Seasonality of reproduction in the three largest terrestrial rodents of French Guiana forest

We investigated the main life history of the three largest terrestrial rodents of French Guiana forest: the acouchy (Myoprocta exilis), the agouti (Dasyprocta leporina) and the paca (Agouti paca), using data collected during several years. There were noticeable differences among the species in sexual maturation and degree of seasonality in reproduction. Percentage of pregnant females, births and juveniles, and body weight of juveniles decreased progressively from the acouchy, through the agouti to the paca. The acouchy was by far the most seasonal: no births occur in the period August–October, 56% of births were encountered in November–January; consequently, young form an unique cohort in the population. The agouti was also seasonal, but to a lesser degree. Newborns appeared in every period of the year in paca, without any formation of cohort of young. These differences tended to be linked to the seasonal importance of fruits in diets, the most aseasonal species having the most diversified diet during the poor fruit season.

Zusammenfassung

Jahreszeitliche Fortpflanzung von den drei größten terrestrischen Nagern im Regenwald von Französisch GuayanaDie Untersuchungen beziehen sich auf die wichtigsten Merkmale der Lebenszyklen der drei größten terrestrischen Nager, Acouchi, Aguti und Tieflandpaka, im Regenwald von Französisch Guayana, unter Verwendung von über mehrere Jahre währenden Beobachtungen, die beachtenswerte Unterschiede in bezug auf Geschlechtsreife und Fortpflanzung aufzeigen. Fortpflanzung und Populationsstruktur, wie Prozentsatz trächtiger Weibchen, Geburten, Auftreten von Jungen sowie deren Körpergewicht verringern sich kontinuierlich von Acouchis über Agutis hin zu Tieflandpakas. Während Acouchis die bei weitem am stärksten ausgeprägte jahreszeitlich gebundene Fortpflanzung mit 56% der Geburten in den Monaten November bis Januar zeigen, konnten von August bis Oktober keine Geburten beobachtet werden. Demzufolge treten die Jungen in der Population als eine einheitliche Altersklasse auf. Eine periodische Fortpflanzung zeigen auch Agutis, wenn auch weniger ausgeprägt, wohingegen bei Tieflandpakas über das gesamte Jahr hinweg Junge geboren werden, ohne jegliche Bildung von einer Altersklasse. Diese Unterschiede scheinen an die jahreszeitlich bedingte Produktion von für die Ernährung wichtigen Früchten gebunden zu sein, wobei die am wenigsten periodische Art in der früchtearmen Zeit das breiteste Nahrungsspektrum aufweist.     

Two new species of Myrsinaceae from French Guiana

Herbarium studies leading to a treatment of the Myrsinaceae for the Flora of Central French Guiana resulted in the discovery of two heretofore undescribed species,Cybianthus prevostiae andStylogyne incognita. The species are described and illustrated, and hypotheses regarding phylogenetic relationships with their respective congeners are provided.Cybianthus prevostiae is unusual among members ofCybianthus subgen.Weigeltia owing to its monoaxial habit and ellipsoid pistil, and deeply cupuliform calyx.Stylogyne incognita, a taxon often confused withS. micrantha, is most closely related toS. sordida but is separated from it by the corymbose inflorescence, entire leaves, longer petioles, and membranaceous perianth.     

Guarea michel-moddei (meliaceae), a new species from central French Guiana

Guarea michel-moddei, a new species from central French Guiana is described and illustrated. It differs from the morphologically similarG. cristata of western Amazonia by its unbranched habit; shorter, less dense indumentum of the young parts, leaves, and inflorescence; bullate leaves, shorter inflorescence, shorter pubescence on the corolla; and smaller corolla and staminal tube.     

Coussarea granvillei (Rubiaceae, Coussareeae), a new species from French Guiana

Coussarea granvillei is newly described and illustrated from material collected in the environs of Mount Galbao, near Saül, French Guiana. This new species is compared toC. amapaensis, for which the morphological and distributional ranges are extended and briefly discussed, and toC. leptophragma andC. revoluta.     

A new species of Bactris (Palmae) from French Guiana

A new species,Bactris nancibaensis, from French Guiana, is described and illustrated.     

Two new species of Eugenia (Myrtaceae) from Central French Guiana

Eugenia argyrophylla andE. morii from Saül in Central French Guiana are described and illustrated.     

Two new species of Lauraceae from central French Guiana

Aiouea opaca andBeilschmiedia hexanthera, recently collected in central French Guiana, are described and illustrated.     

Calathea maasiorum (Marantaceae), a new species from French Guiana and Surinam

Calathea maasiorum from French Guiana and Surinam is described as new. It belongs toCalathea sectionBreviscapus Bentham. The foliage is patterned with a light green band along the midrib above. This new species has previously been confused withC. cyclophora Baker from Amazonian Colombia, Brazil, Venezuela, and Guyana but it is distinguished fromC. cyclophora by the absence of bracteoles, the elliptic to obovate leaf blade, and shorter (1–2 cm long) bracts.     

Two new species of Protium from French Guiana. Studies in neotropical Burseraceae VIII

Revision of Protium in French Guiana has revealed two new species. Protium gallicum is related to P. aracouchini (Aubl.) Marchand and P. elegans Engl., although its fruits resemble those of P. plagiocarpium Bénoist. Protium inodorum, which also occurs in northern Pará, Brazil, is related to P. pallidum Cuatrec. and P. cuneatum Swart; it is known only from flowers and very young fruits. Even in relatively well-known regions of tropical forest, botanical exploration continues to yield new taxa.     

Evidence for coevolution of sociality and relative brain size in three orders of mammals

As the brain is responsible for managing an individual's behavioral response to its environment, we should expect that large relative brain size is an evolutionary response to cognitively challenging behaviors. The "social brain hypothesis" argues that maintaining group cohesion is cognitively demanding as individuals living in groups need to be able to resolve conflicts that impact on their ability to meet resource requirements. If sociality does impose cognitive demands, we expect changes in relative brain size and sociality to be coupled over evolutionary time. In this study, we analyze data on sociality and relative brain size for 206 species of ungulates, carnivores, and primates and provide, for the first time, evidence that changes in sociality and relative brain size are closely correlated over evolutionary time for all three mammalian orders. This suggests a process of coevolution and provides support for the social brain theory. However, differences between taxonomic orders in the stability of the transition between small-brained/nonsocial and large-brained/social imply that, although sociality is cognitively demanding, sociality and relative brain size can become decoupled in some cases. Carnivores seem to have been especially prone to this.     

Fractionation of phosphate in sediments of four representative mangrove stages (French Guiana)

Phosphate was fractionated in Guianese mangrove sediments. Fe(OOH)P was extracted using a Ca-EDTA + Na-dithionite solution buffered at pH 8. CaCO₃P was extracted using Na₂-EDTA solution at pH 4.5. Next, Acid Soluble Organic Phosphate (ASOP) was extracted by H₂SO₄ 0.5 N. Finally, Residual Organic Phosphate (ROP) was digested with H₂SO₄ + H₂O₂. Four representative mangrove stages have been studied: sea edge pioneer mangroves, mature coastal mangroves, mixed riverine mangroves, and declining to dead mangroves. The sum of the P-fractions varied between 638 to 804 g g^-1 in pioneer and mixed mangroves respectively. In all the stages, the percentage of inorganic phosphate was larger than 50% of the total P. Fe(OOH)P varied between 221 (pioneer mangrove) to 426 g g^-1 (dead mangrove). CaCO₃P varied between 75 to 102 g g^-1 in mixed, dead or mature mangroves and attained 125 g g^-1 in pioneer mangrove. The sum of the concentrations of organic phosphate (ASOP + ROP) increased markedly from the dead mangrove (189 g g^-1) to the mixed mangrove (380 g g^-1). Guianese mangroves, are relatively rich in total phosphate, possibly because they are narrowly related to the 'Amazon dispersal system. Each mangrove stage can be characterised by a prevailing form of phosphate. The concentrations of these different forms were ascribed to the marked relations with the seawater which controls import or export of suspended matters and to the wave action which controls the resuspension of the sediments and subsequently exchange of phosphate between the suspended matter and the water column.     

Report on wind dispersal in a lowland moist forest in central French Guiana

An analysis of the flowering plant flora of a lowland moist forest in central French Guiana reveals 298 species with adaptations for wind dispersal. This represents 16.2% of the flowering plant flora and 9.8% of the class Magnoliopsida (dicotyledons). The most diverse wind-dispersed families are the Orchidaceae in the Liliopsida (monocotyledons) with 135 species and the Bignoniaceae in the Magnoliopsida with 37 species. The wind-dispersed species of central French Guiana have evolved either small, dust-like seeds, fruits or seeds with various kinds of wings, fruits or seeds with tufts of hairs, or expanded wing- or parachute-like persistent calyces. Most wind-dispersed species, among the liliopsids, are epiphytes and, among the magnoliopsids, trees or lianas. In central French Guiana, collections of these species with mature diaspores have been gathered most often in October and March, the months with peak wind velocities. In contrast, collections from June and July, when wind velocities are at a minimum, are rare.     

A survey of adult anophelines in French Guiana: enhanced descriptions of species distribution and biting responses

In French Guiana, Anopheles darlingi is considered the main malaria vector. However, several reports have hypothesized the implication of other anopheline species in malaria transmission for the territory. Data on the ecology of these other potential vectors is rare or even unexplored in French Guiana. The aim of this study was to describe the biting habits of several anopheline species in multiple localities in French Guiana. Six sampling sites yielded 1,083 anopheline adults. Results indicated the presence of An. darlingi in all study locations and it was the only species to be collected inside villages. Other anophelines collected included An. aquasalis, An. braziliensis, An. intermedius, An. mediopunctatus, An. nuneztovari, An. oswaldoi, and An. triannulatus, all of which were associated with open areas and forests. The environment and time, at which biting behavior was recorded, varied for each species. It was noted that An. oswaldoi showed a daytime rhythm in open areas. This study is the first to report on the biting habits of a range of anophelines in French Guiana that may play a role in malaria transmission. This information is vital to fully describe the risk of malaria transmission and thereby design appropriate vector control measures and malaria prevention programs.     

Molecular characterization and mitochondrial sequence variation in two sympatric species of Proechimys (Rodentia: Echimyidae) in French Guiana

Variations in mitochondrial DNA characters were used to characterize two morphologically similar and sympatric species of Neotropical terrestrial rodents of the genus Proechimys (Mammalia: Echimyidae). We sequenced both cytochrome b (1140 pb) and part of the control region (445 pb) from four individuals of P. cuvieri and five of P. cayennensis from French Guiana, which allowed us to depict intra- and inter-specific patterns of variation. The phylogenetic relationships between the nine sequences evidence the monophyly of each species, and illustrate that more polymorphism might exist within P. cuvieri than within P. cayennensis. By developing species-specific primers to amplify a fragment of the cytochrome b gene, we were able to identify 50 individuals of Proechimys spp. caught in two localities of French Guiana. In both sites of primary rainforests, we showed that the two species live in syntopy, and this observation emphasizes the need to document ecological differences which should exist in order to diminish inter-specific competition.     

Specific epithets of the flowering plants of central French Guiana

The epithets of the flowering plants of central French Guiana are classified into derivation categories. Specific epithets of the flowering plants of central French Guiana refer mostly to shapes (274 species), persons (252), places (212), appearance (146), and size (140). These categories account for 55% of names given to the plants of this flora. The most prolific publishers of names for the flora of central French Guiana are Aublet and Linnaeus, who were respectively the authors of 177 and 110 of the names of species (15% of the total) found in the flora of central French Guiana. Although many of the species names, such as those relating to place and person, are easy to categorize, many others are open to different interpretations. Specific epithets with different orthographies derived from Guiana or Guyana are discussed. In addition, problems in the use of diacritical marks and inconsistencies with spacing between the abbreviations of given names and surnames of authors of plant names are noted.     

Polymorphic microsatellites for the study of fragmented populations of Pitcairnia geyskesii L. B. Smith (Bromeliaceae), a specific saxicolous species of inselbergs in French Guiana

Pitcairnia geyskesii is a saxicolous bromeliad endemic to the granitic inselbergs of French Guiana and Surinam. Seven polymorphic microsatellite markers were characterized to investigate the polymorphism among individuals sampled on five inselbergs in French Guiana. The total number of alleles per locus varied from four to 14. Mean observed heterozygosities at each microsatellite locus ranged from 0.114 to 0.629. This set of microsatellites offers an efficient tool for more detailed investigations on the genetic structure of fragmented populations living on such a singular and insular habitat within tropical rainforest.     

Body shape, diet and ontogenetic diet shifts in young fish of the Sinnamary River, French Guiana, South America

A total of 1468 young fish representing 66 taxa from the Sinnamary River, French Guiana was classified by complete cluster analysis of mean relative body width and mean relative body height into four groups. These had anguilliform, disciform, flat or intermediate body shapes and belonged chiefly to Gymnotiformes, Perciformes, Siluriformes and Characiformes, respectively. Several of the taxa shifted from one to another body shape during ontogenesis. Seven diet groups were defined by complete cluster analysis. Among these, six groups were represented by carnivorous fish. The three most frequent groups had diets of (1) mainly insect larvae and small crustaceans, (2) insect larvae, and (3) predominantly terrestrial insects. The majority of the fish taxa showed ontogenetic diet shifts. Carnivorous fish usually switched from small-size prey, such as small crustaceans, to intermediate-size prey, such as insect larvae and/or to large-size prey, such as insects and/or fish. However, taxa differed in their capacities to switch from small prey to intermediate and/or to large prey. Taxa of different body shapes had significantly different diets. Disciform fish fed mainly on aquatic insect larvae and terrestrial insects but also, in small amounts, on small curstaceans. Most anguilliform taxa ate insect larvae. Individuals belonging to the depressiform or intermediate morphotype had varied diets ranging from plant debris and substratum to fish.     

Health evaluation of translocated free-ranging primates in French Guiana

Among over 40 mammal species threatened by the filling of a hydroelectric dam reservoir in French Guiana, three species of primates have been translocated, comprising 124 red howler monkeys, six white-faced sakis, and 95 golden-handed tamarins. Health status of the animals was evaluated by direct physical examination and by hematological, biochemical, virological, and parasitological surveys of collected blood. The physical condition of the howlers was slightly worse toward the end of the capture period, but that of sakis and tamarins remained satisfactory. Several ectoparasites (ticks, larvae of dipterous insects, fleas, and lice) were collected, and various wounds, apparently nondebilitating, were recorded in howlers. Hematological and biochemical profiles determined for the three species revealed a slight anemia in howlers. Entamoeba, Strongyloides, and Trypanoxyurus were common in fecal samples of howlers. A survey of blood smears from the three species revealed infection by several types of microfilaria, Trypanosoma rangeli-like and Plasmodium brasilianum in all three, and Trypanosoma cruzi-like in howlers. These infections had no significant impact on the health status or the hematological profiles. Serologic investigations revealed occasional reactions against Toxoplasma gondii, a strong anti-Plasmodium response in the two Cebidae species, and a weaker one in tamarins. Attempts to isolate arbovirus failed, but antibody responses to Mayaro and yellow fever viruses were strong, especially in the howlers. A strong correlation between age and serological status led to a better understanding of the epidemic cycles. Our survey indicates French Guianan primates are reservoirs for several anthropozoonoses, including malaria, Chagas disease, and arboviruses.     

Disteganthus lateralis (Bromeliaceae), a new combination for the flora of central French Guiana

The new combination,Disteganthus lateralis, is coined based onAechmea lateralis. An illustration for this species is provided.