Effect of reservoir drawdown on biomass of three species of aquatic macrophytes in a large sub-tropical reservoir (Itaipu, Brazil)

The biomass and maximum depth of colonization (Z _max) of Egeria najas Planchon (submerged), and the biomass and area covered by a stand of Eichhornia crassipes (Mart.) Solms and Salvinia herzogii Raddi (floating species) were assessed to measure the effects of a 5 m drawdown in water level of the Itaipu Reservoir (Brazil–Paraguay), which lasted about 3 months. The frequency of occurrence of the two first species, and of Salvinia spp was also assessed in the main arms of the reservoir. A conspicuous decrease of E. najas biomass was observed and this attribute did not reach the previous values even 10 months after the water level had returned to normal. Rapid growth of free-floating species (surface t _doub = 2.9 and 3.2 days for total biomass of S. herzogii and E. crassipes, respectively, and 2.3 days for surface area covered by both species) was recorded immediately after the water level returned to normal. This fast growth was related to phosphorus increases in water. A clear succession was observed over a period of 103 days, during which S. herzogii was slowly substituted by E. crassipes. The effects of water level drawdown were also observed on E. najas frequency, given that this species occurred in 38% of the stands investigated before the water drawdown, but in only 9 and 6% of stands following 1 and 10 months of water level recovery, respectively. Water drawdown did not affect the frequency of occurrence of the floating species, which remained approximately constant, and lower than 15% in several of the reservoir arms investigated.     

Neosartorya takakii, a new species from soil in Brazil

Among the isolates from soil of grassland in Roraima State, Brazil, a new species ofNeosartorya, N. takakii is described and illustrated.Neosartorya takakii differs from the other known species of the genus in having lenticular ascospores with two distinct equatorial crests and with roughly circularly arranged projections on the convex walls. A comparative SEM view of ascospores from six relatedNeosartorya species is also provided.     

Dacryodes edilsonii, a new species from southwestern Amazonia. Studies in neotropical Burseraceae XII

Dacryodes edilsonii Daly (Burseraceae) is one of at least 14 still undescribed neotropical species in the genus; it is also one of a large number of new species emerging from intensified botanical exploration of the Brazilian state of Acre in southwestern Amazonia. The new species is easily distinguished from most other Neotropical species of the genus by its usually densely long-pubescent petiole, rachis, petiolules, and abaxial midvein.     

Influence of life history and seasonal hydrology on lipid storage in three neotropical fish species

The seasonal dynamics of energy (lipid) storage in three neotropical fish species with differing life histories were evaluated. Lipid content was substantially greater in the liver than in dorsal musculature of all three species. Two piscivores ( Cichla temensis and Serrasalmus manueli ) showed large, statistically significant seasonal fluctuations in liver lipid content. Liver lipid content increased during high water, through the falling water, and into the early dry season for both piscivores. Seasonal variation in dorsal muscle lipid content was large and statistically significant for C. temensis , but was small and non‐significant for S. manueli . Cichla temensis appeared to 'finance' costs associated with reproduction by accumulating lipids during the falling‐water period when migratory prey allowed the species to subsidize their energetic dynamics. Semaprochilodus kneri , a migratory algivore and detritivore, showed no significant seasonal variation in dorsal muscle lipid content and minimally significant seasonal variation in liver lipid content. Statistically significant effects of lipid content on δ¹³C was observed when tissue lipid content varied by >12%, while biological interpretation of food web statistics based on δ¹³C values appears robust to minor variations in lipid content. Nonetheless, when lipid content varied by larger amounts ( e.g . >35% for C. temensis and S. manueli liver tissue) lipids appeared to have a large potential effect on δ¹³C and food web statistics calculated from such measurements may have been biased. Surprisingly, even large variation in tissue lipid content did not affect δ¹⁵N.     

Two new species of Hippocrateaceae from Brazil

Two new species of Hippocrateaceae from Brazil are described and illustrated:Pristimera sclerophylla Lombardi, the one species of the genus that occurs in the xerophytic vegetation of northeastern Brazil, andCheiloclinium puberulum Lombardi, a species with puberulent inflorescences from the rain forests of the Amazon basin.     

Female-to-male shift of mouthbrooding in a cichlid fish,Tanganicodus irsacae,with notes on breeding habits of two related species in Lake Tanganyika

Synopsis Parental-care patterns and mating systems of three goby-like cichlids in Lake Tanganyika were investigated. In Tanganicodus irsacae females mouthbrooded eggs and small young for about two weeks and then males took over the role for about one week. Field observations of tagged fish suggest that this species is monogamous: a male's home range largely overlapped with that of its mate, while their home ranges were segregated from those of similar-sized consexual adults. Eretmodus cyanostictus also performed female-to-male shift of mouthbrooding and appeared to be monogamous. The third species, Spathodus marlieri, however, exhibited exclusively maternal mouthbrooding. The differences in parental care and mating system among the three species are discussed in relation to their feeding habits, and the pattern of monogamy in the goby-like cichlids is compared with those of other fishes.     

Ceiba rubriflora (Malvaceae: Bombacoideae), a new species from Bahia, Brazil

Summary   Ceiba rubriflora Carv.-Sobr. & L. P. Queiroz, a new species of Malvaceae subfamily Bombacoideae from the State of Bahia, Brazil, is described and illustrated. It is considered to be endemic to calcareous outcrops in the valley of the Rio S?o Francisco, in the western region of the state. Notes on distribution, ecology and phenology are given. Relationships with related species are discussed and an addition to the key to species of Ceiba Mill. published by Gibbs & Semir (2003) are provided.     

Croton dissectistipulatus, a new species of Euphorbiaceae from Amazonian Brazil

A new species ofCroton,C. dissectistipulatus, is described from Amazonian Brazil. This species is superficially similar toC. timandroides from northeastern and southeastern Brazil, but differs in having petiolate leaves with glandular margins, persistent stipules, conspicuous racemose inflorescences, staminate flowers having externally glabrous sepals and 3 stamens, and pedicellate pistillate flowers. The systematic position ofC. dissectistipulatus relative to the sections ofCroton is discussed.     

Serjania lancistipula (Sapindaceae), a new species from Bahia,Brazil

A new species ofSerjania (S.lancistipula) from Bahia belonging to theS. paradoxa group is described and illustrated. A key to the species in theparadoxa group is provided.     

Aechmea itapoana,a new species from Bahia (Brazil): Taxonomy and ecology

Aechmea itapoana is a new, conspicuous and distinct species from the coastal sand dune scrub of N.E. Brazil. Its possible relationships within subgenusChevaliera, toA. multiflora andA. rodriguesia are discussed.     

Schefflera aurata, a new species of Araliaceae from southern Bahia, Brazil

Schefflera aurata, a new species of Araliaceae endemic to the restinga forests of southern Bahia, Brazil, is described and illustrated. It is probably related toS. morototoni, but can be distinguished by leaflets with strongly coriaceous blades, cuspidate apices, goldensericeous indument of the abaxial surfaces, partial inflorescences with 8–12 subsessile flowers, elongated ovaries, and distinctly larger fruits.     

A new species of Aspidosperma Mart. (Apocynaceae) from Bahia, Brazil

A new species,Aspidosperma thomasii, collected in the vicinity of Uruçuca is described. It belongs to subgenusAspidosperma sectionAspidosperma and is closely related to theA. parvifolium A. DC. group.     

Three new species of Croton (Euphorbiaceae) from Brazil

Summary   Croton imbricatus L. R. Lima & Pirani from Bahia, C. muellerianus L. R. Lima from Paraná and C. pygmaeus L. R. Lima from Rio Grande do Sul are described and illustrated. They are included in Croton section Lamprocroton (Müll. Arg.) Pax because they are much branched subshrubs or shrubs, bearing leaves with a lepidote indumentum (at least in part), inflorescences lacking bisexual cymules, and pistillate flowers with bifid styles.

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Résumé   Croton imbricatus L. R. Lima & Pirani da Bahia, C. muellerianus L. R. Lima do Paraná e C. pygmaeus L. R. Lima do Rio Grande do Sul s?o descritas e ilustradas. Elas s?o representantes de Croton section Lamprocroton (Müll. Arg.) Pax e tal posicionamento sistemático é devido ao hábito arbustivo ou subarbustivo bastante ramificado, com indumento da folhagem lepidoto pelo menos em parte, inflorescências sem címulas bissexuadas e flores pistiladas com estiletes uma vez bífidos.

     

Ant species confer different partner benefits on two neotropical myrmecophytes

The dynamics of mutualistic interactions involving more than a single pair of species depend on the relative costs and benefits of interaction among alternative partners. The neotropical myrmecophytes Cordia nodosa and Duroia hirsuta associate with several species of obligately symbiotic ants. I compared the ant partners of Cordia and Duroia with respect to two benefits known to be important in ant-myrmecophyte interactions: protection against herbivores provided by ants, and protection against encroaching vegetation provided by ants. Azteca spp., Myrmelachista schumanni, and Allomerus octoarticulatus demerarae ants all provide the leaves of Cordia and Duroia some protection against herbivores. However, Azteca and Allomerus provide more protection than does Myrmelachista to the leaves of their host plants. Although Allomerus protects the leaves of its hosts, plants occupied by Allomerus suffer more attacks by herbivores to their stems than do plants occupied by other ants. Relative to Azteca or Allomerus, Myrmelachista ants provide better protection against encroaching vegetation, increasing canopy openness over their host plants. These differences in benefits among the ant partners of Cordia and Duroia are reflected in the effect of each ant species on host plant size, growth rate, and reproduction. The results of this study show how mutualistic ant partners can differ with respect to both the magnitude and type of benefits they provide to the same species of myrmecophytic host.     

A new species of Heteropterys (Malpighiaceae) from the semideciduous forests of Bahia, Brazil

Heteropterys andersonii, related to seriesMetallophyllis Nied., is described as new and illustrated.

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Resumen   Heteropterys andersonii, relacionada a sérieMetallophyllis Nied., é descrita como nova e ilustrada.

     

Three new species of melastomataceae from the southeastern Atlantic Forest of Brazil

Three species are described here that occur in montane and high-montane forests in Southeastern Brazil.Miconia shepherdii belongs to sectionGlossocentrum and occurs on the Serra da Mantiqueira, on the border between the states of São Paulo, Minas Gerais, and Rio de Janeiro.Miconia kollmannii belongs to sectionHypoxanthus (formerChaenanthera) and occurs in the state of Espírito Santo.Ossaea suprabasalis was also collected in the state of Espírito Santo.     

New species ofRelbunium (Rubiaceae) from Brazil,with notes on flavonoid and peroxidase patterns

Three new species ofRelbunium, R. humilioides, R. catarinense, andR. longipedunculatum (Rubiaceae), endemic in the southern states of Brazil, are described. Flavonoid patterns from two-dimensional thin layer chromatography and peroxidase patterns from gel electrophoresis are presented for two of them. The relationships of the new species, their taxonomic position, and their evolutionary significance within the genus are discussed.The Systematics and Evolution of the GenusRelbunium (Rubiaceae), I.     

Names, types, and distribution of neotropical species of Erythroxylum (Erythroxylaceae)

A list is provided of all 358 taxa ofErythroxylum described from the Neotropics through the year 2000, including type specimen citations, probable synonymy, geographic distribution, and designation of 41 new lectotypes and one new neotype. The list includes 187 accepted species, eight accepted varieties, 27 infraspecific names of uncertain status, and 136 synonyms. A searchable specimen database and type image archive may be accessed at www.fieldmuseum.org/research_collections/database.htm. T. Plowman, deceased 7 January 1989.