Roberto Munehisa Shimizu's research while affiliated with University of São Paulo and other places

Publications (22)

Article
Aegla lata Bond-Buckup & Buckup, 1994 is a critically endangered species, extinct in its type-locality. Its currently known geographical distribution is restricted to small streams of the lower Tibagi River Basin (Paraná state, southern Brazil), where it is vulnerable to the environmental degradation that takes place in these watersheds. Scientific...
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The family Aeglidae comprises three genera, one extant (Aegla) and two extinct genera (Protaegla and Haumuriaegla), the latter two genera are known only from fossils from marine sediments (indicating a marine origin for the group). Aegla contains all extant species and constitutes a monophyletic group within the Anomura. All 78 species and subspeci...
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We describe the reproductive cycle, population structure, growth and longevity of Aegla schmittiHobbs, 1978 from the Betari River, at the Alto Ribeira Tourist State Park (24°31′57″S, 48°42′09″W), on the southern portion of state of São Paulo. A total of 1528 specimens (1204 males and 324 females) were sampled from September 2010 to December 2011. C...
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Allometric growth of chelae dimensions was analyzed to assess the average size at the onset of morphometric maturity (ASOMM) and sexual dimorphism regarding the pair of chelae in the Aegla castro. Both adult males and females are heterochelous with the most robust chela occurring predominantly on the left side. Both chelae are larger in males than...
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We investigated the influence of environmental factors in spatial and temporal distribution of the seabob shrimp Xiphopenaeus kroyeri in Santos Bay and São Vicente Estuary, state of São Paulo, Brazil. Monthly samples were obtained, from May 2008 through April 2010, from four locations in the estuary and four in the bay. No individual was collected...
Article
The effect of some environmental factors on the distribution and abundance of different demographic categories of Xiphopenaeus kroyeri (Heller, 1862) was tested for three 12-month periods over 13 years in Ubatuba Bay, Sao Paulo State, southeastern Brazil. Four sites with different characteristics were sampled monthly from January to December 1998,...
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During a two-year field study (July 2008-June 2010), we observed a sharp decrease in the number of the freshwater decapods, Aegla perobae, sampled monthly at the type locality. A series of population size estimates by means of the Schumacher and Eschmeyer mark-recapture method confirmed the decreasing trend of population size. Density dropped rapid...
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We used the Schumacher-Eschmeyer method for closed populations to estimate and compare the population size of adults of Aegla paulensis, from Jaraguá State Park (São Paulo, Brazil), in two periods of the year with contrasting climatic conditions (late winter and late summer). The calculated density of adult individuals was considerably higher in th...
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We used the Schumacher-Eschmeyer method for closed populations to estimate and compare the population size of adults of Aegla paulensis, from Jaraguá State Park (São Paulo, Brazil), in two periods of the year with contrasting climatic conditions (late winter and late summer). The calculated density of adult individuals was considerably higher in th...
Article
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We used the Schumacher-Eschmeyer method for closed populations to estimate and compare the population size of adults of Aegla paulensis, from Jaraguá State Park (São Paulo, Brazil), in two periods of the year with contrasting climatic conditions (late winter and late summer). The calculated density of adult individuals was considerably higher in th...
Article
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The importance of decapod crustaceans has induced scientific studies in various fields of biology. Therefore, structure, reproductive biology and fecundity of a population of Potimirim brasiliana Villalobos, 1959 from Jureia-Itatins Ecological Station in Peruibe, State of Sao Paulo, were studied. Shrimps were captured at 4-month intervals from spri...
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We describe growth, longevity, sex ratio, reproductive period, and recruitment of Aegla paulensis from Jaraguá State Park, São Paulo, Brazil (23°27′27.9″S; 46°45′32.3″W). The population was sampled monthly (September 2007 through August 2009) with the aid of traps. Over five thousand individuals were captured, sexed, measured (carapace length  =  C...
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The distribution of benthic organisms is directly or indirectly associated with the physical and chemical properties of the water and sediment. This study analysed the spatial and temporal distribution of Rimapenaeus constrictus in unconsolidated sublittoral sediments of two areas off the northern coast of the state of Sao Paulo, Brazil. We also an...
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Females of Aegla strinatii (n  =  466) were sampled monthly (September 2003 to September 2005) by means of sieves and traps from Rio das Ostras (24°38′16.2″S; 48°24′05.2″W), at Jacupiranga State Park, South of São Paulo State, Brazil. The reproductive period was markedly seasonal (from May to September) encompassing the Austral late autumn through...
Article
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The study of the population structure of A. armillatus was based on monthly collections (March 2000–February 2002) from two tidal flats—São Francisco Beach (SF), São Sebastião County, and Engenho d'Água Beach (EA), Ilhabela County—located at the northern portion of the State of São Paulo coast and separated by the 6 km wide São Sebastião Channel. C...
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The Schumacher-Eschmeyer and the Schnabel estimators for closed population were employed to estimate the population size of Aegla franca from an isolated section (30 m long; area: 76.125 m2) of the Barro Preto stream (20°18′47″S; 47°16′37″W) in the summer and winter seasons of the year 2005. These methods involve mark-recapture technique with multi...
Article
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We describe the reproductive period, fecundity, and average size at the onset of functional maturity of female Aegla franca, the northernmost distributed aeglid species. The reproductive period is markedly seasonal and takes place from May (austral mid-autumn) to August (late winter). Ovigerous females appear quite abruptly in the population by May...

Citations

... No morphological divergence was observed in the relative growth of the greater chelipod in A. concepcionensis males. The absence of this dimorphic pattern in males has been described in some species of the same genus, suggesting a growth model with a unique ontogenetic trajectory directed directly towards reproductive functionality (Bueno & Shimizu, 2008Chaves et al., 2019;Marçal et al., 2018;Takano et al., 2016). ...
... Troglodyte aeglids such as A. leptochela Bond-Buckup & Buckup, 1994 are considered separately their densities are extremely low, with less than one individual m -2 (Maia et al., 2013). Differences in population densities could be attributed in part to the different sampling methods used in studies (Bueno et al., 2007;Dalosto et al., 2014;Masunari, 2020;Shimizu & Bueno, 2020). We used the same sampling method across the sampled sites, and we therefore consider that densities are an exclusive characteristic of each population and of their particular sites. ...
... In some caridean shrimps, different male morphotypes can be found (submissive and dominants). The most evident difference between these males is the weapon morphology (first or second pair of pereiopods), which is variable in size, ornaments, and color (Bueno et al., 2016;Karplus & Barki, 2019). The genus Macrobrachium Spence Bate, 1868, is the decapod group with the highest number of species with male morphotypes described so far, with a total of approximately 28 species, including formal descriptions and assumptions from observations of reproductive behavior or morphological variation (Rojas et al., 2012;Karplus & Barki, 2019;Nogueira et al., 2020;Rios et al., 2021;Vargas-Ceballos et al., 2021). ...
... Maturity is strongly related to size; and the ratio between SOM and the asymptotic size of a population tends to be con-stant, named the relative size at onset of morphological sexual maturity (RSOM) (Charnov, 1990). The proportional size at onset of morphological sexual maturity (PSOM) is an approximation of the RSOM by dividing the SOM by the maximum population size, following the method proposed by Takano et al. (2016). Therefore, we calculated the PSOM for each sampling area to evaluate whether the pattern remains between transects, even without the influence of the maximum size variation. ...
... Similar to the case of the studies on population dynamics and structure, investigations in the topic of animal growth, based in the von Bertalanffy (1938) models, have also received considerable attention in recent years, with highlights to the studies performed with Aegla platensis Schmitt, 1942, Aegla leptodactyla Buckup & Rossi, 1979(Noro & Buckup 2003, Aegla jarai Bond-Buckup & Buckup, 1994(Boos Jr et al. 2006, Aegla longirostri Bond-Buckup & Buckup, 1994, Aegla itacolomiensis Bond-Buckup & Buckup, 1994(Silva-Gonçalves et al. 2009), Aegla paulensis Schmitt, 1942(Cohen et al. 2011, Aegla manuinflata Bond-Buckup & Santos, 2009(Trevisan & Santos 2011 and Aegla schmitti (Chiquetto-Machado et al. 2016). ...
... Similarly, the same pattern was also found for the white shrimp (de Carvalho et al., 2021;Miazaki et al., 2018;Silva et al., 2019). Against the ''latitudinal paradigm'', which states that shrimps tend to grow faster, live less and attain smaller maximum sizes in lower latitudes mainly due to the warmer climates (Bauer, 1992), we must highlight the increasing body of evidence suggesting that the influence of environmental variability in a regional scale may strongly influence population parameters in penaeid shrimps (Heckler et al., 2014;Lopes et al., 2017;Pérez-Castañeda and Defeo, 2005;Zink et al., 2017), which considerably distorts the proposed relationship proposed by the paradigm and reinforces the increasing importance of considering environmental factors that are key to penaeid life cycle when analyzing population structures. In fact, Miazaki et al. (2021), which studied growth dynamics of the seabob shrimp in several regions of southeastern Brazil, instead of finding a consistent latitudinal gradient, observed that the population parameters are in accordance with the patterns of environmental variation. ...
... We also tested if the Poisson- Gamma Bayesian mathematical model is a promising estimator of population size in mark-recapture samples of closed populations. These tests were chosen due to their robustness and because other estimations of aeglids population size have been performed using the Schumacher-Eschmeyer and Schnabel estimators (Bueno et al., 2007;Cohen et al., 2013), which facilitate comparisons. The Bayesian model was chosen because it has mainly been applied to marine and terrestrial environments rather than freshwater environments and has never been used for estimating crustacean populations. ...
... The seasonality of the density of A. uruguayana matches observations in other species of Aegla such as A. abtao Schmitt, 1942from Chile (De los Ríos-Escalante et al., 2020 and A. paulensis Schmitt, 1942from Brazil (Cohen et al., 2013, where the minimum density was observed in winter. We did not find a general pattern for the maximum densities, although the spring maximum density of DC populations were described for A. platensis and A. manuinflata in Brazil (Bueno & Bond-Buckup, 2000;Trevisan & Santos, 2014); the highest summer density in the EE populations matched records for A. paulensis in Brazil (Cohen et al., 2013). ...
... The threat assessments for this group largely focus on localised threats such as water pollution and land-use change (Pérez-Losada et al., 2002;Magalhães et al., 2016;Santos et al., 2017). While not necessarily directly attributed to climate change, rainfall anomalies have been associated with shorter reproductive periods in aeglids, and flooding events are postulated to impede juvenile recruitment (Bueno & Shimizu 2008;Bueno et al., 2014). Increasing frequencies of extreme weather events in the Neotropical region can thus potentially increase the vulnerability of aeglids, most of which have highly restricted distributions (Bond-Buckup et al., 2008;Bueno & Shimizu 2008;Marengo et al., 2009). ...
... Although the presence of the same sediment type could create similar environment to Caravelas and Atafona, it is also important to consider that Atafona, which is still under the influence of South Atlantic Central Water (SACW), presents lower temperature and salinity than Caravelas (Bissaro et al.). Also, Atafona has reproductive peaks occurring in autumn and winter (Davanso et al., 2017), which would make more difficult the gene flow among this stock and others analyzed herein, like Ubatuba, Santos and Cananéia with spring and summer reproductive peaks, and Caravelas, with summer reproductive peak (Santos & Silva; Heckler et al., 2014;Davanso et al.). Balneário Camboriu (Santa Catarina) was found as one separate group. ...