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1.
《Journal of Natural History》2012,46(11-12):741-761
Crocodylus acutus, a coastal species nesting in sand beaches, could be affected by increasing tropical cyclone frequency. We studied key characteristics of C. acutus reproductive ecology on Banco Chinchorro atoll from 2006 to 2009, including the impact of two tropical cyclones. Hurricanes increased canopy openness causing earlier nesting the following year. Crocodiles nested at the beginning of the wet season with hatching in mid-wet season; this could represent a compromise between risking nest flooding and increasing freshwater availability for hatchlings. Tropical cyclones dramatically reduced nesting success by cooling and flooding clutches. Nursery sites were usually hypersaline, but heavy rainfall from tropical cyclones can likely benefit hatchling survival by decreasing salinity. While tropical cyclones have negative short-term impacts on crocodile nesting, they likely have an overall beneficial effect by creating and maintaining open sandy nesting areas used by C. acutus and they may explain its widespread distribution in Caribbean coastal areas.  相似文献   

2.
ABSTRACT

In the Cerrado, native grasslands have been dramatically lost, leading to an alarming decline in populations of bird species that require these vegetation physiognomies. Species such as the Black-masked Finch Coryphaspiza melanotis (Gray, 1840) are vulnerable to extinction and remain poorly studied. The objective of this study was to examine home ranges of the Black-masked Finch at the Parque Nacional da Chapada dos Veadeiros, central Brazil. Ten males were studied in a patch of shrubby grassland (campo sujo) between February and December 2008. The mean sizes of home ranges were 4.47 ± 1.49 ha (Minimum Convex Polygon) and 3.48 ± 1.44 ha (Kernel 95%), and this varied significantly between seasons. Home ranges were significantly larger in the non-breeding dry season than during other periods, and significantly smaller in the breeding season than during other periods. Core areas (Kernel 50%) had a mean of 0.46 ± 0.26 ha. A large overlap of home ranges was observed. The home ranges of all banded males overlapped those of at least three co-specifics, and most had an area overlap of more than 50%. A nest containing an egg and a nestling was found in November. Small and largely overlapped home ranges can be considered as positive for the conservation of the Black-masked Finch. This is because both small grassland fragments and conservation units can substantially contribute to the conservation of its populations through the Cerrado extension.  相似文献   

3.
Summary

Monthly samples of the burrowing mud crab, Macrophthalmus hirtipes (Jacquinot 1853) were collected from February 1978 to April 1979 from a marine inlet, Governors Bay (43°38′S, 172°39′E) and from the Avon-Heathcote Estuary (43°33′S, 172°44′E), New Zealand. The estuarine population was generally unimodal and had an annual cycle of population change sustained by a concentrated summer recruitment. In contrast, the bay population was unimodal and bimodal at different times, and recruitment occurred thoughout the year with no clear peak. Both populations had equal sex ratios and were dominated by immature individuals (crabs?10·0 mm carapace width). Estuarine crabs were generally smaller than marine crabs.

At both sites, ovigerous females were found from late May to early March; the smallest egg-bearing female measured CW 10·0 mm at the estuary and CW 10·5 mm at the bay. Cycles of ovarian and embryological development were similar at the two localities. Three peaks of egg oviposition occurred within one breeding season and mature females were capable of producing successive broods. Fecundity was related exponentially to female carapace width and did not alter during the breeding season. Estuarine females carried more eggs than marine females of similar size. Egg volume was related to time of oviposition and eggs laid at the start of the breeding season were significantly larger than those deposited during the second half; however, estuarine eggs showed less reduction in size at this time than did marine eggs.

Estuarine sediments had higher levels of chlorophyll ‘a’, ATP, and microorganism activity and productivity than marine sediments. As M. hirtipes is a detritus feeder, the differences in food resources are believed to account for the elevated fecundity of estuarine crabs. At the bay, salinities were high with little tidal and seasonal variation, whereas in the estuary sea water was diluted significantly both daily and seasonally. The differences in salinity characteristics between the sites may be affecting larval distribution; recruitment in the estuary was concentrated to the summer and in the bay it was almost continuous.  相似文献   

4.
ABSTRACT

Acoustic monitoring provides the opportunity to study ecological processes that are difficult to assess with traditional surveys. Elachistocleis matogrosso is an anuran species, described in 2010, for which limited biological information is available. This study investigated the calling activity of the species in the north-eastern portion of the Pantanal, Brazil, a wetland area with marked seasonality between the dry and wet seasons. The calling activity of E. matogrosso was monitored using automated digital recorders in combination with automated signal recognition software over two different annual cycles. The species was vocally active only during the wet season (October – April), with a peak in November-December during the 2013–2014 annual cycle and in February-March during the 2015–2016 annual cycle. The peak calling activity occurred at dusk. This species has nocturnal habits and an explosive breeding activity. The detection of the species was intermittent, which suggests that environmental predictors or site-specific conditions might play an important role in species detection. Moreover, this intermittent occupancy indicated that surveys that employ traditional field techniques would likely fail to detect this species. We describe an effective protocol for detecting E. matogrosso with acoustic monitoring, which requires recording during 20 days in February from 17:01 to 05:00. Our procedure would be easy to adapt to other anuran species, and it could be used for investigating new localities and assessing population changes over time.  相似文献   

5.
《Journal of Natural History》2012,46(37-38):2351-2367
ABSTRACT

A new species of Passalus is described from the Brazilian Atlantic Forest. A synthesis of the current state of knowledge concerning the Brazilian species of the Petrejus group is presented with a new key to the described Passalus lockerum sp. nov., which is characterized by the frontal area finely and sparsely punctate, interstices shiny; anteriorly with distinct rounded, coarse and shallow punctures, contiguous or not. Also, the secondary median frontal tubercles are close, vestigial to small and subcontiguous at base. Unique characteristic specific to the aedeagus are also important. The species is restricted to a protected conservation area of the Atlantic Forest in the state of Rio de Janeiro.

www.zoobank.org/urn:lsid:zoobank.org:pub:A0A6251E-DFD0-4BB7-90EE-D7FA29AE8243  相似文献   

6.
Summary

Hourly observations on six days during the 1965–66 breeding season are presented, graphically, and analysed. Although there was distinct diurnal change in temperature and light intensity the changes in the numbers of adults, pairs of adults, comfort movements, birds upright asleep, ecstatic displays, birds building and birds entering and leaving the rookery in the 10 min observational periods were not so rhythmical. Some evidence of diurnal variation in numbers, with mid-day minimum, appeared in January. It is suggested that this is due to the necessity for breeding birds to bring food to their chicks at regular intervals; earlier in the season when the demands of the chicks do not have to be met behaviour is governed largely by climatic expediency.  相似文献   

7.
ABSTRACT

A new species of Limnoporeia is described. The material examined was collected on the scope of the Mini Biological Trawl Project, off southeastern Brazil’s coast on the states of Rio de Janeiro and São Paulo, ranging from 34 to 72 metres depth. Limnoporeia infirmichelata sp. nov. is diagnosed by: head with short rostrum; gnathopods weakly chelate; gnathopod 1, propodus wider than long; gnathopod 2, basis posterodistal corner with a long plumose seta; telson with 1 stout seta on each lobe. This is the first record of the genus for the Atlantic Ocean. An identification key is provided for all world species of Limnoporeia.

http://www.zoobank.org/urn:lsid:zoobank.org:act:CB9A8E15-196F-4CCC-8EE4-235246760111  相似文献   

8.
Summary

A new species of mysid, Parvimysis pisciscibus, is described from leaf litter banks in the Igarapé Tarumazinho, a freshwater side stream of the Rio Negro, Brazil. This small species is the first freshwater mysid to be described from the Amazon basin.  相似文献   

9.
《Journal of Natural History》2012,46(29-32):1979-1988
The objective of this study was to furnish information on the natural history of the Neotropical marsupial Thylamys macrurus in the southern Cerrado of Brazil. A range expansion of the species was observed to the northeast of the Mato Grosso do Sul state, Brazil. Specimens were surveyed in fragments of savannah (40–600 ha) during dry and wet seasons in 2003 and 2004 with live‐trap grids and pitfall lines. With an effort of 9767 trap nights and 2200 pitfall nights, we obtained 102 captures and 49 recaptures of T. macrurus. The data analyzed (57 males and 40 females) showed that males are more abundant in the dry season and females in the wet season. Young were recorded mostly during the wet season. Thylamys macrurus was scansorial, using the floor and the understorey. Sexual dimorphism was recorded, with males being larger than females. Information on ectoparasites is supplied.  相似文献   

10.
《Journal of Natural History》2012,46(45-46):2935-2947
ABSTRACT

Akamboja was recently described based on five species with relatively small geographic ranges, all of which are within the boundaries of the South-eastern Atlantic Rainforest in Brazil. Recent expeditions in the continental island of Ilha Grande (Angra dos Reis, Rio de Janeiro State, Brazil) resulted in the discovery of a new species of the genus. Akamboja insularis sp. nov. has all diagnostic features of the genus, except for the branches of the antennomere IX, which are separated, unlike any other Akamboja. Here, we describe this new species, provide a new record for Akamboja minimum Roza et al. and propose a new diagnosis for the genus.

urn:lsid:zoobank.org:pub:DC47825C-B276-49CC-88DC-DFDC5D843356  相似文献   

11.
《Journal of Natural History》2012,46(3-4):229-240
We studied patterns of microhabitat use by adults of two sympatric Bokermannohyla species at the Reserva Particular do Patrimônio Natural Santuário do Caraça, southeastern Brazil. We selected three streams, one where both species occurred in syntopy and the other two where each one occurred alone. We sampled 150-m transects in each stream throughout 1 year, recording microhabitat features for each frog located (substrate type, height and distance from water). Microhabitat availability varied between dry and wet seasons in all streams, and overall microhabitat diversity changed in two streams. Bokermannohyla nanuzae seemed to have a niche contraction in the presence of Bokermannohyla martinsi, but this only happened during the dry season. Microhabitat requirements during the wet season may be closely linked to similar reproductive needs that probably represent a strong selective pressure, forcing niche overlap.  相似文献   

12.
Summary

O, I and II group flounders showed a regular increase in length and weight between April and September, but did not grow during the winter months. These immature fish showed highest condition factors and calorific values in summer and lowest in winter. III and ? IV group flounders had highest condition factors and calorific values in winter prior to spawning and lowest when they returned to the estuary as spents in April. Males matured towards the end of their third year and females towards the end of their fourth. Gonad development started in October and peak gonad weights were attained in November (males) and February to April (females).

Diurnal variations in the numbers of fish were very marked on the Sleek of Tarty where larger numbers were caught at night. Little diurnal variation was noticeable on the Forvie Bank mud flat.

Largest numbers of flounders were recorded between May and September when the population was 50–100 times larger than the winter low (January to March). Estimates of the total population size are given, based on observed densities on underwater transects.

Seasonal changes in the population of flounders on the intertidal mud flats were influenced by four major migrations:
  • (1)A spring immigration (April and May) of immature (except the O group) and spent fish, the spent females being present in significantly greater numbers than males.

  • (2)O group flounders entered the estuary in late June early/July, approximately two months later than the immigration of O group plaice.

  • (3)A proportion of III and ? IV group flounders left the mud flats in July and tagging data suggested that they left for the sea.

  • (4)The winter emigration of all age classes started in October and continued through the winter, leaving a small population composed mainly of O group and maturing fish. Cormorants preyed mainly on I and II group flounders in winter and probably accounted for the low numbers of these age groups at this time.

  相似文献   

13.
ABSTRACT

Manakins (Pipridae) are a group of Neotropical birds well known for their spectacular lekking displays and non-monogamous mating system. Nevertheless, the two species of Antilophia have been traditionally considered monogamous and, therefore, an exception to this rule. In this paper, we studied the home range and the mating system of a colour-ringed population of the Helmeted Manakin Antilophia galeata in southeastern Brazil. We propose that it is a non-monogamous species that ranges widely during the breeding season, presenting a lekking behaviour in the form of unspectacular but aggressive chasing courtship displays.  相似文献   

14.
Summary

Plagues of small mammals in Australia are nearly confined to rodents, both native and introduced. Only in the arid regions do small marsupials reach plague numbers.

Records of plagues have been found as early as 1845, but in many of them there is insufficient information to identify the species involved.

Plagues can develop under three main conditions, namely (a) when species are introduced into new environments, (b) in the artificial environment of crop plants, and (c) in the natural environment.

There are records of the introduced Rattus rattus forming plagues. On colonizing Lord Howe Island in 1918 the species built up to plague numbers in two years. On other islands the species is likely to have built up large populations also. Of various reported plagues on the Australian mainland, Rattus rattus has been identified definitely on only one occasion, in western New South Wales in 1887. There are earlier reports of the introduced rats and mice occurring in large numbers in unsettled areas, but it seems more likely that the animals were native species, wrongly identified, than introduced species which had spread into the areas concerned.

Two groups of species build up to plague numbers in the artificial environment of crop plants. These are Rattus conatus and some other native species which infest sugar-cane in Queensland, and Mus musculus which often infests wheatfields but also forms plagues in other habitats. Both groups infect the crop from a neighbouring natural habitat. Detailed ecological studies have been carried out on both these types of infestation. Reports of dispersal of plagues of Mus musculus need investigation.

Mus musculus can form plagues over a wide range of habitats, from the arid regions of central Australia to the high rainfall areas of tropical Queensland. The status of the form inhabiting the arid regions needs study.

The arid regions of Australia provide a special environment in which live a number of species of small mammals, both eutherians (rodents) and marsupials. In this habitat breeding occurs when there is a sufficient rainfall, and is not regulated at its extremes by an annual climatic cycle. Some of the riverine lands within the region receive drainage from outside, and this modifies the relationship with rainfall in the Lake Eyre Basin particularly. Under favourable conditions several species of the small mammals can build up to plague numbers. In this they appear to differ markedly from the small mammals of other deserts of the world. The special features of the Australian arid environment which allow this are unknown.

Plagues of Rattus villosissimus are generated in the tablelands to the south of the Gulf of Carpentaria, and hordes of the rodents disperse in large numbers, mostly moving out of the home territory along the course of rivers draining it to the south, and sometimes also to the north. The little information available concerning the populations suggests similarities with the cyclic changes which take place in populations of voles and lemmings in the northern hemisphere. There is no good information about the period of recurrence of the plagues, present records showing a range from three to seventeen years.

The little information available about the plagues of small mammals in Australia suggests parallels with such plagues elsewhere. The common factors are a small size, an herbivorous (? or insectivorous) diet, a high reproductive potential and a polymorphism which permits quick adaptation to the different population structures found under different population densities.  相似文献   

15.
Summary

The swarming flights of 23 species of termite were observed at three localities within Brazil and data collected on the periodicity of swarms, the predators which attach the exposed termites and the defensive behaviour of the three castes of termites.

The principal predators on termites during swarming were ants at ground level and birds in the air. The defensive behaviour of workers and soldiers effectively protected the termite alates from terrestrial predators, but only the low level of light at dawn and dusk protected them from aerial predators.

Most of the termites released their alates at the beginning of the rainy season, either at dawn or at dusk and protected them from grounded predators with a ‘blanket’ cordon of workers and soldiers.

Three species of the subterranean, soldierless Anoplotermes constructed special launching towers for the release of alates and protected them from predation with these structures. Armitermes euamignathus and Cornitermes cumulans also built launching structures on their nests for alates, but showed the ‘blanket’ behaviour of most termitids in their defence.

The towers constructed by the three species of Anoplotermes indicated, by their distribution and number, the density and approximate size of the subterranean colonies which built them. A mean density of 240 nests ha-1 and 258·24 termites m-2 was estimated for Anoplotermes sp I.  相似文献   

16.
In this study, the population fluctuations, phenology and sex ratio of the bromeliad-dwelling jumping spider Psecas chapoda were investigated in an area of semi-deciduous forest in south-eastern Brazil. Psecas chapoda occurred and reproduced on Bromelia balansae (Bromeliaceae) throughout the year. The number of egg sacs increased at the beginning of the rainy season (September to December), but the population size and phenology were stable over time and correlated weakly with rainfall and temperature. The principal factor affecting the dynamics of P. chapoda was the blooming of B. balansae, which expelled spiders because of the drastic change in plant architecture. Male spiders were more frequent than females during the juvenile phase, whereas females were more frequent than males during the subadult and adult phases, suggesting a sex ratio that favoured males. The biotic and abiotic factors that influence the population dynamics and sex-dependent vulnerability determination are discussed.  相似文献   

17.
《Journal of Natural History》2012,46(39-40):2497-2507
Brachycephalus garbeanus is an aposematic toadlet, endemic to the Atlantic Forest in the mountains of the state of Rio de Janeiro, southeastern Brazil. Information regarding the ecology of species in this genus is scarce, with no information on most species, including B. garbeanus. We provide ecological information about B. garbeanus, in particular regarding microhabitat use, sexual dimorphism in body size, and feeding habits. Our study was conducted in a montane area of the Parque Estadual dos Três Picos, the largest State park in Rio de Janeiro. Most of the B. garbeanus in the study area were found on the forest floor leaf litter. Females were larger on average than males. Brachycephalus garbeanus consumed a wide array of prey, comprising exclusively invertebrates and predominantly arthropods. There were seasonal differences in the diet composition, but mites and ants were important in both wet and dry seasons.  相似文献   

18.
Summary

Diplogrammus (Climacogrammus) pygmaeus sp. nov. is described and compared with other species of the genus Diplogrammus. Features which distinguish it from the allied species are as follows: 1. (1)The combination of four spines in the first dorsal fin, eight rays in the second dorsal fin, and seven rays in the anal fin, with a preopercular spine formula of ;

2. (2)the unusually broad snout (seen from above);

3. (3)the anterior spines of the first dorsal fin in the male elongate but not filamentous;

4. (4)colour markings.

  相似文献   

19.
《Journal of Natural History》2012,46(29-30):1837-1851
ABSTRACT

Trichomycterid catfishes of the Sarcoglanidinae, which includes small-sized species living in sandy river substratum, have been poorly represented in collections. We herein describe two new species of the sarcoglanidine genus Microcambeva, endemic to river basins draining the Brazilian Atlantic Forest. The presence of a distal widening on the posterior process of the autopalatine and a rudimentary anterior autopalatine ossification shared by the two new species, M. mucuriensis sp. nov. from the Rio Mucuri and M. jucuensis sp. nov. from the Rio Jucu basin, and M. draco from the Rio Jucuruçu basin indicates that these three species are more closely related to each other than to other congeners. Microcambeva mucuriensis seems to be more closely related to M. draco than to M. jucuensis in that the first two species share the presence of a well-developed anterior process of the interopercle. The two new species are also distinguished from congeners by the number of opercular odontodes and premaxillary teeth, and the relative size of the sesamoid supraorbital. Available evidence taken from this study and previous reports indicates that different sarcoglanidine lineages have adapted to live in distinct riverine habitats, with species of Atlantic Forest Microcambeva inhabiting clearwater streams and Amazonian sarcoglanidines found in tea-stained acidic-water streams.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:8CFF9C88-1CEC-44AF-AD26-1D4A56F3D946  相似文献   

20.
Summary

A population of Chaetogaster limnaei limnaei Gruffydd, living on various molluscs in the Worcester-Birmingham canal, was studied from February 1971 to February 1973 in the course of a detailed study of the digeneans parasitizing the molluscs.

The incidence of C. l. limnaei on each of its hosts was recorded for each month during the sampling period.

The incidence of the worms was high during the winter months on Physa fontinalis (and Lymnaea peregra) but low during the summer, and was high during the summer and low during the winter on Bithynia tentaculata.

It is postulated that this pattern of incidence may have been due to a migration of the worms from the pulmonate hosts to B. tentaculata in late spring, when the large pulmonates died after breeding, and a return migration to the pulmonates the following autumn.

There was found to be no association between the digeneans parasitizing the molluscs and the occurrence of the oligochaetes, and it is suggested that in this case the oligochaetes have no influence on the parasitic burden of the molluscs.  相似文献   

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