Evaluation of genotoxicity using the micronucleus assay and nuclear abnormalities in the tropical sea fish Bathygobius soporator (Valenciennes, 1837) (Teleostei, Gobiidae)

The micronucleus and nuclear abnormalities assays have been used increasingly to evaluate genotoxicity of many compounds in polluted aquatic ecossystems. The aim of this study is to verify the efficiency of the micronucleus assay and nuclear abnormality assay in field and laboratory work, when using erythrocytes of the tropical marine fish Bathygobius soporator as genotoxicity biomarkers. Gill peripheral blood samples were obtained from specimens of Bathygobius soporator. In order to investigate the frequencies of micronuclei and to assess the sensitivity of species, the results were compared with samples taken at the reference site and maintained in the laboratory, and fish treated with cyclophosphamide. The micronucleus assay was efficient in demonstrating field pollution and reproducing results in the labotatory. There were significant higher frequencies of micronuclei in two sites subject to discharge of urban and industrial effluents. The nuclear abnormality assay did not appear to be an efficient tool for genotoxicity evaluation when compared with field samples taken at a reference site in laboratory, with a positive control.     

Neotropical schistosomiasis: African affinities of the host snail Biomphalaria glabrata (Gastropoda: Planorbidae)

Schistosoma mansoni , the blood fluke responsible for human intestinal schistosomiasis in the Neotropics, was imported repeatedly with African slaves during the period 1500–1800. This trematode, and its intermediate host snails of the genus Biomphalaria , are widely distributed across Africa and the disease is thought to have quickly become established in South America and the West Indies because of the presence of an endemic susceptible congener, B. glabrata. We compared B. glabrata with four other Neotropical and three African species of Biomphalaria using 20 allozyme loci and found that it is phenetically and phylogenetically more like the African species; both parasite and American host snail are apparently of historically or geologically recent African origin. Furthermore, genetic distances, cladistic analyses and fossil data suggest the African Biomphalaria species may themselves have evolved from Neotropical founders following an initial trans-Atlantic dispersal in the reverse direction 2.3–4.5 Mya. Interpretation of existing patterns remains problematic as few African snails have been characterized genetically and both B. glabrata and African B. pfeifferi appear to comprise several cryptic species.     

Anaesthetic effects of clove oil on seven species of tropical reef teleosts

The anaesthetic potential of the clove oil was tested on the following species of tropical reef fishes: Abudefduf saxatilis , Stegastes variabilis , Pareques acuminatus , Acanthurus chirurgus , Sparisoma axillare , Lutjanus apodus and Bathygobius soporator . Induction and recovery times from anaesthesia were compared using various concentrations (20, 30, 40, 50 and 60 mg l⁻¹). Induction and recovery times were not affected by variations in fish total length. When exposed to any of the five tested concentrations of clove oil, specimens achieved a deep state of anaesthesia, with induction and recovery times of <180 and <300 s, respectively. Nevertheless, to maximize safety and reduce fish mortality and stress, the lowest concentration (20 mg l⁻¹) is recommended during field sampling.     

Phylogeny of the African murid tribe Otomyini (Rodentia), based on morphological and allozyme evidence

Based on a cladistic analysis of 45 morphological (craniodental) and 46 binary allozyme characters, previous systematic treatments of the African murid tribe, Otomyini (laminate-toothed rats), are reviewed. Cladistic analysis of the craniodental data, involving eight outgroup taxa, confirmed the monophyly of the Otomyini, and suggested Pelomys to represent the sister genus of the Otomyini. Craniodental synapomorphies provided strong support for certain basal relationships among Otomyini rodents, reinforcing available palaeontological evidence. However, poor statistical (Bremer decay index) support was obtained for terminal relationships. The data presented revealed a 'mesic clade' of southern and eastern African species, with Otomys sloggetti basal to this group. The arid-adapted, southern Africa-endemic species, Parotomys littledalei , P. brantsii and O. unisulcatus , were all placed basal to the 'mesic clade', but did not form a separate 'arid clade', as suggested by earlier biochemical studies. Two allozyme synapomorphies supported the existence of the 'mesic clade', separate from arid-adapted southern African species. A strict cladistic interpretation of the present data did not support the existence of two genera in the tribe, and the two species of Parotomys (whistling rats) should be transferred to Otomys . At the species level, specific identity of O. lacustris and O. barbouri , distinct from O. anchietae , was supported by several autapomorphies, and O. tropicalis burtoni was shown to be included in O. angoniensis rather than O. tropicalis , extending the range of the former species into West Africa.     

The eastern Pacific species of Bathygobius (Perciformes: Gobiidae)

The circumtropical gobiid genus Bathygobius Bleeker is defined and three Eastern Pacific species are redescribed, with first dorsal fin pattern and postorbital blotches being shown to be additional characters of diagnostic value. Two mainland species are recognised, the Mexican-Panamanian B. ramosus Ginsburg 1947 and the Panamanian B. andrei (Sauvage 1880). B. ramosus is now reported from Clarión Island, Revillagigedos, and also from Cocos Island. Meristic variation of ramosus is tabulated for local populations and PCA analysis of their morphometry suggests regional differentiation in this species, with Tres Marias and Revillagigedos populations clustering away from mainland and Montuosa material. An insular species, B. lineatus (Jenyns 1842) from the Galapagos is defined, with B. arundelii (Garman 1899) from Clipperton Island and B. l. lupinus Ginsburg 1947 from Lobos de Afuera, off Peru, placed as nominal subspecies of lineatus. This species resembles the Indo-west Pacific B. fuscus and Atlantic basin B. soporator more closely than it does ramosus and andrei and may be the product of transpacific dispersal. A similar origin for B. ramosus is discussed but it seems more likely that both B. ramosus and B. andrei have Caribbean sister species.     

Distribution and routes of drift migrations in larvae of three species of flatfish Bothus (Bothidae) in open waters of the northern Atlantic

On the basis of large collections, comprehensive data on the distribution of larvae of three species of flatfishes of the genus Bothus (B. ocellatus, B. robinsi, and B. podas) in the northern Atlantic are provided, and the routes of their drift migrations are discussed. Special attention is focused on discussing problems of identification of larvae of the listed species and the specification of evidence on meristic characters of adult flatfishes of these species used for the diagnostics of their larvae. It is shown that larvae of two American species of Bothus carried out from the shelves to the system of western boundary currents are widely distributed in the northern Atlantic drifting in waters of the Northern Subtropical Gyre (NSG). Some of them reach the Azores, and some are drifted along the periphery of the circulation system of the NSG currents towards North America. Unlike larvae of American species, larvae of the eastern Atlantic B. podas perform no transatlantic drift migrations, and the area of their distribution is confined to the waters of the eastern Atlantic. Such differences in the extent of latitudinal passive migrations between B. podas and western Atlantic species are explained according to Torson (1965) by differences in temperature conditions during the drift of larvae of species under comparison that directly affect the decrease (during water temperature increase) or increase (at temperature decrease) of the pelagic phase in their development. The latitudinal drift of larval B. podas from West Africa westwards proceeds due to currents that gradually warm during their motion, which causes a decrease of the dates of their staying in the pelagial. The transatlantic drift of larval American Bothus spp. from North America eastwards is observed in gradually cooling currents, which leads to an increase in the duration and extent of their passive migrations.     

The tropical history and future of the Mediterranean biota and the West African enigma

Aim Since the opening of the Suez Canal in 1869, many tropical taxa from the Indo‐West Pacific (IWP) realm have entered the Mediterranean Sea, which is experiencing rising temperatures. My aims are: (1) to compare biogeographically this tropical transformation of the Mediterranean biota with the tropical faunas of the Mediterranean and adjacent southern European and West African seas during the Late Oligocene to Pliocene interval; (2) to infer the relative contributions of the tropical eastern Atlantic and IWP to the tropical component of the marine biota in southern Europe; and (3) to understand why West Africa is not now a major source of warm‐water species. Location Southern Europe, including the Mediterranean Sea, and the coast of tropical West Africa. Methods I surveyed the literature on fossil and living shell‐bearing molluscs to infer the sources and fates of tropical subgenus‐level taxa living in southern Europe and West Africa during the Late Oligocene to Pliocene interval. Results Ninety‐four taxa disappeared from the tropical eastern Atlantic (including the Mediterranean) but persisted elsewhere in the tropics, mainly in the IWP (81 taxa, 86%) and to a lesser extent in tropical America (36 taxa, 38%). Nine taxa inferred to have arrived in the tropical eastern Atlantic from the west after the Pliocene did not enter the Mediterranean. The modern West African fauna is today isolated from that of other parts of the marine tropics. Main conclusions Taxa now entering the Mediterranean through the Suez Canal are re‐establishing a link with the IWP that last existed 16 million years ago. This IWP element, which evolved under oligotrophic conditions and under a regime of intense anti‐predatory selection, will continue to expand in the increasingly warm and increasingly oligotrophic Mediterranean. The IWP source fauna contrasts with the tropical West African biota, which evolved under productive conditions and in a regime of less anti‐predatory specialization. Until now, the post‐Pliocene West African source area has been isolated from the Mediterranean by cold upwelling. If further warming should reduce this barrier, as occurred during the productive and warm Early Pliocene, the Mediterranean could become a meeting place for two tropical faunas of contrasting source conditions.     

Systematics and phylogeny of West African gerbils of the genus Gerbilliscus (Muridae: Gerbillinae) inferred from comparative G- and C-banding chromosomal analyses

Comparative analysis of the G- and C-banding patterns in six morphologically similar species of the genus Gerbilliscus(G. gambianus, G. guineae, G. kempi, Gerbilliscus sp., G. robustus and G. leucogaster) and one belonging to the genus Gerbillurus (G. tytonis) from 27 West, East and South African localities was carried out. Our study revealed that 17 rearrangements comprising seven fissions, five translocations and five inversions occurred in the evolution of this group, with 1-13 rearrangements differentiating the various species. In addition the unusually large sex chromosomes appear to be species-specific as judged by size and morphology reflecting structural rearrangements as well as the variable presence of a large amount of C-heterochromatin found in each species at a particular chromosomal location. These karyotypic features allow us to recognize five distinct species in West Africa (compared to the two recognized in recent taxonomic lists) and to roughly delimit their geographical distributions. The pattern of phylogenetic relationships inferred from a cladistic analysis of the chromosomal data is in good agreement with recent molecular phylogenetic studies that recognize a West African species group within the genus Gerbilliscus, and the monophyly of both Gerbilliscus and Gerbillurus.     

Implications of isolation and low genetic diversity in peripheral populations of an amphi-Atlantic coral

Limited dispersal and connectivity in marine organisms can have negative fitness effects in populations that are small and isolated, but reduced genetic exchange may also promote the potential for local adaptation. Here, we compare the levels of genetic diversity and connectivity in the coral Montastraea cavernosa among both central and peripheral populations throughout its range in the Atlantic. Genetic data from one mitochondrial and two nuclear loci in 191 individuals show that M. cavernosa is subdivided into three genetically distinct regions in the Atlantic: Caribbean-North Atlantic, Western South Atlantic (Brazil) and Eastern Tropical Atlantic (West Africa). Within each region, populations have similar allele frequencies and levels of genetic diversity; indeed, no significant differentiation was found between populations separated by as much as 3000 km, suggesting that this coral species has the ability to disperse over large distances. Gene flow within regions does not, however, translate into connectivity across the entire Atlantic. Instead, substantial differences in allele frequencies across regions suggest that genetic exchange is infrequent between the Caribbean, Brazil and West Africa. Furthermore, markedly lower levels of genetic diversity are observed in the Brazilian and West African populations. Genetic diversity and connectivity may contribute to the resilience of a coral population to disturbance. Isolated peripheral populations may be more vulnerable to human impacts, disease or climate change relative to those in the genetically diverse Caribbean-North Atlantic region.     

Recent radiation in West African Taterillus (Rodentia, Gerbillinae): the concerted role of chromosome and climatic changes

West African gerbils of the genus Taterillus constitute a complex of seven sibling species distributed from sudano-guinean to saharo-sahelian regions. They display radically rearranged karyotypes despite low genic divergence and a very recent differentiation, that is, within the last 0.4 Myr for the six most derived species. We here provide a comparison of the seven specific karyotypes and perform a cladistic analysis using chromosomal rearrangements character states. When a posteriori polarized mutations were mapped onto the phylogenetic tree, 38 rearrangements were identified as fixed during the evolution of these rodents. This makes Taterillus one of the most striking examples of accelerated chromosomal evolution within placental mammals. Taking into account the types of chromosomal changes involved, divergence times between lineages, genetic distances, as well as reassessed geographic distributions, we suggest that (1) speciation in West African Taterillus was driven by chromosomal changes, and (2) the paleoclimatic oscillations of the Sahara desert have played a major role in their evolution. In particular, elevated plasticity of the Taterillus genome, as suggested by the patterns observed for some repetitive elements, would have led to a higher probability of mutation. We hypothesize that the process underpinning cladogenesis most probably involved highly underdominant genomic rearrangements that were fixed following pronounced populational bottlenecks resulting from drastic climatic and subsequent environmental changes. Major African rivers formed significant barriers to dispersal, limiting expansion during the more moist and so favorable periods. This scenario would explain the current parapatric species distributions and their relationship to the West African hydrographic features.     

A new species of arboreal pitviper from the Atlantic versant of northern Central America

A new species of green, prehensile-tailed pitviper of the genus Bothriechis is described from the Atlantic slopes of eastern Guatemala and western Honduras. This species appears to be most closely related to B. bicolor of the Pacific versant of Chiapas (Mexico) and Guatemala. Several other species of Bothriechis occur on the Atlantic versant of northern Central America, including two montane species, B. aurifer and B. marchi but, with one possible exception, these are not known to be sympatric with the new species and occur in different mountain ranges. The widespread B. schlegelii occurs up to at least 900 m on the Sierra de Caral, where the lowest elevation recorded for the new species is 885 m.     

Genetic Variation at the Mitochondrial 16S rRNA Gene among Trichiurus lepturus (Teleostei:Trichiuridae) from Various Localities: Preliminary Evidence of a New Species from West Coast of Africa

The taxonomic classification of large head hairtail (Trichiurus lepturus) is controversial because of similar body appearance and silvery coloration. Ten samples of T. lepturus caught off the west coast of Africa and 43 samples of T. lepturus caught off the western Atlantic coast and Indo-Pacific waters were used for sequence comparison of mitochondrial DNA encoded partial 16S ribosomal RNA(16S rRNA) gene. Ten samples of T. japonicus (obtained from various parts of southern Japan) were also included in the comparative analysis. For the 509 bp sequence determined, 58 sites were variable, of which 53 were parsimony informative. Phylogenetic analyses using maximum parsimony, maximum likelihood and Bayesian algorithm with Eupleurogrammus muticus as outgroup, showed that the haplotypes of T. lepturus obtained from the West coast of Africa, Indo-Pacific and Western Atlantic coast constituted clearly distinct and well supported lineages without any sharing and overlapping between them. Previous morphological analyses and this genetic study strongly indicate that the morphotypes of T. lepturus obtained from the West African coast are genetically distinct and probably represents a separate species.     

Genetic diversity,evolutionary history and implications for conservation of the lion (Panthera leo) in West and Central Africa

Aim In recent decades there has been a marked decline in the numbers of African lions (Panthera leo), especially in West Africa where the species is regionally endangered. Based on the climatological history of western Africa, we hypothesize that West and Central African lions have a unique evolutionary history, which is reflected by their genetic makeup. Location Sub‐Saharan Africa and India, with special focus on West and Central Africa. Method In this study 126 samples, throughout the lion’s complete geographic range, were subjected to phylogenetic analyses. DNA sequences of a mitochondrial region, containing cytochrome b, tRNAPro, tRNAThr and the left part of the control region, were analysed. Results Bayesian, maximum likelihood and maximum parsimony analyses consistently showed a distinction between lions from West and Central Africa and lions from southern and East Africa. West and Central African lions are more closely related to Asiatic lions than to the southern and East African lions. This can be explained by a Pleistocene extinction and subsequent recolonization of West Africa from refugia in the Middle East. This is further supported by the fact that the West and Central African clade shows relatively little genetic diversity and is therefore thought to be an evolutionarily young clade. Main conclusions The taxonomic division between an African and an Asian subspecies does not fully reflect the overall genetic diversity within lions. In order to conserve genetic diversity within the species, genetically distinct lineages should be prioritized. Understanding the geographic pattern of genetic diversity is key to developing conservation strategies, both for in situ management and for breeding of captive stocks.     

New evidence of hexaploidy in' large' African Barbus with some considerations on the origin of hexaploidy

Three species of' large' African Barbus from the Republic of Guinea (West Africa), were characterized by the chromosome numbers (2N) of 148 (B. bynni occidentalis and B. wurtzi ) and 150 (B. petitjeani Daget, 1962). All these species have a karyotype which corresponds to the evolutionary hexaploid level. The karyotype of B. petitjeani is composed of chromosomes clearly grouped into morphologically homomorphic sextets which may document the origin of hexaploidy via an autopolyploidic event. Present findings extend the known distribution of evolutionary hexaploidy in' large' African Barbus to West Africa and show evidence of the pan-African distribution of this phenomenon.     

The genus Borassus (Arecaceae) in West Africa, with a description of a new species from Burkina Faso

Borassus akeassii Bayton, Ouédraogo & Guinko sp. nov. (Arecaceae) is described as a new species from western Burkina Faso in West Africa. It has been confused with the widely distributed African species B. aethiopum and more recently with the Asian B. flabellifer . However, it is distinguished by its glaucous, green leaves with weakly armed petioles and a characteristic pattern of lamina venation. The fruits have a pointed apex and are greenish when ripe, and the flowers of the pistillate inflorescence are arranged in three spirals. The pollen has a reticulate tectum and distinctive ornamentation. The distribution of B. akeassii is discussed and the status of the varieties of Borassus aethiopum (var. bagamojensis and var. senegalensis ) is examined.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 419–427.     

Age and growth of grey triggerfish Balistes capriscus from trans-Atlantic populations

Anthropogenic factors that negatively impact reef fishes can include changes in life-history patterns of fisheries-targeted species. Understanding these impacts on growth and population age structure is essential in the management of exploited populations of fishes. This is the first study to directly compare age and growth for a major fisheries species between east and west populations of a transatlantic reef fish. The main goal of this study was to document age and growth in grey triggerfish Balistes capriscus from coastal waters of Ghana in the Gulf of Guinea (GOG) and compare those with the previous growth studies from that region and with the western Atlantic population. A secondary objective of this study was to evaluate the use of otoliths to age triggerfish and to provide a preliminary comparison with spine-derived age estimates. The results obtained from this study provided an updated understanding of the growth and age structure of the eastern B. capriscus population in GOG. The authors documented that shifts in population attributes occurred for B. capriscus after its major decline in abundance. The differences in physical and biotic characteristics of the East and West Atlantic regions and the differences in collection methods of samples make direct comparisons of growth parameters difficult. Nonetheless, overall differences in maximum sizes and ages were apparent; the western Atlantic population had a larger maximum size and older maximum age. The authors also documented that sagittal otoliths can be used to provide age estimates for triggerfish species, and otoliths as an ageing structure had better between-reader precision compared to dorsal spines.     

A gastropod from the tropical Atlantic becomes an established alien in the Mediterranean

We report the occurrence of an established population of the gastropod Mitrella psilla (Duclos, 1846), native on west African coasts of Mauritania, Senegal and Angola, on the shore of La Goulette, Bay of Tunis. The molluscan species of tropical West African affinity hitherto ascertained in the Mediterranean are not aliens, but have a native range which encompasses at least part of the Alboran Sea since historical times. Mitrella psilla appears therefore as the first instance of a mollusc with a tropical Atlantic origin being added to the Mediterranean fauna. The species was found near an important commercial harbour and is presumed to have been introduced by shipping.     

Biogeographical relationships among tropical forests in north-eastern Brazil

Aim To use parsimony analysis of endemicity and cladistic analysis of distributions and endemism to evaluate two hypotheses addressing biogeographical relationships among Amazonia, the Caatinga forest enclaves, Pernambuco Centre and the southern Atlantic Forest. Location North‐eastern Brazil, South America. Methods To find the most parsimonious areagram we analysed a matrix composed of the presence (1) or absence (0) of 745 taxa (i.e. 293 genera and 452 species of woody plants) within 16 localities belonging to the four large regions addressed in this study. Results One most parsimonious areagram was found and it shows a basal separation between the southern Atlantic Forest and all other regions. This break is followed by a separation between all Caatinga forest enclaves (except Baturité) from a cluster composed of Baturité, the Pernambuco Centre and Amazonia. In this cluster, the most basal separation isolates Baturité from the cluster formed by localities from Amazonia and the Pernambuco Centre. The biogeographical relationships among sites could not be explained by either a random distribution of species among sites or by the geographical distance between sites. Main conclusions We found strong cladistic signal within the raw distribution and phylogenetic data used in our analysis, indicating structured species assemblages in the surveyed localities. They have resulted from the fragmentation of an ancestral biota that was once widely distributed in the region. Our results also support the hypothesis that Atlantic Forest is not a biogeographically natural area, because the Pernambuco Centre is more closely related to Amazonia than to the southern Atlantic Forest. Finally, our data do not support the notion that Caatinga forest enclaves comprise a single biogeographical region, because one Caatinga forest enclave (Baturité) is much more closely related to the cluster formed by Amazonia and the Pernambuco Centre than to other sites. These relationships suggest the occurrence of forest connections between Amazonia and the Atlantic Forests across Caatinga during several periods of the Tertiary and Quaternary. However, palaeoecological data currently available for the Caatinga region are still scarce and do not have either the spatial or temporal resolution required to reconstruct the history of connections among the forests in north‐eastern Brazil.     

Phylogeny of Parabuthus (Scorpiones, Buthidae)

A cladistic analysis of the 20 southern African species of Parabuthus Pocock, 1 890 (Scorpiones, Buthidae) and five of the eight north-eastern African and Arabian species is presented, based on 53 characters, mostly of the adult morphology. The resultant topology is largely congruent with Lamoral's (1978) unpublished topology for 14 Namibian species. Monophyly of the genus Parabuthus is supported, but monophyly of the disjunct southern African vs. north-eastern African and Arabian species is unsupported. The implications of the cladogram for understanding ecological specialization in Parabuthus , Afrotropical arid biogeography and Parabuthus envenomation are discussed.     

A new species of Enterognathus (Copepoda, Cyclopoida, Enterognathidae) collected from the Seto Inland Sea, western Japan

A new species of the endoparasitic copepod Enterognathus (Cyclopoida, Enterognathidae) is described from a crinoid host in the Seto Inland Sea, western Japan. This is a third species of the genus and its first occurrence in the Pacific Ocean. The new species is distinguished from two previously known congeners by the morphology of the body somites, caudal rami, antennae and legs. Crinoid parasites belonging to Enterognathus and the closely related genus Parenterognathus have a broad distribution from the northeastern Atlantic through the Red Sea to the West Pacific.