Revision of the genus Diplotaxis (Brassicaceae) in the Cape Verde Islands, W Africa

The genus Diplotaxis (Brassicaceae) in the Cape Verde Islands, W Africa, is revised. Nine taxa are accepted, of which five are described as new: D. antoniensis sp. nov., D. glauca, D. gorgadensis sp. nov., D. gorgadensis ssp. brochmannii ssp. nov., D. gracilis, D. hirta, D. sundingii sp. nov., D. varia sp. nov., and D. vogelii . All species are suffruticose, yellow-flowered perennials and belong to sect. Catocarpum . The species are endemic to the Cape Verde Islands, but show morphological and karyolog-ical affinity to the N African and Mediterranean D. harra s. lat. Analyses of morphological variation in 90 populations (400 plants) revealed a complex pattern, in particular in vegetative characters, most likely evolved by parallel ecogeographical differentiation in different islands. The chromosome number is 2n = 26 (n = 13) in the five taxa investigated. Self-pollination experiments indicate that the species are self-incompatible and outcrossing. Experimental F₁ hybrids with full seed set after open pollination were obtained in 30 interspecific combinations, and the taxa are considered fully interfertile. The taxa are thus isolated mainly by geographical and partly by ecological barriers and have evolved by vicariant evolution (most islands) and adaptive radiation (one island).     

The taxonomy and affinities of Papaver gorgoneum from the Cape Verde Islands

A new subspecies of Papaver gorgoneum , ssp. theresias is described from the Cape Verde Islands, West Africa. A detailed comparison of the 2 subspecies is made and the ecology, the affinities of the species in the genus and the origin are discussed. The chromosome numbers of both subspecies (2n = 38) are reported for the first time and a note on the compatibility system is made.     

Morphology and taxonomy of the genus Cochlearia (Brassicaceae) in Northern Scandinavia

The morphological variation between populations of Cochlearia in Northern Scandinavia has been analysed. The variation is correlated to ecology, and four ecotypes are recognized. Based on the morphological differentiation of the ecotypes and the results of crossing experiments, the populations are referred to the following three taxa: C. officinalis ssp. officinalis which includes the common beach ecotype and the bird cliff ecotype; C. officinalis ssp. integrifolia stat. nov. which includes the spring ecotype growing in inland localities up to about 600 m a.s.l. in cold more or less eutrophic springs, and C. officinalis ssp. norvegica ssp. nov. which includes the estuary ecotype, growing in poor, often inundated habitats near river outlets at the fjord ends. All the differentiation has taken place at the tetraploid level (2n = 24). The subspecies are kept more or less distinct due to ecological and seasonal isolating mechanisms rather than internal, reproductive barriers. A key to the subspecies and distribution maps for ssp. integrifolia and ssp. norvegica are presented.     

Prioritizing species conservation: does the Cape Verde kite exist?

The Cape Verde kite (Milvus milvus fasciicauda) is considered to be one of the rarest birds of prey in the world and at significant risk of extinction. For this reason there is great interest in both the taxonomic and the population status of this group. To help resolve its taxonomic status, we provide phylogenetic analyses based on three mitochondrial genes for a sampling of kites in the genus Milvus, including a broad geographical sampling of black kites (Milvus migrans), red kites (Milvus milvus), Cape Verde kite museum specimens collected between 1897 and 1924, and five kites trapped on the Cape Verde Islands during August 2002. We found that the historical Cape Verde kites, including the type specimen, were non-monophyletic and scattered within a larger red kite clade. The recently trapped kites from the Cape Verde Islands were all phylogenetically diagnosed as black kites. Our findings suggest that the traditional Cape Verde kite is not a distinctive evolutionary unit, and the case for species status, as recently suggested by others, is not supported. We do find support for recognition of at least one clade of yellow-billed kites, traditionally considered as a black kite subspecies, as a distinctive phylogenetic species.     

Variability of essential oils of Satureja montana L. and Satureja kitaibelii wierzb. ex Heuff. from the central part of the balkan peninsula

The results of the essential oil composition confirm that there are differences between populations within the same subspecies (Satureja montana ssp. montana, between the subspecies (Satureja montana ssp. montana and Satureja montana ssp. pisidica) and the species (Satureja montana and S. kitabelii). The essential oil composition of S. montana ssp. montana is more related to the Satureja montana ssp. pisidica than S. kitaibelii which separates as a whole species.     

Phylogeography of the Calonectris shearwaters using molecular and morphometric data

We investigated phylogenetic relationships and the biogeographic history of the Calonectris species complex, using both molecular and biometric data from one population of the Cape Verde shearwater Calonectris edwardsii (Cape Verde Islands), one from the streaked shearwater C. leucomelas (western Pacific Ocean) and 26 from Cory's shearwater populations distributed across the Atlantic (C. d. borealis) and the Mediterranean (C. d. diomedea). The streaked shearwater appeared as the most basal and distant clades, whereas the genetic divergences among the three main clades within the Palearctic were similar. Clock calibrations match the first speciation event within Calonectris to the Panama Isthmus formation, suggesting a vicariant scenario for the divergence of the Pacific and the Palearctic clades. The separation between the Atlantic and Mediterranean clades would have occurred in allopatry by range contraction followed by local adaptation during the major biogeographic events of the Pleistocene. The endemic form from Cape Verde probably evolved as a result of ecological divergence from the Mediterranean subspecies. Finally, one Mediterranean population (Almeria) was unexpectedly grouped into the Atlantic subspecies clade, both by genetic and by morphometric analyses, pointing out the Almeria-Oran oceanographic front (AOOF) as the actual divide between the two Cory's shearwater subspecies. Our results highlight the importance of oceanographic boundaries as potentially effective barriers shaping population and species phylogeographical structure in pelagic seabirds.     

Differentiation patterns in the Scutellaria albida group (Lamiaceae) in the Aegean area

An experimental investigation of the mainly white-flowered Scutellaria albida group in the Aegean area was carried out. Eight populations representing maximum morphological variation as well as geographic separation were chosen for crosses between populations. Strong sterility barriers were observed in the Cretean endemic species, S. sieberi Benth., which also deviated morphologically and is probably an ancient relic. Strong crossing barriers were also found in plants from Euboea, and, in spite of little morphological differentiation from S. albida L. s. str., they are treated as a separate species, S. goulimyi Rech. fil. Crossing barriers of intermediate strength were present in morphologically distinct material from N Sporades, which is also treated as a separate species, S. sporadum Bothmer sp. nov. All other populations showed high compatibility in crosses among themselves, viz. populations from Bulgaria, Thrace, Andros, Naxos, and Rodhos. These were treated as the same species, S. albida , having large local as well as clinal variation. Three subspecies are retained: ssp. albida in the north; ssp. perhispida (Bornm.) Bothmer in E Macedonia, Thrace and on the islands; and the mainly purple-flowered, ssp. vacillans (Rech. fil.) Bothmer, endemic to the peninsula of Athos. Evolutionary pathways and phytogeographical patterns are discussed.
S. sporadum is mainly inbreeding and, in S. sieberi , indications of a self-incompatibility system were found. The other taxa have a more versatile system.     

Decapoda from Antipatharia, Gorgonaria and Bivalvia at the Cape Verde Islands

The shrimps Balssia gasti, Palaemonella atlantica, Periclimenes platalea, Periclimenes wirtzi, Pontonia manningi, Pontonia pinnophylax, Pontonia sp. nov., Pseudocoutierea wirtzi and the crabs Galathea intermedia and Micropisa ovata were collected from Antipatharia, Gorgonaria and Bivalvia at S?o Tiago Island, Republic of Cape Verde. Most of the associations between decapods and invertebrate hosts are reported here for the first time. This is also the first record of B. gasti and of P. wirtzi for the Cape Verde Islands. We briefly review the literature on littoral decapod crustaceans of the Cape Verde Islands. Received in revised form: 12 March 2001 Electronic Publication     

Chloroplast DNA evidence for the roles of island colonization and extinction in Tolpis (Asteraceae: Lactuceae)

Tolpis consists of ～13 species native to Africa, Europe, and Macaronesia, with at least one species endemic to each of the four major archipelagos of the Azores, Madeira Islands, Canary Islands, and Cape Verde Islands. All but two of these species develop woody stems by maturity. Chloroplast DNA restriction site variation was analyzed for all species of Tolpis and four outgroups in order to understand the patterns of island colonization and evolution of woodiness in this genus. Parsimony analyses revealed a strongly supported monophyletic Tolpis. Within the genus, the following three well-supported groups were detected: all species from the Canary Islands and Cape Verde Islands, both Azorean species, and both continental species. The Canary Island/Cape Verde clade was sister to the two continental species, and the Azorean clade was sister to this group. The two Madeiran species of Tolpis occupied the basalmost positions within the genus. When biogeography was mapped onto this phylogeny, nine equally parsimonious reconstructions (five steps each) of dispersal history were detected, which fell into two groups: eight reconstructions implied that Tolpis colonized Madeira from the continent, followed by continental extinction and subsequent continental recolonization, while one reconstruction implied that Tolpis colonized Macaronesia four times. Two of the reconstructions involving continental extinction required the least amount of overall dispersal distance. The cpDNA phylogeny also suggests that woodiness arose in the common ancestor of all extant Tolpis, followed by two independent reversals to an herbaceous habit. Assuming that one of the eight reconstructions favoring continental extinction and recolonization is true, our results suggest that Tolpis may represent the first documented example of a woody plant group in Macaronesia that has recolonized the mainland in herbaceous form.     

Patterns of cladogenesis in the venomous marine gastropod genus Conus from the Cape Verde islands

Isolated oceanic archipelagos are excellent model systems to study speciation, biogeography, and evolutionary factors underlying the generation of biological diversity. Despite the wealth of studies documenting insular speciation, few of them focused on marine organisms. Here, we reconstruct phylogenetic relationships among species of the marine venomous gastropod genus Conus from the Cape Verde archipelago. This small island chain located in the Central Atlantic hosts 10% of the worldwide species diversity of Conus. Analyses were based on mtDNA sequences, and a novel nuclear marker, a megalin-like protein, member of the low-density lipoprotein receptor gene family. The inferred phylogeny recovered two well-defined clades within Conus. One includes Cape Verde endemic species with larger shells, known as the "venulatus" complex together with C. pulcher from the Canary Islands. The other is composed of Cape Verde endemic and West Africa and Canary Island "small" shelled species. In both clades, nonendemic Conus were resolved as sister groups of the Cape Verde endemics, respectively. Our results indicate that the ancestors of "small" and "large" shelled lineages independently colonized Cape Verde. The resulting biogeographical pattern shows the grouping of most Cape Verde endemics in monophyletic island assemblages. Statistical tests supported a recent radiation event within the "small shell" clade. Using a molecular clock, we estimated that the colonization of the islands by the "small" shelled species occurred relatively close to the origin of the islands whereas the arrival of "large" shelled Conus is more recent. Our results suggest that the main factor responsible for species diversity in the archipelago may be allopatric speciation promoted by the reduced dispersal capacity of nonplanktonic lecithotrophic larvae.     

A revision of the genus Lasianthus (Rubiaceae) in Africa, excluding Madagascar

23 species, one subspecies and three varieties have been described or named for the pan-tropical genus Lasianthus Jack (Rubiaceae) in continental Africa. In the present revision thirteen species, five subspecies and one variety are recognized; additionally two hybrids are proposed. Of the previously named taxa, the subspecies is raised to species rank whereas two species are degraded to subspecies and variety status, respectively. Five species are synonymised including two varieties, and four are left with uncertain status, including one variety. The distribution of the genus in Africa consists of two distinct elements: one component is found in the Guineo-Congolian regional centre of endemism and one in the eastern part of Afiomontane Archipelago-like regional centre of endemism. A centre of species diversity is found in Eastern Arc Mts., where six endemic species occur together with L. laxinervis and the more widespread L. kilimandscharicus. Four of the species are strict endemics of the Uluguru Mts. In addition to the presentation of the new section: Lasianthus Sectio Membranacei, sect. nov., this revision contain two hybrids from Uluguru Mts.: L. macrocalyx × pedunculatus and L. cereifizorus × pedunculatus, and following new taxa and new combinations: L. africanus ssp. biokoensis, subsp. nov.; L. africanus ssp. mayumbensis, comb. et stat. nov.; L. kilimandscharicus ssp. glabrescens, ssp. nov.; L. kilimandscharicus ssp. glabrescens var. xanthospermus, comb. et stat. nov.; L. kilimandscharicus ssp. hirsutus, ssp. nov.; L. laxinervis, stat. nov.; L. pedunculatus ssp. angustisepalus, ssp. nov.     

Environmental regulation of stomatal response in the <Emphasis Type="Italic">Arabidopsis</Emphasis> Cvi-0 ecotype

The Arabidopsis Cape Verde Islands (Cvi-0) ecotype is known to differ from other ecotypes with respect to environmental stress responses. We analyzed the stomatal behavior of Cvi-0 plants, in response to environmental signals. We investigated the responses of stomatal conductance and aperture to high [CO₂] in the Cvi-0 and Col-0 ecotypes. Cvi-0 showed constitutively higher stomatal conductance and more stomatal opening than Col-0. Cvi-0 stomata opened in response to light, but the response was slow. Under low humidity, stomatal opening was increased in Cvi-0 compared to Col-0. We then assessed whether low humidity affects endogenous ABA levels in Cvi-0. In response to low humidity, Cvi-0 had much higher ABA levels than Col-0. However, epidermal peels experiments showed that Cvi-0 stomata were insensitive to ABA. Measurements of organic and inorganic ions in Cvi-0 guard cell protoplasts indicated an over-accumulation of osmoregulatory anions (malate and Cl⁻). This irregular anion homeostasis in the guard cells may explain the constitutive stomatal opening phenotypes of the Cvi-0 ecotype, which lacks high [CO₂]-induced and low humidity-induced stomatal closure.     

Ecotypic differentiation of response to enhanced CO2 and temperature levels in Arabidopsis thaliana

Five ecotypes of Arabidopsis thaliana, from widely dispersed origins, were grown under combinations of ambient and elevated atmospheric CO₂ concentrations and ambient and elevated temperatures within solardomes. Total above-ground plant biomass was measured when the majority of plants across all ecotypes and treatments had formed seed pods. There were substantial differences in biomass between the ecotypes across all treatments. Temperature had no effect on biomass whilst CO₂ had a significant effect both alone and in interaction with ecotype. The CO₂ x ecotype interaction was mostly due to the enhancement of a single ecotype from the Cape Verde Islands.     

A study of Draba cacuminum (Brassicaceae)

A morphological analysis of the Scandinavian mountain endemic Draba cacuminum Elis. Ekman is presented, based on Scandinavian herbarium collections and a population sample from the Finse area, S Norway. It is compared with supposedly close relatives, especially D. norvegica Gunnerus, and is found to be a distinct species with infraspecies variation at two levels. The populations of southern and northern Scandinavia have been separated as subspecies, ssp. cacuminum and ssp. angusticarpa Elven ssp. nov., respectively, and there is also variation within the southern subspecies. A lectotype has been chosen for D. cacuminum , a revised distribution map is presented, and the ecology and phytogeography of the species is discussed. It seems to be a weak competitor, and its present very discontinuous area is assumed to be a remnant of one continuous or more probably two areas (in S Norway and N Scandinavia) in the late Weichselian.     

EVOLUTIONARY AND ECOLOGICAL DIFFERENTIATION IN THE PANTROPICAL TO WARM-TEMPERATE SEAWEED DIGENEA SIMPLEX (RHODOPHYTA)1

Genetic differentiation among geographic isolates of the pantropical to warm-temperate red alga Digenea simplex (Wulfen) C. Agardh was investigated using random amplified polymorphic DNA (RAPD) markers, crossing studies, and temperature tolerances experiments. Eleven isolates representing populations from the Caribbean, eastern Atlantic, and Indo-West Pacific were compared. RAPD analysis clearly revealed an Indo-West Pacific group, a Caribbean/Cape Verde Islands group, and a Canary Islands group. Crossing studies showed different levels of inter fertility. In most crosses between Western Australian and Atlantic isolates, no hybrid tetrasporophytes were formed. In crosses between Caribbean and Cape Verde Islands isolates, tetrasporophytes developed, but the viability of tetraspores was reduced. Full sexual compatibility was observed among Cape Verde Islands isolates and among isolates from Bonaire. Temperature tolerance studies indicate that Pacific isolates have a broader temperature survival range than Atlantic isolates, which may be correlated to local temperature extremes. Despite the reduced level of sexual compatibility between Caribbean and Cape Verde Islands isolates, their shared position in the RAPD analysis and similar temperature responses suggest trans-Atlantic dispersal in the near geological past. In addition to their discrete position in the RAPD distance analysis, the Canary Islands isolates were significantly more cold-tolerant than the other Atlantic isolates. This finding is consistent with the hypothesis that the Canary Islands were recolonized from cold-adapted eastern Mediterranean populations after the last Pleistocene glaciation.     

Molecular evidence in <Emphasis Type="Italic">Diplotaxis</Emphasis> (Brassicaceae) suggests a Quaternary origin of the Cape Verdean flora

In comparison with other Macaronesian Islands (e.g., the Canary Islands), the Cape Verde Islands have received little attention in terms of plant molecular phylogenetic studies, which might also elucidate the general floristic history of this archipelago. The Cape Verdean vascular plant flora (ca. 12% endemics) has traditionally been regarded as relict of a former subtropical Tertiary flora. In contrast, it has been postulated more recently that the flora is much younger and of Pleistocene origin. To test these hypotheses, we have produced molecular phylogenies associated with a molecular clock approach, sampling all nine Cape Verdean endemic Diplotaxis taxa and 21 accessions representing the D. harra complex from across its distributional range. Analyzing three molecular markers from the nuclear and chloroplast genome, we provide evidence that the Cape Verdean endemic Diplotaxis originated from North African D. harra populations in Pleistocene times, putatively linked to the genesis of the (western) Sahara. This adds to the emerging picture that the present Cape Verdean flora is of Pleistocene origin.     

Explosive radiation of Cape Verde Conus, a marine species flock

Nearly 50 species of the marine gastropod genus Conus are restricted to the Cape Verde archipelago. This unusual concentration of endemics within a single set of oceanic islands is extremely uncharacteristic of marine taxa. Here we used phylogenetic analyses of 90 Conus species, including 30 endemics from Cape Verde, to reveal the relationships and origins of the endemic Cape Verde Conus. Results show that these species group in two distinct clades and represent a marine species flock that is restricted to a very narrowly confined geographical area. Species' originations occurred in exceptionally limited parts of the archipelago and in some cases radiations took place solely within single islands. Finally, comparison of levels of divergence between Cape Verde endemics and other Conus species suggests that the radiation of Conus in Cape Verde occurred during the last few million years.     

Genetic isolation of Cape Verde Island Phoenix atlantica (Arecaceae) revealed by microsatellite markers

Increasing human pressure on the environment in the isolated Macaronesian island group of Cape Verde is threatening many endemic species with extinction. The status of Phoenix atlantica, the Cape Verde Island date palm, is one of the unresolved taxonomic issues not only of the archipelago’s flora but also in the genus Phoenix. We applied 15 nuclear microsatellite markers and one chloroplast minisatellite marker to individuals of Phoenix from the Cape Verde Islands, P. dactylifera, P. canariensis and P. sylvestris, in order to assess the taxonomic position of P. atlantica within the genus. Our analysis showed that P. atlantica is clearly distinct from its close relatives and that its closest relative is likely to be its nearest geographical neighbour, P. dactylifera. Comparable levels of genetic diversity were found in insular P. atlantica and continental P. dactylifera despite the large difference in geographic range size. Our findings highlight the importance of conserving the relatively fragmented and isolated populations of P. atlantica as one of only␣two endemic trees on the islands and emphasise the need for further studies into its evolution and relationship with P. dactylifera.     

Systematic study of the genusDelilia (Asteraceae,Heliantheae)

A taxonomic study of the genusDelilia is presented. Two species are recognized:D. biflora, a widespread weed of tropical and subtropical regions of the New World, extending from Mexico to northern Argentina and recently introduced in the Cape Verde Islands; andD. repens, endemic to the Galapagos islands. A key to the species, illustrations, distribution maps, and complete synonymy are presented.