Ntem River Research Articles

African Arts — Global Conversations

African Arts — Global Conversations

Identification of cryptic species in allopatric populations of Hypostomus tietensis (Siluriformes: Loricariidae) through cytogenetics analyses

Abstract Hypostomus is the most specious genus of Hypostominae, composed of several species with high intraspecific morphological and color pattern variation, making their identification a complex issue. One of the species with problematic identification is Hypostomus tietensis that was described from a single specimen, resulting in uncertainties about its color pattern and correct identification. To assist in this context, cytogenetic analyzes were carried out in three putative populations of H. tietensis from the Upper Paraná River basin, one of them from the type locality. The three populations showed considerable cytogenetic differences, with 2n = 72 chromosomes for the population from the type locality and 2n = 76 chromosomes for the others. Terminal NORs were detected (Ag- and 18S rDNA-FISH), being simple for the type locality population (acrocentric pair 23, long arm) and the Pirapó River (subtelocentric pair 11, short arm), and multiple for Do Campo River (subtelocentric pairs 11 and 12, short and long arm, respectively). C-banding was efficient in differentiating the type locality population from the others. Cytogenetic data revealed that populations from Pirapó and Do Campo rivers, although treated until now as Hypostomus aff. tietensis, represent a cryptic species, and those morphological analyses are necessary to differentiate and for describing this new species.

Cast netting new species: Integrative taxonomy of emDistichodus/em emnotospilus/em (Characiformes: Distichodontidae) discovers new species and overlooked areas of endemism in Central Africa.

Distichodus notospilus was described from the Ogooué River and is considered to occur throughout the Lower Guinea ichthyofaunal province and the western tributaries of the middle and lower Congo River. Recent expeditions in Equatorial Guinea collected D. notospilus specimens in the Mbini River drainage and the Mbia River; a small coastal river that is located between the Ntem and Mbini river drainages. Detailed morphological analyses and multilocus molecular analyses confirm that these two populations are distinct from one another. Topotypic populations of D. notospilus were included in the analyses and demonstrated that populations in the Mbini and Mbia rivers are distinct and these two new species are described herein. Distichodus microps sp. nov. is endemic to the Mbia River drainage and is distinguished from D. notospilus in having more scales along the lateral line (41, rarely 40 versus 37-39, rarely 40), a nearly inferior mouth versus subterminal in D. notospilus, a curved posterolateral margin of the opercle versus straight in D. notospilus, a smaller eye (56.7-80.4 versus 70.1-104.3 % of snout length), and a less prominent elongated spot at the base of the caudal fin. Distichodus mbiniensis sp. nov. is endemic to the upper Mbini River drainage and distinguished from D. notospilus in having more scales along the lateral line (41-42, rarely 40 versus 37-39, rarely 40), a much less prominent elongated dark spot at the base of the caudal fin, and a shorter dorsal fin (21.4-27.2 versus 22.7-34.2% standard length). Distichodus microps is distinguished from D. mbiniensis in having a shallower body (usually six scales from lateral line to the pelvic fin versus seven), fewer anal-fin rays (usually 12 total rays versus 13 or 14), a more inferior mouth, a deeper and longer caudal peduncle, a smaller eye, and differences in several features associated with the head. In addition to the two new species described this study also revealed potential undescribed diversity in the D. notospilus species complex in the Ntem River and Dja River (Congo R. basin) in Cameroon. The biogeography of these fishes in the rivers of Lower Guinea suggests that the Mbini River and smaller coastal rivers are overlooked areas of endemism. Studies of other reported widespread species will likely reveal additional diversity and further elucidate the processes promoting and maintaining freshwater diversity in Central Africa.

Three new Critically Endangered Inversodicraea (Podostemaceae) species from Tropical Africa: I. senei, I. tanzaniensis and I. botswana

SummaryThree new species of Inversodicraea (Podostemaceae), I. senei from the Memv’ele falls of the Ntem River, Cameroon, I. tanzaniensis from the Ruhudji River near Lupembe, Southern Highlands, Tanzania, and I. botswana from the Kasane rapids on the Chobe River, Botswana, are described and illustrated. All three species are known from single sites. All three are assessed as Critically Endangered using the IUCN standard. With 35 species, Inversodicraea is the most species-diverse genus of Podostemaceae in continental Africa, to which it is endemic. Four species of Inversodicraea are now known to be sympatric and point endemics at Memv’ele Falls in Cameroon where a hydro-electric dam is being constructed, threatening them with global extinction. Equally, I. tanzaniensis is threatened by proposed hydro-electric projects in Tanzania. In contrast, I. botswana is threatened by sewage discharge and also by bridge construction.

Application of Coefficient of Anisotropy to the Geophysical Prospecting of Campo—Ma’an Area of the Ntem Complex in Cameroon

Audiomagnetotelluric data were acquired for 10 sounding stations in open fields and roads along the main highways from Campo to Ma’an in Cameroon. An application of the coefficients of anisotropy was used to determine the tectonic settings and the nature of the contacts between the sedimentary formation of the Kribi-Campo basin and the cratonic Ntem Complex. The results of this study show that apart from the sedimentary formation, the metamorphic formation in this area comprises two metamorphic blocks: a regional metamorphic block which might be igneous or granitic in nature and composition and seem to be Precambrian and plutonic in origin and a contact or transitional metamorphic block, which might represent schist or gneiss rocks. The contact or transitional metamorphic block might be as a result of a long period of contact between regional metamorphic rocks and rocks of sedimentary formation. These contact/transitional metamorphic rocks which are found sandwiched between rocks of sedimentary formation and rocks of the regional metamorphic block and at varied depths confirm the existence of vertical and sub-vertical contacts between the Kribi-Campo basin and the cratonic Ntem complex. Two types of rock contacts have been identified: a sedimentary-schist contact which is found at the boundary between the sedimentary formation and the transitional metamorphic block and a schist-granite contact between the transitional and regional metamorphic blocks. Two main formations: a sedimentary formation, which is found in the Kribi-Campo sub-basin and the Ntem River bed and its flood plains and the metamorphic formation which includes both the transitional and regional metamorphic rocks have also been identified in the area of study. Subsurface rocks and rock materials have been observed to be highly resistive and occupying almost the entire subsurface in the area of study confirming the high vertical tectonic stability of the Ntem Complex even at contact with the sedimentary Kribi-Campo basin.

Magnetotelluric Investigation of the Geo-Tectonic Stability of Campo-Ma’an Area in South Cameroon

The magnetotelluric prospection method has been widely used in Cameroon not only as a reconnaissance method for geophysical investigations but also to determine the nature of the subsurface and the structural settings of the various geological formations in the country that resulted from the global geo-tectonic movements. The present study is aimed at employing the magnetotelluric method to provide evidence on major tectonic dislocations which might have led to the presence of plutonic intrusions in the cratonic structure of the Ntem Complex as well as determining the nature of the contact between the sedimentary Campo Basin and the metamorphic cratonic Ntem Complex. The analyses and interpretations of iso-resistivity maps and geoelectric sections from magnetotelluric data has enabled us to show that tectonic forces at contact between the sedimentary Campo Basin and the metamorphic Ntem Complex were of three different categories: gravity gliding, magmatic upwelling and lateral compressions. The results of the action of these forces were the development of vertical and sub-vertical faulting systems at Craton-Sedimentary Basin contact and subsidence of overburden that appears to have also paved the way for the setting-up of the Ntem River bed and its flood plains. This river bed and its flood plains have been characterized as having a sedimentary deposit depth of 500 m and width of 20 km. Meanwhile, the deep-seated contact faulting systems within the two identified formations have varied fault magnitudes with a maximum of 60 km. The relatively high apparently resistivity values (up to1.0 kΩ•m) for the sedimentary and the very high values for the metamorphic formations (up to and above 10.0 kΩ•m) suggest that the whole area is at present relatively geo-tectonically stable.

Water quality in the upper stream bed of the campo river- in the Campo Mourão county - Paraná state, Brasil

Nesse trabalho foi avaliada a qualidade da água no alto curso do rio do Campo no município de Campo Mourão-PR. O rio do Campo é o manancial responsável pelo abastecimento de 80% da população daquele município. A qualidade da água foi avaliada a partir da determinação dos seguintes parâmetros físico-químicos: temperatura da água, turbidez, oxigênio dissolvido (OD), potencial hidrogeniônico (pH), teor de fósforo, coliformes termotolerantes (E. coli), e dos seguintes elementos químicos cobre, zinco, chumbo, cádmio, arsênio, níquel, selênio, cromo, manganês e ferro. As amostras foram coletadas em 5 pontos ao longo do rio e monitoradas durante 14 meses, abrangendo tanto a área rural quanto a área urbana. Foram efetuadas 7 campanhas de coletas com periodicidade bimestrais entre os meses de junho de 2012 a julho de 2013. Os resultados obtidos foram comparados com aqueles da Resolução nº357/2005 do CONAMA. Os parâmetros que apresentaram concentrações superiores a aquelas estabelecidas pela resolução foi o ferro e da bactéria E.coli. As amostras coletadas durante os períodos de chuva apresentaram aumento nas concentrações de vários parâmetros analisados, especialmente de E. coli, sst, de turbidez, de fósforo, de ferro, de manganês, de cobre e de chumbo. Esses resultados evidenciam a influência da precipitação e do escoamento superficial na qualidade da água, isto é, devido ao aporte de sedimentos para o corpo hídrico. Entretanto, os valores de Demanda Bioquímica de Oxigênio e de Oxigênio Dissolvido se mantiveram dentro do valor máximo permitido (VMP) estipulados pela Resolução nº 357/2005 do CONNAMA em todas as campanhas. A B S T R A C T The river Campo is the water source that has been supplying 80% of the municipality population in Campo Mourão County, Paraná State, Brazil. In the current research, we monitored the water quality from the high course of the rive. The records collected from the physico-chemical parameters of the water were the temperature, turbidity , dissolved oxygen (OD), pH, phosphorus, thermo-tolerant faecal coliform ( E. coli ), copper, zinc, lead, cadmium, arsenic, nickel, selenium, chrome, manganese and ironº In each of seven bi-month trips in the rural and urban area monitored for 14 months from June, 2012 to July, 2013 we collected samples always at five places along the river course. The results were compared with those from the Act number 357/2005 released by the CONAMA. The parameters with concentrations higher than established by the CONAMA Act were iron and the faecal coliform E. coli . Samples from the rainy period had increases in concentration of parameters as the E. coli , total suspended solids (tss), water turbidity, phosphorus, iron, manganese, copper and lead. These results highlight the influence of the rainfall and the water by runoff on the water quality because of the supply of soil sediments into the hydro-course. In all the trips, however, the BOD and the DO were within the highest values allowed in the 357/2005 CONAMA Act. Keywords : Water quality. Soil use. Water monitoring.

Influence of urban area on the water quality of the Campo River basin, Paraná State, Brazil

The Campo River basin is located on the third plateau of the Paraná State or trap plateau of Paraná, at the middle portion between the rivers Ivaí and Piquiri, southern Brazil, between the coordinates 23° 53 and 24° 10' South Latitude and 52° 15' and 52° 31' West Longitude. The basin has 384 Km² area, being 247 km² in the municipality of Campo Mourão and 137 km² in the municipality of Peabiru, in Paraná State. The Campo River is a left bank tributary of the Mourão River, which flows into the Ivaí River. The objective of this study was to monitor water quality in the Km 119 River and the Campo River, tributaries of the Mourão River, with monthly collection of water samples to determine pH, temperature, turbidity, biochemical oxygen demand, dissolved oxygen, fecal coliforms, total solids, total nitrogen, ammoniacal nitrogen, nitrite, nitrate and total phosphorus. The results obtained were compared with the indices established by the environmental legislation and applied in the determination of the Water Quality Index (WQI) used by the Water Institute of Paraná State, regulating environmental agency. Poor water quality in these rivers presents a worrying scenario for the region, since this river is the main source of water supply for the public system. Results of organic matter, fecal coliforms and total phosphorus were higher than the limits established by Resolution CONAMA 357/2005 to river class 2, specially at downstream of the Km 119 River and the Campo River, due to the significant influence of the urban anthropic activity by the lack of tertiary treatment and also rural by the lack of basic sanitation in this area. Results of WQI of Km 119 River and do Campo River indicated that water quality can be classified as average in 71% and good in 29% of the sites evaluated.

Catalase activity in Smicridea McLachlan, 1871 (Insecta, Trichoptera) collected from natural and altered/impacted streams

Aim: We compare catalase activity in SmicrideaMcLachlan, 1871 (Insecta, Trichoptera) collected in natural and agricultural streams and correlates the enzyme pattern with metal content in the water.MethodsOrganisms were collected in sites classified as natural (riparian vegetation in buffer zone) and altered/impacted (agricultural land use in drainage area) environments, located at Cravo River and Campo River sub-basins (RS, Brazil). Next the collected larvae were identified and used to proteins quantification and catalase activity measure. The concentration of Mg, Cr, Cu, Pb and Cd in the water was determined by atomic absorption spectrometry.ResultsCatalase activity in Smicridea ranged from 1.5 to 6 U, with mean values about 2.63 ± 0.096 U (SEM). The presence of metals was higher in the streams located at agricultural drainage area, except for Mg at the Cravo sub-basin and Cu at the Campo sub-basin. Catalase was higher in Smicridea collected in natural streams as compared to that agriculture streams and was correlated with Pb and Cd levels.ConclusionsThe data showed the potential of this biomarker as a useful tool for complementation of water quality biomonitoring studies using Smicridea as bioindicator.

Challenges towards the elimination of Human African Trypanosomiasis in the sleeping sickness focus of Campo in southern Cameroon.

The sleeping sickness focus of Campo lies along the Atlantic coast and extends along the Ntem River, which constitutes the Cameroonian and Equatorial Guinean border. It is a hypo-endemic focus with the disease prevalence varying from 0.3 to 0.86% during the last few decades. Investigations on animal reservoirs revealed a prevalence of Trypanosoma brucei gambiense of 0.6% in wild animals and 4.83% in domestic animals of this focus. From 2001 to 2012, about 19 931 tsetse were collected in this focus and five tsetse species including Glossina palpalis palpalis, G. pallicera, G. nigrofusca, G. tabaniformis and G. caliginea were identified. The analysis of blood meals of these flies showed that they feed on human, pig, goat, sheep, and wild animals such as antelope, duiker, wild pig, turtle and snake. The percentage of blood meals taken on these hosts varies according to sampling periods. For instance, 6.8% of blood meals from pig were reported in 2004 and 22% in 2008. This variation is subjected to considerable evolutions because the Campo HAT focus is submitted to socio-economic mutations including the reopening of a new wood company, the construction of autonomous port at "Kribi" as well as the dam at "Memve ele". These activities will bring more that 3000 inhabitants around Campo and induce the deforestation for the implementation of farmlands as well as breeding of domestic animals. Such mutations have impacts on the transmission and the epidemiology of sleeping sickness due to the modification of the fauna composition, the nutritional behavior of tsetse, the zoophilic/anthropophilic index. To achieve the elimination goal in the sleeping sickness focus of Campo, we report in this paper the current epidemiological situation of the disease, the research findings of the last decades notably on the population genetics of trypanosomes, the modifications of nutritional behavior of tsetse, the prevalence of T. b. gambiense in humans, domestic and wild animals. An overview on the types of mutations occurring in the region has been raised and a discussion on the strategies that can be implemented to achieve the elimination of the disease has been made.

Un nouveau Psychotria (Rubiaceae) rhéophyte du sud Cameroun

Background - A new species of Psychotria (Rubiaceae) from Cameroon is described and illustrated, in the framework of a regional revision of the genus. Methods - Normal practices of herbarium taxonomy have been applied. Key results - Psychotria torrenticola O.Lachenaud & Sene is remarkable in its rheophytic habit, narrowly lanceolate leaves, and in having very large flowers for the genus. It is closely related to P. psychotrioides (DC.) Roberty, from which, in addition to flower size, it also differs in having smooth pyrenes and fewerflowered inflorescences. The species is only known from the Ntem river valley near Nyabessan. Since the construction of a dam is scheduled in the region, the species is considered as Critically Endangered (CR B1a,b(iii)) according to IUCN criteria. © 2012 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

Genetic characterization of the Aphyosemion calliurum species group and description of a new species from this assemblage: A. campomaanense (Cyprinodontiformes: Aplocheiloidei: Nothobranchiidae) from Southern Cameroon

The Aphyosemion calliurum species group is poorly diagnosed by chromatic and meristic characteristics leading various authors to propose different species as members. We used partial sequence of the mitochondrial cytochrome b gene to characterize all species that have been at one time or another included in the A. calliurum species group. Results obtained allowed a clear definition of the group which is composed of 10 species: A. ahli, A. australe, A. calliurum, A. celiae, A. edeanum, A. franzwerneri, A. heinemanni, A. lividum, A. pascheni, and a herein newly described species A. campomaanense. This new species is described from 26 specimens captured in small streams of the Campo-Ma’an region within the Ntem River basin of southern Cameroon. A. campomaanense n. sp. is distinguished from all the other species of the A. calliurum species group, and above all from A. ahli, by asymmetric coloration of the caudal fin with a yellow lower margin and a white upper margin, and a body with a dark blue background against which red spots are arrayed in horizontal rows towards the head merging into vertical rows posteriorly. This species is also genetically distinguished from the other species of the A. calliurum species group by its mitochondrial genome and its karyotype, characterized by an unusually high number of chromosomes and arms (2n= 44, NF=58).

Diversity patterns of fish assemblages in the Lower Ntem River Basin (Cameroon), with notes on potential effects of deforestation

As part of an ongoing project on freshwater fish diversity and conservation of the Lower Ntem River Basin, a synecological study of fish assemblages was undertaken. Two different techniques were used to depict the structural and functional patterns of these fish assemblages: Canonical Correspondence Analysis, an appropriate ordination technique designed for finding the correspondence between physical factors in the environment and biotic factors in the communities, and cluster analysis. Results obtained show a change in both species richness and species composition along the longitudinal gradient. Upstream sites were characterized by a pattern of species addition, while intermediate and downstream sites showed a pattern of species loss and replacement. Measurements of habitat diversity revealed that opposite to depth variability, substrate diversity did not significantly increase downstream. The functional pattern of these fish assemblages almost conformed to the prediction of the River Continuum Concept, with an exception that species richness of invertivores did not increase significantly downstream. A model comprising catchment area, mean % canopy closure, substrate types and chemical variables accounted for 51% of the variation in community composition. Partial variance explained by forward selected environmental variables highlighted amongst others the importance of the bankside cover (mean % canopy closure) in the model. This statistical insight provide further evidence of the role played by this variable in the structure and function of stream fish communities. With regard to the ongoing deforestation in this area, the implications of these findings for the conservation of freshwater biodiversity are discussed.

Patterns of microhabitat use among fourteen abundant fishes of the lower Ntem River Basin (Cameroon)

Une etude de la segregation spatiale dans les microhabitats de quatorze especes abondantes a ete entreprise dans le cours inferieur du bassin du Ntem au Cameroun (Afrique) pendant les saisons seches de 1994 et de 1995. Soixante-et-onze microhabitats comprenant des mouilles, des plats et des radiers ont ete etudies. Les resultats obtenus par une Analyse Canonique de Correspondance (ACC) montrent une bonne separation des niches spatiales des especes le long des axes d'ordination I (λ 1 = 0,37) et II (λ 2 = 0,20). La selection du microhabitat par les especes depend des facteurs physiques tels que: la largeur, la profondeur, la vitesse du courant et le type du substrat. Cependant une part importante de la variation est expliquee par la presence d'un couvert vegetal sur le substrat (% de feuilles, bois morts, racines d'arbres et plantes aquatiques) et au-dessus du microhabitat (% de fermeture de la canopee). Fait remarquable, plusieurs especes notamment, Brycinus longipinnis, Barbus camptacanthus, Distichodus notospilus, et D. hypostomatus montrent une selection de l'habitat liee a la taille des individus. Les differentes associations revelees par l'ACC montrent une correlation espece-habitat elevee (0,957 et 0,938, respectivement pour les axes 1 et 2 ). La significativite de ces associations est testee a l'aide d'un test de Monte Carlo (avec 99 permutations) et montre qu'elles ne sont pas dues au hasard (p = 0,01), mais bien a l'action des variables de l'habitat. Les implications de ces resultats pour une gestion et une prediction des travaux qui induisent des modifications physiques des rivieres sont discutees.

The golden mudsuckers (Labeo spp.) from above and below the Victoria Falls: Sibling species along different invasion routes

The colonization of Lake Kariba with species of the Upper Zambezi fauna brought home the fact that only scant knowledge is available concerning the distribution principles prevailing above and below the Victoria Falls . It, therefore, seemed apparent that a study contributing to a better understanding of this was necessary . To this effect fishes were sampled at the edge of this formidable geographical barrier (Balon, 1974b) . When collection and analysis were completed it became clear that the taxonomic status of the large yellow-fish (Barbus marequensis) and the golden mudsuckers (Labeo spp .) had to be resolved first . The question was: are these species upstream and downstream from the Victoria Falls identical or different, and if so to what extent? Labeo annectens was first described from a small tributary of the Campo River near Efulen in Cameroon . It was originally thought to be limited to the Congo River system (Boulenger, 1909 ; Jackson, 1961), however, when recorded from the Upper Zambezi River at Chavuma in 1963 and from the Kafue River at Itumbi in 1964 by BellCross (1965a) it appeared to replace (Jubb, 1964b) the earlier identifications -Labeo cylindricus and L. forskalii (see Jackson, 1961 and 'linyonga' in Jubb, 1964a) -of the golden mudsuckers above the Victoria Falls . L. forskalii was at the same time diagnosed (Bell-Cross, 1965a) as a new species L. lunatus Jubb, 1963 . The identity of L. cylindricus and L. annectens was, however, doubted by Jubb (1967, p . 240) . Nevertheless Bell-Cross and Kaoma (1971) decided that fish previously identified as L. annectens are L. cylindricus . In the Kafue and Middle Zambezi