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Morphological variation of freshwater crabs Zilchiopsiscollastinensis and Trichodactylusborellianus (Decapoda, Trichodactylidae) among localities from the middle Paraná River basin during different hydrological periods.

Torres MV, Collins PA, Giri F - Zookeys (2014)

Bottom Line: During falling water, the shapes of Zilchiopsiscollastinensis were not related to latitude-longitude gradient (i.e., showing greater overlap in shape), while during rising water the shapes were ordered along a distributional gradient according to geographical location.Contrary, shapes of Trichodactylusborellianus were related to latitude-longitude during falling water and were not related to distributional gradient during rising water.The cephalothorax shape showed, in general, no statistically significant covariations with environmental variables for either species.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto Nacional de Limnología (CONICET-UNL). Ciudad Universitaria Paraje El pozo s/n, Santa Fe, Argentina.

ABSTRACT
Measures of hydrologic connectivity have been used extensively to describe spatial connections in riverine landscapes. Hydrologic fluctuations constitute an important macrofactor that regulates other environmental variables and can explain the distribution and abundance of organisms. We analysed morphological variations among individuals of two freshwater crab species, Zilchiopsiscollastinensis and Trichodactylusborellianus, from localities of the middle Paraná River basin during two phases of the local hydrological regime. Specimens were sampled at sites (localities) of Paraná River, Saladillo Stream, Salado River and Coronda River when water levels were falling and rising. The conductivity, pH, temperature and geographical coordinates were recorded at each site. The dorsal cephalothorax of each crab was represented using 16 landmarks for Zilchiopsiscollastinensis and 14 landmarks for Trichodactylusborellianus. The Canonical Variate Analyses showed differences in shape (for both species) among the crabs collected from the Paraná and Salado Rivers during the two hydrologic phases. We did not find a general distribution pattern for shape among the crab localities. During falling water, the shapes of Zilchiopsiscollastinensis were not related to latitude-longitude gradient (i.e., showing greater overlap in shape), while during rising water the shapes were ordered along a distributional gradient according to geographical location. Contrary, shapes of Trichodactylusborellianus were related to latitude-longitude during falling water and were not related to distributional gradient during rising water. The cephalothorax shape showed, in general, no statistically significant covariations with environmental variables for either species. These results show that each freshwater crab species, from different localities of the middle Paraná River, remain connected; however, these connections change throughout the hydrologic regime of the floodplain system. This study was useful for delineating how the relation among shapes of crabs of localities varies during two phases of the hydrological regime and for estimating the connections and geographical patterns in the floodplain system.

No MeSH data available.


Related in: MedlinePlus

Graphics of Canonical Variate Analyses (CVA) of cephalothorax shapes of Trichodactylusborellianus between localities. Ellipses represent the confidence interval at 90%. Paraná River (PR1, PR2 PR3, PR4); Saladillo Stream (SS1, SS2); Salado River (SR2); Coronda River (CR). a falling water b rising water.
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Figure 5: Graphics of Canonical Variate Analyses (CVA) of cephalothorax shapes of Trichodactylusborellianus between localities. Ellipses represent the confidence interval at 90%. Paraná River (PR1, PR2 PR3, PR4); Saladillo Stream (SS1, SS2); Salado River (SR2); Coronda River (CR). a falling water b rising water.

Mentions: Differences in shape variation were observed among the crabs of the Paraná and Salado Rivers during the two phases of the hydrologic regime (Figs 4 and 5) (Procrustes pairwise permutation tests with CVA). For Zilchiopsiscollastinensis, individuals of localities in the Paraná River were similar in shape when water levels were falling. Additionally, individuals collected from PR1 had shapes similar to those collected in SR2 (Salado River site) (Fig. 4a) (Table 3) and in CR (Fig. 4a) (Table 3). When water levels were rising, individuals collected from localities in the Paraná River were similar in shape (Fig. 4b) (Table 3). No differences in shape were observed among individuals in localities in both rivers compared to those in CR (Fig. 4b) (Table 3). Individuals collected from both rivers were more similar in shape when water levels were falling than when water levels were rising (Fig. 4a and b). When water levels were rising, crabs collected from localities in the Paraná River had overlapping shapes but these shapes were different from those of crabs collected from the Salado River site (Fig. 4b).


Morphological variation of freshwater crabs Zilchiopsiscollastinensis and Trichodactylusborellianus (Decapoda, Trichodactylidae) among localities from the middle Paraná River basin during different hydrological periods.

Torres MV, Collins PA, Giri F - Zookeys (2014)

Graphics of Canonical Variate Analyses (CVA) of cephalothorax shapes of Trichodactylusborellianus between localities. Ellipses represent the confidence interval at 90%. Paraná River (PR1, PR2 PR3, PR4); Saladillo Stream (SS1, SS2); Salado River (SR2); Coronda River (CR). a falling water b rising water.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4283370&req=5

Figure 5: Graphics of Canonical Variate Analyses (CVA) of cephalothorax shapes of Trichodactylusborellianus between localities. Ellipses represent the confidence interval at 90%. Paraná River (PR1, PR2 PR3, PR4); Saladillo Stream (SS1, SS2); Salado River (SR2); Coronda River (CR). a falling water b rising water.
Mentions: Differences in shape variation were observed among the crabs of the Paraná and Salado Rivers during the two phases of the hydrologic regime (Figs 4 and 5) (Procrustes pairwise permutation tests with CVA). For Zilchiopsiscollastinensis, individuals of localities in the Paraná River were similar in shape when water levels were falling. Additionally, individuals collected from PR1 had shapes similar to those collected in SR2 (Salado River site) (Fig. 4a) (Table 3) and in CR (Fig. 4a) (Table 3). When water levels were rising, individuals collected from localities in the Paraná River were similar in shape (Fig. 4b) (Table 3). No differences in shape were observed among individuals in localities in both rivers compared to those in CR (Fig. 4b) (Table 3). Individuals collected from both rivers were more similar in shape when water levels were falling than when water levels were rising (Fig. 4a and b). When water levels were rising, crabs collected from localities in the Paraná River had overlapping shapes but these shapes were different from those of crabs collected from the Salado River site (Fig. 4b).

Bottom Line: During falling water, the shapes of Zilchiopsiscollastinensis were not related to latitude-longitude gradient (i.e., showing greater overlap in shape), while during rising water the shapes were ordered along a distributional gradient according to geographical location.Contrary, shapes of Trichodactylusborellianus were related to latitude-longitude during falling water and were not related to distributional gradient during rising water.The cephalothorax shape showed, in general, no statistically significant covariations with environmental variables for either species.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto Nacional de Limnología (CONICET-UNL). Ciudad Universitaria Paraje El pozo s/n, Santa Fe, Argentina.

ABSTRACT
Measures of hydrologic connectivity have been used extensively to describe spatial connections in riverine landscapes. Hydrologic fluctuations constitute an important macrofactor that regulates other environmental variables and can explain the distribution and abundance of organisms. We analysed morphological variations among individuals of two freshwater crab species, Zilchiopsiscollastinensis and Trichodactylusborellianus, from localities of the middle Paraná River basin during two phases of the local hydrological regime. Specimens were sampled at sites (localities) of Paraná River, Saladillo Stream, Salado River and Coronda River when water levels were falling and rising. The conductivity, pH, temperature and geographical coordinates were recorded at each site. The dorsal cephalothorax of each crab was represented using 16 landmarks for Zilchiopsiscollastinensis and 14 landmarks for Trichodactylusborellianus. The Canonical Variate Analyses showed differences in shape (for both species) among the crabs collected from the Paraná and Salado Rivers during the two hydrologic phases. We did not find a general distribution pattern for shape among the crab localities. During falling water, the shapes of Zilchiopsiscollastinensis were not related to latitude-longitude gradient (i.e., showing greater overlap in shape), while during rising water the shapes were ordered along a distributional gradient according to geographical location. Contrary, shapes of Trichodactylusborellianus were related to latitude-longitude during falling water and were not related to distributional gradient during rising water. The cephalothorax shape showed, in general, no statistically significant covariations with environmental variables for either species. These results show that each freshwater crab species, from different localities of the middle Paraná River, remain connected; however, these connections change throughout the hydrologic regime of the floodplain system. This study was useful for delineating how the relation among shapes of crabs of localities varies during two phases of the hydrological regime and for estimating the connections and geographical patterns in the floodplain system.

No MeSH data available.


Related in: MedlinePlus