Morphological variation among populations of Aphanius fasciatus Nardo, 1827 (Teleostei, Cyprinodontidae) from the Mediterranean

Abstract

The amount of osteological variation among 11 Italian killifish Aphanius fasciatus populations was examined by the univariate and multivariate analysis of 40 morphometric and meristic variables of the skull and vertebral column. Populations were sampled in three geographically distinct areas (the Adriatic, Sardinia and Sicily). The statistical analysis confirmed that several populations were well differentiated. In particular, discriminant analysis revealed a strong discriminating power of the morphometric variables. Morphometrics of the vertebrae, bony elements of the pharyngeal jaws, supraoccipital and parasphenoid were the most important in discriminating populations. The dendrogram obtained by UPGMA cluster analysis shows the separation of the south‐eastern Sicilian populations, that of the Sardinian populations and that of the central‐northern Sicilian plus Adriatic populations, as well as the isolation of the Sicilian population from Pantano Viruca and of the Sardinian populations from Pauli Figu from all the others. The significance of the observed differentiation pattern is discussed.

Genetic divergence among and within four Italian populations ofAphanius fasciatus(Teleostei, Cyprinodontiformes)

“…In other cases (Cimmaruta et al 2003), this divergence does not seem related to geographic distance, as is shown by the morphological data (Tigano et al 2001;Ferrito et al 2003). Recently, analysis of the highly variable D-loop tract of the mitochondrial DNA (Tigano et al 2004a;Ferrito et al 2007) has indicated substantial genetic divergence among populations of this species. Mitochondrial control regions have been regarded as a molecular marker of choice for studying rapidly evolving populations, because they accumulate mutations up to ten times faster than the rest of the mitochondrial genome (Sturmbauer & Meyer 1992;Meyer 1993).…”

“…Those results revealed a morphological and molecular differentiation between these populations, with genetic distance values similar to those obtained in the present study. Research conducted on a morphological basis (Tigano et al 2001;Ferrito et al 2003Ferrito et al , 2007 into the same populations as those investigated in the present study corroborates the molecular data obtained here, thus confirming the good overall agreement between morphological and molecular studies (Stepien & Kocher 1997). A low molecular differentiation was found in populations that are geographically remote from one another, such as the Maltese and Tunisian ones (the rate of divergence ranges from 0.2% to 1.3%) or those of western Sicily and Malta (0.0%-0.5%) (Tigano et al 2006).…”

“…The aim of the present study is to use analyses of the mitochondrial DNA sequence and of the polymorphisms generated by RAPD-PCR to evaluate the level of genetic divergence present in four different Italian populations of A. fasciatus; the work is part of the ongoing studies to analyse the structuring of this species using various investigative approaches: osteology, allozymes, and DNA (Ferrito et al 2000(Ferrito et al , 2003(Ferrito et al , 2007Tigano et al 2001Tigano et al , 2006. The geographic distribution of these populations is related to their natural history in order to understand the geographic patterns that may result from divergence.…”

Morphological differentiation among species of the genus Mugil Linnaeus, 1758 (Mugilidae) from Côte d’Ivoire

“…In similar studies, the strong discriminating power of morphometric variables has been recognized (Waldman et al, 1997;Murta, 2000;Garcia-Davila et al, 2005;Ferrito et al, 2007;Anastasiadou and Leonardos, 2008;Anastasiadou et al, 2009). This has shown that the morphometric characters used in this study have an application in taxonomy and may be used as indices to measure morphometric variation among Mugil groups.…”

“…For DFA, significant traits for group assignment were accessed through a stepwise inclusion procedure to reduce the number of variables (Jain et al, 2000;Poulet et al, 2004Poulet et al, , 2005 and identify the combinations of variables that best separate the groups (Hair et al, 1996). The Mahalanobis distances matrix was used to evaluate population relationships, as implemented by Slabova and Frynta (2007) and Ferrito et al (2007). Descriptive statistics (standard error, standard deviation, maximum, and minimum) of all measurements were recorded for each species.…”