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Evolution of river dolphins

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Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) of the Mpala Research Centre and environs, Laikipia District, Kenya

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The dung beetle fauna of the subfamily Scarabaeinae (Coleoptera: Scarabaeidae) occurring in the Laikipia District of Kenya was surveyed. A total of 79 species were found which are diagnosed, keyed, and known dung preferences discussed. Seven species are new records for Kenya, namely Allogymnopleurus indigaceous, Copris denticulatus, Euoniticellus parvus, Gymnopleurus reichei, Oniticellus egregius, Oniticellus pseudoplanatus and Sisyphus tibialis.

Temporal patterns of nutrient availability around nests of leaf-cutting ants (Atta colombica) in secondary moist tropical forest

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Leaf-cutting ants consume up to 10% of canopy leaves in the foraging area of their colony and therefore represent a key perturbation in the nutrient cycle of tropical forests. We used a chronosequence of nest sites on Barro Colorado Island, Panama, to assess the influence of leaf-cutting ants (Atta colombica) on nutrient availability in a neotropical rainforest. Twelve nest sites were sampled, including active nests, recently abandoned nests (1 year). Waste material discarded by the ants down-slope from the nests contained large concentrations of nitrogen and phosphorus in both total and soluble forms, but decomposed within one year after the nests were abandoned. Despite this, soil under the waste material contained high concentrations of nitrate and ammonium that persisted after the disappearance of the waste, although soluble phosphate returned to background concentrations within one year of nest abandonment. Fine roots were more abundant in soil under waste than control soils up to one year after nest abandonment, but were not significantly different for older sites. In contrast to the waste dumps, soil above the underground nest chambers consistently contained lower nutrient concentrations than control soils, although this was not statistically significant. We conclude that the [`]islands of fertility' created by leaf-cutting ants provide a nutritional benefit to nearby plants for less than one year after nest abandonment in the moist tropical environment of Barro Colorado Island.

Resurrection of Stenocercus torquatus Boulenger, a spiny-tailed iguanid lizard (Squamata : Iguania) from Peru

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We resurrect and redescribe Stenocercus torquatas from the Andes of central Peru in departamentos Junin and Pasco at elevations between 800 and 1800 m. This species was erroneously synonymized with Stenocercus crassicaudatus, which occurs allopatrically in the Andes of southeastern Peru, departamento Cusco. In addition to several scale counts, Stenocercus torquatus differs from S.crassicaudatus in having a black antehumeral collar, two black transverse bands anterior to the antehumeral collar, a shorter tail, the ability to change color, and an arboreal life-style.

New species of Stenocercus (Squamata : Iguania) from the Andes of central Peru with a redescription of Stenocercus variabilis

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A new species of Stenocercus is described from the eastern slopes of the Andes in central Peru, Departamentos Ayacucho and Huancavelica. It differs from other Stenocercus by the combination of the following characters: scales on posterior surface of thighs granular, lateral body scales imbricate and keeled, vertebral row of enlarged scales present, gular scales unnotched, neck folds present, three caudal whorls per autotomic segment, postfemoral mite pocket absent, dorsal ground color gray or brown, without a black shoulder patch in males. Specimens of the new species have been misidentified as Stenocercus variabilis, which occurs allopatrically in Departamento Junin.

The abdominal skeleton of tropidurid lizards (Squamata : Tropiduridae)

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Morphological variation in the abdominal skeleton of Tropiduridae was examined from radiographs and cleared-and-stained specimens of 61 species. Based on the numbers of xiphisternal and postxiphisternal inscriptional ribs, as well as the presence of inscriptional ribs articulating ventromedially, seven patterns of rib attachment are described. The distribution of these patterns among the species studied reveals intra- and interspecific variation, which indicates that the abdominal skeleton of lizards is a good source of fixed and polymorphic characters for phylogenetic analyses.

Cranial osteology of the Andean lizard Stenocercus guentheri (Squamata : Tropiduridae) and its postembryonic development

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In spite of the great diversity of iguanian lizards, detailed descriptions of their osteocrania and postembryonic development are rare. Herein, the adult cranial osteology of the tropidurid lizard Stenocercus guentheri and its postembryonic development are described based on cleared and double-stained and dry skeletal specimens from a single Ecuadorian population. The amphikinetic skull of S. guentheri is short and elevated and bears teeth on the premaxilla, maxillae, and pterygoids. Mandibular teeth are present on the dentaries. Ossification of the articular from Meckel's cartilage and growth of the parietal (ossification and investment of the frontoparietal fontanelle) are the most significant ontogenetic changes of the splanchnocranium and dermatocranium, respectively. The ossification of the cartilage separating the bones of the braincase is the most relevant postembryonic ontogenetic event of the neurocranium. The number of teeth does not vary ontogenetically and replacement teeth are present throughout postembryonic life. This study includes a list of the osteocranial characters of Stenocercus that have been used in systematic studies, as well as a discussion of functional morphology and kinesis. (C) 2002 Wiley-Liss, Inc.

The effect of exposure to sea water on germination and vegetative growth of an epiphytic bromeliad

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Vascular epiphytes call be quite abundant in vegetation close to the ocean surf. where they are exposed to a more or less Continuous input of salt spray. The ecophysiological basis of their Occurrence, i.e. salt tolerance or avoidance is Unresolved. because all previous Studies were observational and conclusions thus circumstantial. Here. the effect of varying concentrations of salt water on germination. and growth and survival of seedlings and established plants was investigated in a growth cabinet study under controlled conditions. Seeds (1500). seedlings (750) and small tank plants (336) were front four populations of Werauhia sanguinolenta that were growing either close to the sea or inland in Panama. Changes of Na+ and K+ concentrations in plant tissue were also determined. No differenccs in the sensitivity to salt were found among populations. nor among life stages. External concentrations (C-ext) of up to 15% sea water (c. 0.5% Na+) allowed complete germination as well as positive growth and survival in both seedlings and established plants over short periods (8-10 wk). After longer exposure ( 12 wk) of established plants visible damage and increased mortality were observed at lower C-ext, but critical tissue Na+ levels were similar: c. 50 mg gDW(-1). It is concluded that this Common epiphyte does not meet. the definition of a halophyte. but still possesses a rather high tolerance to sodium.

Ambient temperature is more important than food availability in explaining reproductive timing of the bat Sturnira lilium (Mammalia: Chiroptera) in a montane Atlantic Forest

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Reproduction of bats is determined by a suite of endogenous and exogenous factors. Among exogenous influences, special attention has been given to the influence of food availability. However, in highland forests, severe decreases in temperature during the cold and dry season may also play an important role. In the present study we tested the influence of ambient temperature and food availability on the timing of reproduction in the frugivorous bat Sturnira lilium (E. Geoffroy, 1810). We conducted a 15-month mist-netting sampling in a mountain area of the Brazilian Atlantic Forest during which time we assessed the bats' diet through fecal samples, monitored fruit production of the main food plants, and recorded variations in ambient temperature. Sturnira lilium fed almost exclusively on Solanaceae. Similarly to the lowlands, reproduction was bimodal, but reproductive season tended to be shorter in the highlands and peaked in the warmer months of the year. Overall, 44% to 53% of the reproductive pattern was explained by variations in ambient temperature, while the relationship with food availability was nonsignificant. We conclude that variations in ambient temperature in tropical mountains may be a stronger selection pressure than food availability in determining reproductive timing of bats.

An evaluation of farmers' experiences planting native trees in rural Panama: implications for reforestation with native species in agricultural landscapes

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In the Republic of Panama, reforestation with native species is of great interest, but many landholders often do not participate in tree planting projects and little information exists about landholder interest in, or experiences with, native trees. This study evaluates the experiences of farmers participating in a native species reforestation initiative in rural Panama to identify lessons learned that can guide on-going or future tree planting efforts. Based on the results of a questionnaire administered to program participants and non-participants (n = 68), we found that trees are important to farmers for multiple reasons, primary a variety of environmental and economic benefits. No relationship between the size of landholdings or land tenure status and the desire to plant trees was found. All participants in the program considered their experience to be positive, few had problems with their plantations, and most were interested in planting more native trees. The program's frequent and ongoing technical support was an important factor for farmers. These results indicate widespread interest in, and success with, planting native species and underscore the need to systematically examine farmers' interests and perceptions when planning, implementing, and evaluating reforestation initiatives.
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