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The manipulation of river ecosystems through dam construction or other changes transforms their natural state into a reservoir and causes aquatic animals to face new ecological and evolutionary challenges. This study was conducted to survey the impacts of Tarik dam on the body shape of two isolated populations of riffle minnows using the geometric morphometric method. Thirty specimens were captured from each side of Tarik dam. The left side of each specimen was photographed using a digital camera, and eighteen landmark points were digitized on two-dimensional images using TpsDig2. After GPA, landmark data were analyzed using DFA and TtestHotelling and the patterns of body shape differences between two populations were illustrated on a wireframegraph. The Results revealed significant differences between the body shape of the two studied populations (P<0.0001).Body shape differences between the two populations were related to head, snout, anal fin and caudal peduncle regions. These findings suggest that the characteristics of a new reservoir along with geographical separation act as evolutionary factors bringing about change to the morphological attributes of the fish inhabiting these areas

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The phenotype of an organism not only reflects its genome, but also it can display its habitat and life style features. Hence, this study was aimed to apply the landmark-based geometric morphometric method in the study of the phenotypic plasticity of killifish (A. sophiae) from Cheshme-Ali Damghan and Shour river of Eshtehard. A total of 86 specimens were sampled from Cheshme-Ali (52 specimens) and Shour river (34 specimens). The left side of each specimen was photographed using a digital camera and fifteen landmark points were digitized on 2D images using TpsDig2. The landmark data of the two sexes of both populations were analyzed separately using DFA and T-test Hotelling after GPA superimposition. The patterns of body shape differences between the two sexes of both populations were illustrated. The results revealed significant differences between the body shape of two sexes in both populations (P<0.001). The morphological difference patterns between the two sexes were found in the depth of the body and caudal peduncle and the position of the pectoral fin. The findings of this study suggest that different characteristics of the habitats have driven changes in the morphological attributes of the inhabitant killifish populations along with geographical separation as evolutionary factors.

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This study was conducted to investigate the interspecies morphological variation of Sabzug (Cyprinion watsoni) in response to environmental factors using geometric morphometrics method in Southern and Southeastern Iran. Hence, nine populations including 270 specimens of Sabzug were collected from four Southern and Southeastern basins of Iran during summer 2012 using electrofishing. The specimens were anesthetized in clove solution 1gl-1, fixed into 4% formalin and then transported to the laboratory for further examinations. The left view of specimens was photographed and fifteen landmark-points were defined and digitized on 2D images using tpsDig2 software. The shape data were analyzed based on Principal Component Analysis (PCA), Canonical Variate Analysis (CVA) and Cluster Analysis (CA). The results revealed a significant difference between populations in terms of body shape (P<0.01). Also, the Bastak population was considerably separated from all other populations. The results can be summarized as: the Sarze, Ilood, Jegin and Sarbaz populations had more body height, in Ilood, Kash, Mashkil, HalilRood and Jegin the head was longer and in Ilood, HalilRood and Jegin the head height were more than other populations. The Bastak population was differentiated due to possessing the least body height, longer head, more up-warded mouth and less caudal peduncle length than others. These results revealed some morphological responses of Sabzug to environmental selective pressures, which can be used in taxonomic and systematic study of the genus Cyprinion.

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To evaluate the feasibility of using the shape of neurocranium in identifying the species of the genus Cyprinion by geometric morphometric technique, 30 specimens of five Iranian species were caught. For this purpose, 17 homologues landmark points were defined and digitized on 2D pictures taken from the dorsal view of their neurocranium. The data (coordinates of the landmarks) were analyzed according to Principal Component Analysis (PCA), Canonical Variate Analysis (CVA) and Cluster Analysis (CA) using MorphoJ and PAST soft wares. The statistical analyses could discriminate five species according to the shape of neurocranium. The key characters that can be used to describe species are the following: C. kais bears the least cranial width at lateral ethmoid region, the least narrowing at mediolateral neurocranium and the least distance between anterior to posterior connection point of palatines. C. macrostomum possesses the least supraethmoid width and there is a notch in its anterior most border and also has the most distance between the anterior to posterior connection points of the palatines. C. milesi has the narrowest and more elongated neurocranium among Iranian Cyprinion genera, and has the narrowest neurocranium in the mediolateral of the neurocranium. In C. tenuiradius, the neurocranium is wide at pterotic region, decreases in mediolateral regions and then increases at lateral ethmoid region. Finally C. watsoni has the widest and shortest supraethmoid among Iranian Cyprinion fishes.

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The present study was performed to aim the comparison of the body shape of large scale tongue sole (C. arel) fish from coastal waters of north Persian Gulf. To fulfill this purpose, a total of 120 fish individuals captured by bottom trawlers from the four stations of Kangan, Bushehr, Daylam, and Abadan were used. In order to study traditional morphometrics, 13 morphometric traits (measurable) and 6 meristic traits (countable) were selected and examined. Results of morphometric and meristic comparison showed a significant overlap among studied populations. Based on these results, the total length of fish was measured from 206.51 to 265.04 mm, 110-130 soft rays from the dorsal fin, 10-16 soft rays from the caudal fin and 82-98 soft rays from anal fin were counted. The mean number of scales between two lateral lines was 7.72. Comparison of means resulted from traditional morphometric study revealed no significant differentiation between different stations. The results of geometric morphometrics revealed significant differences between the studied stations in that the highest difference was belonged to specimens from Abadan and Kangan, whereas the lowest difference was observed in the specimens from Bushehr and Daylam samples. Based on the results of the present study, it can be concluded that geometric morphometric method possesses higher potential to discriminate populations of the studied species compared to the traditional method. 

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The aim of this study was to evaluate the efficiency of geometric morphometrics for describing the body shape of fish larvae, and identifying them to speciess. Species of sillaginid fishes (Perciformes: Sillaginidae) were chosen as the model group, as the larval stages in this family are particularly difficult to identify. 47 individuals collected from the central creeks of Bushehr province between June 2013 and April 2014 using bongo net. The individuals were first divided to three developmental stages, preflexion, flexion and postflexion. Then flexion and postflexion larvae were divided into three groups, depending on 34, probably 34 and 38 myomers. The larvae with 34 myomeres were identified as Sillago sihama. After counting myomers, 8 landmarks were digitized on pictures taken from left side of specimens. Data were analyzed using PCA and DFA after procrustes superimposition and data standardization. There are some meaningful shape differences between three groups (P<0.001), especially between 34 myomers group and other two groups. The preanal length in 34 myomers group was shorter than that of 38 and probably 34 myomers groups. The body height in 38 myomers group was higher than probably 34 myomers group. Therefore, geometric morphometrics is a promising tool for identifying fish larvae to species level.

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The present study aimed to compare traditional and geometric morphometrics to distinguish populations of Alburnus doriae in some Iranian basins. 132 specimens were collected and photographed. To remove effects of size, the general procrustes analysis was performed. Multivariate analysis of variance and procrustes analysis of variance were performed for traditional and geometric analyses. Both methods detected significant differences among the populations. The McNemar test indicated that these methods discriminated populations similarly.
 

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Oxynemacheilus bergianus is found in several inland water basins of Iran. Due to its wide distribution, this study was conducted to investigate its morphological variation in basins of Caspian Sea and Namak Lake of Iran using geometric morphometric technique. For this purpose, a total of 115 specimens from five river (Sefid and Ghezel Ozan (Caspian Sea basin), Jajrood, Kordan, Qom (Namak Lake basin)) were caught and compared using geometric morphometric method. The results indicated a completely different body shape patterns in the studied populations. The results also showed a significant difference between the body shape of the studied and groups the most differences were related to tail length and depth, body depth, head length and position of the dorsal, anal and pectoral fins. The observed shape patterns can indicate habitat-dependent morphological separation and geographical distances that the geometric morphometric method was highly capable of separating morphological features due to their high capability.