbings 1961, Crosnier and Forest 1966, Forest and Guinot 1966, Manning 1973, de Saint Laurent and Le Loeuff 1979; Octocorallia: Tixier-Durivault 1961; fishes: Arnoult 1966; Amphipoda: Mateus and Mateus 1986). As part of a Calypso expedition, Rose and Denizot made several botanical collections in São Tomé and Príncipe, including living material; herbarium specimens were deposited at Herb. P (Figueiredo 1998; Figueiredo et al. 2009).

The French National Museum of Natural History in Paris commissioned several excursions throughout the twentieth century to the Gulf of Guinea region, also resulting in many new studies (Diptera: Alexander 1957; amphibians and reptiles: Angel 1920; Tenebrionidae: Ardoin 1958; Coleoptera: Basilewsky 1957, 1958; Orthoptera: Chopard 1958; Osoriinae: Fagel 1958; Lepidoptera: Herbulot 1958; Dermaptera: Hincks 1958; Orthoptera: Kraus 1960; Trichoptera: Marlier 1959; insects: Viette 1956, 1957, 1958; Coleoptera: Villiers 1957). After the creation of the Institut fondamental d’Afrique noire [Fundamental Institute of Black Africa] (IFAN) by the French naturalist Théodore Monod (1902–2000), its academic journal published several papers regarding the Gulf of Guinea (Anthocleista: Monod 1957; bryophytes: Potier de la Varde 1959; Annelida: Rullier 1965; fish: Blanc et al. 1968; Lepidoptera: Darge 1970; insects: Kumar 1975; Decapoda: Monod 1975).

In 1936, in an effort to better understand the biological richness of its overseas colonies, Portugal launched a scientific project for their study, Junta das Missões Geográficas e de Investigações Coloniais (later renamed Junta de Investigação do Ultramar and later still Junta de Investigações Científicas do Ultramar) (Marques et al. 2018). The zoologist Fernando Frade [Viegas da Costa] (1898–1983; Fig. 5.5) was in charge of the Centro de Zoologia de Lisboa, the zoological division under the Junta. During the 1950s and 1960s, several zoological expeditions were commissioned by the institution and from these expeditions important publications were produced by an extended network of researchers up to present day (insects: Bacelar 1948, 1950, 1956a, b, Castel-Branco 1955a, b, 1956a, b, c, 1958a, b, c, 1963a, b, c, 1964, 1965, 1969, 1970a, 1972, Alves 1956a, b, 1965, Castel-Branco and Alves 1957, 1958, Tendeiro 1956a, b, c, d, 1957, Tordo 1956, 1969, 1974, Schmidt 1967a, b, Fernandes 1974; Diptera: Dias 1955, Azevedo et al. 1956, 1961, 1962, Gandara 1956, Pinhão and Mourão 1961; birds, insects, and mammals: Frade 1955a, 1956; fishes: Frade and Correia da Costa 1956, Correia da Costa 1959, Alves and Castel-Branco 1962, Almeida and Alves 2019; Copepoda: Marques 1956, 1960, 1965, 1975; diseases: Mourão 1964; Miocene fauna: Silva GH 1956a, b, 1958a, b, Serralheiro 1957; amphibians and reptiles: Manaças 1958, 1973; Foraminifera: Reis Moura 1961; Hymenoptera: Diniz 1964; Arachnida: Cabral and Carmona 1968/69, Dias 1958, 1988; Aphidoidea: Ilharco and Van Harten 1975, Van Harten 1976; birds: Frade 1959, Frade and Santos 1977; Gastropoda: Simões 1989; Chiroptera: Lopes and Crawford-Cabral 1992).

Fig. 5.5
A photograph of 3 men and a woman standing outside an airplane before boarding.

A party of the participants of Missão Científica de São Tomé e Principe, in 1954 in São Tomé, including the zoologist Fernando Frade (1), Isolina Campos (2) accompanying the husband Ezequiel de Campos (3), and “Jaime” (4). Courtesy of the Herb. PO, Museu de História Natural e da Ciência, Universidade do Porto

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From 1954 to 1955, Frade and Armando Castel-Branco (1909–1977) conducted an expedition to the archipelago of São Tomé and Príncipe (Frade 1955b). This expedition was part of the so-called Missão Científica de São Tomé e Principe. The mission was conceived in 1954, comprising multiple scientific subjects and had the specific aim of providing data to the International West African Conference (Conferência Internacional dos Africanistas Ocidentais—C.I.A.O.) held in 1956 in São Tomé. It was created by the Junta, with the objective of studying various aspects of natural history, ethno-sociology, and economics of São Tomé and Príncipe (Vieira and Viegas 2019). In 1956, C.I.A.O. started to work under the aegis of C.C.T.A./C.S.A. (Commission for Technical Co-operation in Africa South of the Sahara/ Scientific Council for Africa South of the Sahara), international organizations aiming to promote the application of science to the resolution of African problems and that included several African and European countries (Anonymous 1956). This mission was led by the previously mentioned Ezequiel de Campos. Campos, already in his 80s, returned to São Tomé and Príncipe (Fig. 5.5), where he had begun his professional activities. He collected new data, which together with his previous knowledge of the islands resulted in important works about changes in the environment, ecological disturbances, and landscape changes that he had observed over the preceding decades (Campos 1956a, b, 1958).

The botanist Arnaldo Rozeira (1912–1984)—born in São Tomé and raised in Portugal (Porto)—professor at the University of Porto, joined the Missão Científica de São Tomé e Principe, as Mission Assistant and Chief of the Brigada de Sociologia Botânica [Botanical Sociology Brigade]. During his participation in this mission Rozeira visited São Tomé and Príncipe at least three times, in 1954, 1957, and 1958. In 1957, the Portuguese botanist Jorge Martins d’Alte (1912–death unknown) accompanied the botanical expedition, making botanical collections (Costa 2020). As a result of this mission a great diversity of material was collected and deposited in Herb. PO. It comprised vascular plants (including pteridophytes), bryophytes, lichens, algae, and a wood collection (Vieira and Viegas 2019). The singularity of these collections lies in the fact that Rozeira carried out the first botanical collections on Pico do Príncipe, the highest mountain on the island which had scarcely been accessed in earlier times. Furthermore, it was during these expeditions that species collected by Barter were re-collected for the first time.

The African botanical collections at Herb. PO were only recently subject to an inventory (Costa 2020), but some of these have been cited in previous works, namely by Exell and Rozeira (1958; which included one species new to science and new records for the islands, with pteridophytes identified by Alston), Rozeira (1958), Barros-Ferreira (1963, 1965,1968a, b, Begoniaceae, Malvaceae, Melastomataceae; including a new species of Tristemma), and Sampaio (1958, 1962, cyanophytes). The Portuguese collector and naturalist Joaquim Sampaio (1899–1981) again published about cyanophytes (Sampaio 1963), but this time on specimens collected by Joaquim R. dos Santos Júnior (1901–1990) from Príncipe (specimens at Herb. PO).

During the C.I.A.O. in 1956, several authors who had been working on the islands of the Gulf of Guinea presented communications dedicated to botanical topics (Campos 1956b; Almeida and Morais 1958a, b, c; Boughey 1958). Both the French naturalist Théodore Monod (1902–2000) and the English botanist Charles Aubrey Thorold (1906–1998) visited São Tomé and Príncipe during C.I.A.O. and made botanical collections (specimens at Herb. BM and COI; Exell 1962, Liberato 1994). The pteridophytes were studied by Alston (1959), with several new records being added to the flora of the islands (Figueiredo 1998). Exell (1959) published the novelties for the Flora, referring to Monod’s material as “excellent collections”. Exell (1959) referred to collections from Espírito Santo (see below). The majority of the bryophytes collected by Monod and Thorold constituted the basis for the publication by Robert André Léopold Potier de la Varde (1878–1961) (1959). It was Monod (1960) who established and proposed the most commonly used classification of São Tomé vegetation, based on species composition (Figueiredo et al. 2011).

Between 1956 and 1973, the Santomean Joaquim Viegas da Graça Espírito Santo (1901–unknown) made numerous botanical collections in São Tomé and Príncipe (Espírito Santo 1970, 1974), with duplicates at Herb. COI, LISC, BM, and K, including endemic plants (Figueiredo 1994c). In 1968, he was appointed by the Brigada de Fomento Agro-Pecuária de S. Tomé to undertake botanical prospecting, a task he executed for six months (Exell et al. 1952, Figueiredo 1994c, d, Liberato 1994).

In 1956, Helder Lains e Silva (1921–1984) and José Carvalho (dates of birth and death unknown) also made a considerable collection in São Tomé and Príncipe. The list of their collections was published by Silva HL (1958b). These collections were made under the auspices of the Junta de Exportação do Café and are housed at Herb. LISC (Exell, 1962, Silva HL 1958b, Sobrinho 1959, Liberato 1994).

Thomas Christopher Wrigley (1935–) and Fenella Ann Melville (later Mrs. Wrigley) (1936–), both English botanists, participated in a joint Spanish-British expedition to Bioko and Annobón in July and August 1959, together with Julio Álvarez (dates of birth and death unknown), a Spanish zoologist. It was the most significant biological expedition to Annobón since that of Mildbraed in 1911. They collected 316 specimens which are at Herb. K, with duplicates at Herb. BM, BR, MPU, and MA. This collection was identified and published by Exell (1963). Although Exell identified the majority of the collection, the pteridophytes had not been studied until recently (Figueiredo et al. 2009). These collections were kept at Herb. BM but had not been incorporated into the main collection (Figueiredo et al. 2009).

The French botanist Bernard Marie Descoings (1931–2018) collected in Annobón from 24 February to 3 March 1964, as part of an expedition with several researchers. There are 233 specimens of his collections deposited at Herb. MPU, including 56 pteridophytes (Figueiredo et al. 2009; Velayos et al. 2014).

In cooperation with the Junta, the Brigada de Fomento Agro-Pecuário de São Tomé e Príncipe (established in 1964) carried out studies regarding the fauna of the islands, with special relevance to the Entomologists’ meeting in São Tomé and Príncipe in August of 1967 (Quinta 1967; Carvalho 1968). The results of those missions were published in the journal with the same name as the initiative (e.g., Castel-Branco 1967a, b, c, d, e, f, 1970b, 1971; Ferreira 1967a, b, c, d, 1968, 1969, 1971; Quinta 1967).

René de Naurois (1906–2006), a World War II veteran and catholic priest turned ornithologist, authored dozens of papers and books regarding the birds of the coast of West Africa and its offshore islands. From the early 1970s to the late 1990s, Naurois thoroughly studied the ornithological fauna of the Gulf of Guinea and published the results of his research (Naurois 1972a, b, 1973a, b, 1975a, b, 1979, 1980, 1981, 1982, 1983a, b, 1984a, b, c, d, 1985a, b, 1987a, b, c, 1988a, b, 1994; Naurois and Antunes 1973; Naurois and Wolters 1975; Fry and Naurois 1984), which culminated with the “Les oiseaux des îles du Golfe de Guinée: São Tomé, Prince et Annobon” published in 1994. On behalf of the zoologist Henri Heim de Balsac (1889–1979), Naurois also collected shrew specimens, in addition to his work with birds (Heim de Balsac and Hutterer 1982).

Up until 1974, several more incursions to the Gulf of Guinea were commissioned, with the extent of their collections resulting in important publications from various taxonomic groups. Aurélio Basilio conducted an expedition to Annobón in 1957 (Basilio 1957) and some years later, in 1961, C.H. Fry did the same (Fry 1961). The entomologist Jacques O. Derron, with the Brigada, spent three years (1972–1975) studying the insects associated with cacao plantations in São Tomé, from which stemmed several publications (Fursch 1974; Badonnel 1976; Wirth and Derron 1976).

On the years leading up to the independence of the country, many of the collections in herbaria were revisited and studied by other researchers, or compared to new material, resulting in new publications often focusing on a particular group, family, genus, or even a species (e.g. Calvoa robusta: Cogniaux 1908/09; Fungi: Henriques 1922; Câmara and Luz 1938; botanic collections: Romariz 1952; vascular plants: Sobrinho 1952; Hepaticae: Arnell 1956; Algae: Rodrigues 1960; marine algae: Steentoft 1967; Achyranthes: Cavaco 1968; Loranthaceae: Balle 1964; Nicandra, Physalis, and Withania: Fernandes 1969; Erythrina: Bocquet and Derron 1976; Uvaria: Paiva 1978/79).

In 1972, Maria Cândida Liberato (1944–) and Espírito Santo began taxonomic revisions of families of the flora of the islands with the objective of producing a Flora of São Tomé and Príncipe (Liberato and Espírito Santo 1972–1982). The project was never completed, and only a few families were published (Papilionaceae, Mimosaceae, Caesalpiniaceae, Connaraceae, Rosaceae: Liberato 1972, 1973, 1976, 1980a, b, 1982; Aquifoliaceae, Alangiaceae: Espírito Santo 1973a, b).

The common names of the plants of this archipelago were not neglected, being the subject of multiple publications (Rozeira 1958; Silva HL 1959a; Espírito Santo 1969a). These approaches were often included in studies dedicated to the use of plants for medicinal purposes. Several works and research were dedicated to pharmacology/pharmacognosy and uses of medicinal plants across this period (Alves and Prista 1958, 1959, 1960; Prista and Alves 1958, 1959; Prista et al. 1960; Alves et al. 1961, 1962; Alves et al. 1960; Espírito Santo 1969b).

In geographical and economic studies undertaken on these islands, it was common to include an analysis of vegetation, ecology, landscape change, and productive aptitude, providing data on vegetation cover and habitats (Chevalier 1906, 1910, 1938/39; Campos 1920, 1956a, 1958; Tenreiro 1961; Rodrigues 1971; White 1983/84). Throughout the twentieth century, there were several studies and reviews of applied botany, namely with an agronomic perspective, addressing topics such as agricultural suitability, crops and associated problems (e.g. Câmara and Coutinho 1923; Cortesão 1956/57; Silva HL 1958a, 1959b; Ascenso 1964; Mariano 1966; Espírito Santo 1973c; Rodrigues 1974), with a special focus on cocoa, coffee, and quinine crops (e.g. cocoa: Cortesão 1921; Thorold 1955, 1959; Silva HL 1960; Ascenso 1963, 1965; quinine: Costa 1941, 1944; coffee: Silva HL 1958b; coffee and cocoa: Vieira da Silva 1960).

The First Decades of Independence

Following independence from Portuguese rule in 1975, São Tomé and Príncipe was engulfed in a wave of political unrest that hindered the possibility of new biological missions in the area (Jones 1994). Although the taxonomic enterprise continued, the 1970s saw the birth of the modern nature conservation movement and the raise of public and scientific concerns regarding human impacts on the natural world. This has led to an almost radical change of interests in the research community, who became much more dedicated to the conservation aspects of biodiversity research, which in the Gulf of Guinea archipelago translated to the study of the ecology and conservation status of vertebrates.

In 1984, a team of zoologists from the Zoology and Anthropology Sections of the Faculty of Sciences of the University of Lisbon led by entomologist Luis Mendes (1946–) conducted a one-month zoological expedition to São Tomé (Mendes et al. 1988). The resulting publications were published by himself and other authors (Diptera: Grácio 1988, 1999; insects: Mendes 1988a, b, c; Mendes et al. 1988; Drosophilidae: Rocha Pité 1993; Culicidae: Ramos and Capela 1988, Ramos et al. 1989, 1994; Ribeiro 1993, Ramos et al. 1994; Serrano et al. 1995; Ribeiro et al. 1998). Most of the vertebrates collected were not studied until very recently (see Ceríaco et al. 2022).

From 1987 onwards, the International Council for Bird Preservation (ICPB) sponsored several projects for the study of endemic birds of São Tomé and Príncipe (Jones and Tye 1987, 1988; Burlinson and Jones 1988), one of them in cooperation with the University of East Anglia (UEA) (Atkinson et al. 1991, 1994), as well as the creation of a conservation educational programme with the support of the European Economic Community (Harrison and Steel 1989). With the information Atkinson and colleagues were able to gather in the UEA expedition, Dave E. Sargent travelled with other birders in 1989 and 1991, publishing the results of their observations (Sargent et al. 1992; Sargent 1994), which included the rediscovery of the São Tome Grosbeak Crithagra concolor, 101 years after the previous record.

After a one-week trip to São Tomé, Eccles (1988) published the results of his ornithological observations, highlighting the rediscovery of São Tome Short-tail Motacilla bocagii. A short research stint to Annobón was conducted by Michael J. S. Harrison in March 1989, as a part of a larger mission to São Tomé and Príncipe sponsored by ICPB. The visit resulted in an updated bird checklist of some parts of the island (Harrison 1990). The Polish entomologist Tomasz W. Pyrcz conducted two small expeditions in 1989 (January–March) and 1990 (July–September) to São Tomé and Príncipe aiming to create the first checklist for the butterfly species in the archipelago, which resulted in three publications (Pyrcz 1991, 1992a, b). In cooperation with the Natural History Museum (NHM), the entomologist Janusz Wojtusiak (1942–2012) was entrusted to lead a project to identify and catalogue the macrolepidoptera species of São Tomé extant at the NHM as well as those collected in September of 1990 in a small trip to the island (Honey and Wojtusiak 1994; Wojtusiak and Pyrcz 1995; Wojtusiak 1996a, b, c). Other entomological expeditions to the region resulted in the description of new species and contributed to the growth of knowledge regarding the entomofauna of the Gulf of Guinea (Pinhey 1974; Villiers 1976; Darge 1991; Allard 1990; Herbulot 1991a, b; Antoine 1992; Basquin 1992; Bomans 1992; Canu 1994).

In the late 80s and early 90s, teams of Spanish researchers began working in the Gulf of Guinea, some of them under the Spanish programme “Research and Nature Conservation Programme in Equatorial Guinea” (Castroviejo et al. 1994b). Those expeditions led to several publications on insects (Viejo 1984, 1990), mammals (Juste and Ibañez 1993a, b, c, 1994), molluscs (Fernandes and Rolan 1989, 1992; Kosuge and Fernandes 1989; Gofas and Fernandes 1991; Rolan and Fernandes 1990, 1991, 1992, 1995; Rubio and Rolan 1990; Rolan and Templado 1993; Rolan 1996), and sea turtles (Castroviejo et al. 1994a).

Funded by Cooperación Española and led by the Associación Amigos de Doñana, a Spanish expedition including the botanist Manuel Fidalgo de Carvalho (dates of birth and death unknown) visited the island of Annobón. Between September and October of 1987, Carvalho collected 113 specimens, now deposited at Herb. MA (Figueiredo et al. 2009; Velayos et al. 2014). In August 1986, in an expedition to São Tomé organized by the Secció de Petits Països del CIDOB, Neus Gabaldá Casado (dates of birth and date unknown) and Núria García Jacas (1961–) collected specimens of 114 taxa, including pteridophytes; the specimens are deposited at Herb. COI and BC (Gabaldá and Jacas 1988).

Herpetological expeditions to São Tomé and Príncipe from 1989 and 1991 led by Catherine Loumont (1942–) resulted in reviews of the amphibians and reptiles of these islands (Loumont 1992; Schätti and Loumont 1992). Previously, Ronald Nussbaum (1942–) and Michael Pfrender (1960–) had collected herpetological specimens during June and July of 1988, with a particular special focus on caecilians. Those collections are currently extant in the University of Michigan’s Museum of Zoology.

In the spring of 1991, a team of researchers from the University of Dresden (Germany) conducted an exploratory mission to the Gulf of Guinea, with numerous publications resulting (amphibians, reptiles and arachnids: Haft 1992, 1993a, b; amphibians and reptiles: Schatti and Loumont 1992; amphibians and arachnids: Fahr 1993a, b; Feiler 1993; mammals: Feiler et al. 1993, Dutton and Haft 1996; Cnidaria: Kock 1993; Phthiraptera: Mey 1993; birds: Feiler and Nadler 1992, Nadler 1993; Nadler and Feiler 1993; reptiles: Nill 1993; Gastropoda: Schniebs 1993; Lepidoptera: Schutz 1993; Myriapoda: Spelda 1993; Teleostei: Zarske 1993; amphibians: Haft and Franzen 1996). Previously, Feiler and Günther had travelled to the region and published several papers regarding the mammals of the Gulf of Guinea (Feiler 1984, 1988; Günther and Feiler 1985).

Although the ichthyofauna of the islands is quite diverse, after the pioneering work of Balthazar Osório there was a lack of further studies. Russian expeditions in 1983 and 1986 (Domanevskaya 1987, 1988) provided additional information on the biodiversity and were followed by Project d’Évaluation des Ressources Halieutiques, which resulted in important publications for improved baseline knowledge (Worms 1996a, b; D’Almeida 1996; Afonso et al. 1999).

The work of the English zoologist Angus Robin Gascoigne (1962–2012), who lived in São Tomé for many years (Melo 2012), greatly contributed to the knowledge of the molluscan fauna and other aspects of the biodiversity of the Gulf of Guinea (Gascoigne 1993, 1994a, b, c 1995a, b). He also collected plants that were deposited at Herb. LISC and co-authored some papers on flora (Figueiredo and Gascoigne 2001; Figueiredo et al. 2009).

A collaboration between the European Community conservation programme for the forest ecosystems of central Africa (ECOFAC) and the U.S. Peace Corps originated the first major survey on the sea turtles of the Gulf of Guinea (1994–1996), which resulted in baseline information to move towards conservation programmes (Graff 1996; Rosseel 1997). The ECOFAC programme is associated with generating interest in the flora of these islands among the Belgium academic community, which resulted in numerous collections made and the description of new species (e.g. La Croix and Brune 1997; Cribb et al. 1999; Stévart and Geerinck 2000; Joffroy 2001).

Continuing the dynamics implemented by the ECOFAC programme on São Tomé, further botanical inventories took place in the 1990s, notably those carried out by the botanist Jean Lejoly (1945–) and his students between 1994 and 1998, and by the Angolan agronomist Gilberto Cardoso de Matos (1935–) from 1994 to 1999. These collections are deposited at Herb. BRLU and LISC. Some duplicates are also deposited at Herb. STPH (Figueiredo et al. 2011). Matos was one of the main collectors active in São Tomé and Príncipe in the 1990s, amassing ca. 3000 specimens during several expeditions. He often collected with Kathleen Van Essche (fl. 1991–2001). Matos also produced agro-ecological and vegetation maps for São Tomé and Príncipe with the agronomist Alberto Castanheira Diniz (1923–2008) (Diniz and Matos 2002a, b).

Some collecting initiatives focused on orchids were developed by Belgian botanist Tariq Stévart (1974–). With the collaboration of Faustino de Oliveira (1963–) he carried out a systematic survey of the island throughout 1998, after two preliminary missions. On the island of Príncipe, three surveys were organized with the aim of carrying out botanical inventories in the southwestern parts of the island. The results were published in several papers and a guide to orchids of São Tomé and Príncipe (Stévart et al. 2000; Stévart and Oliveira 2000).

The botanist Jorge Paiva (1933–) who undertook over 20 collecting expeditions to São Tomé and Príncipe deposited his collections at Herb. COI. Many of his botanical surveys and collections took place within the scope of diverse projects. For instance, between 1989 and 1993, he collaborated on a project funded by the European Communities Commission regarding the impact of coffee nematodes in the different cultivars (Abrantes 1993).

Additionally, there are collections made in the 1990s by many others, such as the Santomeans Sabino Pires Carvalho (1959–) and Oliveira, at Herb. BRLU and LISC, Estrela Figueiredo (1963–; collected from 1993 to 2002) at Herb. K and LISC, Gascoigne (collected in 1999) at Herb LISC, Maria Fernanda Pinto Basto (1938–; collected in 1990) at Herb. LISC, and Maria do Céu Madureira (1961–) and Ana Paula Martins (1962–) at Herb. COI. Most collections made in the 1990s were deposited at Herb. BRLU, COI, and LISC.

By the end of the twentieth century, a series of taxonomic revisions of the flora of the islands was initiated with the publication of a catalogue of pteridophytes (Figueiredo 1998) and several revisions produced for Equatorial Guinea (e.g. Fernández Casas 1992, Hepper 1992, Morales 1992, Leeuwenberg 1992). These revisions would later give rise to the Flora de Guinea Ecuatorial.

In 1993, an ethnopharmacological study was initiated in São Tomé and Príncipe in collaboration with the Ministry of Health of the country (Madureira 2006, 2012; Madureira et al. 2008; Martins 2002). This study involved a survey of species and had the collaboration of Paiva for the identification of the plant collections. Further projects of applied botany ensued, including the doctoral project of Cristina Galhano (1969–) (Galhano 2006) during which collections were made by Paiva in 1996. In Bom Sucesso Botanical Garden (São Tomé), a tribute is paid to many of the botanists mentioned here, who developed work on the flora of the arquipelago (Fig. 5.6).

Fig. 5.6
A photograph depicts a signboard with the names of different botanists hanging outside a botanical garden.

Commemorative plate on the botanists who studied São Tomé and Príncipe flora, funded by ECOFAC and placed in the Bom Sucesso Botanical Garden. Photo credits: Luis Ceríaco

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In December 1994, the journal Biodiversity and Conservation published a special issue dedicated exclusively to the review of old and new data regarding the Gulf of Guinea’s species richness and endemism (Juste and Fa 1994). This publication was based on works presented at the workshop “Biodiversity and Conservation of the Gulf of Guinea Islands”, held in June 1993 at the Jersey Wildlife Preservation Trust (Butnyski and Koster 1994; Castelo 1994; Castroviejo et al. 1994a, b; Colell et al. 1994; Del Val Pérez et al. 1994; Dutton 1994; Gascoigne 1994c; Jones 1994; Juste and Fa 1994; Juste and Ibañez 1994; Peet and Atkinson 1994; Schaaf 1994; Figueiredo 1994b; Sequeira 1994).

In the 1990s, environmental awareness initiatives stimulated the emergence of publications dedicated to biodiversity conservation, such as the book Conservação dos ecossistemas florestais na República Democrática de São Tomé e Príncipe (Jones et al. 1991). Figueiredo (1997) produced a preliminary assessment of the conservation status of 38 trees of São Tomé and Príncipe in a report for the World Conservation Monitoring Centre (Oldfield et al. 1998).

Following the work of Espírito Santo (1969a, b) and Silva HL (1959a), the medicinal uses and the common names of plants continued to be studied and compiled (Sequeira 1994). Studies of agronomic content were also continued, some directed to particular products (seeds: Ferrão 1979, Ferrão and Ferrão 1984; plant uses: Roseira 1984; woods: Freitas 1987).

Twenty-First Century: A New Generation of Researchers

Taxonomic research initiated in the previous century continued well into the twenty-first century, with several revisions and checklists being published. The flora of Annobón was treated in a series of checklists of the flora of Equatorial Guinea (e.g. Fero et al. 2003; Parmentier and Geerinck 2003; Cabezas et al. 2004) and in the volumes of Flora de Guinea Ecuatorial, an on-going project with the first volume being issued in 2008 (Velayos et al. 2008). Regarding São Tomé and Príncipe, several papers on pteridophytes (Figueiredo 2001, 2002; Figueiredo and Gascoigne 2001; Figueiredo and Roux 2008; Figueiredo et al. 2009) and a checklist of the pteridophytes and lycophytes (Klopper and Figueiredo 2013) were published. A new catalogue of the flora of São Tomé and Príncipe that updated the over 35-years-old checklist produced by Exell (1973b) was finally published (Figueiredo et al. 2011). In the same year a catalogue of the bryophytes was also published (Sérgio and Garcia 2011). The Rubiaceae, one of the dominant families of the flora, was treated in a series of revisions (Alves et al. 2005; Figueiredo 2005; Davies and Figueiredo 2007). Applied botany studies integrated into environmental protection strategies also continued (e.g. Martins 2002; Madureira 2006; Madureira et al. 2008).

At the dawn of the new century, a new wave of biodiversity researchers hit the islands. Furthering knowledge gathered by the previous generations, this new generation has not only continued to contribute to cataloguing the still undocumented and undescribed fauna and flora of the oceanic islands of the Gulf of Guinea, but also implemented new techniques, methodologies, and approaches. Other topics, such as biodiversity conservation, ethnobiology, ecosystem health, and ecology have experienced a considerable growth. This research has been conducted by an increasingly diverse group of international and national researchers and is mostly covered in the subsequent chapters of the volume. Nevertheless, some aspects of this new wave of research need to be highlighted here—both because they represent an important turning point on the study and preservation of the local biodiversity, but also due to the dimension and intensity of some of these activities.

One fundamental difference in the research carried out in the twenty-first century is the use of molecular methods to study the taxonomy, phylogenety, and biogeography of the biodiversity of the islands. While this has not yet been applied to all taxonomic groups, the use of molecular methods has been widely applied to the study of the island’s herpetofauna (Bell et al. 2022; Ceríaco et al. 2022), birds (Melo et al. 2022) and, to a lesser extent, plants (Plana et al. 2004; Soares et al. 2010). The growing importance of ecological and conservation studies has also marked the research landscape in the oceanic islands of the Gulf of Guinea, with dozens of works and theses produced on the topic, especially at the University of Lisbon (see Lima et al. 2022, Soares et al. 2022), but also the seminal works on marine turtles (see Ferreira-Airaud et al. 2022), plants (see Stevart et al. 2022), and even land molluscs (see Panisi et al. 2022). Finally, a revival of field expeditions to further catalogue the diversity and distribution of islands’ species has resulted in important modern collections, many of which have not yet been fully studied. Of critical importance is the programme led by the California Academy of Sciences (CAS), whose activities started in 2001. This programme, led by Robert “Bob” Drewes, has conducted over a dozen expeditions to the islands and involved researchers from across the world with expertise in a wide array of taxonomic groups. A considerable part of the recently produced knowledge on the archipelago’s biodiversity stems from this programme.