Sirdavidia, an extraordinary new genus of Annonaceae from Gabon

Abstract A distinctive new monotypic genus from Gabon is described in the tropical plant family Annonaceae: Sirdavidia, in honor to Sir David Attenborough. Molecular phylogenetic analyses confirm that Sirdavidia, which is very distinct from a morphological standpoint, is not nested in any existing genus of Annonaceae and belongs to tribe Piptostigmateae (subfamily Malmeoideae), which now contains a total of six genera. The genus is characterized by long acuminate leaves, fully reflexed red petals, 16–19 bright yellow, loosely arranged stamens forming a cone, and a single carpel topped by a conspicuous stigma. With just three known collections, a preliminary IUCN conservation status assessment is provided as “endangered” as well as a distribution map. The discovery of Sirdavidia is remarkable at several levels. First, it was collected near the road in one of the botanically best-known regions of Gabon: Monts de Cristal National Park. Second, its sister group is the genus Mwasumbia, also monotypic, endemic to a small area in a forest in Tanzania, some 3000 km away. Finally, the floral morphology is highly suggestive of a buzz pollination syndrome. If confirmed, this would be the first documentation of such a pollination syndrome in Magnoliidae and early-diverging angiosperms in general.


Introduction
Th e Central African country of Gabon is merely 270 000 km² in size, but is home to an incredible botanical diversity (Sosef et al. 2006). Around 82% of its territory is covered with tropical rain forest and with around 5000 vascular plant species, Gabon is an important center of plant biodiversity in Central Africa (Sosef et al. 2006). Th e country is botanically one of the best known in the region (Sosef et al. 2006;Wieringa and Sosef 2011) with several parts of its territory well inventoried, such as the Monts de Cristal area (Wieringa and Sosef 2011).
Annonaceae (Magnoliidae) is a pantropical fl owering plant family of trees, shrubs and lianas. With around 2500 species (Chatrou et al. 2012;Couvreur et al. 2011) it is one of the most diverse plant families in tropical rain forests, and the largest in order Magnoliales (Haywood et al. 2009). Recently a new phylogenetic classifi cation of the family recognizes four subfamilies and 14 tribes (Chatrou et al. 2012). Th is was followed by a scratchpad website (World Annonaceae; Couvreur 2014b) documenting Annonaceae diversity and taxonomy worldwide. Taxonomic understanding of African Annonaceae has been increasing since the publication of "Flore du Gabon, Annonaceae, volume 16" (Le Th omas 1969) more than 40 years ago (Botermans et al. 2011;Couvreur 2014a;Deroin and Luke 2005;Fero et al. 2014;Versteegh and Sosef 2007). As a consequence, several new species and a new genus have been described in Africa these past years, mainly from Tanzania (Couvreur et al. 2006;Couvreur et al. 2009;Johnson et al. 1999;Luke and Deroin 2005;Marshall et al. in press). New species, however, from Central Africa, and in particular Gabon, have been rarer with only a few such descriptions (Jongkind 2002).
A probable new genus of Annonaceae was collected during fi eld work in Monts de Cristal National Park, as part of a larger fi eld trip focusing on the study Magnoliidae fl oral diversity. Th e objective of this paper was to confi rm its status as a new species and its classifi cation in a new genus. Th e taxon was fi rst seen near the Kinguélé dam, and further prospection in the area revealed several individuals. It is the unusual fl oral structure of this species for Annonaceae that led us to suspect it might represent a new taxon and to undertake both a phylogenetic analysis and more thorough morphological observations. As we show here, interesting tropical taxa unknown to science can still be discovered in places even considered to be well known botanically.

Material and methods
Herbarium, alcohol and photographic materials were used to produce the descriptions. In order to identify other specimens of this new genus, we looked at all undetermined Annonaceae specimens in the herbaria located at BR, BRLU, LBV, P and YA (herbarium acronyms according to Th iers 2012). We also looked at sterile plot specimens of Annonaceae for Gabon held at BRLU. Th e conservation status was assessed by calculating the extent of occurrence (EOO) and the area of occupancy (AOO) using the GeoCAT tool (Bachman et al. 2011) and applying the IUCN Red List Category criteria (Standards-and-Petitions-Working-Group 2006).
A preliminary phylogenetic analysis indicated that the new taxon was nested in tribe Piptostigmateae of the Malmeoideae subfamily. Th erefore, the data matrix of Couvreur et al. (2009) was used to undertake the analyses. Th e matrix was based on two plastid markers (rbcL and trnL intron / trnL-trnF spacer) and contains 35 out of the 47 genera of Malmeoideae, representing all major lineages. Representative species from all other subfamilies were also sampled: Anaxagoreoideae (1 genus), Ambavioideae (2 genera out of 8), Annonoideae (17 genera out of 50). Eupomatia bennettii (Eupomatiaceae) was chosen as the outgroup (Massoni et al. 2014;Sauquet et al. 2003). All six genera currently recognized in Piptostigmateae were sampled. Sampling within genera was restricted to one species in the Annonoideae and Ambavioideae, and varied from one to two species in the Malmeoideae.
DNA extractions of silicagel-dried leaf samples from two individuals of Sirdavidia solannona Couvreur & Sauquet were performed using a DNeasy Plant Mini Kit (Qiagen, Valencia, CA). Th e universal primers C/D and E/F (Taberlet et al. 1991) were used to amplify and sequence the trnL intron and trnL-trnF spacer. Th e rbcL marker was amplifi ed using two primer combinations, 1F/724R and 636F/1460R (Fay et al. 1998). PCR amplifi cations were conducted using the FailSafe kit with Premix E (Epicentre, Madison, WI), according to manufacturer's instructions and by adding 0.5 U of Taq DNA polymerase (Promega, Madison, WI) in a total volume of 50 μL. Th e PCR program was as follows: 35 thermal cycles at 94 °C for 1 min, 50-55 °C for 50 s, 72 °C for 50 s and a fi nal extension at 72 °C for 3 min. Sequencing was performed at Macrogen (Th e Netherlands). Sequences were edited using Geneious 1.5.6 (Drummond et al. 2010) and manually aligned in the PAUP* text editor (version 4.10b;Swoff ord 2002). Gaps were coded following the simple coding model of Simmons and Ochoterena (2000). Microsatellites and ambiguously aligned regions (in the trnL intron and trnL-trnF spacer) were excluded from the analyses.
Maximum Parsimony (MP) analyses were performed using PAUP* (version 4.10b; Swoff ord 2002). Heuristic searches were performed with 100 random taxon addition sequence iterations, saving 100 trees at each iteration, with tree bisection-reconnection branch swapping. Relative support for each node was assessed by performing 1000 bootstrap (BS) replicates (Felsenstein 1985) with TBR branch swapping (20 random addition sequences, saving 20 trees per replicate).
Maximum likelihood analyses were conducted using RAxML version 7.2.7 (Stamatakis 2006) on the CIPRES portal teragrid (Miller et al. 2009). ML bootstrap analyses and the inference of the optimal tree were conducted simultaneously. Th e optimal tree was inferred using a GTR+Γ model, whereas a similar yet more computationally effi cient model (GTR+CAT) was employed for the 1000 bootstrap iterations (Stamatakis et al. 2008).
Both markers represented 2669 total characters, 187 of which were excluded because of ambiguity in the alignment and 407 (16.5%) were parsimony informative. Both MP and ML phylogenetic analyses led to the same topology, with similar levels of support (Fig. 1). In these trees, Sirdavidia solannona is nested in Piptostigmateae with strong support and is sister to Mwasumbia alba Couvreur & Johnson (MP-BS = 95%; ML-BS = 97%). Small trees with distichous, simple pinnately veined leaves with an entire margin and reticulate third-order venation. Species androdioecious (?) (fl owers unisexual staminate or bisexual). Infl orescences one to three-fl owered, axillary on old branches or at base of trunk, with one to three short sympodial rachilla. Flowers actinomorphic. Perianth of 9 free tepals in 3 alternate, valvate whorls of 3 each, diff erentiated in outer tepals (sepals) and middle and inner tepals (petals). Petals similar (subequal in length), spreading horizontally or refl exed at anthesis. Stamens 16-19, free, basifi xed with a very short fi lament. Anthers introrse, probably opening by two longitudinal slits, connectives tongue shaped, yellow. Carpel one, densely pubescent, stigma cylindrical coiled, ovules 7-10, uniseriate. Monocarp sessile, cylindrical densely pubescent.

Sirdavidia
A single species only known to Gabon (Fig. 2). Etymology. We dedicate this new genus to Sir David Attenborough, British broadcaster and naturalist, in honor of his lifelong dedication to nature, conservation, evolution and natural history programs. His passion for nature have infl uenced and inspired a generation of biologists and naturalists, including the fi rst and senior authors of this paper. Tree 4-6 m tall, 2 to 4 cm in diameter at breast hight (d.b.h.), bark dark brown with patches of green, old branches black, glabrous, young branches black, sometimes pubescent. Leaves distichous, simple, entire, pinnately veined. Petiole 3-4 mm long, 2-3 mm in diameter, glabrous or sparsely pubescent when young, slightly grooved on top, leaf lamina inserted on top. Lamina 20-26 cm long, 4.5 to 9 cm wide, length:width ratio 2.5 to 4.5, narrowly elliptic to elliptic to narrowly ovate to ovate, apex long acuminate, acumen 2-3 cm long, base obtuse, coriaceous, young sparsely pubescent to glabrous above, glabrous below, old leaves glabrous above and below, mid rib sunken above, sparsely pubescent when young below, glabrous above, glabrous above and below when old, secondary veins 9-12 pairs. Infl orescences axillary, on old branches and caulifl orous towards the base of the trunk. Sympodial rachis up to 6 mm long, but sometimes up to 1.5 cm long, densely covered with short appressed hairs, with 0-10 minute densely packed lower bracts densely pubescent brown. Flowering pedicels 2 to 10 mm long, densely covered with short appressed hairs, red, upper bract inserted at base or up to ½ of pedicel, covered with short appressed hairs, red. Flowers actinomorphic, bisexual or unisexual staminate (androdioecious), with 9 tepals in total, diff erentiated in one whorl of 3 sepals and 2 whorls of 3 petals, all alternate. Sepals 2-3 mm long, 1.5-2 mm wide, length:width ratio 1.5, ovate, valvate, apex acute, base truncate, densely covered with short appressed hairs outside, glabrous inside, red. Outer petals 4-10 mm long, 2.5 to 5 mm wide, length:width ratio 2 to 2.5, elliptic, apex acute, base truncate, densely pubescent with appressed hairs outside, densely pubescent with short tomentose hairs inside, deep red. Inner petals 4-9 mm long, 2-4 mm wide, length:width ratio=2 to 2.5, elliptic, apex acute, base truncate, densely pubescent with short tomentose hairs outside, densely pubescent with short tomentose hairs inside along margins, glabrous towards center, deep red. Petals spreading horizontally or recurving backwards at anthesis. In staminate and bisexual fl owers, stamens 16-19, 3-4 mm long, outer ones shorter than inner ones, fi lament shorter than 0.2 mm, narrow, connective umbonate (tongue shaped), glabrous, bright yellow. Anthers introrse, probably opening by two longitudinal slits. In bisexual fl owers, carpel one, 4-5 mm long, ca. 1 mm wide, densely pubescent with silvery long appressed hairs, ovules uniseriate, 7-10, stigma cylindrical coiled, 2-3 mm long, sparsely pubescent towards the top, white cream. Mature fruits not seen, young fruiting pedicel 6 mm long, densely pubescent with appressed hairs. Young monocarp cylindrical, densely pubescent with silvery appressed hairs. Seeds not seen. (Figs 3 and 4) Phenology. Flowers collected in April and November, young fruits collected in November.

Sirdavidia solannona
Distribution and habitat. Sirdavidia is endemic to Gabon, with three known collections: two near the Kinguele dam in the Monts de Cristal National Park, Mbé sector, and one south of the Ivindo National Park (Fig. 2). Floristic comparisons in Gabon emphasize that the Monts de Cristal fl ora has a high resemblance with many other areas across Gabon, including the Ivindo NP region (Wieringa and Sosef 2011). Th us it is not unusual to fi nd species occurring in Monts de Cristal and elsewhere in the county. Sirdavidia grows in the understory of mature to old secondary rain forests around 300-600 m, near rivers or on inundated soils.
Preliminary conservation assessment. Endangered [EN B1ac]. Two localities in Gabon are known for this species: Monts de Cristal N.P. and south of the Ivindo N.P. Th e population found in Kinguele (Monts de Cristal) was close to the road and several  (around 10) individuals were seen. We also looked for this species in other parts of the Park (around Tchimbélé) and did not see it again. Th e herbarium specimen collected from Ivindo indicates "en peuplement" (in population) suggesting that several individuals were seen. However, the coordinates on the herbarium sheet place this collection outside the national park. Th e Area of occupancy (AOO) is 12,000 km² and the Extent of occurrence (EOO) is 6.2 km², suggesting a very restricted overall distribution. We thus suggest a status of endangered given that only a handful of individuals have been seen and that these populations are quite close to disturbances.
Etymology. Th e species name epiteth highlights the striking resemblance with fl owers of some species of Solanum, an unusual and new feature for a fl ower of Annonaceae.
Note. Th e androdioecious nature of Sirdavidia solannona has yet to be properly confi rmed. We only saw two individuals one of which appeared to have only staminate fl owers. Because other members of the tribe Piptostigmateae are known to have this condition, it would not be surprising. Paratypes

Molecular and morphological characterization of Sirdavidia
Th e molecular phylogenetic analyses presented here confi rms that Sirdavidia solannona belongs to tribe Piptostigmateae, which now contains a total of six accepted genera (though Piptostigma is paraphyletic, Couvreur et al. 2009). Th is new taxon was found to be sister with strong support to the monotypic East African genus Mwasumbia Couvreur & Johnson (see below, Fig. 1). Th e two genera, together with Polyceratocarpus Engl. & Diels and Piptostigma Oliv., form a strongly supported clade (Fig. 1), referred to here as the SMPP clade.
Sirdavidia diff ers morphologically from Mwasumbia in several important respects, warranting its status as a new species and a new genus. Tertiary venation is a useful character for distinguishing genera within the tribe Piptostigmateae ) and contains useful phylogenetic information at the family level (Doyle and Le Th omas 1996). All three major tertiary venation types in Annonaceae (reticulate, parallel and intermediate between the two fi rst ones) are found in Piptostigmateae (Table 1). Parallel tertiary venation occurs in both Piptostigma and most Polyceratocarpus species whereas Mwasumbia has an intermediate tertiary venation. In contrast, Sirdavidia is characterized by a reticulate tertiary venation and in this sense resembles Greenwayodendron (Table 1). Th is type of venation appears to be rare in Annonaceae and was reconstructed as being ancestral for the family as a whole (Doyle and Le Th omas 1996). Sepal aestivation in Sirdavidia is valvate like in most other genera in Table 1. Morphological characters of the six genera found in tribe Piptostigmateae. Modifi ed from Couvreur et al. (2009).
Piptostigma is represented by two columns because it is paraphyletic (Fig. 1).  (Table 1). Aestivation was considered an important character to separate genera in Annonaceae (Chatrou et al. 2012), but phylogenetic studies have underlined its homoplastic nature (Couvreur et al. 2008c;Doyle and Le Th omas 1996). Th e presentation of petals at anthesis is also very diff erent between Sirdavidia and Mwasumbia. In Mwasumbia, the outer petals are refl exed, whereas the inner petals are pendulous and sometimes connivent at the tips. A similar confi guration is observed in some species of Polyceratocarpus (Marshall et al. in press). In contrast, the petals in Sirdavidia are horizontally spreading to highly refl exed at anthesis, a condition not found in any other genera within Piptostigmateae (Table 1, Figs 1e,3B,4a,b,c ). Stamen number and connective shape have played an important part in Annonaceae classifi cation (Chatrou et al. 2012). In Sirdavidia they are very distinct to those in Mwasumbia. Sirdavidia has 16-19 stamens with, in general, a tongue shaped connective apex (Fig. 3M), while Mwasumbia has numerous stamens (more than 30) with a discoid or fl at connective apex ( Figure 3L of Couvreur et al. 2009). We suggest that the morphological diff erences outlined above are suffi cient to erect a new species for Sirdavidia solannona and also justify the creation of a new genus, distinct from Mwasumbia, given the morphological characters that discriminate among genera of Annonaceae in general (Chatrou et al. 2012;Le Th omas 1969).

Annickia
Morphological similarities and differences of Sirdavidia with Piptostigmateae genera Table 1 summarizes the morphological similarities and diff erences of Sirdavidia with the other genera within Piptostigmateae. Two characters appear important for delimiting the SMPP clade: -Infl orescence position: Within Piptostigmateae both terminal or axillary types of infl orescences can be found (Fries 1959). In Sirdavidia, infl orescences are axillary, a character also found in Mwasumbia, Piptostigma and Polyceratocarpus (Table 1) confi rming it as a good synapomorphy for the SMPP clade within Piptostigmateae. Th e position of infl orescences has also previously been recognized as a good character for separating genera in Annonaceae (Chatrou et al. 2000). -Monocarp base: Another synapomorphy for the SMPP clade is the sessile monocarps. In contrast, Annickia Setten & Maas and Greenwayodendron Verdc. have monocarps with conspicuous stipes. Even though immature fruits were only observed for Sirdavidia to date, it is clear that the single monocarp is sessile ( Fig.  3P; Fig. 4f). Although this character was previously thought to contain little taxonomic information, it has proven useful in delimitating other African tribes of Annonaceae such as Monodoroideae (Chatrou et al. 2012;Couvreur et al. 2008c).
Other characters appear to have little taxonomic use but are interesting as they underline the important fl oral morphological variability within Piptostigmateae.
-Androdioecy in Annonaceae is not unusual (van Heusden 1992). Within tribe Piptostigmateae two other genera are documented as being androdioecious: Greenwayodendron and Polyceratocarpus ). However, with only two individuals seen, it is diffi cult to conclude precisely on the type of reproductive strategy for Sirdavidia. -Sirdavidia is unique within the tribe in having a single carpel, a feature found in only 10% of Annonaceae (Deroin 1991). Other genera such as Sanrafaelia Verdc., Dielsiothamnus R.E.Fr., and Tridimeris Baill. are also monocarpellate (van Heusden 1992; Verdcourt 1996).

A fascinating new genus
Sirdavidia is fascinating at a number of other diff erent levels. First, it had remained undescribed until now, even though it occurred in a well known and well inventoried region of Gabon; second, its closest relative is another monotypic genus restricted to Tanzania, some 3000 km away; and, fi nally, it could be the fi rst documentation of a buzz pollination syndrome in Magnoliidae.

A hidden genus
Sirdavidia was discovered in the Monts de Cristal National Park (N.P.), one of the most species-rich and botanically best collected regions in Gabon (Wieringa and Sosef 2011). Moreover, it was collected just a few meters from the main road that connects Kinguele to Tchimbele. Th is discovery suggests that there may still be a number of undescribed species and genera in this region and thus might not be as well collected as suggested. Interestingly, the small population was located near a recent botanical inventory of the Monts de Cristal (Sunderland et al. 2004). Because it is a tree that so far has been observed to be smaller than 6 m and is less than 10 cm in diameter, it is likely that it was not collected during the inventories (in general such inventories only focus on trees with a diameter larger than 10 cm). Th is underlines the importance of collecting woody individuals with a diameter less than 10 cm when undertaking inventory plots (Gentry and Dodson 1987;Kenfack et al. 2007). An alternative explanation is that because it superfi cially doesn't look like an Annonaceae fl ower, putative collections might have been identifi ed under diff erent plant families.

An incredible disjunction
Th e closest relative to Sirdavidia is another recently described monotypic genus, Mwasumbia ). Th is rain forest genus is endemic to a small locality in the east African forests of Tanzania, corresponding to a biogeographic disjunction of ca. 3000 km with Sirdavidia. East West/Central disjunctions between rain forest restricted species are a common feature in African plants (Burgess et al. 2007;Couvreur et al. 2008b;Lovett 1993). However, this might represent an extreme disjunction between two locally restricted rain forest monotypic genera on opposite sides of Africa. Several disjunctions between East and West/Central African Annonaceae have been dated to occur at signifi cantly diff erent periods of increased aridity suggesting a repeated continental scale fragmentation of a once pantropical rain forest (Couvreur et al. 2008b). Th ese two genera provide another example of the role of this vicariant pattern in generating endemicity (both faunistic and fl oristic) across tropical Africa (Couvreur et al. 2008b;Tolley et al. 2013). It will be interesting to estimate the temporal origin of this disjunction in order to measure the evolutionary time these two species represent and to determine whether their splitting coincides with those of other East/ West African disjunctions in Annonaceae and other tropical plant families.

A possible new pollination syndrome type for Magnollideae
Th ough the fl ower has all the structural characters of a typical Annonaceae fl ower (3 sepals, 2 whorls of 3 petals), the overall aspect is very unusual, resembling fl owers of some species of Solanum L. (Solanaceae). Th e morphological appearance is strongly suggestive of a special type of pollination syndrome referred to as buzz pollination syndrome. Buzz pollination relies mostly on sonicating bees that use vibrations to extract pollen from the anthers (De Luca and Vallejo-Marín 2013). Th e fl owers of Sirdavidia are characterized by several traits typically associated with the evolution of buzz pollination. Refl exed petals. Most buzz pollinated fl owers show strongly refl exed petals exposing the stamens and the carpels. Refl exed petals are quite common in Annonaceae, occurring in a number of genera such as Uvaria and Isolona.
Stamens: Th e stamens of Sirdavidia are bright yellow, a color known to attract bees (De Luca and Vallejo-Marín 2013). Such a color is unusual for Annonaceae, at least in Africa. In general, stamens are pale in color, varying between red, green and yellow. In addition, typical stamens of Annonaceae are never fully exposed as they are in Sirdavidia, being generally tightly packed together and appressed by the petals. Non appressed stamens by the petals are also found in the sister genus Mwasumbia ). In Sirdavidia the stamens form a "cone" of loosely arranged stamens (relative to other Annonaceae species) around the single carpel, a feature also found in buzz pollinated Solanum-type fl owers (De Luca and Vallejo-Marín 2013).
Anthers. In typical buzz pollinated fl owers, the anthers generally have apical pores or short slits that release the pollen grains during vibration. However, non-poricidal anthers have also been linked with buzz pollination in a number of other genera (Buchmann 1985;de Oliveira and Sazima 1990). Based on macromorphological observations, no evidence of apical pores can be seen in Sirdavidia, which would thus rather represent a case of non-poricidal buzz pollination. It is possible that the structural longitudinal slits we have observed only eff ectively dehisce apically, thus functioning as short apical slits. However, detailed anatomical observations will have to confi rm this. In addition, buzz pollination will only be eff ective if pollen grains are very small and extremely numerous (dust like). To date, we have no information about the size and quantity of pollen grains in Sirdavidia. Pollen in Annonaceae is generally large in size compared to other angiosperms (Doyle and Le Th omas 2012). Pollen grains in the sister genus Mwasumbia are monads and were measured to be ca. 59 μm in length for the polar axis, which ranks as a medium-sized pollen grain in Annonaceae (Couvreur et al. 2008a;Doyle and Le Th omas 2012). However, pollen size is highly homoplasic in Annonaceae (Doyle and Le Th omas 2012), and thus it is hard to speculate on the size of the pollen grains in Sirdavidia.
Long stigma. Th e conspicuous stigma sticking out of the stamens in Sirdavidia is also a typical feature of buzz pollinated fl owers (De Luca and Vallejo-Marín 2013). Th e stigma rubs against the abdomen of the visiting bee allowing the potential pollination.
Annonaceae fl owers are visited by a large variety of insects (Saunders 2012;Silberbauer-Gottsberger et al. 2003) such as beetles, thrips fl ies and even cockroaches, suggesting a large array of pollination systems. In contrast, bees have rarely been documented to pollinate or visit Annonaceae fl owers (Silberbauer-Gottsberger et al. 2003). Bee pollination is suspected in Unonopsis guatterioides (A.DC.) R.E.Fr. and Uvaria concava Teijsm. & Binn. However, fl owers of these two species are apparently not buzz pollinated, and are very diff erent in morphology than those of Sirdavidia. Additional fi eld observations will be required to determine whether Sirdavidia is indeed buzz pollinated. In addition to observations of pollinator behavior, it would be particularly interesting to learn more about the fl oral biology of this species. Indeed, nearly all early-diverging angiosperms (including Annonaceae) are protogynous, a feature commonly associated with wind, beetle, fl y, and thrips pollination, whereas the remaining angiosperms are predominantly protandrous and bee or butterfl y pollinated (Endress 2010). Th erefore, one would expect that Sirdavidia might have shifted away from protogyny to allow eff ective buzz pollination by pollen collecting bees. If the buzz pollination syndrome was to be confi rmed for Sirdavidia, it would be the fi rst record in Annonaceae and for Magnoliidae and early-diverging angiosperms in general (Endress 2001). In any case, this represents the fi rst "Solanum-type" fl ower described in Magnoliidae to date (De Luca and Vallejo-Marín 2013; Endress 2001).
Hans de Vries is kindly thanked for his botanical illustration of Sirdavidia solannona. Last, we also thank Jürg Schönenberger, Yannick Staedler, and Peter Endress for discussions on buzz pollination and comments on earlier versions of the article. Field work in Gabon was supported by the Agence Nationale de la Recherche (grant number ANR-12-JVS7-0015-01 to HS).