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Ivana Maguire - One of the best experts on this subject based on the ideXlab platform.
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Conservation strategy for the endangered crayfish species of the family Astacidae: the ESHIPPO crayfish model
Hydrobiologia, 2015Co-Authors: Vladica Simić, Milka Rajković, Ivana Maguire, Ana PetrovićAbstract:A conservation strategy for crayfish from the Astacidae family was developed for the populations inhabiting the aquatic ecosystems of the Central Balkans (territories of Serbia and Montenegro). The strategy, based upon the ESHIPPO crayfish model, uses the Ecological Specialization of taxa, the factors endangering the biodiversity (HIPPO: Habitat alteration, Invasive species, Pollution, Population growth, Overexploitation) and the Index of the Local Adaptive Population of Crayfish (ILAP) (genetic, morphological and structural characteristics of the local population). The crayfish populations with the highest values in model have the highest conservation priority and represent primary Elemental Conservation Units (ECUp). The results indicate that genetic factors play an important role in the final assessment of the value of conservation priorities in 25% of cases. The results obtained by the model indicate that in the area of the Central Balkans, the populations of Astacus astacus and Austropotamobius italicus meridionalis have a greater risk of extinction and a higher conservation priority than Austropotamobius torrentium . The new structure of the model enables a more precise estimation of the local extinction risk, and it provides the choice of the most rational conservation measures, therefore, having both ecological and economic importance on national and/or regional level.
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Morphological and genetic features of crayfish (Astacidae)in Croatia
2010Co-Authors: Nina Marn, Goran Klobučar, Ivana MaguireAbstract:Species of freshwater crayfish of the familiy Astacidae are divided in three genera and are indigeniuos to Europe (genera Astacus and Austropotamobius) and western North America (genus Pacifastacus). There are four native Croatian crayfish species of the family Astacidae. Phylogenetic relationships among different populations of some of these species are not yet completely resolved. In this research morphological characteristics and phylogenetic relationships of 61 individuals were studied. The crayfish were collected from nine sites situated in Žumberak - Samoborsko gorje Nature Park. Mitochondrial genes were used for molecular phylogenetic analyses and in morphological aspect of research we measured morphometrical and meristic characteristics, which were then grouped in accordance with the results of previous genetic analyses and processed with statistical methods. Obtained results show a large genetic diversity of studied populations and statistical analyses of morphological data show significant differences for geographically separated populations. Such high genetic diversity and morphological variation present an unique phenomenum on the European scale and will probably demand special care and protection in the near future.
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the distribution of freshwater crayfish of the Astacidae family in the banovina region
2010Co-Authors: Ivana Maguire, Misel JelicAbstract:Dosad na podrucju Banovine nisu nikada provođena sustavna istraživanja rasprostranjenosti rakova iz porodice Astacidae pa su u ovome radu prikazani preliminarni rezultati zabilježni tijekom istraživanja u okviru Nature 2000 kao prilog poznavanju astako-faune na tom podrucju. Tijekom istraživanja 2008. i 2009. godine utvrđena je prisutnost dvije vrste - potocnog raka (Austropotamobius torrentium) i uskoskarog raka (Astacus leptodactylus).
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Karyological analysis of three Astacidae species : a preliminary report
2008Co-Authors: Mirjana Pavlica, Ivana Maguire, Jelena Mlinarec, Margerita Mužić, Maja Šrut, Goran KlobučarAbstract:This is a preliminary report on the karyotype analysis of three freshwater crayfish species (Astacus astacus, A. leptodactylus and Austropotamobius torrentium) belonging to family Astacidae, all native to Croatian freshwater habitats. Chromosome number and heterochromatin distribution was studied on metaphase spreads of mitotic and meiotic cells of testis tissue. Chromosomes were stained with 4, 6-diamino-2-phenylindole stain (DAPI) specific for AT rich regions. Preliminary results showed that the chromosome number ranged from 2n=164 for Austropotamobius torrentium, 2n= 176 for Astacus astacus to 2n=180 for Astacus leptodactylus. In karyotype of each species AT rich heterochromatin blocks were observed in centromere region of all chromosomes. Terminal heterochromatin was not observed. Intercalary heterochromatin blocks were also observed on longer chromosome arm of some chromosomes in all three karyotypes (but only the largest ones).
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Seasonal changes of the hepatosomatic indices in the noble crayfish (Astacus astacus) and the stone crayfish (Austropotamobius torrentium)
2004Co-Authors: Andreja Lucić, Ivana Maguire, Radovan ErbenAbstract:A comparative study was conducted on two autochthon species of Astacidae in Croatia, the noble crayfish, Astacus astacus (Linne, 1758) and the stone crayfish, Austropotamobius torrentium (Schrank, 1803). Hepatosomatic indices (wet and dry hepatosomatic index) and hepatopancreas moisture content (HM) are considered useful to describe the physiological condition of wild crayfish populations. Noble crayfish were trapped from the Vukovina gravel pit and the stone crayfish from the Kraljevec Stream. Each month five to ten animals were sacrificed and dissected. Hepatopancreases were weighed, dryed for 24 hours on 80oC and weighed again. Seasonal changes of the hepatosomatic indices and HM in two populations were observed.Hepatopancreas mean weight varied from 2% of wet body weight after winter starvation period to 6% during spring and summer period. HM was higher during autumn and winter periode (70-80%) and lower during spring and summer periode (50-60%). Wet hepatosomatic indeks (Hiwet) was between 4, 0 and 6, 5% and changed from month to month, while dry hepatosomatic indeks (Hidry) varied between 0, 6 and 2, 8%. All investigated parameters indicated nutritional status of the animals and differences between two species were evident.
Hamid Niksirat - One of the best experts on this subject based on the ideXlab platform.
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fine structure of the spermatozoon in three species of cambaridae arthropoda crustacea decapoda cambarus robustus orconectes propinquus and orconectes rusticus a comparative biometrical study
PeerJ, 2016Co-Authors: B Yazicioglu, Přemek Hamr, Pavel Kozak, Antonin Kouba, Hamid NiksiratAbstract:: The ultrastructure of spermatozoa in three species of cambarid crayfish, Cambarus robustus, Orconectes propinquus, and Orconectes rusticus, were studied and compared with eight previously studied species from different crayfish families using morphological features and biometrical data. The ultrastructure of spermatozoa show a generally conserved pattern including an acrosome and nucleus in the anterior and posterior parts of the cell, respectively, radial arms that wrap around the nucleus, and the whole cell is enclosed by an extracellular capsule. The most outstanding morphological feature in spermatozoa of three studied cambarid crayfish is the crest-like protrusions in the anterior part of the acrosome that can be used as one of the features for distinguishing the members of this family. Results of biometrical data reveal that acrosome size in the representatives of ParAstacidae are the smallest, while representatives of Astacidae show the biggest acrosome. The acrosome size in species belonging to Cambaridae occupy an intermediate position between the two other families of freshwater crayfish. In conclusion, a combination of morphological features and biometrical data of spermatozoa can help distinguishing different species of the freshwater crayfish.
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comparative ultrastructure of spermatozoa of the redclaw cherax quadricarinatus and the yabby cherax destructor decapoda parAstacidae
Micron, 2015Co-Authors: Antonin Kouba, Hamid Niksirat, Martin BláhaAbstract:Abstract Ultrastructure of spermatozoa of redclaw Cherax quadricarinatus and yabby Cherax destructor were described and compared. The acrosome complex and nucleus are located at the anterior and posterior region of the spermatozoon, respectively. The acrosome is a complex vesicle divided into two parts: the main body of the acrosome appears as a dense cup-shaped structure in longitudinal sagittal view, with the subacrosome zone occupying the central area of the vesicle. The acrosome is larger in C. quadricarinatus (width 2.37 ± 0.27 μm, length 1.31 ± 0.23 μm) than in C. destructor (width 1.80 ± 0.27 μm, length 1.01 ± 0.15 μm). There was no significant difference in L:W ratios of the studied species. The subacrosome zone in both species consists of two areas of different electron density. The nucleus is substantially decondensed and irregular in shape, with elaborate extended processes. The examined species exhibited a well-conserved structure of crayfish spermatozoon, similar to those of Cherax cainii and Cherax albidus. Small acrosome size, the absence of radial arms, and an extracellular capsule seem to be the morphological features that mostly distinguish Cherax from the Astacidae and Cambaridae.
Antonin Kouba - One of the best experts on this subject based on the ideXlab platform.
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fine structure of the spermatozoon in three species of cambaridae arthropoda crustacea decapoda cambarus robustus orconectes propinquus and orconectes rusticus a comparative biometrical study
PeerJ, 2016Co-Authors: B Yazicioglu, Přemek Hamr, Pavel Kozak, Antonin Kouba, Hamid NiksiratAbstract:: The ultrastructure of spermatozoa in three species of cambarid crayfish, Cambarus robustus, Orconectes propinquus, and Orconectes rusticus, were studied and compared with eight previously studied species from different crayfish families using morphological features and biometrical data. The ultrastructure of spermatozoa show a generally conserved pattern including an acrosome and nucleus in the anterior and posterior parts of the cell, respectively, radial arms that wrap around the nucleus, and the whole cell is enclosed by an extracellular capsule. The most outstanding morphological feature in spermatozoa of three studied cambarid crayfish is the crest-like protrusions in the anterior part of the acrosome that can be used as one of the features for distinguishing the members of this family. Results of biometrical data reveal that acrosome size in the representatives of ParAstacidae are the smallest, while representatives of Astacidae show the biggest acrosome. The acrosome size in species belonging to Cambaridae occupy an intermediate position between the two other families of freshwater crayfish. In conclusion, a combination of morphological features and biometrical data of spermatozoa can help distinguishing different species of the freshwater crayfish.
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comparative ultrastructure of spermatozoa of the redclaw cherax quadricarinatus and the yabby cherax destructor decapoda parAstacidae
Micron, 2015Co-Authors: Antonin Kouba, Hamid Niksirat, Martin BláhaAbstract:Abstract Ultrastructure of spermatozoa of redclaw Cherax quadricarinatus and yabby Cherax destructor were described and compared. The acrosome complex and nucleus are located at the anterior and posterior region of the spermatozoon, respectively. The acrosome is a complex vesicle divided into two parts: the main body of the acrosome appears as a dense cup-shaped structure in longitudinal sagittal view, with the subacrosome zone occupying the central area of the vesicle. The acrosome is larger in C. quadricarinatus (width 2.37 ± 0.27 μm, length 1.31 ± 0.23 μm) than in C. destructor (width 1.80 ± 0.27 μm, length 1.01 ± 0.15 μm). There was no significant difference in L:W ratios of the studied species. The subacrosome zone in both species consists of two areas of different electron density. The nucleus is substantially decondensed and irregular in shape, with elaborate extended processes. The examined species exhibited a well-conserved structure of crayfish spermatozoon, similar to those of Cherax cainii and Cherax albidus. Small acrosome size, the absence of radial arms, and an extracellular capsule seem to be the morphological features that mostly distinguish Cherax from the Astacidae and Cambaridae.
Radovan Erben - One of the best experts on this subject based on the ideXlab platform.
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Seasonal Changes of Hepatosomatic Indices and Moisture Content in the Noble Crayfish (Astacus astacus) and the Stone Crayfish (Austropotamobius torrentium)
2006Co-Authors: Andreja Lucić, Radovan ErbenAbstract:A comparative study was conducted on two autochthonous species of Astacidae in Croatia, the noble crayfish, Astacus astacus (Linne, 1758) and the stone crayfish, Austropotamobius torrentium (Schrank, 1803). Hepatosomatic indices (wet and dry hepatosomatic index) and hepatopancreas moisture content (HM) were measured and used to describe the physiological condition of crayfish populations during an annual cycle. Noble crayfish were trapped from the Vukovina gravel pit and the stone crayfish from the Kraljevec Stream. Each month five to six animals were sacrificed and dissected. Hepatopancreata were weighed, dryed for 24 hours on 80oC and weighed again. Approximately half of the each hepatopancreas was prepared for histological analysis. Seasonal changes of the hepatosomatic indices and moisture content in two populations were measured. Hepatopancreas moisture content was higher during reproductive period then during moulting period. Proportion of hepatopancreas in body weight (Hiwet) was not statistically different between males and females of both species. Changes in proportion of R-, B- and F-cells in tubule epithelium of hepatopacreas during a year cycle were observed. Analysis of variance showed no statistically significant differences in hepatosomatic indices and moisture content of two investigated species.
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Seasonal changes of the hepatosomatic indices in the noble crayfish (Astacus astacus) and the stone crayfish (Austropotamobius torrentium)
2004Co-Authors: Andreja Lucić, Ivana Maguire, Radovan ErbenAbstract:A comparative study was conducted on two autochthon species of Astacidae in Croatia, the noble crayfish, Astacus astacus (Linne, 1758) and the stone crayfish, Austropotamobius torrentium (Schrank, 1803). Hepatosomatic indices (wet and dry hepatosomatic index) and hepatopancreas moisture content (HM) are considered useful to describe the physiological condition of wild crayfish populations. Noble crayfish were trapped from the Vukovina gravel pit and the stone crayfish from the Kraljevec Stream. Each month five to ten animals were sacrificed and dissected. Hepatopancreases were weighed, dryed for 24 hours on 80oC and weighed again. Seasonal changes of the hepatosomatic indices and HM in two populations were observed.Hepatopancreas mean weight varied from 2% of wet body weight after winter starvation period to 6% during spring and summer period. HM was higher during autumn and winter periode (70-80%) and lower during spring and summer periode (50-60%). Wet hepatosomatic indeks (Hiwet) was between 4, 0 and 6, 5% and changed from month to month, while dry hepatosomatic indeks (Hidry) varied between 0, 6 and 2, 8%. All investigated parameters indicated nutritional status of the animals and differences between two species were evident.
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The present status of freshwater crayfish in Croatia: distribution and legislation
2002Co-Authors: Ivana Maguire, Goran Klobučar, Radovan ErbenAbstract:Little is known about biology and distribution of freshwater crayfish in Croatia as they have been sporadicaly studied. Data on the distribution we collected were compiled with historical data, gathered from literature and different crayfish collections. During our research we found no evidence of non-native crayfish species in Croatian waters, and four out of five native european species from family Astacidae are defined - Astacus leptodactylus, Astacus astacus, Austropotamobius pallipes, Austropotamobius torrentium. In Croatia A. astacus, A. pallipes, A. torrentium are protected by Law of Nature Conservation - Rule Book on Protection of Crayfish (Crustacea, Astacidae). Generally, A. leptodactylus and A. astacus are distributed in the continental region, but the populations of latter are found in some rivers on Adriatic coast. A. pallipes is distributed in rivers belonging to Adriatic (Mediterranean) drainage system, while A. torrentium could be found in streams and rivers of continental and mountain region. Some of our findings are not in accordance with existing literature data so further research distribution is needed.
W. J. Thomas - One of the best experts on this subject based on the ideXlab platform.
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The setae of Austropotamobius pallipes (Crustacea: Astacidae)
Journal of Zoology, 2009Co-Authors: W. J. ThomasAbstract:The author presents here the results of an introductory study into the setal armature of the British species of crayfish, Austropotamobius pallipes (Lereboullet, 1858). Using an ordinary optical microscope, it is demonstrated that a considerable variety of setae exist on the body and appendages of A. pallipes. These setae are described, and their distribution indicated. The setae fall into two main groups: (1) Setae with relatively thick walls and inconspicuous ampulla, and having no basal septum. (2) Those setae with relatively thin walls, a well-developed ampulla and basal septum. Further subdivisions of these two groups are made on the bases of outgrowths and outlines of the setal wall. Finally, the significance of the distribution and the variation, is discussed in relation to crayfish behaviour and function, linking the observed morphological facts with the results of some current electro-physiological experiments performed on related decapods.
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Aspects of Egg Attachment in Austropotamobius Pallipes (Lereboullet, 1858) (Decapoda, Astacidae)
Crustaceana, 1991Co-Authors: W. J. ThomasAbstract:[Die Eier von A. pallipes sind am Weibchen durch einen spiraligen Funikulus befestigt, der bei der Eiablage gebildet wird. Bei seiner Enstchung kommt es zu einer Fusion der weichen Ausenschicht eines frish abgelegten Eies mit einer Gruppe von Borsten (Ooseten), die sich auf den Pleopoden und Sterna des Hinterleibs befinden. Seine endgultige Form erhalt der Funikulus in einer spaten Phase des Eiablagegeschehens., Die Eier von A. pallipes sind am Weibchen durch einen spiraligen Funikulus befestigt, der bei der Eiablage gebildet wird. Bei seiner Enstchung kommt es zu einer Fusion der weichen Ausenschicht eines frish abgelegten Eies mit einer Gruppe von Borsten (Ooseten), die sich auf den Pleopoden und Sterna des Hinterleibs befinden. Seine endgultige Form erhalt der Funikulus in einer spaten Phase des Eiablagegeschehens.]
