Morphological Variations in Astacus Astacus L. And Austropotamobius Pallipes (Lereboullet) Populations

Abstract

Genetic studies on crayfish have shown that the differences between crayfish populations can be greater than it is assumed at the first view. Studies have demonstrated that some of these differences are not only found in the genome but are also expressed in the morphology of crayfish. Statistical analysis of a large set of morphological parameters from several autochthonous crayfish populations of Astacus astacus (Linnaeus, 1758) and Austropotamobius pallipes (Lereboullet, 1858) were applied in order to define distinct characteristics of different populations. Preliminary results of a multivariate discriminant analysis suggest that some morphological parameters are useful attributes to identify distinct populations. A positive correlation was obtained between carapace shape, described as the ratio postorbital length/width of carapace, and carapace curvature. Our results showed that the development and application of methods to characterize the uniqueness of individual populations is important, especially when they may have adapted in various ways to specific environmental conditions due to separation for a long time. Key-words:Crayfish, endangered species, morphometry, environmental adaptation. VARIATIONS MORPHOLOGIQUES DES POPULATIONS D'ASTACUS ASTACUS L. ET D'AUSTROPOTAMOBIUS PALLIPES (LEREBOULLET) RÉSUMÉDes études génétiques sur des écrevisses ont démontré que les différences entre les populations d'écrevisses peuvent être plus importantes qu'on ne pouvait le supposer a priori. Des études ont démontré que certaines différences ne sont pas uniquement génétiques mais aussi morphologiques. Des analyses statistiques sur un grand nombre de paramètres morphologiques sur plusieurs populations d'Astacus astacus (Linnaeus, 1758) et d'Austropotamobius pallipes (Lereboullet, 1858) ont été menées pour définir des caractères distinctifs des différentes populations. Les résultats préliminaires d'une analyse multivariée discriminante suggèrent que quelques caractéristiques morphologiques sont utiles pour identifier des populations distinctes. Si la forme de la carapace, ici décrite par le coefficient de la longueur post orbitale/largeur de la carapace, et la courbure de la carapace sont utilisés, une corrélation positive entre ces deux paramètres est obtenue.

The Genus Austropotamobius in the Ausserfern Region (Tyrol, Austria) With an Overlap in the Distribution of A. Torrentium and A. Pallipes Populations

“…It is well known that differences in crayfish morphology may occur not only on the level of species but also between distinct populations, caused by adaptations to local environmental conditions (GRANDJEAN and SOUTY-GROSSET, 2000;SINT, DALLA VIA and FÜREDER, 2005).…”

“…The size normalization procedure and selection of the relevant morphological characters was done as described in SINT, DALLA VIA and FÜREDER (2005). In addition, several ratios (e.g.…”

Morphometry of the stone crayfish (Austropotamobius torrentium) in the Czech Republic: allometry and sexual dimorphism

“…This traditional morphometric attempt have used e.g. by Grandjean et al (1997), Sint et al (2005) or Zekić et al (2013) in A. pallipes or by Pârvulescu (2010), Sint et al (2005) and partially by Maguire and Klobučar (2009) in A. torrentium. Other studies have focused on finding a geographical gradient in morphology or differences among separated populations.…”

“…Other studies have focused on finding a geographical gradient in morphology or differences among separated populations. Whereas Grandjean and Souty-Grosset (2000) assumed traditional biometrics as useless for that purposes, Sint et al (2005) have been able to find some geographical gradient in morphology of A. pallipes using linear measurements of the carapace. Scalici et al (2010) underlined major ontogenetic changes in the carapace shape and marked them as well as sexual dimorphism as confound elements affecting interpretation of such a comparative studies.…”

“…However, most of the above mentioned studies are focused on A. pallipes and only few biometric analyses concerning A. torrentium have been performed up to now (e.g. Streissl and Hödl, 2002;Maguire et al, 2005;Sint et al, 2005;Maguire and Klobučar, 2009;Pârvulescu, 2010). Consequently, the aim of this study is to supply missing data about the morphology of the stone crayfish, including on the sexual dimorphism, and the evaluation of allometric growth of selected size parameters.…”